Specific Activities

Radiation-related consulting and services from Integrated Environmental Management, Inc.

The term "specific activitity" is defined as the amount of radioactivity - or the decay rate - of a particular radionuclide per unit mass of the radionuclide. For example, the specific activity of Ra-226 is 1, meaning that one gram of Ra-226 contains one (1) curie (assumed to be uniformly distributed throughout that mass). It also means that there are 37,000,000,000 Ra-226 atoms disintegrating every second in a gram of Ra-226. In general, the higher a radionuclide's specific activity, the shorter its half-life (decay rate), and the more "radioactive" it is when compared to one with a lower specific activity.

The following is a listing of specific activities, in units of "curies per gram" for a variety of radionuclides. For this listing the elements are shown alphabetically.  The specific activities are written in scientific notation (i.e., 7.2E1 is equal to 7.2 x 10, or 72).

Actinium

• Ac-227 - 7.2E1
• Ac-228 - 2.2E6

Americium

• Am-241 - 3.2E0
• Am-243 - 1.9E-1

Antimony

• Sb-122 - 3.9E5
• Sb-124 - 1.8E4
• Sb-125 - 1.4E3

Argon

• Ar-37 (compressed or uncompressed) - 1.0E5
• Ar-41 (uncompressed) = 4.3E7
• Ar-41 (compressed) - 4.3E7

Arsenic

• As-73 - 2.4E4
• As-74 - 1.0E5
• As-76 - 1.6E6

Astatine

• At-211 - 2.1E6

Barium

• Ba-131 - 8.7E4
• Ba-133 - 4.0E2
• Ba-140 - 7.3E4

Berkelium

• Bk-249 - 1.8E3

Beryllium

• Be-7 - 3.5E5

Bismuth

• Bi-206 - 9.9E4
• Bi-207 - 2.2E2
• Bi-210 - 1.2E5
• Bi-212 - 1.5E7

Bromine

• Br-77 - 7.1E5
• Br-82 - 1.1E6

Cadmium

• Cd-109 - 2.6E3
• Cd-115m - 2.6E4
• Cd-115 - 5.1E5

Calcium

• Ca-45 - 1.9E4
• Ca-47 - 5.9E5

Californium

• Cf-249 - 3.1E0
• Cf-250 - 1.3E2
• Cf-252 - 6.5E2

Carbon

• C-11 - 8.4E8
• C-14 - 4.6E0

Cerium

• Ce-139 - 6.5E3
• Ce-141 - 2.8E4
• Ce-143 - 6.6E5
• Ce-144 - 3.2E3

Cesium

• Cs-129 - 7.6E5
• Cs-131 - 1.0E5
• Cs-134m - 7.4E6
• Cs-134 - 1.2E3
• Cs-135 - 8.8E-4
• Cs-136 - 7.4E4
• Cs-137 - 9.8E1

Chlorine

• Cl-36 - 3.2E-2
• Cl-38 - 1.3E8

Chromium

• Cr-51 - 9.2E4

Cobalt

• Co-56 - 3.0E4
• Co-57 - 8.5E3
• Co-58m - 5.9E6
• Co-58 - 3.1E4
• Co-60 - 1.1E3

Copper

• Cu-64 - 3.8E6
• Cu-67 - 7.9E5

Curium

• Cm-242 - 3.3E3
• Cm-243 - 4.2E0
• Cm-244 - 8.2E0
• Cm-245 - 1.0E-1
• Cm-246 - 3.6E-1

Dysprosium

• Dy-165 - 8.2E6
• Dy-166 - 2.3E5

Erbium

• Er-169 - 8.2E4
• Er-171 - 2.4E6

Europium

• Eu-152m - 2.2E6
• Eu-152 - 1.9E2
• Eu-154 - 1.5E2
• Eu-155 - 1.4E3

Fluorine

• F-18 - 9.3E7

Gadolinium

• Gd-153 - 3.6E3
• Gd-159 - 1.1E6

Gallium

• Ga-67 - 6.0E5
• Ga-68 - 4.0E7
• Ga-72 - 3.1E6

Germanium

• Ge-68 - 7.0E3
• Ge-71 - 1.6E5

Gold

• Au-193 - 9.3E5
• Au-196 - 1.2E5
• Au-198 - 2.5E5
• Au-199 - 2.1E5

Hafnium

• Hf-181 - 1.6E4

Holmium

• Ho-166 - 6.9E5

Hydrogen

• H-3 (uncompressed) - 9.7E3
• H-3 (compressed) - 9.7E3
• H-3 (activated luminous paint) - 9.7E3
• H-3 (adsorbed on solid carrier) - 9.7E3
• H-3 (tritiated water) - 9.7E3
• H-3 (other forms) - 9.7E3

