NSS No. 5 Identification of Radioactive Sources and Devices

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Main		KEY INFORMATION ON RADIOACTIVE SOURCES AND DEVICES
Main		HOW TO IDENTIFY A RADIOACTIVE DEVICE, SOURCE OR PACKAGE
Main		A radioactive device is the object in which a radioactive source is mounted for use in its given application. It provides shielding of the radiation, and allows a controlled beam of radiation to be used for the desired purpose.
Main		A radioactive transport package is the object or packaging in which a radioactive source or sources are transported. It provides shielding of the radiation.
Main		Radioactive devices and transport packages usually contain lead, tungsten or other dense radiation shielding material, so they are heavy for their size.
Main		Many devices in industrial applications are brightly coloured.
Main		Many devices incorporate a ‘shutter’ device with a lock to allow the contained source to be accessed, or a beam of radiation to be let out.
Main		Radioactive transport packages may also be devices, and they may also look similar to other industrial packages with a wooden or cardboard shipping crate to provide damage protection.
Main		All devices and transport packages containing a source should have a trefoil symbol clearly marked on them with the type (isotope) of radioactive material.
Main		Radioactive sources should have a trefoil symbol, or the word ‘radioactive’ engraved, but this may be too small to see.
Main		An unshielded radioactive source, open to view, may be extremely hazardous. DO NOT APPROACH.
Main		A source is referred to as ‘dangerous’ if, under conditions that are not controlled, it could give rise to exposure sufficient to cause severe deterministic health effects.¹ Picking up a dangerous source is particularly hazardous. Analyses of past emergencies show that severe deterministic health effects have resulted from holding or carrying (e.g. in a pocket) a dangerous source for just a few minutes. Therefore, efforts must be made to prevent the handling of possibly radioactive material. However, limited periods of time (a few minutes) spent near a very dangerous source,² for example, for life saving purposes, should not result in severe deterministic health effects [1, 2].
Main		INDICATIONS OF A DANGEROUS SOURCE
Main		Indications of a dangerous source [1] include the following: A heavy container with the trefoil symbol.³ An item with labels of packages with potentially dangerous sources (I white, II and III yellow labels) [3]. An item with transport UN numbers or markings (a package marked Type IP, A, B, C,) [3]. A device used for cancer treatment (teletherapy or brachytherapy). Radiography cameras or sources. Well logging sources used in drilling operations.
Main		WHAT TO DO IF A POTENTIALLY DANGEROUS RADIOACTIVE SOURCE, DEVICE OR TRANSPORT PACKAGE IS FOUND
Main		If a radioactive source, device or transport package is found, the following steps should be observed: Do not touch the object. Evacuate the immediate area and prevent access (secure the area). Maximize the distance that people are from the object (for guidance, the radiation dose rate and danger is significantly reduced in most cases by retreating a distance of at least 5 m). Notify civil authorities, emergency services (rescue services, police) — your local contact details should be readily available.
Main		Actions of first responders are described in Ref. [1].
Main		This publication is intended to assist non-specialists and organizations that may come in contact with radioactive sources, devices and packages in the initial identification of them. It will further help identify the sources involved in events which are subsequently reported to the IAEA Illicit Trafficking Database (ITDB).
Main		In addition to this publication, the IAEA and the relevant governmental agencies of Member States hold, or have access to, an international database with details of the designs of most radioactive devices, sources or transport packages known to be in use, or to have been used in the past. This is known as the International Catalogue of Sealed Radioactive Sources and Devices (Source Catalogue). Access to the Source Catalogue may be gained through nationally appointed contacts (provision is made in Section 3 under ‘Contact Information’ for individuals to input national contact details and other information relevant to their situation). Due to security reasons, the Source Catalogue is not publicly available, so this publication is intended to provide information and identification aids at a more general level. This is consistent with the IAEA’s approach to improving control over radiological accidents, as well as prevention, detection of and response to illegal trafficking or malicious use of radioactive sources.
Main		The level of detail in this manual is consistent with the need to minimize the dissemination of information to those who may use it for malicious purposes
Main		The objectives of this publication are to: Assist in the recognition and identification of objects thought to be radioactive devices, sources and transport packages. Provide instruction on what to do and how to obtain further help. Enhance awareness of the existence of radioactive devices, sources and transport packages. Provide information regarding the existence and use of the International Catalogue of Sealed Radioactive Sources and Devices (Source Catalogue) through nominated coordinators in IAEA Member States.
Main		This manual is likely to have two user groups: A primary user, i.e. people within an organization or body who are actively seeking to identify and locate radioactive devices, sources and transport packages, for example: Personnel at border control points; First response civil authorities, such as police, fire services and emergency services personnel; Industrial and hospital decommissioning agents and operators; Scrap metal and industrial waste processors; A secondary user, i.e. people within an organization or body who may passively encounter a radioactive source, device or transport package out of control of its ‘owner’ or in an unexpected location, for example: Non-specialist civil authorities, such as police; Road maintenance personnel; Rescue services; Scrap metal processors not applying a gate monitor.
Main		The manual is presented in eight sections. Following this introduction, Section 2 describes how to recognize a source, device or transport package. It is envisaged that this section would be useful in identifying radioactive devices, sources and transport packages. Section 3 describes what to do if a radioactive source, device or transport package is found; it also provides information that would be useful in determining if the source, device or transport package is not under appropriate control, and what actions to take in that situation. Sections 4–7 are provided as additional information that could be useful to users in becoming familiar with the identification, uses and potential hazards associated with radioactive sources, devices and transport packages. Section 4 describes typical uses of radioactive devices and sources. Sections 5–7 illustrate a range of typical radioactive devices, sources and transport packages to aid the user in the identification of suspect objects.
Main		Appendix I provides basic information on the properties of radiation. Appendix II is an index of devices and summary reference data described in Section 5; and Appendix III is an index of sources and application crossreferences described in Section 6.
Main		There are two key areas of potential danger associated with the use of radioactive sources: Death or injury through accidents involving radioactive sources; Death or injury through malicious use of radioactive sources.
Main		A radioactive source which is not under regulatory control, either because it has never been under regulatory control, or because it has been abandoned, lost, misplaced, stolen or otherwise transferred without proper authorization is known as an “orphan source”. Such sources represent the greatest risk in the case of either an accident or involving malicious use. For example, an incident occurred where a source had been used in a therapy unit in a hospital that has since closed down. No action was taken to manage the source correctly, and after some years the source and associated shielding were stolen by scrap metal collectors. They did not recognize, or did not heed, warning signs and dismantled the shielding and source, causing widespread contamination, injury and illness not only to themselves, but to people with whom they were in contact.
Main		There have been numerous incidents [4–8] where individuals have been exposed to high doses of radiation, either as a result of their own actions or the negligent actions of others, resulting in serious injury and death (see Fig. 1)
Main		FIG. 1. Injuries suffered from radiation burns.
Main		Many such incidents have been caused as a result of lack of knowledge about how to identify a radioactive source, either through its appearance or labelling. A new warning label has been developed with the intention of transmitting information of potential danger in a better way. The potential for the malicious use of sources has now also been identified, and such use would almost certainly require a high activity radioactive source or sources to be transported or abandoned in a public place.
Main		The objectives of this manual are to help reduce the risk of either of the above by providing a clear guide, explaining the nature of radioactive sources, and helping personnel to be able to identify a radioactive source, device or transport package.
Main		There is a concise description of the relative levels of danger associated with radioactive devices, sources and transport packages in Section 4. A source is referred as ‘dangerous’ if, under conditions that are not controlled, it could give rise to exposure sufficient to cause severe deterministic health effects. Picking up a dangerous source is particularly hazardous. Analyses of past emergencies show that severe deterministic health effects have resulted from holding or carrying (e.g. in a pocket) a dangerous source for just a few minutes. Therefore, efforts must be made to prevent the handling of possible radioactive material. However, limited periods of time (a few minutes) spent near a very dangerous source, for example, for life saving purposes, should not result in severe deterministic health effects [1].
Main		There is a more comprehensive explanation of the properties of radiation in Appendix I.
Main		Radioactive sources, devices and transport packages vary a great deal in their appearance, depending on the specific application for which they may be used. Section 4 provides a more detailed discussion of devices, sources and transport packages. The primary method of recognizing a radioactive device, source or transport package is by its identification labelling. The following sections provide a brief description of radioactive devices, sources and transport packages and their labelling.
Main		The machine, instrument or shielded package in which a radioactive source is located during use is referred to as the ‘device’.
Main		Devices vary widely in their appearance according to the amount, type and energy of the radiation from the internal radioactive source, as well as the specific application for which the device is intended.
Main		In general, most devices contain gamma emitting radioactive sources, which are most efficiently shielded by dense metals, such as lead, tungsten or depleted uranium. Therefore, many devices can be characterized as being heavy in relation to their size [9].
Main		Devices may be intentionally portable, such as radiography cameras and road gauges, or they may also be loaded with a source at a dedicated facility and then transported to a permanent place of use. It is quite legitimate, therefore, for a device to be used to transport a source provided the user is authorized to do so and the device is labelled accordingly. In this case, the labelling should correspond both to the system of labelling for transport packages described in the discussion that follows, and to that required for a device. Many devices used for transport of the source feature an ‘overpack’ or shipping crate which is used to protect the device from damage or interference in transit. These may have the appearance of standard industrial packaging with the exception of the transport labelling [3].
Main		Examples of ‘portable’ devices include: Gamma radiography projectors; Moisture density gauges for road building and civil engineering; X ray fluorescence detectors for material characterization.
Main		Examples of devices used as transport packages to move a radioactive source to its place of use include gamma and beta radiation density and thickness gauges, teletherapy heads, blood irradiators and smoke detectors.
Main		All such devices are illustrated in Section 5.
Main		Labelling of a device
Main		Devices containing radioactive sources should be clearly labelled. Their size means that the labelling is clearer to read and acts as a warning to deter interference. The exact wording on device labels varies according to local regulations but should always include the trefoil symbol, the nuclide and atomic number, and normally the word ‘ radioactive’. If possible, the trefoil is represented in black or red on a yellow background (see Fig. 2).
Main		FIG. 2. Examples of the trefoil symbol.
Main		In addition to the symbols shown in Fig. 2, a new symbol is being introduced which will generally appear inside the outer covers of devices, to further warn unauthorized personnel against gaining access to the source within (see Fig. 3).
Main		FIG. 3. New symbol to warn against gaining access to a source.
Main		Most sources are recognizable as stainless steel capsules in the form of a cylinder of varying dimensions. They are normally of stainless steel, which may darken or tarnish with use, particularly when very high activity sources are involved.
Main		In general, if a suspected sealed radioactive source is identified without being located in any shielding, it could be dangerous and should not be approached by untrained personnel without appropriate radiological protection and detection equipment.
Main		Most radioactive sources are rather small, and it is very difficult to read labelling without getting close enough to cause potential injury from the radiation.
Main		It is essential that: No attempt be made to read labelling without specialized knowledge or equipment; No attempt be made to touch a radioactive source.
Main		Note that the physical size of a source is not an indication of its relative danger.
Main		Sources are illustrated in Section 6.
Main		Labelling of a source
Main		All sealed sources (unless physically too small) are marked with the trefoil symbol, the word ‘radioactive’, or both. They may also carry the nuclide and atomic number, the manufacturer’s symbol and a serial number. In addition, the activity (amount of radioactive material or source strength) and date of manufacture (see Fig. 4) may also be indicated.
Main		FIG. 4. Examples of trefoil symbols.
Main		As with devices, transport packages vary significantly in size, weight and appearance, depending on the activity, type and energy of the radioactive source or sources contained within.
Main		Packages can vary from fin-cooled steel flasks containing lead or depleted uranium shielding and weighing in excess of 5 t for very high activity gamma radioactive sources, to small, disposable cardboard boxes for low activity sources.
Main		Examples of the wide variety of transport packages in use are provided in Section 7.
Main		Labelling of a transport package
Main		The labelling of transport packages generally conforms to international regulatory conventions outlined in the IAEA’s Regulations for the Safe Transport of Radioactive Material [3]. These requirements also apply to devices when they are being used to transport radioactive sources.
Main		All packages containing radioactive sources, unless containing very low levels of radioactive material (for example, smoke detectors or exempt quantities) must be labelled clearly with one of the types of labels shown in Fig. 5, as a minimum.
Main		FIG. 5. Examples of the types of labels required for packages containing radioactive sources.
Main		The label is chosen according to a combination of the maximum radiation dose rate on the surface of the package and the maximum radiation dose rate at a distance of 1 m from the surface of the package. Category 1 labelling indicates the lowest dose rates while category 3 labelling is associated with the highest dose rates.
