# Average decay energies

$\bar{E_x}$ Average decay energy (eV) of radiation x (neutrinos excluded), e.g., for decay heat applications.

The average decay energy $\bar{E_x}$ for decay heat application is given for three general radiation types, $\bar{E}_{LP}$ (for light particles), $\bar{E}_{EM}$ (for electromagnetic radiation), and $\bar{E}_{HP}$ (for heavy particles), followed by the individual components. The sum of these three general quantities is the total average (neutrino energies excluded) energy available per decay to the decay heat problem. The three quantities are more precisely defined as:

$\bar{E}_{LP}$ = $\bar{E}_{beta-}$ + $\bar{E}_{beta+}$ + $\bar{E}_{e-}$ + ... (average energy of all light particles)

$\bar{E}_{EM}$ = $\bar{E}_{gamma}$ + $\bar{E}_{x-ray}$ + $\bar{E}_{annih.rad.}$ + ... (average energy of all electromagnetic radiation)

$\bar{E}_{HP}$ = $\bar{E}_{alph}$ + $\bar{E}_{SF}$ + $\bar{E}_{proton}$ + $\bar{E}_{neutron}$ + ... (average energy of all heavy particles)

where $\bar{E}_{LP}$ means the average energy of all ”electron-related” radiation such as β−, β+ conversion-electrons, Auger, etc. The quantity $\bar{E}_{EM}$ means the average energy of all ”electromagnetic” radiations such as gamma-rays, x-rays, and annihilation radiation. The quantity $\bar{E}_{HP}$ is the average energy of all heavy charged particles and neutrons, and also includes the recoil energy; but the alpha energy alone can be separated out by the usual MR/(MR + Mα) factor, where MR and Mα are the recoil nucleus and alpha masses, respectively.

References

ENDF-6 Formats Manual, p166