I.1. Table 2 gives examples of sources that have been or were in 2004 in common use (column I). The list is not exhaustive — there may be sources with a higher or lower activity than those described, and this may also change over time with technological developments. Column II identifies the radionuclide(s) typically used. Columns III–V give examples of maximum, minimum and typical activity. The D values are given in column VI and activity ratios A/D in column VII. The categorization is shown in columns VIII and IX. Column VIII shows the initial categorization based on A/D and column IX shows the recommended categorization with account taken of additional factors generally known to be associated with particular types of source. The regulatory body may modify this categorization on the basis of specific knowledge of relevant factors, such as method of construction, physical or chemical form of the source, use in remote or harsh environments, history of accidents and portability. Note that Table 2 lists only single sources; where sources are aggregated, the recommendations in para. 3.5 should be followed.
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended RTGsCategory 1 Sr-90Max6.8E+052.5E+041.0E+002.5E+041 Sr-90Min9.0E+033.3E+021.0E+003.3E+0221 Sr-90Typ2.0E+047.4E+021.0E+007.4E+022 Pu-238Max2.8E+021.0E+016.E-021.7E+022 Pu-238Min2.8E+011.0E+006.E-021.7E+0121 Pu-238Typ2.8E+021.0E+016.E-021.7E+022 Irradiators used in sterilization and food preservation
Co-60Max1.5E+075.6E+053.E-021.9E+071 Co-60Min5.0E+031.9E+023.E-026.2E+0311 Co-60Typ4.0E+061.5E+053.E-024.9E+061 Cs-137Max5.0E+061.9E+051.E-011.9E+061 Cs-137Min5.0E+031.9E+021.E-011.9E+0311 Cs-137Typ3.0E+061.1E+051.E-011.1E+061 Self-shielded irradiatorsCs-137Max4.2E+041.6E+031.E-011.6E+041 Cs-137Min2.5E+039.3E+011.E-019.3E+0221 Cs-137Typ1.5E+045.6E+021.E-015.6E+031
Co-60Max5.0E+041.9E+033.E-026.2E+041 Co-60Min1.5E+035.6E+013.E-021.9E+0311 Co-60Typ2.5E+049.3E+023.E-023.1E+041 Blood/tissue irradiatorsCs-137Max1.2E+044.4E+021.E-014.4E+031 Cs-137Min1.0E+033.7E+011.E-013.7E+0221 Cs-137Typ7.0E+032.6E+021.E-012.6E+031 Co-60Max3.0E+031.1E+023.E-023.7E+031 Co-60Min1.5E+035.6E+013.E-021.9E+0311 Co-60Typ2.4E+038.9E+013.E-023.0E+031 Multi-beam teletherapy (gamma knife) sources
Co-60Max1.0E+043.7E+023.E-021.2E+041 Co-60Min4.0E+031.5E+023.E-024.9E+0311 Co-60Typ7.0E+032.6E+023.E-028.6E+031 Teletherapy sourcesCo-60Max1.5E+045.6E+023.E-021.9E+041 Co-60Min1.0E+033.7E+013.E-021.2E+0311 Co-60Typ4.0E+031.5E+023.E-024.9E+031
