Principal gs in Th decay chain.

Table (1) below lists the 20 most intense gs from the Th decay chain (in equilibrium). These are the lines most likely to be observed from Th external to detectors. Table (2) lists these lines in order of energy.

For Th within detectors, effective intensities must include any conversion electrons - Table (3) - and observed energies will be modified by the coincident a or b decays.

(1) by g intensity

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(2) by g energy
 
g a b from
I(c) E(b) (a,c) Ic.e. E(b) E(b)
0.436 239.0 0.396   334.0 212Pb
0.356 2615 0.003   2379 208Tl
0.304 583.0 0.006   1796 208Tl
0.266 911.0 0.003   1173 228Ac
0.162 969.0 0.002   1173 228Ac
0.113 338.0 0.003   1746 228Ac
0.081 511.0 0.009   1286 208Tl
0.067 727.0 9.4 × 10-4   1519 212Bi
0.051 965.0 5.6 × 10-4   1119 228Ac
0.045 861.0 0.001   1519 208Tl
0.044 463.0 0.002   710.0 228Ac
0.043 795.0 8.7 × 10-4   1019 228Ac
0.040 241.0 0.011 5449   224Ra
0.039 209.0 0.003   1746 228Ac
0.034 270.0 0.002   1814 228Ac
0.033 300.0 0.016   157.0 212Pb
0.033 1588 3.3 × 10-5   496.0 228Ac
0.030 328.0 9.0 × 10-4   1814 228Ac
0.025 129.0 0.093   1955 228Ac
0.023 277.0 0.013   1519 208Tl
 
g a b from
E(b) I(c) (a,c) Ic.e. E(b) E(b)
129.0 0.025 0.093   1955 228Ac
209.0 0.039 0.003   1746 228Ac
239.0 0.436 0.396   334.0 212Pb
241.0 0.040 0.011 5449   224Ra
270.0 0.034 0.002   1814 228Ac
277.0 0.023 0.013   1519 208Tl
300.0 0.033 0.016   157.0 212Pb
328.0 0.030 9.0 × 10-4   1814 228Ac
338.0 0.113 0.003   1746 228Ac
463.0 0.044 0.002   710.0 228Ac
511.0 0.081 0.009   1286 208Tl
583.0 0.304 0.006   1796 208Tl
727.0 0.067 9.4 × 10-4   1519 212Bi
795.0 0.043 8.7 × 10-4   1019 228Ac
861.0 0.045 0.001   1519 208Tl
911.0 0.266 0.003   1173 228Ac
965.0 0.051 5.6 × 10-4   1119 228Ac
969.0 0.162 0.002   1173 228Ac
1588 0.033 3.3 × 10-5   496.0 228Ac
2615 0.356 0.003   2379 208Tl

(3) by g + conversion electron intensity

 

g + c.e. a b from
I(c) E(b) E(b) E(b)
0.832 239.0   334.0 212Pb
0.765 57.8   2084 228Ac
0.500 6.7   39.0 228Ra
0.358 2615   2379 208Tl
0.310 583.0   1796 208Tl
0.286 84.4 5340   228Th
0.279 39.9 6051   212Bi
0.269 911.0   1173 228Ac
0.229 59.0 3954   232Th
0.164 969.0   1173 228Ac
0.118 129.0   1955 228Ac
0.116 338.0   1746 228Ac
0.113 13.5   14.5 228Ra
0.100 1.000   39.0 228Ra
0.090 511.0   1286 208Tl
0.080 30.6   14.5 228Ra
0.072 16.1   14.5 228Ra
0.067 727.0   1519 212Bi
0.066 99.5   611.0 228Ac
0.052 965.0   1119 228Ac

Total decays, chain in equilibrium: 2.651 g, 3.194 c.e., 6 a, 4 b.

Notes:                                                                     

  1. c.e.: conversion electrons
  2. Energies in keV
  3. Intensities per `parent' Th decay
  4. Data from compilations and amendments in Nuclear Data Sheets to Vol. 64 (1991)