Characterising the Optical Response of the SNO+ Detector



Stainforth, R
(2016) Characterising the Optical Response of the SNO+ Detector. PhD thesis, University of Liverpool.

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Abstract

SNO+ is a liquid scintillator based neutrino experiment located 2039 m underground in VALE's Creighton mine, Lively, Ontario, CA. It is a re-purposing of the original Cherenkov detector used in the SNO experiment to study neutrino oscillations. The advent of neutrino oscillations has revealed that neutrinos have a small yet non-zero mass. However, the nature of this mass has yet to be determined. It is possible that the neutrino is its own anti-particle, a Majorana fermion. If so, such particles necessitate lepton number violating processes such as neutrinoless double beta decay. SNO+ intends to search for the neutrinoless double beta decay of Te-130. Other physics objectives include the study of low-energy solar neutrinos, reactor anti-neutrinos, geo-neutrinos and sensitivity to nucleon decay and supernova neutrinos. To fulfil these objectives, SNO+ will operate over three detector phases; water, scintillator and tellurium (loading of the scintillator with tellurium). Prior to each phase, the experiment will undergo a full detector calibration. This includes an optical calibration that seeks to characterise the optical response of the detector using two types of in-situ light sources; one of these is called the laserball. The laserball provides a pulsed, near-isotropic light distribution throughout the detector. Laserball data is used in conjunction with a parameterised model that characterises the optical response; the parameters are determined using a statistical fit. This thesis presents an implementation of said model to all three phases of the SNO+ experiment. A characterisation of the optical response in water is presented using a combination of original laserball data from SNO and MC data of the SNO+ detector. Thereafter, the two scintillator based phases are considered, wherein the increased attenuation of light due to absorption and reemission introduced by the scintillator is addressed alongside a model of the scintillation time profile.

Item Type: Thesis (PhD)
Uncontrolled Keywords: Physics, Particle Physics, Scintillator, Optical Calibration, Optical, Calibration, SNO, SNO+, Sudbury Neutrino Observatory, Neutrino, Neutrino Oscillations, Neutrinoless Double Beta Decay, Majorana, Attenuation
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 15 Dec 2016 15:06
Last Modified: 19 Jan 2023 07:34
DOI: 10.17638/03002005
Supervisors:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3002005