OBSERVATION OF NUCLEAR RECOIL EVENTS FROM NEUTRON-SCATTERING IN LOW-TEMPERATURE CALORIMETRIC DETECTORS

Energy spectra are obtained for low temperature calorimetric detectors exposed to a neutron source to produce nuclear recoil events simulating those which would occur in a "dark matter" detector. The targets used were a 4 g Si crystal and a 32 g LiF crystal, fitted with Ge temperature sensors to observe the particle scattering events as thermal pulses at a temperature approximately 50 mK. Monte Carlo calculations were used to predict the spectra expected from both the neutrons and photons emitted by the Am/Be neutron source. Comparison with observed spectra shows that the nuclear recoil events are being registered by the detectors with the correct rate and energy spectrum.