PARTICLE-DETECTION AND NONEQUILIBRIUM PHONONS - EXPERIENCE WITH LARGEGERMANIUM-CRYSTALS AND NTD GE THERMISTORS

We have studied particle detectors consisting of neutron transmutation doped (NTD) Ge phonon sensors attached with a eutectic bonding proces s to large mass germanium crystals. These thermistors remain one of th e most performant temperature sensors at temperatures as low as 20 mK. We summarize the experimental evidence for the significant role of no n-equilibrium phonons in their observed behavior. However, the difficu lties of forming a high transparency interface and the lack of inelast ic channels appear to limit their effectiveness as non-equilibrium pho non sensors.