MEASUREMENT OF ELECTRON-PHONON DECOUPLING IN NTD31 GERMANIUM

We have measured the electron-phonon decoupling in Neutron Trasmutation Doped (NTD) Germanium thermistors down to 20 mK. We find that, in our sample (NTD 31), the thermal decoupling can be well described by the hot-electron model. Thanks to the particular experimental configuration, both electron-phonon decoupling parameters and contact parameters (Kapitza resistence) are obtained from the fit of data. Our results are consistent with those obtained for other doping concentrations of NTD Ge^1,2,3. Thermistors made of NTD 31 Ge will be used as sensors in the CUORICINO⁴ experiment, a forerunner and test of the larger CUORE (Cryogenic Underground Obsevatory for Rare Events) experiment. The knowledge of the electron-phonon decoupling parameters, together with the measure of pulse rise-time detected in a bolometer, allows the electronic thermal heat capacity of the sensor to be evaluated.