Neutron damage tests of a GRETINA prototype detector

Gamma ray energy tracking arrays such as GRETINA/GRETA and AGATA are the latest evolution in gamma ray detection. By locating the interaction points, in 3-dimensions, of individual gamma ray interactions such arrays allow the energies of gamma rays to be reconstructed. This leads to excellent energy resolution, superior peak-to-total ratio and photo peak efficiency and resolving powers up to a thousand times superior to the best current generation array. The position information is extracted from the detailed pulse shapes recorded in each segment. It is anticipated that these tracking-detectors will experience significant neutron fluxes during in beam experiments. Thus it is important to test the response of highly-segmented Ge detectors when subjected to high-energy neutrons. In a one week test carried out at the 88-Inch Cyclotron at LBNL the P3 prototype detector for the GRETINA array was exposed to a neutron flux equivalent to at least one and a half years normal use. The detector was then successfully annealed. Preliminary results for the energy and position resolution, prior to and after neutron damage, and after annealing, will be presented.