Principal gs in 235U decay chain.

Table (1) below lists the 10 most intense gs from the 235U decay chain in natural U (in equilibrium). These are the lines most likely to be observed from 235U external to detectors. Table (2) lists these lines in order of energy.

For U 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)
0.025 186.0 0.003 4414   235U
0.006 25.6 0.029   305.0 231Th
0.006 269.0 0.005 5607   223Ra
0.006 351.0 0.001 6279   211Bi
0.005 236.0 3.4 × 10-4 5757   227Th
0.005 144.0 0.001 4414   235U
0.004 271.0 9.0 × 10-4 6553   219Rn
0.004 27.4 0.015 5030   231Pa
0.004 50.2 0.002 5989   227Th
0.003 256.0 7.6 × 10-4 5757   227Th
 
g a b from
E(b) I(c) (a,c) Ic.e. E(b) E(b)
25.6 0.006 0.029   305.0 231Th
27.4 0.004 0.015 5030   231Pa
50.2 0.004 0.002 5989   227Th
144.0 0.005 0.001 4414   235U
186.0 0.025 0.003 4414   235U
236.0 0.005 3.4 × 10-4 5757   227Th
256.0 0.003 7.6 × 10-4 5757   227Th
269.0 0.006 0.005 5607   223Ra
271.0 0.004 9.0 × 10-4 6553   219Rn
351.0 0.006 0.001 6279   211Bi

(3) by g + conversion electron intensity

g + c.e. a b from
I(c) E(b) E(b) E(b)
0.035 25.6   305.0 231Th
0.034 58.6   58.6 231Th
0.028 186.0 4414   235U
0.027 19.6 4400   235U
0.022 4.4 5865   223Ra
0.019 17.2   288.0 231Th
0.019 27.4 5030   231Pa
0.019 18.9 5011   231Pa
0.018 9.3   34.0 227Ac
0.016 29.9 6009   227Th

 

Total decays, chain in equilibrium: 0.111 g, 0.362 c.e., 0.309 a, 0.177 b. .

Notes:                                                                     

  1. c.e.: conversion electrons
  2. Energies in keV
  3. Intensities per `parent' decay of natural U (i.e. 0.956 238U, 0.044 235U)
  4. Data from compilations and amendments in Nuclear Data Sheets to Vol. 64 (1991)