Semi-classical treatment of photon cascades in nuclei

A simple semi-classical treatment of photon cascades in nuclei has been developed. The basic assumption is that a nucleus with a classical spin vector J can be represented by the maximally aligned quantum state J , M = J with the quantization axis being the spin direction J / J . It is furthermore assumed that a photon emission yields a daughter state of a similar form, J ′, M ′ = J ′ , but with its alignment direction having been modified as a consequence of the angular momentum recoil. The overall good quality of the treatment is illustrated for a variety of E 1 and E 2 two-photon cascades having non-trivial angular correlations. The method is suitable for use in nuclear fission simulation codes, making it possible to address photon-photon correlation observables quantitatively.