Speaker
Description
As modern physics experiments begin to require lower and lower backgrounds to reach their sensitivity goals, be it dark matter searches or experiments seeking to probe the nature of neutrinos, new technology is needed in order to reach these stringent requirements. In the realm of light detection devices, silicon photomultipliers (SiPMs) offer an upper-hand in terms of radiopurity when compared to photomultipler tubes, which would otherwise be used. The nEXO experiment, specifcally, intends to line a monolithic time-projection chamber containing 5 tonnes of xenon enriched in the isotope Xe-136 with thousands of SiPMs to detect the scintillation light from said isotope in the search for neutrinoless double-beta decay. For this, a large-scale testing infrastructure is under development at McGill to allow for mass-testing of SiPM staves, which consist of twenty square-meter-large panels grouping together approximately two thousand SiPMs before their eventual installation in the nEXO detector. The setup consists of an aluminum chamber with approximately half a cubic meter in volume under high vacuum, capable of reaching pressures down to 1 × $10^{−7}$ mbar. Inside the chamber, an XY gantry and linear rail system is used to guide a laser whose optical characteristics mimic those of xenon scintillation light onto the SiPMs, allowing for automated testing of all SiPMs on a stave within a vacuum cycle. A cryocooler is used to cool the SiPMs to 165 K, the temperature at which xenon remains liquid when at pressures expected for nEXO. This talk would outline the mechanical and electrical engineering challenges involved with instrumenting this detector with the proper sensors and peripherals to enable its use for the outlined research goals.
| Keyword-1 | Silicon Photomultiplier |
|---|---|
| Keyword-2 | Cryogenics |
| Keyword-3 | Vacuum Chamber |