Iodine

• I-123 - 1.9E6
• I-125 - 1.7E4
• I-126 - 7.8E4
• I-129 - 1.6E-4
• I-131 - 1.2E5
• I-132 - 1.1E7
• I-133 - 1.1E6
• I-134 - 2.7E7
• I-135 - 3.5E6

Indium

• In-111 - 4.2E5
• In-113m - 1.6E7
• In-114m - 2.3E4
• In-115m - 6.1E6

Iridium

• Ir-190 - 6.2E4
• Ir-192 - 9.1E3
• Ir-194 - 8.5E5

Iron

• Fe-52 - 7.3E6
• Fe-55 - 2.2E3
• Fe-59 - 4.9E4

Krypton

• Kr-85m(uncompressed) - 8.4E6
• Kr-85m (compressed) - 8.4E6
• Kr-85(uncompressed) - 4.0E2
• Kr-85(compressed) - 4.0E2
• Kr-87(uncompressed) - 2.8E7
• Kr-87(compressed) - 2.8E7

Lanthanum

• La-140 - 5.6E5

Lead

• Pb-201 - 1.7E6
• Pb-210 - 8.8E1
• Pb-212 - 1.4E6

Lutetium

• Lu-177 - 1.1E5

Magnesium

• Mg-28 - 5.2E6

Manganese

• Mn-52 - 4.4E5
• Mn-54 - 8.3E3
• Mn-56 - 2.2E7

Mercury

• Hg-197m - 6.6E5
• Hg-197 - 2.5E5
• Hg-203 - 1.4E4

Molybdenum

• Mo-99 - 4.7E5

Neodymium

• Nd-147 - 8.0E4
• Nd-149 - 1.1E7

Neptunium

• Np-237 - 6.9E-4
• Np-239 - 2.3E5

Nickel

• Ni-59 - 8.1E-2
• Ni-63 - 4.6E1
• Ni-65 - 1.9E7

Niobium

• Nb-93m - 1.1E3
• Nb-95 - 3.9E4
• Nb-97 - 2.6E7

Nitrogen

• N-13 - 1.5E9

Osmium

• Os-185 - 7.3E3
• Os-191 - 4.6E4
• Os-191m - 1.2E6
• Os-193 - 5.3E5

Palladium

• Pd-103 - 7.5E4
• Pd-109 - 2.1E6

Phosphorus

• P-32 - 2.9E5

Platinum

• Pt-191 - 2.3E5
• Pt-193m - 2.0E5
• Pt-197m - 1.2E7
• Pt-197 - 8.8E5

Potassium

• K-40 - 7.04E-6
• K-40 - 8.54E-10 per gram of natural K

Plutonium

• Pu-238 - 1.7E1
• Pu-239 - 6.2E-2
• Pu-240 - 2.3E-1
• Pu-241 - 1.1E2
• Pu-242 - 3.9E-3