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Cs-137Max1.5E+035.6E+011.E-015.6E+022 Cs-137Min5.0E+021.9E+011.E-011.9E+0221 Cs-137Typ5.0E+021.9E+011.E-011.9E+022 Category 2 Industrial radiography sources
Co-60Max2.0E+027.4E+003.E-022.5E+022 Co-60Min1.1E+014.1E-013.E-021.4E+0122 Co-60Typ6.0E+012.2E+003.E-027.4E+012 Ir-192Max2.0E+027.4E+008.E-029.3E+012 Ir-192Min5.0E+001.9E-018.E-022.3E+0032 Ir-192Typ1.0E+023.7E+008.E-024.6E+012 Se-75Max8.0E+013.0E+002.E-011.5E+012 Se-75Min8.0E+013.0E+002.E-011.5E+0122 Se-75Typ8.0E+013.0E+002.E-011.5E+012 Yb-169Max1.0E+013.7E-013.E-011.2E+003 Yb-169Min2.5E+009.3E-023.E-013.1E-0142 Yb-169Typ5.0E+001.9E-013.E-016.2E-014
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Tm-170Max2.0E+027.4E+002.E+013.7E-014 Tm-170Min2.0E+017.4E-012.E+013.7E-0242 Tm-170Typ1.5E+025.6E+002.E+012.8E-014 Brachytherapy sources — high/medium dose rate
Co-60Max2.0E+017.4E-013.E-022.5E+012 Co-60Min5.0E+001.9E-013.E-026.2E+0032 Co-60Typ1.0E+013.7E-013.E-021.2E+012 Cs-137Max8.0E+003.0E-011.E-013.0E+003 Cs-137Min3.0E+001.1E-011.E-011.1E+0032 Cs-137Typ3.0E+001.1E-011.E-011.1E+003 Ir-192Max1.2E+014.4E-018.E-025.6E+003 Ir-192Min3.0E+001.1E-018.E-021.4E+0032 Ir-192Typ6.0E+002.2E-018.E-022.8E+003 Calibration sourcesCo-60Max3.3E+011.2E+003.E-024.1E+012 Co-60Min5.5E-012.0E-023.E-026.8E-014a Co-60Typ2.0E+017.4E-013.E-022.5E+012
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Cs-137Max3.0E+031.1E+021.E-011.1E+031 Cs-137Min1.5E+005.6E-021.E-015.6E-014a Cs-137Typ6.0E+012.2E+001.E-012.2E+012 Category 3 Level gaugesCs-137Max5.0E+001.9E-011.E-011.9E+003 Cs-137Min1.0E+003.7E-021.E-013.7E-0143 Cs-137Typ5.0E+001.9E-011.E-011.9E+003 Co-60Max1.0E+013.7E-013.E-021.2E+012 Co-60Min1.0E-013.7E-033.E-021.2E-0143 Co-60Typ5.0E+001.9E-013.E-026.2E+003 Calibration sourcesAm-241Max2.0E+017.4E-016.E-021.2E+012 Am-241Min5.0E+001.9E-016.E-023.1E+003a Am-241Typ1.0E+013.7E-016.E-026.2E+003 Conveyor gaugesCs-137Max4.0E+011.5E+001.E-011.5E+012 Cs-137Min3.0E-031.1E-041.E-011.1E-0353 Cs-137Typ3.0E+001.1E-011.E-011.1E+003
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Cf-252Max3.7E-021.4E-032.E-026.8E-024 Cf-252Min3.7E-021.4E-032.E-026.8E-0243 Cf-252Typ3.7E-021.4E-032.E-026.8E-024 Blast furnace gaugesCo-60Max2.0E+007.4E-023.E-022.5E+003 Co-60Min1.0E+003.7E-023.E-021.2E+0033 Co-60Typ1.0E+003.7E-023.E-021.2E+003 Dredger gaugesCo-60Max2.6E+009.6E-023.E-023.2E+003 Co-60Min2.5E-019.3E-033.E-023.1E-0143 Co-60Typ7.5E-012.8E-023.E-029.3E-014 Cs-137Max1.0E+013.7E-011.E-013.7E+003 Cs-137Min2.0E-017.4E-031.E-017.4E-0243 Cs-137Typ2.0E+007.4E-021.E-017.4E-014 Spinning pipe gaugesCs-137Max5.0E+001.9E-011.E-011.9E+003 Cs-137Min2.0E+007.4E-021.E-017.4E-0143 Cs-137Typ2.0E+007.4E-021.E-017.4E-014
