Response of a High-Resolution High-Energy Photon Spectrometer (HHS) to Monochromatic High-Energy Gamma Rays

The response function of a high-resolution high-energy photon spectrometer (HHS), consisting of a twin Ge detector and BGO (Bi 3 Ge 4 O 12 ) anti-coincidence shields, has been measured for 10.763 MeV monochromatic γ-rays generated in a resonant reaction 27 Al(p,γ) 28 Si. The experimental response functions measured with and without the anti-coincidence were compared with results by Monte Carlo simulations, in which a pulse-height degradation effect associated with a surface channel of the twin Ge detector has been included. Excellent agreement was obtained between the experimental response functions and the simulations.