NUV and VUV sensitive Silicon Photomultipliers technologies optimized for operation at cryogenic temperatures

The silicon photomultipliers (SiPMs) emerged as a promising solution in many applications, like high-energy physics experiments and recently, they are the detector of choice for the readout of liquid noble gases scintillators (e.g. liquid Xenon and liquid Argon) in large-area physics experiments. Here the SiPMs are operated at cryogenic temperatures. Important studies have been done to optimize SiPM performance for such conditions and we developed the NUV-HD-cryo and the VUV-HD-cryo technologies, with sensitivity optimized for the blue-wavelength and NUV range, or for the VUV range respectively. Important technological improvements have been demonstrated: (i) reduction of electric field, to lower band-to-band tunneling, (ii) doping profiles modifications to reduce afterpulsing at low temperatures and (iii) reduction of quenching resistor variation over temperature. In this work we show and compare the recent characterization results of primary noise, correlated noise and the dependences of the photon detection efficiency (PDE) and photon-number resolution of these SiPMs over temperature, between 300 K and 75 K. Primary dark count rate reduces to few counts per second already at 200 K, and of 7 orders of magnitude going towards liquid nitrogen temperature and the afterpulsing increment is mitigated. The PDE in the blue-wavelength region remain high in the investigated temperature range (%), while it changes at longer wavelengths and a good photon number resolution is preserved.