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Research reactor startup sources
Am-241/BeMax5.0E+001.9E-016.E-023.1E+003 Am-241/BeMin2.0E+007.4E-026.E-021.2E+0033 Am-241/BeTyp2.0E+007.4E-026.E-021.2E+003 Well logging sourcesAm-241/BeMax2.3E+018.5E-016.E-021.4E+012 Am-241/BeMin5.0E-011.9E-026.E-023.1E-0143 Am-241/BeTyp2.0E+017.4E-016.E-021.2E+012 Cs-137Max2.0E+007.4E-021.E-017.4E-014 Cs-137Min1.0E+003.7E-021.E-013.7E-0143 Cs-137Typ2.0E+007.4E-021.E-017.4E-014 Cf-252Max1.1E-014.1E-032.E-022.0E-014 Cf-252Min2.7E-021.0E-032.E-025.0E-0243 Cf-252Typ3.0E-021.1E-032.E-025.6E-024 PacemakersPu-238Max8.0E+003.0E-016.E-024.9E+003 Pu-238Min2.9E+001.1E-016.E-021.8E+003b Pu-238Typ3.0E+001.1E-016.E-021.9E+003
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Calibration sourcesPu-239/BeMax1.0E+013.7E-016.E-026.2E+003 Pu-239/BeMin2.0E+007.4E-026.E-021.2E+003a Pu-239/BeTyp3.0E+001.1E-016.E-021.9E+003 Category 4 Brachytherapy sources — low dose rate
Cs-137Max7.0E-012.6E-021.E-012.6E-014 Cs-137Min1.0E-023.7E-041.E-013.7E-0354 Cs-137Typ5.0E-011.9E-021.E-011.9E-014 Ra-226Max5.0E-021.9E-034.E-024.6E-024 Ra-226Min5.0E-031.9E-044.E-024.6E-0354 Ra-226Typ1.5E-025.6E-044.E-021.4E-024 I-125Max4.0E-021.5E-032.E-017.4E-035 I-125Min4.0E-021.5E-032.E-017.4E-0354 I-125Typ4.0E-021.5E-032.E-017.4E-035 Ir-192Max7.5E-012.8E-028.E-023.5E-014 Ir-192Min2.0E-027.4E-048.E-029.3E-0354 Ir-192Typ5.0E-011.9E-028.E-022.3E-014
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Au-198Max8.0E-023.0E-032.E-011.5E-024 Au-198Min8.0E-023.0E-032.E-011.5E-0244 Au-198Typ8.0E-023.0E-032.E-011.5E-024 Cf-252Max8.3E-023.1E-032.E-021.5E-014 Cf-252Min8.3E-023.1E-032.E-021.5E-0144 Cf-252Typ8.3E-023.1E-032.E-021.5E-014 Thickness gaugesKr-85Max1.0E+003.7E-023.E+011.2E-035 Kr-85Min5.0E-021.9E-033.E+016.2E-0554 Kr-85Typ1.0E+003.7E-023.E+011.2E-035 Sr-90Max2.0E-017.4E-031.E+007.4E-035 Sr-90Min1.0E-023.7E-041.E+003.7E-0454 Sr-90Typ1.0E-013.7E-031.E+003.7E-035 Am-241Max6.0E-012.2E-026.E-023.7E-014 Am-241Min3.0E-011.1E-026.E-021.9E-0144 Am-241Typ6.0E-012.2E-026.E-023.7E-014
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Pm-147Max5.0E-021.9E-034.E+014.6E-055 Pm-147Min2.0E-037.4E-054.E+011.9E-0654 Pm-147Typ5.0E-021.9E-034.E+014.6E-055 Cm-244Max1.0E+003.7E-025.E-027.4E-014 Cm-244Min2.0E-017.4E-035.E-021.5E-0144 Cm-244Typ4.0E-011.5E-025.E-023.0E-014 Fill level gaugesAm-241Max1.2E-014.4E-036.E-027.4E-024 Am-241Min1.2E-024.4E-046.E-027.4E-0354 Am-241Typ6.0E-022.2E-036.E-023.7E-024 Cs-137Max6.5E-022.4E-031.E-012.4E-024 Cs-137Min5.0E-021.9E-031.E-011.9E-0244 Cs-137Typ6.0E-022.2E-031.E-012.2E-024 Co-60Max5.0E-011.9E-023.E-026.2E-014 Co-60Min5.0E-031.9E-043.E-026.2E-0354 Co-60Typ2.4E-028.7E-043.E-022.9E-024
