High Impedance TES Bolometers for EDELWEISS

The EDELWEISS collaboration aims for direct detection of light dark matter using germanium cryogenic detectors with low threshold phonon sensor technologies and efficient charge readout designs. We describe here the development of Ge bolometers equipped with high impedance thermistors based on a NbxSi1-x TES alloy. High aspect ratio spiral designs allow the TES impedance to match with JFET or HEMT front-end amplifiers. We detail the behavior of the superconducting transition properties of these sensors and the detector optimization in terms of sensitivity to a-thermal phonons. We report preliminary results of a 200 g Ge detector that was calibrated using Ge-71 activation by neutrons at the LSM underground laboratory.

Automated summary

The EDELWEISS collaboration is working on directly detecting light dark matter using germanium cryogenic detectors. They have developed Ge bolometers with high impedance thermistors based on a NbxSi1-x TES alloy, allowing the TES impedance to match with JFET or HEMT front-end amplifiers. The behavior of the superconducting transition properties of these sensors and the detector optimization in terms of sensitivity to a-thermal phonons are discussed, along with the preliminary results of a 200 g Ge detector calibrated using Ge-71 activation.