Gamma transitions, recoil energy

When nuclear decay is a pure )S-emission or by p with low energy, unconverted gamma-transition recoil energy is unimportant, and electronic... 

The recoil effect mentioned above is due to the impact of the gamma-photon on the sample nucleus. The nucleus thereby takes some of the photon energy so that insufficient remains to match the required transition energy. It is therefore necessary to bind the nucleus (and its atom) into a solid matrix. Under these circumstances, the recoil energy can be... 

Each radionuclide among the more than one thousand that are known has a unique decay scheme by which it is identified. For this reason, among others, researchers have studied decay schemes over the years and their reported information has been compiled and periodically updated. The compiler surveys the reported information for each radionuclide and attempts to select the most reliable information for constructing a self-consistent decay scheme. The fraction of beta particles that feed an excited state must match the fraction of gamma rays plus conversion electrons emitted by the excited state. The energy difference between any two states must be consistent with the energies of the transition radiations plus the recoil energy of the atom that emitted the radiations. 

Fundamentals. The energy of a gamma quantum emitted or absorbed by an atomic nucleus usually differs somewhat fi om the actual energy difference between the nuclear states because of recoil and Doppler-broadening induced by thermal movement. At room temperature, the value differs by about 10 to 10 eV from the true energy value vo of the nuclear transition. The recoil energy r and the corresponding momentum p are... 

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