Polonium

• Po-210 - 4.5E3

Potassium

• K-42 - 6.0E6
• K-43 - 3.3E6

Praseodymium

• Pr-142 - 1.2E4
• Pr-143 - 6.6E4

Promethium

• Pm-147 - 9.4E2
• Pm-149 - 4.2E5

Protactinium

• Pa-230 - 3.2E4
• Pa-231 - 4.5E-2
• Pa-233 - 2.1E4

Radium

• Ra-223 - 5.0E4
• Ra-224 - 1.6E5
• Ra-226 - 1.0E0
• Ra-228 - 2.3E2

Radon

• Rn-222 - 1.5E5

Rhenium

• Re-186 - 1.9E5
• Re-187 - 3.8E-8
• Re-188 - 1.0E6
• Re (natural) - 2.4E-8

Rhodium

• Rh-103m - 3.2E7
• Rh-105 - 8.2E5

Rubidium

• Rb-81 - 8.2E6
• Rb-86 - 8.1E4
• Rb-87 - 6.6E-8
• Rb (natural) - 1.8E-8

Ruthenium

• Ru-97 - 5.5E5
• Ru-103 - 3.2E4
• Ru-105 - 6.6E6
• Ru-106 - 3.4E3

Samarium

• Sm-147 - 2.0E-8
• Sm-151 - 2.6E1
• Sm-153 - 4.4E5

Scandium

• Sc-46 - 3.4E4
• Sc-47 - 8.2E5
• Sc-48 - 1.5E6

Selenium

• Se-75 - 1.4E4

Silicon

• Si-31 - 3.9E7

Silver

• Ag-105 - 3.1E4
• Ag-110m - 4.7E3
• Ag-111 - 1.6E5

Sodium

• Na-22 - 6.3E3
• Na-24 - 8.7E6

Strontium

• Sr-85m - 3.2E7
• Sr-85 - 2.4E4
• Sr-87m - 1.2E7
• Sr-89 - 2.9E4
• Sr-90 - 1.5E2
• Sr-91 - 3.6E6
• Sr-92 - 1.3E7

Sulphur

• S-35 - 4.3E4

Tantalum

• Ta-182 - 6.2E3

Technetium

• Tc-96m - 3.8E7
• Tc-96 - 3.2E5
• Tc-97m - 1.5E4
• Tc-97 - 1.4E-3
• Tc-99m - 5.2E6
• Tc-99 - 1.7E-2

Tellurium

• Te-125m - 1.8E4
• Te-127m - 4.0E4
• Te-127 - 2.6E6
• Te-129m - 2.5E4
• Te-129 - 2.0E7
• Te-131m - 8.0E5
• Te-132 - 3.1E5

Terbium

• Tb-160 - 1.1E4

Thallium

• Tl-200 - 5.8E5
• Tl-201 - 2.2E5
• Tl-202 - 5.4E4
• Tl-204 - 4.3E2

Thorium

• Th-227 - 3.2E4
• Th-228 - 8.3E2
• Th-230 - 1.9E-2
• Th-231 - 5.3E5
• Th-232 - 1.1E-7
• Th-234 - 2.3E4
• Th (natural) - 2.2E-7

Thulium

• Tm-270 - 6.0E3
• Tm-171 - 1.1E3

Tin

• Sn-113 - 1.0E4
• Sn-119m - 4.4E3
• Sn-125 - 1.1E5

Tungsten

• W-181 - 5.0E3
• W-185 - 9.7E-3
• W-187 - 7.0E5

Uranium

• U-230 - 2.7E4
• U-232 - 2.1E1
• U-233 - 9.5E-3
• U-234 - 6.2E-3
• U-235 - 2.1E-6
• U-236 - 6.3E-5
• U-238 - 3.3E-7
• U (natural) - 7.1E-7 (0.72% U-235 present, by weight)
• U (depleted) - 5.0E-7 - (0.45% U-235 present, by weight)
• U (enriched) - 7.6E-7 (1% U-235 present, by weight)
• U (enriched) - 1.0E-6 (1.5% U-235 present, by weight)
• U (enriched) - 2.7E-6 (5% U-235 present, by weight)
• U (enriched) - 4.8E-6 (10% U-235 present, by weight)
• U (enriched) - 1.0E-5 (20% U-235 present, by weight)
• U (enriched) - 2.0E-5 (35% U-235 present, by weight)
• U (enriched) - 2.5E-5 (50% U-235 present, by weight)
• U (enriched) - 5.8E-5 (90% U-235 present, by weight)
• U (enriched) - 7.0E-5 (93% U-235 present, by weight)
• U (enriched) - 9.1E-5 (95% U-235 present, by weight)

Vanadium

• V-48 - 1.7E5

Xenon

• Xe-127 (uncompressed) - 2.8E4
• Xe-127 (compressed) - 2.8E4
• Xe-131m (compressed) - 1.0E5
• Xe-131m (uncompressed) - 1.0E5
• Xe-133 (uncompressed) - 1.9E5
• Xe-133 (compressed) - 1.9E5
• Xe-135 (uncompressed) - 2.5E5
• Xe-135 (compressed) - 2.5E5

Ytterbium

• Yb-169 - 2.3E5
• Yb-175 - 1.8E5

Yttrium

• Y-87 - 4.5E1
• Y-90 - 2.5E5
• Y-91m - 4.1E7
• Y-91 - 2.5E4
• Y-92 - 9.5E6
• Y-93 - 3.2E6

Zinc

• Zn-65 - 8.0E3
• Zn-69m - 3.3E6
• Zn-69 - 5.3E7

Zirconium

• Zr-93 - 3.5E-3
• Zr-95 - 2.1E4
• Zr-97 - 2.0E6

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