Main		Depending on the shielding of the package, the category labels are not indicative of the quantity of radioactive material, type of radiation or hazard of the material. However, the nuclide, mass number and activity must be written on the label. Labels must be placed on two opposite sides of the package. (The ‘categories’ referred to in the context of labelling packages are not to be confused with the IAEA categorization system, which rates radioactive sources according to the level of danger: Category 1 sources are potentially the most dangerous and Category 5 sources are the most unlikely to be dangerous. Section 4.9 provides a more comprehensive explanation of the categories pertaining to source exposure.)
Main		A package is also required to carry the ‘UN number’ and proper shipping name, e.g. “UN2916 radioactive material Type B(U) package”.
Main		A package in shipment must also be accompanied by a ‘shipper’s declaration’ which states that the package is in compliance with relevant international standards. It must identify and be signed by the consignor.
Main		Any radioactive package in transit which does not comply with the above basic requirements may not be being legitimately moved and, therefore, should be considered under suspicion of being uncontrolled or unauthorized.
Main		Many thousands of radioactive devices and sources are in use worldwide, in the applications listed in Section 4, in industry, hospitals, civil engineering, oil exploration, etc. Thousands of sources annually are transported to their point of use. It is important that these activities not be disrupted. Therefore, the information contained in this manual should be used with caution, and civil authorities should be notified only if there is reasonable suspicion of uncontrolled use or transport of a radioactive source, or if a suspected radioactive device, source or transport package is found to be ‘uncontrolled’.
Main		‘Controlled’ use of a radioactive device, source or transport package may be defined as being used for the intended purpose and that has an identifiable owner. If these requirements are not met, then the device, source or transport package may be considered to be ‘uncontrolled’.
Main		The safe use and transport of radioactive devices, sources and packages are regulated by national authorities to protect public health and safety.
Main		Sections 5, 6 and 7 describe the situations in which devices, sealed sources and transport packages would be expected to be found.
Main		If a suspect device, sealed radioactive source or transport package does not fall into the categories of controlled use, storage or transport as described in Sections 5, 6 and 7, and if no authorized owner can be found, then the actions described below should be taken.
Main		Examples of uncontrolled use may include, but are not limited to: Any source found unshielded and not located in a device or transport package; Any device not in its place of use or authorized storage, or in authorized transit; Any device or source found abandoned.
Main		In the event of a device, sealed source or transport package being found in a situation that is suspected to be unauthorized or uncontrolled, or if its transport is suspected to be uncontrolled, actions to be taken are described in Section 3. If a radioactive source, device or transport package is found, the following steps should be observed: Do not touch the object. Evacuate the immediate area and prevent access (secure the area). Maximize the distance that people are from the object (for guidance, the radiation dose rate and danger is significantly reduced in most cases by retreating a distance of at least 5 m). Notify civil authorities, emergency services (rescue services, police) – your local contact details should be readily available. More details on specific actions can be found in Ref. [1]. Implement any specific procedure or protocol for such an eventand notify civil authorities, bearing in mind the following: Only trained personnel who are equipped with suitable radiation detection equipment should approach the suspect object. Upon initiation of the response the first responders should perform actions on a scene of emergency according to establish emergency plans [1].
Main		The properties of radiation are used in a wide variety of applications. However, in all these applications, the radioactive material is contained within the sealed source and the device allows the radiation to be used in a controlled way.
Main		The application areas for the use of radioactive devices and sources may be broken into six groups: Medical uses; Non-medical irradiation of products; Gauging systems; Imaging systems (radiography); Materials analysis; Miscellaneous uses.
Main		Radioactive devices and sources are used in the field of medicine for cancer therapy and blood irradiation.
Main		In cancer therapy, a tumour is exposed to radiation either by an external beam passing through the body to the cancer site (teletherapy) or by the temporary or permanent implant of a radiation source inside or close to the tumour (brachytherapy). The action of the radiation kills the cancerous cells leading to the elimination or reduction of the tumour.
Main		Blood may be treated by irradiation prior to transfusion to inhibit lymphocyte proliferation. This minimizes the likelihood of problems with the patient’s immune system in the future.
Main		Radioactive devices used in medical applications are likely, therefore, to be found in: Hospital cancer therapy units; Hospital blood transfusion units and blood storage units.
Main		In addition, short lived radioisotopes are used extensively in medical diagnostics but are of minimal danger and are beyond the scope of this manual.
Main		Radioactive devices and sources are used in the field of materials treatment for: Sterilization; Radiation treatment to alter the properties of a material; Radiation treatment of pests (e.g. flies) to impede reproduction; Food irradiation as a means of preserving it.
Main		In sterilization, products which are required to be sterilized (for example, medical devices and surgical dressings) are exposed to a high level of radiation. The radiation dose is carefully controlled to kill any bacteria which may have accidentally entered the packaging during the manufacturing process.
Main		The product itself is unaffected by the process. Materials may be treated by radiation in order to change their properties, for example, a high dose of radiation can be used to cross-link polymer chains in a plastic to strengthen it. Seeds may be irradiated to promote early germination or enhance disease resistance.
Main		Radioactive sources are used within a programme to reduce insect pest populations. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has worked for many years on developing the sterile insect technique (SIT) for tsetse fly control.
Main		Typically, sources used to treat materials by irradiation have high energy and intensity of radiation, and are contained within the most bulky shielding. For process sterilization, for example, of medical products, the device is effectively a building containing a large shielded room through which the product passes.
Main		Materials treatment facilities may be found in: Dedicated sterilization facilities which are factory size units; Medical device manufacturing industries; Research laboratories and educational facilities; Agricultural research facilities.
Main		Radioactive devices and sources are used in the field of gauging for: Thickness; Density; Level.
Main		For thickness gauging, where a sheet of material is being processed through a mill, a radioactive source is placed on one side of the sheet and a detector on the other (see Fig. 6). The amount of radiation transmitted is proportional to the thickness of the material assuming constant density. The signal from the gauging system is fed back into the upstream process control to ensure that the correct thickness is always achieved. The isotope is chosen to have an energy most suited to the relative thickness and density of the strip being measured. The aim is to obtain the optimum attenuation of the radiation in order to provide a high resolution signal to the radiation measurement system [9].
Main		FIG. 6. Schematic of a typical radiation transmission thickness gauge.
Main		Similarly, the density of a material of known thickness may be evaluated by measuring the amount of radiation which is transmitted through it or reflected from it.
Main		For level gauging, the level of material in a container can be determined using a radiation source and detector. The beam of radiation is passed through the container and when the level of material in the container passes the height at which the beam is set, the radiation transmission is attenuated. This provides a signal to control the filling process. This process is used in a wide variety of operations from industrial hoppers to food canning operations.
Main		Radioactive gauging systems may be found in: Mineral processing; Industrial processing plants; Filling lines; Hoppers and chemical processing plants; Cigarette manufacture; Paper manufacture.
Main		The principal use of radioactive sources and devices for non-destructive testing (NDT) imaging is in the field of gamma radiography. Gamma radiography is similar to medical X ray radiography, but instead of using an electrically powered X ray generator to create the image, a radioactive source producing gamma rays is used. A radioactive source is used when there is difficulty in providing power for an X ray generator, or when the work is conducted in small or confined spaces. The source is contained in a transportable device, usually known as a ‘projector’ or ‘camera’, and is exposed in a working position using a remote cable handling system. The gamma rays pass through the specimen being radiographed onto a film to provide an image (see Fig. 7). The system is commonly used for the radiography of structural welds in engineered items, such as buildings and pipelines. Typically, ¹⁹²Ir, ⁷⁵Se and ⁶⁰Co sources are used in gamma radiography. The isotope is chosen to have an energy most suited to the relative thickness and density of the material being radiographed, to provide the optimum image contrast [10].
Main		FIG. 7. Typical gamma radiography system.
Main		NDT systems can be found in: Civil engineering projects; Pipeline welding; General engineering fabrication plants; Maintenance operations in many industrial processing plants; Aeronautical industry.
Main		Radioactive devices and sources are used in the field of materials treatment for: Elemental analysis of materials; Derivation of moisture content.
Main		An example of the elemental analysis of materials is known as X ray fluorescence. Beams of gamma radiation of specific energy may be directed at a metal alloy. These interact with different elements in different ways and the secondary radiation of different energies is ‘reflected’. Analysis of the spectrum of reflected radiation provides a measurement of what the constituent elements are and their relative proportions.
Main		Moisture content and hydrocarbon content in bulk materials and processing lines may be evaluated by measuring the transmission and reflection of neutrons from a neutron radiation source. Neutrons have the same mass as hydrogen atoms and recoil from a collision with a hydrogen atom at much reduced speed. Measurements of the quantity of slowed neutrons recoiled from a bulk material allow the hydrogen content to be evaluated. This can be used to measure water content. In oil exploration, the same technique, combined with other measurements, can be used to evaluate the presence of hydrocarbons in an oil well.
Main		Radioactive sources for materials analysis may be found in: Scrap metal processing; Lead in paint analysis; On-line analysis in materials processing; Wood pulp and slurry analysis in the process industry; Research facilities; Civil engineering and road building; Agriculture; Industrial laboratories; Oil exploration and production.
Main		There are many other applications of radioactive devices and sources not listed here. Some further examples are: Power generation using a radioisotope thermoelectric generator; Smoke detection; Self-luminous signs; Gun sights; Elimination of static electricity; Lightning prevention.
Main		The above applications are described in Sections 5 and 6.
Main		The primary capsule in which the radioactive material is contained is called a sealed radioactive source, also known as a radioactive source, radiation source, sealed source or source (see Fig. 8).
Main		FIG. 8. Sealed radioactive source models showing (a) a typical ²⁴¹Am disc source; and (b) a typical ¹³⁷Cs cylindrical source.
Main		A representative selection of examples of sealed radioactive sources is shown in Section 6. In general, a sealed source has the appearance of a cylindrical stainless steel capsule with a weld at one end.
Main		In nearly all applications of radioactive sources, they are contained within a shielded holder in normal use which also contains or is associated with other instrumentation or mechanical hardware associated with the source’s specific application. This is generally known as a ‘device’. The nature of the device depends on the application. In many cases, the device is also used for the transport of the sealed source to its intended location for use.
Main		The device generally incorporates sufficient shielding to absorb radiation to a level at which it is harmless to the public, and a ‘shutter’ device which allows a beam of radiation from the source to be directed towards the subject when the shutter is opened.
Main		The arrangement is set up in use so that any exposed beam of radiation cannot reach the public, and engineered controls allow only authorized access to the source in the device or to the radiation beam.
Main		Most devices and sources are installed in permanent locations (such as factories, hospitals, gamma sterilization plants), however, there are several key applications where sources are used for a single task on a site and then moved, in their device or a transport package, to another location. Examples of these applications include gamma radiography and construction moisture density gauging.
Main		Section 5 illustrates a wide range of typical devices.
Main		Sources are moved from one location to another either in the device in which they are to be used, or in shielded transport packages designed specifically for the type of source being transported.
Main		The type of transport package will vary from a steel-cased flask weighing over 5 t, with over 20 cm lead shielding for large sterilization sources, to a cardboard box for sources with very low levels of radiation output, or for radiation that is easily absorbed.
Main		Section 7 illustrates a range of typical transport packages.
Main		The IAEA has developed a system of categorization of radioactive sources [11] to provide a simple, logical means for ranking them based on their potential to cause harm to human health. In addition, it provides a means for grouping the applications in which these sources are used into discrete categories.
Main		In recognition of the fact that human health is of paramount importance, the categorization system is based primarily on the potential for radioactive sources to cause deterministic health effects. The categorization system is therefore based on the concept of ‘dangerous sources’ which are quantified in terms of D-values. The D-value is the radionuclide-specific activity of a source which, if not under control, could cause severe deterministic effects for a range of scenarios that include both external exposure from an unshielded source and inadvertent internal exposure following dispersal (such as fire or explosion) of the source material.
Main		The activity of a radioactive material (A) in a source varies over many orders of magnitude; D-values are therefore used to normalize the range of activities in order to provide a reference in comparing risks – this is done by taking the activity A of the source (in TBq) and dividing it by the D-value for the relevant radionuclide.
Main		In some situations it may be appropriate to catagorize a source on the bases of A/D alone, for example, when the practice for which the source may be used is unknown or not confirmed, as may happen at the time of import or export of the source. However, when the circumstances of use of the source is known, the regulatory body may make a judgement to modify this initial categorization using other information about the source or its use. In some circumstances it may be convenient to assign a category on the basis of the practice in which the source is used (see Table 1).
Main		Within this categorization system, sources in Category 1 are considered to be potentially the most ‘dangerous’ because they can pose a very high risk to human health if not managed safely and securely. An exposure of only a few mintes to an unshielded Category 1 may be fatal. At the lower end of the categorization system, sources in Category 5 are potentially the least dangerous; however, even these sources could give rise to doses in excess of the dose limits if not properly controlled, and therefore need to be kept under appropriate regulatory control.
Main		A detailed and comprehensive description of the categories for sources may be found in Ref. [11].
