The Experimental Challenge
Measuring tiny amounts of light at cryogenic temperatures is very complicated and sets stringent requirements on the features of the desired light detector:
- baseline resolution better than 20 eV;
- large active surface (5x5cm2) for an efficient coupling with commonly used cryogenic detectors;
- operation with high performance in a rather wide temperature range (5-15 mK) without need for fine-tuning;
- ease in fabrication and reproducibility;
- ease in operating hundreds of channels with low heat-load for the cryogenic system;
None of the current technologies for light detection fulfills all these requirements. The CALDER collaboration proposes to realize a new light detector by exploiting devices which have already been succesfully used in astrophysics: Kinetic Inductance Detectors (KIDs).