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Calibration sourcesSr-90Max2.0E+007.4E-021.E+007.4E-024 Sr-90Min2.0E+007.4E-021.E+007.4E-024a Sr-90Typ2.0E+007.4E-021.E+007.4E-024 Moisture detectorsAm-241/BeMax1.0E-013.7E-036.E-026.2E-024 Am-241/BeMin5.0E-021.9E-036.E-023.1E-0244 Am-241/BeTyp5.0E-021.9E-036.E-023.1E-024 Density gaugesCs-137Max1.0E-023.7E-041.E-013.7E-035 Cs-137Min8.0E-033.0E-041.E-013.0E-0354 Cs-137Typ1.0E-023.7E-041.E-013.7E-035 Moisture/ density gauges
Am-241/BeMax1.0E-013.7E-036.E-026.2E-024 Am-241/BeMin8.0E-033.0E-046.E-024.9E-0354 Am-241/BeTyp5.0E-021.9E-036.E-023.1E-024 Cs-137Max1.1E-024.1E-041.E-014.1E-035 Cs-137Min1.0E-033.7E-051.E-013.0E-0454 Cs-137Typ1.0E-023.7E-041.E-013.7E-035
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Ra-226Max4.0E-031.5E-044.E-023.7E-035 Ra-226Min2.0E-037.4E-054.E-021.9E-0354 Ra-226Typ2.0E-037.4E-054.E-021.9E-035 Cf-252Max7.0E-052.6E-062.E-021.3E-045 Cf-252Min3.0E-051.1E-062.E-025.6E-0554 Cf-252Typ6.0E-052.2E-062.E-021.1E-045 Bone densitometry sources
Cd-109Max2.0E-027.4E-042.E+013.7E-055 Cd-109Min2.0E-027.4E-042.E+013.7E-0554 Cd-109Typ2.0E-027.4E-042.E+013.7E-055 Gd-153Max1.5E+005.6E-021.E+005.6E-024 Gd-153Min2.0E-027.4E-041.E+007.4E-0454 Gd-153Typ1.0E+003.7E-021.E+003.7E-024 I-125Max8.0E-013.0E-022.E-011.5E-014 I-125Min4.0E-021.5E-032.E-017.4E-0354 I-125Typ5.0E-011.9E-022.E-019.3E-024 Am-241Max2.7E-011.0E-026.E-021.7E-014 Am-241Min2.7E-021.0E-036.E-021.7E-0244 Am-241Typ1.4E-015.0E-036.E-028.3E-024
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Static eliminatorsAm-241Max1.1E-014.1E-036.E-026.8E-024 Am-241Min3.0E-021.1E-036.E-021.9E-0244 Am-241Typ3.0E-021.1E-036.E-021.9E-024 Po-210Max1.1E-014.1E-036.E-026.8E-024 Po-210Min3.0E-021.1E-036.E-021.9E-0244 Po-210Typ3.0E-021.1E-036.E-021.9E-024 Diagnostic isotope generators
Mo-99Max1.0E+013.7E-013.E-011.2E+003 Mo-99Min1.0E+003.7E-023.E-011.2E-0144 Mo-99Typ1.0E+003.7E-023.E-011.2E-014 Medical unsealed sourcesI-131Max2.0E-017.4E-032.E-013.7E-024 I-131Min1.0E-013.7E-032.E-011.9E-024c I-131Typ1.0E-013.7E-032.E-011.9E-024 Category 5 XRF analyser sources Fe-55Max1.4E-015.0E-038.E+026.2E-065 Fe-55Min3.0E-031.1E-048.E+021.4E-0755 Fe-55Typ2.0E-027.4E-048.E+029.3E-075