Main		Throughout Sections 5 and 6, sources and devices are categorized according to their potential to cause harm, as described in this outline.
Main		^a Factors other than A/D alone have been taken into consideration in assigning the sources to a category.
Main		^a The size of the area to be cleaned up would depend on many factors (including the activity, the radionuclide, how it was dispersed and the weather).
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Fig. 9
Main		FIG. 9. Typical industrial gamma sterilization plant (photograph: Nuclear Regulatory Commission (NRC)).
Main		Description of use
Main		The gamma sterilization plant is not strictly a device. It is a shielded building in which a large number of ⁶⁰Co sources are housed in an array.
Main		The product requiring gamma sterilization is put into the shielded area and exposed to the sources for the period required to deliver the gamma dose required to kill bacteria.
Main		Typically sources are exposed in the shielded building during the irradiation process, but are then lowered by remote control into a pit or water filled pond to provide shielding if access to the shielded room is required.
Main		The product may be loaded by batch into the shielded room, and the sources remotely removed from the pit or pond to irradiate the product, or sources may be left semi-permanently exposed, and the product moved through the shielded room on a conveyor system.
Main		Access of personnel to the shielded room is strictly controlled to minimize the possibility of exposure to the sources.
Main		Typical operating environment
Main		Irradiation plants are generally situated on industrial sites and perform contract irradiation of product for a wide range of applications, mostly involving the irradiation of medical devices, but also may be used for foodstuffs and other applications.
Main		Sources are transferred into and out of irradiators in specialized transport containers, where they are loaded by specialized personnel.
Main		Sources
Main		A typical irradiation facility will contain up to 185 PBq (5 MCi) ⁶⁰Co.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 10-15
Main		FIG. 10. Modern teletherapy unit (photograph: MDS Nordion).
Main		FIG. 11. Teletherapy unit.
Main		FIG. 12. Teletherapy unit with source exchange container (white) in place.
Main		FIG. 13. Modern teletherapy unit (photograph: BRIT).
Main		FIG. 14. Old ⁶⁰Co teletherapy heads.
Main		FIG. 15. Damaged ⁶⁰Co or ¹³⁷Cs teletherapy heads.
Main		Description of use
Main		These devices typically use a single ⁶⁰Co source. They are used for cancer therapy by projecting a beam of high energy radiation focused onto a tumour.
Main		The radioactive source is securely located in the heavy shielded housing at the end of the rotating arm. The beam of radiation from the source is exposed when a shutter is opened during use.
Main		The shielded housing may be demounted from the rotating arm, and shipped to a specialized location for the replacement of a depleted source, or a source transfer may be effected in situ, using a special transport container to deliver and install the new source and remove the depleted source in a single operation.
Main		Typical operating environment
Main		These devices are installed in many cancer therapy units in hospitals around the world.
Main		The unit itself is used in a shielded facility to prevent the beam of radiation affecting those outside the room, and the facility would normally have strictly controlled access.
Main		Due to the very high activity of the sources used, very specialized shielded equipment and highly trained personnel only can perform such operations.
Main		When units are decommissioned, the shielded housing, complete with the source, is sometimes removed and stored and the rest of the unit scrapped.
Main		The high activity of the sources used makes these units some of the most potentially hazardous devices.
Main		Sources
Main		Source activity: up to 370 TBq (10 kCi) ⁶⁰Co.
Main		A strictly limited number of machines have been supplied using ¹³⁷Cs sources.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 16-19
Main		FIG. 16. Typical blood irradiator (photograph: MDS Nordion).
Main		FIG. 17. Blood irradiator shielded cavity overpack for transport (photograph: MDSl Nordion).
Main		FIG. 18. Blood irradiator (photograph: BRIT).
Main		FIG. 19. Older style blood irradiator.
Main		Description of use
Main		These devices are used for the treatment of blood and consist of a shielded chamber with a cavity into which a sample of blood in a bag of about 2 L capacity is loaded. The sample enters the cavity through an interlocked door or chamber to eliminate the possibility of operator exposure to radiation.
Main		The shielded chamber is contained within a clinical style cabinet.
Main		These devices generally have an electronic control system to ensure the correct exposure time and, hence, dose given to a sample.
Main		Typical operating environment
Main		These devices are generally used in hospitals for the treatment of blood.
Main		The source or sources are fully contained within the shielded chamber and it is not generally possible to remove them without dismantling the device. This can be done only in a dedicated shielded facility with specialized equipment and trained personnel.
Main		The shielded chambers are normally shipped, with the sources preloaded, from the manufacturer to the user in a special shipping canister or overpack. When the sources are depleted, they are returned to the manufacturer for service and source replacement, also in a special shipping overpack.
Main		Sources
Main		Typical source activity: up to 250 TBq (7 kCi) ¹³⁷Cs; up to 25 TBq (7 kCi) ⁶⁰Co.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 20, 21
Main		FIG. 20. Typical gamma knife (photograph: Elekta).
Main		FIG. 21. Typical gamma knife reloading system (photograph: Elekta).
Main		Description of use
Main		These devices typically use an array of about 200 ⁶⁰Co sources contained in a spheroidal shielded device. A control unit allows collimated beams from selected sources in the array to focus on well defined treatment areas. They are used for medical procedures whereby the focused area of the intersection of beams of radiation is used to cause lesions in tumour cells. The process is generally used in cases of brain cancer and other brain disorders.
Main		The devices are commonly called gamma knives.
Main		Typical operating environment
Main		The devices are installed in specialized hospital radiosurgery units.
Main		The unit itself is used in a shielded facility to prevent scattered radiation affecting those outside the room, and the facility would normally have strictly controlled access.
Main		The sources are generally loaded into the spheroidal shielded housing once the machine has been installed, using a special shielded cell for handling the sources. The shielded cell and cask containing the sources are shipped separately. Depleted sources are unloaded from the machine and returned to a source manufacturer for recycling or disposal.
Main		There are currently relatively few units installed due to the highly specialized nature of the treatment and cost of the machine.
Main		Sources
Main		Typical source activity: about 200 sources, each of up to 1.1 TBq (30 Ci) ⁶⁰Co.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 22-24
Main		FIG. 22. Typical sample irradiator (photograph: BRIT).
Main		FIG. 23. Typical sample irradiator.
Main		FIG. 24. Sample irradiator supplied to schools and educational establishments.
Main		Description of use
Main		These devices typically use one or more ⁶⁰Co sources.
Main		The device consists of a shielded chamber with the radioactive source or sources permanently located inside. Samples for irradiation are loaded into the chamber through a revolving shielded door or interlocked access to prevent any possibility of accidental exposure of the operator.
Main		The shielded chamber is contained within a clinical style cabinet.
Main		Modern devices generally have an electronic control system to ensure the correct exposure time and, hence, dose given to a sample.
Main		Typical operating environment
Main		These devices are generally used in research laboratories, although smaller types used to be more widely supplied to schools and educational establishments in some countries.
Main		The devices are used for the irradiation of samples of tissue, plant matter and other materials.
Main		The source or sources are fully contained within the shielded chamber and it is not generally possible to remove them without dismantling the device. This can be done only within a dedicated shielded facility with specialized equipment and trained personnel.
Main		The devices are normally shipped, with the sources preloaded, from the manufacturer to the user in a special overpack. When the sources have depleted, they are returned to the manufacturer for service and source replacement, also in a special shipping overpack.
Main		Sources
Main		Typical source activity: 70 TBq (2 kCi) to 900 TBq (25 kCi) ⁶⁰Co.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 25-27
Main		FIG. 25. Schematic of a seed irradiator on a truck.
Main		FIG. 26. Mobile caesium irradiators in the former Soviet Union containing 3500 Ci of caesium.
Main		FIG. 27. Seed irradiator detail.
Main		Description of use
Main		These devices typically use one or more ¹³⁷Cs or sometimes ⁶⁰Co sources.
Main		Seeds are irradiated by passing them through a shielded unit loaded with one or more gamma sources.
Main		There is a rudimentary ‘conveyor’ system to move the seeds through the irradiator.
Main		Typical operating environment
Main		These devices were mostly used in the former Soviet Union until the late 1970s for the irradiation of seeds to improve crop yields and delay the germination of harvested grain. The irradiation device was mounted on a truck with associated processing equipment. Such devices were supplied to agricultural research laboratories and transported to different sites to perform the irradiation work. They consist of a shielded container housing the radioactive sources, with an entry and exit point to allow the seeds to pass through on a continuous basis. The entry and exit points are labyrinth-like in order to prevent radiation from shining out through them.
Main		The source or sources are fully contained within the shielded chamber and it is not generally possible to remove them without dismantling the device. This can be done only within a dedicated shielded facility with specialized equipment and trained personnel.
Main		The devices were normally mounted on trucks in order to be mobile, but seed irradiation is no longer done using these types of mobile devices. It is not known how many of these devices were originally supplied; the records indicate that there are relatively few which have been formally decommissioned. It is considered that there may be many orphan devices. The irradiation chambers and associated equipment may be dismounted from the trucks.
Main		Sources
Main		Typical source activity when new: up to 185 TBq (5 kCi) ¹³⁷Cs.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 28-33
Main		FIG. 28. Radioisotope thermoelectric generator.
Main		FIG. 29. Schematic of a ⁹⁰Sr radioisotope thermoelectric generator.
Main		FIG. 30. Radioisotope thermoelectric generator.
Main		FIG. 31. Radioisotope thermoelectric generator.
Main		FIG. 32. Radioisotope thermoelectric generator.
Main		FIG. 33. Radioisotope thermoelectric generator powered heart pacemaker.
Main		Description of use
Main		These devices typically use ²³⁸Pu or ⁹⁰Sr sources.
Main		They are used for the generation of electricity in remote locations where electricity cannot be provided by normal generation. They work by using heat energy created by the absorption of radiation from the radioactive source to generate electricity using a thermocouple device. There are three key applications: Space travel: Long distance space probes and satellites often use RTGs (normally containing ²³⁸Pu) to provide power for instruments or to keep them from freezing. The disposition of space probes and related technology means that these are rarely found. Heart pacemakers: very small ²³⁸Pu based RTGs were used until the 1970s in pacemakers to provide lifelong power. These have been rendered obsolete by improved battery technology, and due to safety and regulatory concerns. The low activity means that these devices are of little concern. Remote location power generation: RTGs were used to power lights and radio beacons on navigational marks, mostly in Arctic areas and also for underwater listening devices for military purposes. These devices typically contain a large 90Sr source (up to 1.85 PBq or 50 kCi).
Main		Typical operating environment
Main		The devices which cause most concern are the large⁹⁰Sr powered RTGs. Many of these were deployed around the remote coastlines of Canada and the former Soviet Union. However, they have fallen into disuse as satellite navigation has rendered them obsolete. There is an extensive programme to recover and decommission them, however, a number remain unaccounted for.
Main		The ⁹⁰Sr RTG consists of a steel shield with cooling fins on the outside, and the ⁹⁰Sr source contained within. The source can be removed from the shield in a specialized shielded facility by trained personnel. The electricity generating component is effectively contained within the shielding.
Main		The RTG would normally be associated with the equipment for which the electricity is required — for lighting or for a radio beacon, but it is believed that many may have been partially dismantled, leaving the shielded device separate from the rest of the unit.
Main		In one instance, the shielded unit from an RTG was found partially dismantled, with the radioactive source removed. The source was recovered, unshielded, some distance away. It is believed that the device was dismantled by a scrap metal scavenger.
Main		Of all radioactive sources and devices, these are considered to be of high concern due to the number unaccounted for, their remote and uncertain locations, and high radioactive content.
Main		Notes
Main		Pacemaker RTGs are of relatively low activity and are unlikely to be found. Space exploration RTGs are also unlikely to be found.
Main		Sources
Main		Typical source activity: 1.85 PBq (50 kCi) ⁹⁰Sr for terrestrial power generation.
Main		110 GBq (3 Ci) ²³⁸Pu for pacemakers.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 34, 35
Main		FIG. 34. Typical 137Cs oil well logging source bull plug (photograph: Schlumberger).
Main		FIG. 35. Typical ¹³⁷Cs oil well logging source carrying shield (transport container), 37 kg × 170 mm diameter × 210 mm length (photograph: Schlumberger).
Main		Description of use
Main		These devices typically use a single ¹³⁷Cs source. Oil well logging is the operation of taking various geophysical measurements in oil wells to evaluate their performance and viability in exploration and production. Gamma sources are used for the density measurement of rock strata around the borehole of an oil well by backscatter measurement.
Main		The source itself is usually constructed in high strength and corrosion resistant metal. It is then usually mounted or welded into a ‘bull plug’. This may act as a collimator for the radiation and provides additional protection for the source in the downhole environment. It can also be attached to the associated instrumentation.
Main		The source and bull plug are of very rugged construction to withstand high external pressures, temperatures and corrosive environments deep in the wells.
Main		The bull plug is in turn loaded into a tubular array of instruments which is lowered into the oil well.
