Speaker
Description
Fondazione Bruno Kessler (FBK) has continuously developed and improved silicon photomultiplier technologies: in particular, one with peak efficiency in the blue region of the spectrum (near-ultra-violet, NUV), another one in the green (red-green-blue, RGB).
Over the last years there has been a growing interest in silicon photomultipliers applications at cryogenic temperatures (e.g.: for the detection of scintillation light from liquefied noble gases in rare-events experiments). One example is the DarkSide experiment, in which the 178nm scintillation light from LAr (87K), down-shifted to 430nm through TPB, is detected by silicon photomultipliers.
For this reason, a dedicated silicon photomultiplier technology has been designed and fabricated in FBK: the NUV-HD-Cryo. SiPMs made in such technology reach primary dark count rates of about 10 mHz/mm2 below 100K and an after-pulsing probability of about 15% when biased at 6V above breakdown.
In other experiments (e.g. in the nEXO experiment), direct detection of vacuum ultra-violet (VUV) light in cryogenic conditions is required. In this case, the sensitivity in VUV has to be combined with the advantages of the Cryo technology.
In this contribution, the latest results from the cryogenic characterization of FBK’s VUV-HD-Cryo technology will be presented. Among the produced devices, one promising split has been identified. In such split, the after-pulsing probability in liquid nitrogen amounts to 10% at 4V above breakdown, more than 6 times lower than a standard VUV-HD device at the same excess bias.
