nEXO is a future 5-tonne scale Liquid Xenon experiment looking for neutrino-less double beta decay of isotope Xe-136. To attain the projected half-life sensitivity of ~10^28 years, at least 1% of energy resolution is required at the Q-value (Qββ = 2.458 MeV) of the decay.
nEXO has planned to employ Silicon Photomultipliers (SiPMs) along the barrel of the cylindrical Time Projection Chamber with the electrons drifting towards anodes located on the cylinder top endcap. The energy resolution is driven in large part by the light detection capability, with a minimum of 3% of scintillation photons having to be detected.
Newly developed vacuum ultra-violet (VUV) SiPMs will be used for detecting scintillation photons with wavelength in the ultraviolet regime (165-195 nm). For achieving the target energy resolution, the SiPMs must have high photon detection efficiency (>15%) accompanied by low correlated avalanche noise and low dark noise rates. The primary goal of this research project is to characterize the VUV-SiPMs and measure their various features like gain, crosstalk, afterpulsing, dark noise rate, reflectivity and photon detection efficiency. Along with all these measurements, a well-established monitoring tool will be required to test the large number of SiPMs before installation in the detector. IV (current-voltage) curve characterisation is being explored as a rapid testing tool for the performances of SiPM. In this talk, the results from characterisation of nEXO SiPMs and IV curve based SiPM monitoring method will be presented.
|Reference to paper (DOI or arXiv)