Main		The instrument array may be lowered into the oil well on a strong wire which holds the weight of the instruments and allows signals to be transmitted to the surface for recording and evaluation, or as a part of an oil well drilling stack unit, in which case the signals are stored within the instruments and read when they are returned to the surface. Sometimes a more sophisticated telemetry system is used to transmit readings to the surface while drilling progresses.
Main		Typical operating environment
Main		Bull plugs are used widely within the oil industry. They are transported by oil well logging companies and can be found at corporate operational bases, and on oil well sites. When not in use, they should be stored in secure compounds.
Main		The bull plug is stored in a dedicated shielded storage and transport container until required for use. The bull plug is then transferred into the instrument array just before it is lowered into the oil well, thus exposing the radiation of the source, unshielded briefly. At this point, a controlled area is set up around the bull plug to prevent exposure of personnel.
Main		In general, oil well logging sources and bull plugs are well controlled with few reports of orphan sources, but because of their mobile nature there is significant scope for loss or misappropriation.
Main		Most gamma oil well logging sources contain ¹³⁷Cs sources, although ⁶⁰Co has been used on rare occasions. Bull plugs have a wide variety of designs.
Main		Sources
Main		Typical source activity: 37 GBq (1 Ci) to 111 GBq (3 Ci) ¹³⁷Cs when new.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 36-42
Main		FIG. 36. Typical ²⁴¹Am/Be neutron oil well logging source.
Main		FIG. 37. Typical ²⁴¹Am/Be neutron oil well logging source — damaged in routine use.
Main		FIG. 38. Typical ²⁴¹Am/Be neutron oil well logging source.
Main		FIG. 39. Typical ²⁴¹Am/Be neutron oil well logging source.
Main		FIG. 40. Typical ²³⁸Pu/Be neutron oil well logging source.
Main		FIG. 41. Typical neutron oil well logging source transport and storage containers.
Main		FIG. 42. Typical neutron oil well logging source transport and storage container.
Main		Description of use
Main		These devices typically use a single ²⁴¹Am/Be neutron source. A small number of units using ²³⁸Pu/Be or ²⁵²Cf spontaneous fission material were also manufactured but are now largely obsolete.
Main		Oil well logging is the operation of taking various geophysical measurements in oil wells to evaluate their performance and viability in exploration and production. Neutron sources are used for measuring hydrogen levels in rock strata around the borehole of an oil well by backscatter measurement. This measurement combined with others give an indication of the presence of hydrocarbons.
Main		The source itself is usually constructed in high strength and corrosion resistant metal. It is then usually mounted or welded into a ‘bull plug’. This provides additional protection for the source in the downhole environment. It also has the means of attaching to the associated instrumentation.
Main		The source and bull plug are of very rugged construction to withstand high external pressures, temperatures and corrosive environments deep in wells.
Main		The bull plug is in turn loaded into a tubular array of instruments which is lowered into the oil well.
Main		The instrument array may be lowered down the oil well on a strong wire which holds the weight of the instruments and allows signals to be transmitted to the surface for recording and evaluation, or as a part of an oil well drilling stack unit, in which case the signals are stored within the instruments and read when they are returned to the surface. Sometimes a more sophisticated telemetry system is used to transmit the readings to the surface while drilling progresses.
Main		Typical operating environment
Main		Bull plugs are used widely within the oil industry. They are transported by oil well logging companies and can be found at corporate operational bases, and on oil well sites. They are stored in secure compounds.
Main		The bull plug is stored in a dedicated shielded storage and transport container until required for use. The bull plug is then transferred into the instrument array just before it is lowered into the oil well, thus exposing the radiation from the source, unshielded briefly. At this point, a controlled area is set up around the bull plug to prevent exposure of personnel.
Main		In general, oil well logging sources and bull plugs are well controlled with few reports of orphan sources, but because of their mobile nature there is significant scope for loss or misappropriation.
Main		While neutron oil well logging is used in the same applications as gamma logging, the Am/Be bull plug has been largely replaced by neutron generators which are not sealed sources. There are, therefore, significantly fewer ²⁴¹Am/Be neutron sources in circulation than ¹³⁷Cs ones.
Main		Neutron bull plugs have a range of different designs. In some cases, the source and bull plug are effectively the same unit, i.e. the sealed source itself forms the bull plug, and is made of high strength corrosion resistant material with the necessary fittings for placement into the instrumentation unit.
Main		Sources
Main		Typical source activity: 74 GBq (2 Ci) to 740 GBq (20 Ci) ²⁴¹Am/Be. Occasionally ²³⁸Pu/Be or ²⁵²Cf.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 43-56
Main		FIG. 43. Typical modern portable gamma radiography projector (photograph: QSA-GLOBAL).
Main		FIG. 44. Typical modern portable gamma radiography projector (photograph: MDS Nordion).
Main		FIG. 45. Typical modern lightweight gamma radiography projector (for ⁷⁵Se) (photograph: MDS Nordion).
Main		FIG. 46. Typical modern portable gamma radiography projector (photograph: BRIT).
Main		FIG. 47. Typical modern portable gamma radiography projector (photograph: QSA-GLOBAL).
Main		FIG. 48. Typical superseded ⁶⁰Co gamma radiography projector (photograph: NE-Seibersdorf).
Main		FIG. 49. Typical modern portable gamma radiography projector (photograph: NE-Seibersdorf).
Main		FIG. 50. Typical source exchange container (photograph: QSA-GLOBAL).
Main		FIG. 51. Example of a superseded gamma radiography projector with control cable exposure of source.
Main		FIG. 52. Example of a superseded gamma radiography projector with manual exposure off source (photograph: NE-Seibersdorf).
Main		FIG. 53. Typical modern semi-portable ⁶⁰Co gamma radiography device (photograph: MDS Nordion).
Main		FIG. 54. Typical modern semi-portable ⁶⁰Co gamma radiography device (photograph: QSA-GLOBAL).
Main		FIG. 55. Radiography guide.
Main		FIG. 56. Radiography guide (transparent display).
Main		Description of use
Main		These devices mostly use ¹⁹²Ir gamma sources, however, ⁷⁵Se, ¹⁶⁹Yb and ⁶⁰Co are also used and, very rarely, ¹³⁷Cs. These devices are used for the radiography of engineered structures. They contain a single source attached to a flexible cable, which can be exposed near the object that is being radiographed. A radiographic film is attached behind the object, and the penetrating gamma rays expose the film. Variations in the density of the item being radiographed are shown in the image of the film.
Main		The devices are often also referred to as radiography cameras, as well as radiography projectors or simply projectors.
Main		These devices are among the more potentially dangerous, as the effective use of the device depends on the source being moved from the container shielding and exposed in an open area.
Main		All users of radiography equipment are highly trained and regulated in setting up controlled areas to prevent public access and to protect themselves while the source is in the exposed position.
Main		There are two main types of radiography projectors: highly portable devices for general use, mostly for making radiographs of welds in metal structures; and semi-portable devices, which usually use higher energy ⁶⁰Co radiation sources and, therefore, have more shielding which makes them heavier and less portable. The principles of operation of both systems, however, are similar.
Main		The shielded part of modern devices often consists of depleted uranium, lead or tungsten, or mixed depleted uranium and tungsten, in which a source is stored on a flexible cable in an ‘s’ shaped tube encased in the shielding. The flexible cable is known as a ‘pigtail’.
Main		The ‘s’ shaped tube has an attachment at each end which is locked to prevent access to the source when it is not in use.
Main		When the source is to be used, a long flexible control cable is attached to the pigtail via an adaptor at one end of the ‘s’ tube, and the source is pushed, on the end of the flexible cable, out of the shielding along a hollow, flexible tubular projection sheath into an exposed position to perform the required radiographic exposure. The control cable is normally manually operated.
Main		Typical operating environment
Main		Radiography projectors are used in many locations, from civil engineering works to factories, but are generally used because of their relatively light weight, mobility and because they require no electric power, unlike electrical X ray sets.
Main		They are, therefore, transported by personnel in vans and cars from site to site on a regular basis.
Main		Most radiography sources have a relatively short half-life, and when they become depleted they are exchanged for new sources by the owner, rather than the entire projector being sent to a specialist facility for the source to be changed. However, devices are usually subject to regular maintenance by the manufacturer or their approved agent. For ‘portable’ devices, a special ‘source changer’ type transport container is used to send a new source to a user, facilitate a source change, and return the depleted source to a manufacturer for recycling or disposal. For the higher activity ⁶⁰Co devices, the whole unit is usually sent to the device manufacturer to facilitate a source change. Although the ‘source changer’ is a transport container, it is illustrated in this section for clarity.
Main		Comments
Main		Before the principle of operation was established to expose the source using a remote control cable, there were systems in use where the source was positioned in a shielded collimator, and a manually removable shutter would be opened or removed to allow the source to be exposed. Such devices are no longer in use, but are illustrated in this section.
Main		Sources
Main		Typical maximum source activities:
Main		5.5 TBq (150 Ci) of ¹⁹²Ir;
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 57-59
Main		FIG. 57. Typical gamma radiography pipeline crawler (photograph: MDS Nordion).
Main		FIG. 58. Pipeline crawler source head in shipping container (photograph: MDS Nordion).
Main		FIG. 59. Pipeline crawler being loaded into an open pipeline (photograph: MDS Nordion).
Main		Description of use
Main		These devices mostly use single ¹⁹²Ir gamma sources, however, ⁷⁵Se may also be used. The devices are used exclusively for the radiography of welds on long sealed pipelines where the source must be exposed at a precise position relative to a weld in the pipe. The pipeline crawler is battery powered and propels itself along a pipeline. Using remote control, it can be made to stop at the position of a circumferential weld on a pipeline, and the source is automatically removed from a shield to expose the radiation. A radiographic film is wrapped around the outside of the pipe at the weld, and the gamma rays penetrating out of the pipe from the exposed source inside the pipe expose the film. Variations in the density of the item being radiographed are shown in the image of the film.
Main		All users of radiography equipment are highly trained and regulated in setting up controlled areas to prevent public access and to protect themselves while the source is in the exposed position.
Main		Typical operating environment
Main		Pipeline crawlers are used in most applications where the quality of newly laid pipelines, or monitoring of the degradation of old pipelines, is required. This includes process, petrochemical and gas distribution industries.
Main		They are, therefore, transported by personnel in vans and cars from site to site on a regular basis.
Main		The source is held in a shielded head which is transported in a separate container and attached to the pipeline crawler on-site before use.
Main		In most instances, sources are changed only by the supplier or manufacturer of the pipeline crawler due to the complexity of the operation and the requirement for specialized shielded handling equipment.
Main		Sources
Main		Typical maximum source activities: 5.5 TBq (150 Ci) ¹⁹²Ir; 2.9 TBq (80 Ci) ⁷⁵Se.
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 60-69
Main		FIG. 60. ¹³⁷Cs gauge source holder (photograph: Endress+Hauser).
Main		FIG. 61. ⁶⁰Co gauge source holder (photograph: Endress+Hauser).
Main		FIG. 62. Various decommissioned gamma gauge source containers.
Main		FIG. 63. Gamma gauge source container.
Main		FIG. 64. Gamma density gauge fitted to a section of tube.
Main		FIG. 65. Compact gamma density transmitter fitted to a section of tube (photograph: Endress+Hauser).
Main		FIG. 66. Pipeline density gauges in position.
Main		FIG. 67. Typical gamma gauge source container.
Main		FIG. 68. Typical line source container (photograph: NRC).
Main		FIG. 69. Typical line source container (photograph: NRC).
Main		Description of use
Main		These devices mostly use ¹³⁷Cs and ⁶⁰Co sources.
Main		Density and thickness gauges measure either the level of transmission or the backscatter of a beam of radiation passing through or reflected from a material. For example, in thickness measurement applications, the transmission of gamma radiation through a strip of steel of constant density that comes from a steel mill is proportional to the thickness of the steel. The measurement can then be used to control the process.
Main		Similarly, in a pipeline carrying a mixed slurry, the level of backscattered radiation is proportional to the density of the slurry, and therefore its composition can be measured.
Main		Depending on the thickness or density of the material to be measured, the energy of the radiation required from the source varies and, therefore, the relative danger from it. Thicker and denser materials require relatively high energy radiation, as shown in this section. Thinner and lighter materials require lower energy radiation and are illustrated in Section 5.13.
Main		In these systems, the device containing the source is called the ‘source container’, ‘source housing’ or collimator. In the case of systems where the source and the detector are included in the same housing, it is called the ‘gamma gauge’ or ‘measuring head’. In addition, the term ‘source holder’ is generally used. However, it may be used ambiguously to refer to the entire device holding the source, or to a component within the device to which the source is attached.
Main		The devices usually consist of a heavy lead-filled steel case, with a single source loaded into the centre, and a simple shutter type device, which is opened to reveal an aperture through which a beam of radiation is transmitted.