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Cd-109Max1.5E-015.6E-032.E+012.8E-045 Cd-109Min3.0E-021.1E-032.E+015.6E-0555 Cd-109Typ3.0E-021.1E-032.E+015.6E-055 Co-57Max4.0E-021.5E-037.E-012.1E-035 Co-57Min1.5E-025.6E-047.E-017.9E-0455 Co-57Typ2.5E-029.3E-047.E-011.3E-035 Electron capture detector sources
Ni-63Max2.0E-027.4E-046.E+011.2E-055 Ni-63Min5.0E-031.9E-046.E+013.1E-0655 Ni-63Typ1.0E-023.7E-046.E+016.2E-065 H-3Max3.0E-011.1E-022.E+035.6E-065 H-3Min5.0E-021.9E-032.E+039.3E-0755 H-3Typ2.5E-019.3E-032.E+034.6E-065 Lightning preventersAm-241Max1.3E-024.8E-046.E-028.0E-035 Am-241Min1.3E-034.8E-056.E-028.0E-0455 Am-241Typ1.3E-034.8E-056.E-028.0E-045
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Ra-226Max8.0E-053.0E-064.E-027.4E-055 Ra-226Min7.0E-062.6E-074.E-026.5E-0655 Ra-226Typ3.0E-051.1E-064.E-022.8E-055 H-3Max2.0E-017.4E-032.E+033.7E-065 H-3Min2.0E-017.4E-032.E+033.7E-0655 H-3Typ2.0E-017.4E-032.E+033.7E-065 Brachytherapy sources: low dose rate eye plaques and permanent implants
Sr-90Max4.0E-021.5E-031.E+001.5E-035 Sr-90Min2.0E-027.4E-041.E+007.4E-0455 Sr-90Typ2.5E-029.3E-041.E+009.3E-045 Ru/Rh-106Max6.0E-042.2E-053.E-017.4E-055 Ru/Rh-106Min2.2E-048.1E-063.E-012.7E-0555 Ru/Rh-106Typ6.0E-042.2E-053.E-017.4E-055 Pd-103Max3.0E-021.1E-039.E+011.2E-055 Pd-103Min3.0E-021.1E-039.E+011.2E-0555 Pd-103Typ3.0E-021.1E-039.E+011.2E-055
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
PET check sourcesGe-68Max1.0E-023.7E-047.E-015.3E-045 Ge-68Min1.0E-033.7E-057.E-015.3E-0555 Ge-68Typ3.0E-031.1E-047.E-011.6E-045 Mossbauer spectrometry sources
Co-57Max1.0E-013.7E-037.E-015.3E-0355 Co-57Min5.0E-031.9E-047.E-012.6E-0455 Co-57Typ5.0E-021.9E-037.E-012.6E-0355 Tritium targetsH-3Max3.0E+011.1E+002.E+035.6E-045 H-3Min3.0E+001.1E-012.E+035.6E-0555 H-3Typ7.0E+002.6E-012.E+031.3E-045 Medical unsealed sourcesP-32Max6.0E-012.2E-021.E+012.2E-035 P-32Min6.0E-022.2E-031.E+012.2E-045c P-32Typ6.0E-012.2E-021.E+012.2E-035 a Calibration sources are found in all categories except Category 1. They have been assigned to Table 2 in accordance with the radionuclide and activity. The regulatory body may modify the assignment on the basis of specific factors and circumstances. b238 Pu sources are no longer manufactured for use in pacemakers. cUnsealed medical sources typically fall into Categories 4 and 5. The unsealed nature of these sources and their short half-life requires their case by case categorization.
TABLE 2. CATEGORIES FOR SOURCES USED IN SOME COMMON PRACTICES (cont.) IIIIII IV V VI VIIVIIIIX SourceRadionuclide Quantity in use (A) D value (TBq)Ratio of A/DCategory Ci TBqA/D basedRecommended
Appendix II
PLAIN LANGUAGE DESCRIPTIONS OF THE CATEGORIES