Speaker
Description
nEXO is a proposed tonne-scale experiment which aims to search for neutrinoless double beta ($0\nu\beta\beta$) decay in the isotope $^{136}$Xe. The observation of $0\nu\beta\beta$ decay would demonstrate lepton number violation in weak processes and the Majorana nature of neutrinos. This would be an explicit signature of physics beyond the Standard Model and also may provide insight into the observed matter-antimatter asymmetry in the Universe. nEXO is being designed to investigate this rare decay with a projected half-life sensitivity that is greater than $10^{28}$ years at the 90% confidence level.
In order to reduce the impact of cosmogenic backgrounds, the experiment is anticipated to be located at SNOLAB, an underground laboratory located two kilometres below the surface. The xenon-filled Inner Detector is designed to be located at the centre of a water tank to shield against radioactive backgrounds and to tag passing cosmogenic muons. This 12.3 m in diameter and 12.8 m in height tank, which is filled with 1.5 kilotonnes of ultra-pure deionized water and instrumented with an array of 8-inch photomultiplier tubes (PMTs), constitutes the Outer Detector. The PMTs will be used to veto potential background events in the Inner Detector that may be introduced by spallation neutrons from passing cosmic muons and other secondary particles.
A calibration system is being developed for nEXO's Outer Detector. The aim of this system is to calibrate the timing properties of the PMT's readout system and monitor the optical properties of the water. I will discuss the design implemented for calibrating the Outer Detector by analyzing the result of a GPU-accelerated ray-tracing software (Chroma) as well as considering the different strategies currently used by other similar experiments.
| Keyword-1 | Neutrinoless Double Beta Decay |
|---|---|
| Keyword-2 | Calibration System |
| Keyword-3 | Muon Veto |