Main		In a small number of applications for level gauging only, an array of sources or a single long source may be used. Typical devices used to house these sources are shown in Figs 60 and 61.
Main		The shutter is usually equipped with a padlock to prevent unauthorized access, and often with an electromechanical or pneumatic actuator which automatically closes the device when the measurement system is not in use.
Main		Typical operating environment
Main		Density, thickness and level gauges are commonly used in many process industries, such as mineral processing, petrochemical industries and most types of mill operation. They are permanently mounted on process vessels, pipelines, hoppers, conveyor belts and mills.
Main		High energy gauges are used in metals and mineral processing, as well as in chemical process reactors. Low energy gamma gauges are used for thickness and density measurements on plastic strips, paper and other thin materials. Low energy gauges are shown in Section 5.13.
Main		In most cases, the source is transported to the site in the device, which is also licensed as a transport container. In some cases, it will be transported in an overpack which is normally a suitably labelled wooden industrial packing crate.
Main		When a source becomes depleted, the entire device is normally changed on-site, and the source is then unloaded from the device in a specialized facility, so it is relatively common for the devices, as illustrated, to be shipped with the source inside.
Main		Sources
Main		Typical source activities:
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 70, 71
Main		FIG. 70. Typical ²⁴¹Am transmission gauge installed on a section of pipe.
Main		FIG. 71. Typical ²⁴¹Am fill-level gauge mounted on a filling line (photograph: NRC).
Main		Description of use
Main		Density and thickness gauges measure either the level of transmission or the backscatter of a beam of radiation passing through a material. For example, the transmission of gamma radiation through a foil of known density coming from a rolling mill is proportional to the thickness of the foil. The measurement can then be used to control the process.
Main		They may also be used to control receptacle filling operations, where the beam of radiation passing through a can or carton is attenuated when the filllevel passes through the beam.
Main		Low energy gamma thickness and density gauges are used for measurements on plastic strips, paper and small bore tubes carrying fluids. High energy gauges are generally used in metals and mineral processing. These are shown in Section 5.12.
Main		The detailed characteristics of the device holding the source usually depend on the application.
Main		In these systems, the device containing the source is called the source container, source housing or collimator. In the case of systems where the source and the detector are included in the same housing, the device is called the ‘gamma gauge’ or ‘measuring head’. In addition, the term ‘source holder’ is generally used. However, it may be used ambiguously to refer to the entire device holding the source, or to a component within the device to which the source is attached.
Main		The devices usually consist of a heavy steel case, with lead or tungsten shielding for the source, which is loaded into the centre, and a simple shutter type device, which is opened to reveal an aperture through which a beam of radiation is transmitted.
Main		The shutter is usually equipped with a padlock to prevent unauthorized access, and often with an electromechanical actuator which automatically closes the device when the measurement system is not in use.
Main		Typical operating environment
Main		Low energy density and thickness gauges are commonly used in many mill process industries, such as plastic strips, foil and paper processing. They are also used to measure the density of fluids in pipes. They are permanently mounted on mills and pipelines.
Main		In many cases, the source holder and radiation measurement device are combined into the same unit, which is mounted on the strip mill on which the measurement is being made.
Main		In most cases, the source is transported to the site in the device, which is also licensed as a transport container. Otherwise the source is transported separately and fitted into the gauge by a trained specialist.
Main		As the ²⁴¹Am half-life is long, source changes during the lifetime of the unit are unusual.
Main		Sources
Main		Typical source activities: ²⁴¹Am 370 MBq (10 mCi) to 111 GBq (3 Ci).
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 72-74
Main		FIG. 72. Beta gauge in place on a web processing mill (photograph: Betarem).
Main		FIG. 73. Detail of a beta gauge source holder (photograph: Betarem).
Main		FIG. 74. Beta gauge in place on a web processing mill (photograph: NRC).
Main		Description of use
Main		These devices mostly use ⁹⁰Sr, ⁸⁵Kr and occasionally ¹⁴⁷Pm sources.
Main		Density and thickness gauges measure either the level of transmission or the backscatter of a beam of radiation passing through a material. For example, the transmission of beta radiation through a strip of paper of known density coming from a paper mill is proportional to the thickness of the paper. The measurement can then be used to control the process.
Main		The radioactive source is chosen depending on the thickness of the material to be measured, in order to optimize the radiation attenuation characteristics. ⁹⁰Sr is used for thicker, denser applications, down to ¹⁴⁷Pm for the thinnest, lower density materials.
Main		The process is similar to gamma thickness and density gauging, but is used to measure thinner or lighter items than gamma gauges.
Main		In these systems, the device holding the source is called the collimator, shield or source holder.
Main		The devices usually consist of a small, heavy, steel case, with the source loaded into the centre, and a simple shutter type device, which is opened to reveal an aperture through which a beam of beta radiation is transmitted.
Main		The shutter is usually equipped with a padlock to prevent unauthorized access, and often with an electromechanical or pneumatic actuator which automatically closes the device when the measurement system is not in use.
Main		Typical operating environment
Main		Beta density and thickness gauges are commonly used in processes where thin webs have to be measured, such as paper, fabric or plastic film processing, or low density measurements, such as cigarette manufacturing.
Main		Sometimes the source is transported to the site in the device, which may also be licensed as a transport container.
Main		When a source becomes depleted, it can normally be changed by trained staff on-site, as the radiation levels are relatively low.
Main		Sources
Main		Typical maximum source activities:
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 75, 76
Main		FIG. 75. Schematic of a bulk material moisture probe fitted to a silo. The source is highlighted in red in the silo (photograph: Berthold Technologies).
Main		FIG. 76. Bulk material moisture measurement device (photograph: Berthold Technologies).
Main		Description of use
Main		Moisture gauges measure the amount of water in a material passing through a conveyor system, slurry pipeline, or in a hopper or silo, by measuring the amount of neutron radiation passing between the source and a detector. Neutron radiation is absorbed or moderated by the presence of light atoms (in this instance, hydrogen atoms in water) and, therefore, the amount of water content in a mixture of known materials can be derived from a measurement of the transmission of neutrons through it or backscattered from it.
Main		The source holder devices usually consist of a heavy steel case, with the source loaded into the centre, and neutron shielding, which may be polyethylene or some other kind of material with high hydrogen content. The device is of a simple shutter type, which is opened to reveal an aperture through which a beam of radiation is transmitted. In most cases, the neutron detector is contained within the same device as the source.
Main		In hoppers and silos, the source and detector are often contained inside the hopper itself, with the hopper contents providing effective shielding of the source.
Main		The shutter is usually equipped with a padlock to prevent unauthorized access, and often with an electromechanical actuator which automatically closes the device when the measurement system is not in use.
Main		Typical operating environment
Main		Moisture gauges are commonly used in many process industries where moisture content in bulk materials must be continuously measured, for example, gravel processing, woodchip processing and coal slurry processing in power generation.
Main		In most cases, the source is transported to the site in the device, which is also licensed as a transport container. In some cases, it will be transported in an overpack.
Main		It is unusual for sources to have to be changed in the devices due to the long half-life, so sources are normally installed in the device in a specialized facility by the manufacturer and remain in the device until it is replaced or decommissioned. The source is shipped inside the device.
Main		Sources
Main		Typical source activities: ²⁴¹Am/Be 1.8 GBq (50 mCi) to 18.5 GBq (500 mCi).
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 77, 78
Main		Fig. 77. Typical soil moisture and density gauge, shown with a carrying case (photograph: Troxler Labs).
Main		FIG. 78. Typical soil moisture and density gauge, shown with a carrying case (photograph: CPN International).
Main		Description of use
Main		These devices use two types of radiation sources together: a ¹³⁷Cs high energy gamma source of approximately 40 MBq (1 mCi) and an ²⁴¹Am/Be neutron source of approximately 2 GBq (55 mCi).
Main		The devices are portable and are normally used to measure the density and moisture content of soil and building materials. The density is determined by measuring the amount of backscattered radiation from the gamma source, and the moisture content is derived from the gamma measurement and a measurement of the amount of backscattered neutron radiation.
Main		The sources are contained in a shielded unit in the device, which is usually made of lead and polythene. They are exposed in use by opening a shutter which allows collimated beams of radiation to be directed into the ground. The shutter is locked when the device is not in use.
Main		Typical operating environment
Main		The devices are in common use in the construction and agricultural industries in many countries. They are portable and normally transported in protective carrying cases.
Main		The sources are usually retained inside their shielding with some kind of tamper proof screws or a permanent fixing, and the sources are not normally exchanged during the working life of the device.
Main		Due to the manner in which they are used on construction sites and agricultural land, these devices have a relatively high probability of being lost or mislaid. However, the hazard level is very low because the activity of the sources is low and they are well protected in the units.
Main		Sources
Main		Typical maximum source activities:
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 79-82
Main		FIG. 79. Typical hand-held X ray analysis device (photograph: Spectro).
Main		FIG. 80. Typical hand-held X ray analysis devices (photograph: Thermo).
Main		FIG. 81. Benchtop XRF analyser.
Main		FIG. 82. In-process XRF analyser.
Main		Description of use
Main		The devices are used in material analysis in a wide variety of industries. When an element is exposed to the radiation of a known energy, it is absorbed and a unique spectrum of secondary X rays is emitted from the element. Analysis of the spectrum allows an accurate determination of the composition of the material.
Main		Different isotopes are used for the detection of different elements because the energy of the primary radiation has to be greater for the detection of materials of higher atomic number.
Main		The sources are contained in a shielded unit in the device. They are exposed in use by opening a shutter which allows collimated beams of radiation to be directed onto the material being analysed. The shutter is locked when the device is not in use.
Main		The detector is normally contained within the same unit as the source with associated electronics to analyse the spectrum of secondary X rays to identify the subject materials being measured.
Main		Typical operating environment
Main		There are several types of devices, depending on the application. They are used in the following main applications: Alloy analysis for checking stock, scrap sorting and checking components; In mining, analysis of material excavated from pits, and cores, chippings and slurries from drilling operations; Analysis of electroplating solutions; General laboratory chemical analysis; Determination of levels of lead in old paint to establish what level of personal protection may be required before removing it.
Main		Many devices are highly portable and are carried in the hand, for example, in paint and scrap metal analysis, whereas other units may be fixed to pipelines or conveyors, and systems are installed in analytical laboratories.
Main		Portable devices also have a carrying case to protect them in transit and storage.
Main		The sources are usually retained inside their shielding with some kind of tamper proof screws or a permanent fixing. For portable or hand-held devices, the sources are not normally exchanged by the user, but the unit is returned to the manufacturer for servicing and source exchange when required.
Main		Due to the manner in which they are used, portable or hand-held devices have a relatively high probability of being lost or mislaid. However, the hazard level is very low because the activity of the sources is low and they are well protected in the units.
Main		Sources in permanently mounted or benchtop devices may be exchanged by trained service engineers when they become depleted.
Main		Sources
Main		Typical maximum source activity:
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 83-88
Main		FIG. 83. Modern ¹⁹²Ir brachytherapy remote afterloading machine (photograph: Nucletron).
Main		FIG. 84. Modern ¹⁹²Ir brachytherapy remote afterloading machine (photograph: Nucletron).
Main		FIG. 85. ¹³⁷Cs brachytherapy remote afterloading machine attached to catheters to transport sources.
Main		FIG. 86. Source exchange container for ¹⁹²Ir remote afterloading machine (photograph: Nucletron).
Main		FIG. 87. Modern ¹³⁷Cs brachytherapy remote afterloading machine (photograph: Seedos/Bebig).
Main		FIG. 88. ¹³⁷Cs source canister for storage and transport (photograph: Seedos/Bebig).
Main		Description of use
Main		These devices typically use multiple ¹³⁷Cs, ¹⁹²Ir or ⁶⁰Co sources. The sources are very small (as small as approximately 1 mm in diameter). They are used for cancer therapy by automatically transporting the sources from their shielding in the container into a catheter type tube which has been positioned previously in a tumour site. This allows the ‘catheter’ to be positioned accurately in the site by an oncologist without any radioactive source being present. Then a radiation dose can be administered directly to the site remotely, maximizing the dose to the tumour with minimal dose to healthy tissue of the patient and no dose to the medical staff. Such devices are installed in many cancer therapy units in hospitals worldwide.
Main		The radioactive sources themselves are stored in a shielded canister in the brachytherapy machine. The catheter is placed in the tumour site with no radioactive source loaded, and correct positioning can be confirmed by radiography.
Main		After the catheter is positioned, it is connected to the brachytherapy machine, which delivers the correct number of sources to the treatment site pneumatically. At the end of the treatment cycle, the sources are retracted into the storage canister in the machine.
Main		Typical operating environment
Main		The units are in common use in hospital oncology departments worldwide. The unit itself is used in a shielded facility to prevent exposure to medical staff, and the facility would normally have strictly controlled access. The unit is mounted on wheels and may be stored in a restricted access area and brought into the treatment area only when in use.
