Use this URL to cite or link to this record in EThOS:
Title: Study of invisible mode nucleon decay in the SNO+ detector
Author: Walker, John M. G.
ISNI:       0000 0004 6422 2171
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2016
Availability of Full Text:
Access from EThOS:
Access from Institution:
SNO+ is a large volume liquid scintillator experiment and is a refurbishment of the SNO detector. 780 tonnes of ultra-pure scintillator will be housed inside a 12 m diameter, 5.5 cm thick, acrylic vessel and observed by ~ 9300 photomultiplier tubes. The primary purpose of the experiment is to search for neutrinoless double-beta decay (Oνββ) of ¹³⁰Te, although it has a broad physics program. Prior to deployment of liquid scintillator the detector will be filled with light water to perform calibrations as well as to enable water phase physics analyses. One such analysis will be to search for 'invisible' mode nucleon decay, in which very little or no energy is deposited in the detector by decay products. This thesis predicts that with three months of data taking SNO+ will set a new limit of T > 1.5 x 10³⁰ years for the lifetime of the proton, and T > 1.3 x 10³⁰ years for the neutron, to decay via an invisible mode. To facilitate this analysis, the development of an energy estimator for the water phase is outlined which uses a detector energy response function. An obstacle for SNO+, both during the water and scintillator phases, will be the large instrumental background (non-radiative events caused by the detector) expected. The expected backgrounds are described, as well as cuts developed for their removal by SNO. The loss of signal events due to these cuts is estimated for the water and scintillator phases of the experiment. The residual background is estimated by developing an instrumental background generator.
Supervisor: McCauley, N. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral