Nonequilibrium phonon detectors in an 'adiabatic' operating mode
Abstract
The paper describes the experimental use of nonequilibrium phonon detectors and the physics related to the operation of the type of detector. Phonons are generated by using 5.5 MeV alpha-particles from an Am-241 sources, and they are detected by three superconducting Al/Al2O3/Al tunnel junctions evaporated onto the surface of the crystal. Scattered and reflected phonons dominate the signals which cannot be explained simply by ballistic propagation nor pure quasi-diffusive propagation. The point of absorption is located to within 0.6 mm, and the absorption threshold is estimated at 250 keV. To force phonons to exit the crystal through the detecting junctions, the operating temperature is reduced and a thermal coupling is used. Alpha-absorption is demonstrated with good detector sensitivity at 60 mK in spite of high conducting-junction resistance, showing that the detection of energy depositions near 1 keV is possible.
- Publication:
-
Low temperature Detectors for Neutrinos and Dark Matter III
- Pub Date:
- 1990
- Bibcode:
- 1990ltdn.work..145P
- Keywords:
-
- Nonequilibrium Radiation;
- Phonons;
- Radiation Detectors;
- Single Crystals;
- Superconductors;
- Alpha Particles;
- Silicon;
- Tunnel Diodes;
- Instrumentation and Photography