Main		Depleted sources are replaced periodically by trained service engineers. The used sources are discharged into a special portable canister, which also delivers the new sources to and from the machine. Alternatively, the complete source canister may be removed from the machine with the sources inside, and be used as a transport container.
Main		The canister is used to transport sources between the manufacturer’s site and the machine in the hospital.
Main		Typically, sources are very small, less than 5 mm in diameter, and may not be engraved with a trefoil or other identification marks.
Main		Sources
Main		Typical source activity:
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 89-91
Main		FIG. 89. Typical static eliminator bar (photograph: Oak Ridge Associated Universities).
Main		FIG. 90. Typical static eliminator air gun (photograph: Oak Ridge Associated Universities).
Main		FIG. 91. Static eliminator bars (photograph: NRC).
Main		Description of use
Main		These types of device use a precious metal rolled foil with ²¹⁰Po incorporated into it with a thin layer of pure precious metal sealing the ²¹⁰Po composite into the foil.
Main		There are two main types of device: bars and guns. Bar devices emit a ‘cloud’ of alpha particles to a distance of about 2 in. (8 cm) from the surface which ionize the surrounding gas (air) and allow any static charges on surrounding materials to be safely conducted to ground by slow discharge. Gun devices are used on pneumatic air lines, and the air passing through is ionized. The resulting stream of air can be used for blowing dust from objects and eliminating static charge on them which attracts dust.
Main		For bars, the foil is contained in a metal casing with a grille to allow free movement of ionized air, but protection to the foil; and for guns, the foil is contained within a tubular metal case which forms part of the air line and gun grip.
Main		Typical operating environment
Main		Bars used to be in quite common use in the mill processing of any web where static charge buildup was a problem or fire hazard. Guns were used in clean room applications, such as electronics manufacturing and high quality paint shops.
Main		In the last ten years, their prevalence has reduced significantly due to improvements in electrically powered static eliminators.
Main		Bars are normally mounted across the span of mills, close to the run of the web where the static charge builds up. Guns are used in clean rooms and paint workshops and should be locked away when not in use.
Main		The half-life of ²¹⁰Po is relatively short (20 weeks), therefore, devices are usually replaced annually on a service contract with their original supplier.
Main		The devices are packaged for transport in normal industrial packaging, such as rigid cardboard or rigid plastic packaging.
Main		Sources
Main		Bars:²¹⁰Po up to 2 GBq (55 mCi) when new;
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 92, 93
Main		FIG. 92. Example of a radioactive lightning preventer.
Main		FIG. 93. Examples of radioactive lightning preventers.
Main		Description of use
Main		Small radioactive sources used to be attached to lightning conductor rods. It was thought that the sources would cause ionization of the air around the conductor rod and would increase the efficiency of the lightning conductor. Various types of source have been reported to have been used, including ²²⁶Ra and ²⁴¹Am alpha sources, as well as ⁶⁹Eu and ⁶⁰Co gamma sources.
Main		The radioactive lightning conductor rod was shown not to be effective during the 1970s and most have now been removed from service.
Main		Typical environment of use
Main		Radioactive lightning conductor rods were used mostly on lightning conductors worldwide where hazardous materials were held in the building being protected. In some countries, they were also installed on many public buildings, such as churches.
Main		Since 1970, most countries have operated a programme to remove radioactive lightning conductor rods from service.
Main		Sources
Main		²⁴¹Am: up to 1.1 GBq (30 mCi);
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 94, 95
Main		FIG. 94. Examples of self-luminous signs.
Main		FIG. 95. Construction of a self-luminous sign.
Main		Description of use
Main		Self-luminous signs use a mixture of beta emitting ³H (tritium) gas sealed into a glass tube that is internally coated with phosphor. The phosphor emits visible light when it interacts with a beta particle.
Main		The gas is sealed into a glass tube and the light can be seen at all times. No power is required, making it ideal for emergency signs which may be required in buildings in the event of a power failure.
Main		No radiation passes out of the glass tube and, in the event of breakage, tritium gas is dispersed in well ventilated areas.
Main		Typical environment of use
Main		The devices are used quite extensively in public buildings and aircraft.
Main		Sources
Main		³H: up to 740 GBq (20 Ci).
Main		Device Category
Main		Typical range of dimensions
Main		Typical range of mass
Main		Application
Main		See Figs 96-98
Main		FIG. 96. Typical smoke detector (back view).
Main		FIG. 97. Typical smoke detector (front view).
Main		FIG. 98. Typical ion chamber containing the radioactive component from a domestic smoke detector (photograph: QSA-Global).
Main		Description of use
Main		Radioactive smoke detectors contain a very small ²⁴¹Am alpha source which ionizes the air in a chamber. Two plates are maintained at a constant voltage difference in the chamber and the ionized air allows a constant current to pass between them. If smoke enters the chamber, the radiation is absorbed by the smoke and the air ionization is reduced. This in turn causes a reduction in current between the plates, causing an alarm to trip.
Main		Typical operating environment
Main		These devices are in common use in homes, offices and factories in all locations.
Main		Smoke detectors are supplied with the radioactive source fitted. The source remains in the smoke detector for the lifetime of the device.
Main		When the smoke detector is replaced, the activity of the source is sufficiently low that the device may be disposed of using domestic refuse collection, depending on regulations.
Main		Sources
Main		²⁴¹Am: maximum activity 37 kBq (1 µCi);
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 99-101
Main		FIG. 99. ⁶⁰Co teletherapy source in a tungsten holder (photograph: Oak Ridge Associated Universities).
Main		FIG. 100. Gamma knife source capsule (photograph: Elekta).
Main		FIG. 101. A variety of ⁶⁰Co teletherapy sources with associated fittings for loading into the teletherapy head (photograph: REVISS Services (UK) Ltd).
Main		Description of use
Main		These sources are used almost exclusively in medical teletherapy applications in hospitals and in gamma knives. They are also used in some radiometric laboratories for calibration measurements, and are normally housed permanently in units similar to teletherapy heads.
Main		Due to the high energy and typically high activity of these sources, they are potentially hazardous. Even short exposure to such a source can result in a fatal radiation dose.
Main		Sources may only be manipulated by trained specialist operators with experience of the source and the device in which they are mounted. Specialized shielded equipment is needed.
Main		Sources are doubly encapsulated in stainless steel, containing cobalt pellets which have been treated in a nuclear reactor to produce the ⁶⁰Co radioisotope.
Main		Sources are manufactured in two or three standard sizes, and may be mounted in tungsten spacers within the teletherapy head.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 102-104
Main		FIG. 102. Typical industrial sterilization source; the inset shows cobalt metal pellets (photograph: REVISS). Approximate dimensions: 11 mm diameter × 450 mm length; typical activity when new: 444 TBq (12 kCi) ⁶⁰Co.
Main		FIG. 103. Typical industrial sterilization source (photograph: REVISS). Approximate dimensions: 35 mm diameter × 720 mm length; typical activity when new: 1.85 PBq (50 kCi) ⁶⁰Co.
Main		FIG. 104. A selection of ⁶⁰Co irradiator sources (photograph: REVISS).
Main		Description of use
Main		These sources are used in permanent gamma sterilization plant installations, which are buildings designed specifically for the purposes of housing the sources and allowing product to enter a large sterilization chamber where it is subject to a controlled dose of radiation, usually intended to kill bacteria.
Main		They are also used in small scale irradiators, mostly in research laboratories for experimental purposes.
Main		Due to the high energy and typically high activity of these sources, they are potentially hazardous, and even short exposure to a depleted source can result in a fatal radiation dose.
Main		Sources must be manipulated only by trained specialist operators, with experience of the source and the device or irradiation facility in which they are used. Specialized shielded equipment is needed.
Main		Sources are usually doubly encapsulated in a stainless steel outer capsule, containing cobalt pellets which have been treated in a nuclear reactor to produce the 60Co radioisotope.
Main		The most common design of the ⁶⁰Co gamma sterilization source is the Nordion C188, REVISS RSL2089 type, used in industrial gamma sterilization plants worldwide. Sources of similar dimensions are made by a number of other manufacturers, and there are also a variety of other design types, used in both industrial irradiators and small scale irradiators.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		Description of use
Main		These sources are used in RTGs, as described in Section 5.7.
Main		They are loaded and sealed into the RTG and should not be removed during its lifetime.
Main		Due to the high energy and typically high activity of these sources, they are potentially hazardous, and even short exposure to a source can result in a fatal radiation dose. The principal radiation is beta radiation, which is relatively short range, but a dangerous and significant level of secondary bremsstrahlung gamma radiation is also created by the source.
Main		Sources must be manipulated by trained specialist operators only, in a heavily shielded facility.
Main		Sources are usually doubly encapsulated in stainless steel, containing pressed pellets of strontium carbonate.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 105-107
Main		FIG. 105. Typical old gamma radiography source/pigtail assemblies (photograph: Oak Ridge Associated Universities).
Main		FIG. 106. Typical modern gamma radiography source/pigtail assembly (photograph: QSA-Global).
Main		FIG. 107. Typical gamma radiography inner source capsule prior to encapsulation in the pigtail (photograph: MAYAK P.A.).
Main		Description of use
Main		These sources are used in gamma radiography devices (Sections 5.10 and 5.11).
Main		The sources are typically attached to a short length of flexible cable (known as a ‘pigtail’), with a connecting link which allows them to be attached to a control cable so that they can be remotely removed from the radiography device and positioned to make a radiograph.
Main		The sources are usually doubly encapsulated in stainless steel, and contain one or more pellets of active material in metal form.
Main		Sources are commonly¹⁹²Ir, but ⁶⁰Co, ⁷⁵Se and ¹⁶⁹Yb are also used. Sources all have a similar appearance.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Fig. 108
Main		FIG. 108. HDR brachytherapy source.
Main		Description of use
Main		These sources are used in HDR brachytherapy devices (see Section 5.18). Sources are usually ¹⁹²Ir. The source diameter is minimized to allow optimized treatment options and is attached to a flexible wire, which allows the remote afterloading machine to position the source at preprogrammed treatment positions.
Main		The sources usually consist of a length of irradiated ¹⁹²Ir wire encapsulated in a welded metal tube, which is in turn welded to the flexible cable.
Main		Older HDR brachytherapy systems use other miniature sources, containing ⁶⁰Co, ¹³⁷Cs or ¹⁹²Ir. These sources are often spherical, and were transported to the treatment sites along catheter tubes using a pneumatic system. They resemble ball bearings.
Main		In general, remote afterloading brachytherapy sources have no readily visible engraved identification markings.
Main		Due to their small size, and the lack of distinctive marks, these sources are considered to be relatively easy to lose, particularly if they are present in decommissioned equipment.
Main		Approximate dimensions:
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 109-112
Main		FIG. 109. Various high energy gamma sources (photograph: QSA-Global).
Main		FIG. 110. Typical ⁶⁰Co gamma source (photograph: MAYAK P.A.).
Main		FIG. 111. Typical ¹³⁷Cs gamma source (photograph: MAYAK P.A.).
Main		FIG. 112. Historic ²²⁶Ra gamma gauging source and source holder.
Main		Description of use
Main		These sources are used in fixed gauging systems in many industrial applications, such as thickness, density and bulk level measurements. The devices are described in Section 5.12. They are usually Category 3 or 4 applications.
Main		They are also used in portable combined soil moisture/density gauges as described in Section 5.16. These are usually Category 4 applications.
Main		Sources emit high energy gamma radiation, and the attenuation or backscatter of the radiation through the media of interest is measured.
Main		Sources are usually ⁶⁰Co or, more often, ¹³⁷Cs. Sources are usually doubly encapsulated in welded stainless steel. The active material is in the form of a metal pellet or pellets for ⁶⁰Co, or a non-leachable ceramic material for ¹³⁷Cs. Some ²²⁶Ra sources were produced but most are believed to have been decommissioned.
Main		The sources are contained in heavy shielded devices, and access to the source itself usually requires specialized tooling.
Main		Sources are usually transported to and from the site where they are used in the device in which they are used, but in some cases they are fitted on-site by suitably trained and qualified technicians.
Main		Most sources are cylindrical capsules, with no other features. In some cases, there may be a screw thread or other handling feature.
Main		There is a wide range in the activity of sources of the same size. For example, ¹³⁷Cs gauging sources can vary from 370 MBq (10 mCi) to 370 GBq (10 Ci) in similar sized capsules, depending on the application. The activity of a source is not always engraved on the capsule, due to decay.
Main		Portable soil moisture and density gauges use a source of approximately 370 MBq (10 mCi).
Main		Other isotopes rarely used in high energy gamma gauges include ¹³⁴Cs and ¹³³Ba.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Fig. 113
Main		FIG. 113. Typical ²⁴¹Am/Be neutron source (photograph: MAYAK P.A.).
Main		Description of use
Main		These sources are used in fixed gauging systems in many industrial applications for bulk moisture measurement, as described in Section 5.15. These are usually Category 3 applications.
