PROMPT PHONON SIGNALS FROM PARTICLE INTERACTIONS IN SI CRYSTALS

We discuss the prompt (ballistic and quasidiffuse) phonon physics asso ciated with elementary particle interactions within silicon crystals a t temperatures below 1 K, and the differences in the ballistic and qua sidiffuse phonon production from primary electron recoils versus prima ry nuclear recoils within these crystals. We then summarize the result s from a growing body of direct experimental evidence on prompt phonon signals from particle detectors bombarded with alphas, x-rays, and ne utrons.