Prompt rays emitted from the neutron capture reaction of Ge

Hara, Kaoru; Kin, Tadahiro; Oshima, Masumi; Nakamura, Shoji  ; Kimura, Atsushi   ; Koizumi, Mitsuo ; Toh, Yosuke   

We studied a decay scheme in the Ge(,)Ge reaction. It is essential information for accurate determination of the neutron capture cross section of Ge with the prompt -ray detection method, when the cross section is derived by summing all the intensities of ground-state or primary transitions. However, the decay from/to Ge-state above 2 MeV is unknown, where the neutron separation energy is 6.5 MeV. The - coincidence experiments were performed at the cold neutron beam line of the Japan Research Reactor of JAEA. The multiple prompt -rays emitted from the Ge(,)Ge reaction were measured by using a -ray spectrometer (STELLA) which consists of eight clover-type Ge detectors and BGO Compton-suppressors. Many unknown -ray transitions, in addition to the known one, were seen in the energy spectrum. The new levels and the new transition -rays in Ge are reported.