Main		They are also used in portable combined soil moisture/density gauges, as described in Section 5.16. These are usually Category 4 applications.
Main		They are often used in conjunction with a density measurement using a gamma source.
Main		The sources emit neutrons, and the level of backscattered neutron radiation is measured to derive the moisture content.
Main		These sources are usually ²⁴¹Am mixed with Be. The alpha decay of the 241Am interacts with Be to initiate secondary neutron radiation from the Be.
Main		Some sources are ²⁵²Cf, which emits neutrons by spontaneous fission.
Main		The sources are usually doubly encapsulated in welded stainless steel. The active material is in the form of a pressed pellet of ²⁴¹Am oxide and beryllium metal. The pellet is relatively robust and non-leachable.
Main		The sources are usually contained in shielded devices, and access to the source itself usually requires specialized tooling. The shielding is normally a material high in hydrogen content and, therefore, is not as dense as the materials used for neutron shielding.
Main		In many bulk measurement applications (for example, in hoppers), the source is located inside the hopper and the contents of the hopper provides effective shielding of the radiation dose.
Main		These sources are usually transported to and from the site where they are used in the device in which they are used, but in some cases they are fitted onsite by suitably trained and qualified technicians.
Main		Most sources are cylindrical capsules, with no other features. In some cases, there may be a screw thread or other handling feature.
Main		Most gamma radiation measurement equipment does not respond to neutron radiation. Nor do personal dosimeters. Special neutron radiation monitors are required. It should also be noted that neutron radiation monitors respond slowly to measurements.
Main		There is a wide range in the activity of sources of the same size. For example, ²⁴¹Am/Be gauging sources can vary from 3.7 GBq (100 mCi) to 185 GBq (5 Ci) in similar sized capsules, depending on the application. ²⁵²Cf sources can have very high dose rates from capsules as small as 6 mm diameter and 12 mm in length.
Main		Portable soil moisture gauges use ²⁴¹Am/Be sources of approximately 1.85 GBq (50 mCi).
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 114, 115
Main		FIG. 114. A selection of ²⁴¹Am/Be and ¹³⁷Cs oil well logging sources (photograph: NRC).
Main		FIG. 115. Typical ²⁴¹Am/Be oil well logging source attached to a bull plug device (photograph: NRC).
Main		Description of use
Main		Gamma sources are nearly always ¹³⁷Cs. Neutron sources are nearly always ²⁴¹Am with Be.
Main		Sources are used widely within the oil industry. They are transported by oil well logging companies and can be found at corporate operational bases and on oil well sites. They are stored in secure compounds.
Main		Usually the source itself is a cylindrical, doubly encapsulated, high strength stainless steel welded capsule similar to those described in Sections 6.6 and 6.7. The active content is a non-leachable ceramic containing ¹³⁷Cs for the gamma sources and a robust and non-leachable pressed pellet of ²⁴¹Am oxide and beryllium metal for neutron sources.
Main		The capsules often have threads or other handling features to allow them to be secured inside bull plugs.
Main		The sources are usually loaded for further protection into a bull plug, as described in Sections 5.8 and 5.9. It would be highly unusual for a source to be removed from the bull plug, and would require specialized handling facilities and trained personnel.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 116-119
Main		FIG. 116. ⁹⁰Sr beta source showing a welded end and window end (photograph: QSAGlobal).
Main		FIG. 117. ⁸⁵Kr beta source showing a window end (photograph: QSA-Global).
Main		FIG. 118. ⁸⁵Kr beta sources with a protective brass window cover, attached and removed (photograph: QSA-Global).
Main		FIG. 119. Large area ²⁴¹Am low energy gamma source showing a welded face (approximately 40 mm diameter) (photograph: QSA-Global).
Main		Description of use
Main		These sources are used in fixed gauging systems in many industrial applications for measuring thickness, density and levels in package filling equipment, as described in Sections 5.13 and 5.14.
Main		Sources emit low energy gamma radiation or beta radiation. The attenuation of the radiation through the media of interest is measured. The type of radiation is chosen to suit the thickness or density of the media to be measured.
Main		Gamma sources are usually ²⁴¹Am. Beta sources are usually ⁹⁰Sr or ⁸⁵Kr. They are usually disc shaped cylinders and are manufactured in stainless steel. The capsule is welded as a single encapsulation. One end of the cylinder is very thin and delicate in order to allow transmission of the radiation. This is known as the ‘window’. The sources must be handled with care to avoid damage to the window. The active material is in the form of a non-leachable ceramic for ⁹⁰Sr and ²⁴¹Am; ⁸⁵Kr is a gas.
Main		The sources are usually contained in heavy shielded devices with a thin window at one port firmly attached to the production line. Access to the source itself usually requires specialized tooling.
Main		Sources may be transported to and from the site where they are used in the device in which they are used, but in many cases they are fitted on-site by suitably trained and qualified technicians.
Main		Due to the low energy of the gamma radiation, and the low transmission of the beta radiation, the radiation output is mostly only through the window of the source. Radiation output can be minimized by covering the window of the source with low density material (such as 1 cm perspex).
Main		Most sources are cylindrical capsules with no other features.
Main		Other isotopes rarely used in low energy gamma and beta gauges include ¹⁴⁷Pm.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 120-122
Main		FIG. 120. Typical ¹²⁵I seeds (photograph: SeeDOS Ltd/BEBIG GmbH).
Main		FIG. 121. Seeds in plastic ribbon (photograph: SeeDOS Ltd/BEBIG GmbH).
Main		FIG. 122. Typical ¹²⁵I seed ribbon dispenser (photograph: SeeDOS Ltd/BEBIG GmbH).
Main		Description of use
Main		These sources are used for low dose rate interstitial brachytherapy or permanent implantation in cancer therapy.
Main		Most sources emit low energy gamma or X ray radiation and use ¹²⁵I.
Main		The sources are supplied singly or packaged into a plastic ‘ribbon’ for easy handling.
Main		They are a welded single encapsulation in stainless steel or titanium. The active material is plated or chemically bound to a substrate.
Main		The sources are not individually identified or marked in any way due to their small size and application.
Main		They are known as ‘seeds’.
Main		Seeds are in wide use as a treatment for prostate cancer. They are permanently implanted using a specialized device and allowed to decay in the body.
Main		SourceCategory
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Fig. 123
Main		FIG. 123. Eye plaque with an applicator, shown using a dummy eyeball.
Main		Description of use
Main		These sources are used for the treatment of cancer of the eye and are found in specialized hospitals.
Main		Most sources emit low energy beta radiation and use ¹⁰⁶Ru plated onto a substrate or incorporated into a foil.
Main		They are positioned on the eyeball for periods of up to several days.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 124-127
Main		FIG. 124. Low energy gamma analytical point source (photograph: QSA-Global).
Main		FIG. 125. Typical low energy gamma large diameter analytical disc source showing a beryllium window and welded ends (photograph: QSA-Global).
Main		FIG. 126. Typical low energy gamma medium diameter analytical disc source showing a beryllium window and welded ends (photograph: QSA-Global).
Main		FIG. 127. Typical low energy gamma small diameter disc source showing a beryllium window (photograph: IPL).
Main		Description of use
Main		These sources are used in analytical instruments and devices in laboratories, materials processing and hand-held material characterization devices, as described in Section 5.17.
Main		Sources emit low energy gamma radiation of distinct energy bands which, when incident on certain elements, reflects certain well defined spectra of secondary X rays. The spectrum allows the material to be analysed for constituent elements.
Main		Gamma sources are usually ²⁴¹Am, ²⁴⁴Cm or ¹⁰⁹Cd. The sources are usually disc shaped cylinders. There are two types of capsule: Those manufactured from stainless steel and welded as a single encapsulation. One end of the cylinder is very thin and delicate in order to allow transmission of the radiation. Those manufactured from a copper alloy with a beryllium disc welded at one end to allow transmission of the radiation. The thin or beryllium end is known as the window.
Main		The sources must be handled with care to avoid damage to the window. The active material is in the form of a non-leachable ceramic for ²⁴¹Am and ²⁴⁴Cm. ¹⁰⁹Cd is plated onto a substrate.
Main		The sources are usually contained in small shielded devices within the instrument. Access to the source itself usually requires specialized tooling.
Main		These sources may be transported to and from the site where they are used, in the device in which they are used, but in many cases they are fitted on-site by suitably trained and qualified technicians.
Main		Due to the low energy of the gamma radiation, the radiation output is mostly only through the window of the source. Radiation output can be minimized by covering the window of the source.
Main		Most sources are cylindrical capsules with no other features.
Main		Source Category
Main		Typical range of dimensions
Main		Typical activity when new
Main		Application
Main		See Figs 128-133
Main		FIG. 128. ¹³⁷Cs point reference source (photograph: Schlumberger).
Main		FIG. 129. Medical point source reference marker (photograph: QSA-Global).
Main		FIG. 130. Various wide area reference sources (photograph: QSA-Global).
Main		FIG. 131. ¹⁵³Gd PET calibration sources, shown in a carrying case (photograph: QSAGlobal).
Main		FIG. 132. Various geometry detector calibration sources (photograph: QSA-Global).
Main		FIG. 133. Calibration blanket for a natural gamma oil well logging detector (photograph: Schlumberger).
Main		Description of use
Main		These sources are usually of very low activity and are used in the calibration of radiation measurement instruments for many applications.
Main		In most instances, the activity is too low for the sources to be formally classified as sealed, but they are included here for completeness.
Main		Source Category
Main		Typical range of dimensions
Main		Typical mass
Main		Typical itotopes and activity
Main		See Figs 134-137
Main		FIG. 134. High activity gamma source container in a transport configuration (photograph: REVISS).
Main		FIG. 135. High activity gamma source container enclosed in a cage to prevent contact with its hot surfaces (photograph: REVISS).
Main		FIG. 136. Checking surface dose rates before dispatch of a high activity gamma source container (photograph: MDS Nordion).
Main		FIG. 137. Container in configuration for loading in an irradiation plant.
Main		Description of use
Main		These containers are used for the transport of high energy gamma radiation sources, as described in Sections 7.1 and 7.2.
Main		The containers usually use lead or depleted uranium shielding. Depleted uranium packages have to be shipped as radioactive even when they carry no payload. A low level of radiation is emitted from the depleted uranium even when no payload is present.
Main		The containers are reusable and are usually shipped by road, rail and sea. Depending on local regulations, special transport arrangements may apply.
Main		Loaded containers are often hot on their outer surfaces.
Main		Source Category
Main		Typical range of dimensions
Main		Typical mass
Main		Typical itotopes and activity
Main		See Figs 138-141
Main		FIG. 138. Source changer in transport configuration (photograph: QSA).
Main		FIG. 139. Source changer ready to link to a radiography device for source exchange (photograph: QSA).
Main		FIG. 140. Source changer ready to link to a radiography device for source exchange (photograph: MDS Nordion).
Main		FIG. 141. Source changers for carrying multiple sources ready to link to a radiography device for source exchange (photograph: MDS Nordion).
Main		Description of use
Main		These containers are used for the exchange of industrial radiography sources as described in Section 6.4.
Main		The containers usually use lead or depleted uranium shielding. Depleted uranium packages have to be shipped as radioactive even when they carry no payload. A low level of radiation is emitted from the depleted uranium even when no payload is present.
Main		The containers are reusable and are usually shipped by road, rail, air and sea. In addition, they are used to ship new radiography sources from the manufacturer to the user. They allow the user to place an old depleted source from the radiography device into the transport container, and remove the new source into the radiography device using the standard remote control system.
Main		Source Category
Main		Typical range of dimensions
Main		Typical mass
Main		Typical itotopes and activity
Main		See Figs 142-145
Main		FIG. 142. High energy gamma source package showing outer package and inner shielded pot.
Main		FIG. 143. High energy gamma source package showing outer package and inner shielded pot (photograph: MAYAK P.A.).
Main		FIG. 144. High energy gamma source package showing outer package and inner shielded pot (photograph: MAYAK P.A.).
Main		FIG. 145. Examples of Type A overpack packages for shipping gamma gauges (photograph: Endress and Hauser).
Main		Description of use
Main		These packages are used for the transport of high energy gamma radiation sources for gauging and other industrial purposes, as described in Section 6.6.
Main		The packages usually use lead shielding. In some instances, depleted uranium may be used. Depleted uranium packages have to be shipped as radioactive even when they carry no payload. A low level of radiation is emitted from the depleted uranium even when no payload is present.
Main		The packages are usually reusable and may be shipped by road, rail and sea.
Main		Packages normally conform to IAEA Type A regulations for the safe transport of radioactive material, otherwise to Type B.
Main		In many instances, radioactive devices as described in Section 5.12 are used for transport and conform to the relevant transport regulations. In these instances, they are often packaged into additional overpacks which may provide additional protection in the event of an accident, or they may simply be used to reduce effective surface dose rate and to aid handling.
