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 (Bi3Ge4O12) anti-coincidence shields, has been measured for 10.763 MeV monochromatic γ-rays generated in a resonant reaction 27Al(p,γ)28Si. 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.