Main		Source Category
Main		Typical range of dimensions
Main		Typical mass
Main		Typical itotopes and activity
Main		See Figs 146, 147
Main		FIG. 146. Components of a typical single use Type A source package (photograph: QSAGlobal).
Main		FIG. 147. Detail of an inner lead shielding container from a typical single use Type A source package (see Fig. 146) (photograph: QSA-Global).
Main		Description of use
Main		These packages are used for the transport of nearly all types of beta, gamma and neutron sources, provided that the activity is low enough for surface dose rates to remain within legal limits.
Main		The packages usually use lead shielding as the primary method of surface dose limitation. The additional distance from the radioactive source maintained by the packaging in the box also reduces the effective dose on the surface of the package.
Main		The packages are intended for single use only and may be shipped by road, rail, air and sea. It is unusual for them to be shipped without radioactive contents.
Main		The packages are visually similar to many other commercial packages and can be identified only by their to indicate radioactivity.
Main		The packages normally conform to IAEA Type A regulations for the safe transport of radioactive materials. Some packages also conform to Type B. This can be determined by the detailed labelling of the package.
Main		Radiation is generally defined as energy in the form of photons or particles propagating through space. Radiation, for the purposes of this publication, refers to ionizing radiation which is capable of ionizing biological materials and therefore causing damage to living cells.
Main		In the context of radioactive sources, ionizing radiation comprises gamma and X ray photons, and alpha, beta and neutron particles.
Main		There are five forms of ionizing radiation relevant to the context of this manual (see Fig. 148): Alpha radiation: This is particulate radiation of relatively large mass and energy. It has a relatively short range. It is absorbed in 1–2 cm of air, or on a sheet of paper or the dead tissue of the outer layer of human skin. Beta radiation: This is an electron emitted by an atom’s nucleus. The particle is of very low mass and has a greater range than alpha radiation. Beta radiation can be absorbed by a sheet of plastic, glass or metal. It can penetrate the outer skin and be absorbed into the living tissue, causing ionization which can be harmful. Gamma radiation: This is a high energy photon emitted from an atom’s nucleus. The photon is of negligible mass and has a great range. It interacts with the electrons of material into which it is absorbed, causing ionization which can be harmful to living tissue. Typically, dense material, such as lead or steel, may be used for shielding. Neutron radiation: This is a neutron emitted from an atom’s nucleus. It is relatively small and light in atomic terms, has no charge and is normally of high energy and, therefore, has quite a long range. Because neutrons have no charge, they do not directly cause ionization, however, when they collide with the nuclei of atoms in an absorbing material they can damage them and make them unstable, which means that they can be very damaging to living tissue. They penetrate many materials relatively easily and can be shielded by hydrogenous material, such as water or paraffin. X rays: These are photons similar to gamma radiation and are produced when energy is lost from electrons as they are slowed down. They behave similarly to gamma rays.
Main		FIG. 148. Forms of ionizing radiation relevant to this manual.
Main		When radiation passes through matter, it deposits some of its energy in the absorbing material by ionization or excitation of the atoms. It is ionization of atoms in tissue, accompanied by chemical changes, that causes the harmful biological effects of radiation. We still do not fully understand all the ways in which radiation damages cells, but many involve changes to deoxyribonucleic acid (DNA). This damage can lead to biological effects, including cell death and abnormal cell development.
Main		There are two main types of radiation health effects. Deterministic effects occur only if the dose or dose rate (i.e. the dose per unit time) is greater than some threshold value. The effects occur early and are more severe for higher doses and dose rates. Examples are acute radiation syndrome (a syndrome which represents the collection of bodily effects resulting from exposure to large amounts of radiation), skin burn and sterility. If the dose is low or delivered over a longer period of time, there is a greater opportunity for the body’s damaged cells to repair themselves; however, harmful effects may still occur. Effects of this type, called stochastic, are not certain to occur, but their likelihood increases for higher doses, whereas the timing and severity of an effect do not depend on the dose. Examples are cancers of various types.
Main		The level of human exposure to ionizing radiation may be controlled and limited in three ways: Distance; Time; Shielding.
Main		For individuals discovering sources or devices, distance and time are the best methods for controlling and limiting exposure to radiation. For civil authority experts, shielding is an additional method for reducing their exposure.
Main		In the event that an uncontrolled source or device is identified, the public can be protected from radiation by a combination of distance and time. As a general rule, the intensity of the radiation field from a point source of radiation is reduced in proportion to the square of the distance. When sources or devices are identified, it is important to leave the area immediately, in order to minimize time and thus radiation exposure. Shielding of sources or devices should be used based on evaluations by civil authority experts.
Main		Additional information is provided in Refs [12–14].
TABLE 1. LIST OF DEVICES AND SUMMARY REFERENCE DATA		^a ‘Category’ refers to the IAEA Categories defined in Section 4.8, where Category 1 is extremely dangerous to the person and Category 5 is most unlikely to be dangerous to the person.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		INTERNATIONAL ATOMIC ENERGY AGENCY, Manual for First Responders to a Radiological Emergency, IAEA-EPR-First Responders, IAEA, Vienna (2006). INTERNATIONAL ATOMIC ENERGY AGENCY, Preparedness and Response for a Nuclear or Radiological Emergency, Safety Requirements, GS-R-2, IAEA, Vienna (2002). INTERNATIONAL ATOMIC ENERGY AGENCY, Regulations for the Safe Transport of Radioactive Material, IAEA Safety Standards Series No. TS-R-1, IAEA, Vienna (2005). INTERNATIONAL ATOMIC ENERGY AGENCY, The Radiological Accident in Goiânia, IAEA, Vienna (1988). INTERNATIONAL ATOMIC ENERGY AGENCY, Accidental Overexposure of Radiotherapy Patients in Bialystok, IAEA, Vienna (2004). INTERNATIONAL ATOMIC ENERGY AGENCY, The Radiological Accident in Yanango, IAEA, Vienna (2000). INTERNATIONAL ATOMIC ENERGY AGENCY, The Radiological Accident in Lilo, IAEA, Vienna (2000). INTERNATIONAL ATOMIC ENERGY AGENCY, The Radiological Accident in Samut Prakarn, IAEA, Vienna (2002). INTERNATIONAL ATOMIC ENERGY AGENCY, Technical Data on Nucleonic Gauges, IAEA-TECDOC-1459, IAEA, Vienna (2005). INTERNATIONAL ATOMIC ENERGY AGENCY, Radiation Protection and Safety in Industrial Radiography, Safety Reports Series No. 13, IAEA, Vienna (1999). INTERNATIONAL ATOMIC ENERGY AGENCY, Categorization of Radioactive Sources, IAEA Safety Standards Series No. RS-G-1.9, IAEA, Vienna (2005). INTERNATIONAL ATOMIC ENERGY AGENCY, Sealed Radioactive Sources Toolkit, Information Booklet, IAEA, Vienna (2005). INTERNATIONAL ATOMIC ENERGY AGENCY, Radiation, People and the Environment, Information Booklet, IAEA, Vienna (2004). INTERNATIONAL ATOMIC ENERGY AGENCY, Security of Radioactive Sources: Interim Guidance for Comment, IAEA-TECDOC-1355, IAEA, Vienna (2003).
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The definitions given below may not necessarily conform to definitions adopted elsewhere for international use. More general terms relating to radiation protection may be found in the IAEA Safety Glossary: Version 2.0 at the following web site: http://www-ns.iaea.org/standards/safety-glossary.htm
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		activity.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The rate at which nuclear transformations occur in a radioactive material. Used as a measure of the amount of a radionuclide present. Unit becquerel, symbol Bq. 1 Bq = 1 transformation per second. Formerly expressed in curie (Ci); activity values may be given in Ci (with the equivalent in Bq in parentheses) if they are being quoted from a reference that uses Ci as the unit. Unit of activity, equal to 3.7 × 10¹⁰ Bq (exactly).
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		alpha particle.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A particle consisting of two protons plus two neutrons (i.e. the nucleus of a helium atom) emitted by a radionuclide.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		atom.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Unit of matter consisting of a single nucleus surrounded by a number of electrons equal to the number of protons in the nucleus. The smallest portion of an element that can combine chemically with other atoms.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		atomic number.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The number of protons in the nucleus of an atom. Symbol Z.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		becquerel.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		See activity.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		beta particle.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		An electron or proton which has been emitted by an atomic nucleus or neutron in a nuclear transformation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		brachytherapy.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The use of a sealed radioactive source in or on the body for treating certain types of cancer.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		depleted uranium.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Uranium containing a lesser mass percentage of ²³⁵U than the 0.7% found in natural uranium. A by-product from the production of enriched uranium. Used as radiation shielding in radioactive transport packaging and some devices.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		deterministic effect.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A health effect of radiation for which generally a threshold level of dose exists above which the severity of the effect is greater for a higher dose. Such an effect is described as a ‘severe deterministic effect’ if it is fatal or life threatening or results in a permanent injury that reduces quality of life.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		device.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A piece of machinery or instrument in which a radioactive source is used, and which safely houses the source. The manufacture of devices generally conforms to national or international safety standards.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		disposal.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		In relation to radioactive waste, emplacement in an appropriate facility without the intention of retrieval.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		electromagnetic radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Radiation consisting of electrical and magnetic fields oscillating at right angles to each other. Ranges from very long wavelengths (low energy), such as radio waves, through intermediate wavelengths, such as visible light, to very short wavelengths (high energy), such as gamma rays.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		electron.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A stable elementary particle having a negative electric charge of 1.6 × 10^–19 C and a mass of 9.1 × 10^–31 kg.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		free radical.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		An uncharged atom or group of atoms having one or more unpaired electrons which were part of a chemical bond. Generally very reactive in a chemical sense.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		gamma ray.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Penetrating electromagnetic radiation emitted by an atomic nucleus during radioactive decay and having wavelengths much shorter than those of visible light.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		half-life.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		For a radionuclide, the time required for the activity to decrease, by radioactive decay processes, by half. Symbol: T_1/2.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		ionization.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The process by which an atom or molecule acquires or loses an electric charge. The production of ions.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		ionizing radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		For the purposes of radiation protection, radiation capable of producing ion pairs in biological material(s). Examples are alpha particles, gamma rays, X rays and neutrons.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		irradiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The act of being exposed to radiation. It can be intentional, for example, through industrial irradiation to sterilize medical equipment; or accidental, for example, through proximity to a source that emits radiation. Irradiation does not usually result in radioactive contamination, but damage can occur depending on the dose received.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		isotopes.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Nuclides with the same number of protons but different numbers of neutrons. Not a synonym for nuclide.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		mass number.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The number of protons plus neutrons in the nucleus of an atom; abbreviation A.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		molecule.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A group of atoms bonded to each other chemically. The smallest portion of a substance that can exist by itself and retain the properties of the substance.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		neutron.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		An elementary particle having no electric charge, a mass of about 1.67 × 10^–27 kg and a mean lifetime of about 1000 seconds.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		nuclear medicine.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The use of radionuclides for diagnosing or treating disease in patients.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		nucleus (of an atom).
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The positively charged central portion of an atom. Contains the protons and neutrons.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		nuclide.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A species of atom characterized by the number of protons and neutrons and the energy state of the nucleus.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		photon.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A quantum of electromagnetic radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Energy, in the form of waves or particles, propagating through space. Frequently used for ionizing radiation in the present text, except when it is necessary to avoid confusion with non-ionizing radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radiation protection (or radiological protection).
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The protection of people from the effects of exposure to ionizing radiation, and the means for achieving this.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radioactive.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Exhibiting radioactivity. For legal and regulatory purposes, the meaning of radioactive is often restricted to those materials designated in national law or by a regulatory body as being subject to regulatory control because of their radioactivity.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radioactive source.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A means of containment of radioactive material such that the radioactive material remains protected in a leaktight capsule but the radiation is allowed to be emitted for its intended purpose. Also known as a sealed source or source. Radioactive sources are manufactured in accordance with international law for integrity.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radioactivity.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The phenomenon whereby atoms undergo spontaneous random disintegration, usually accompanied by the emission of radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radionuclide.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A radioactive nuclide.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		radiotherapy.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The use of radiation beams for treating disease, usually cancer, in patients.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		regulatory body.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		An organization designated by a national government as having legal authority for regulating nuclear, radiation, radioactive waste and transport safety.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		risk.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		The probability of a specified health effect occurring in a person or group as a result of exposure to radiation.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		sealed source.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		See radioactive source.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		source.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		transport package.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		A container in which sealed sources are transported. Transport packages conform to international regulations for the safe transport of radioactive materials.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		X ray.
TABLE 2. LIST OF SOURCES AND APPLICATION CROSS-REFERENCES		Penetrating electromagnetic radiation emitted by an atom when electrons in the atom lose energy, and having wavelengths much shorter than those of visible light, see gamma ray.