Future searches for rare astrophysical signals and detector commissioning in SNO+

• Main Author: Jones, Christopher R.
• Other Authors: Biller, Steve
• Published: University of Oxford 2016
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.729977

SNO+ is a 780 kTonne liquid scintillator experiment, situated 2km underground in the Creighton mine near Sudbury, Ontario and primarily designed to study neutrinoless double beta decay, but also has several other physics goals such as solar neutrinos, reactor and geo-neutrinos and supernova neutrinos. SNO+ may also be sensitive to rare astrophysics signals, such as Axion-Like Particles (ALPs) originating from the Sun. This thesis predicts a limit on the ALP-electron coupling, |g_Ae x g_3AN| < 1.1 x 10^-11 via the axio-electric effect and a limit on the ALP-photon coupling of |g_Aγ x g_3AN| < 3.0 x 10^-11 GeV^-1 via the inverse Primakoff interaction, which could be achieved with 5 years of Te-loaded scintillator phase of SNO+. Both of these upper limits are an order of magnitude improvement on the current published limits on ALP couplings. SNO+ should also be sensitive to another rare astrophysics signal: a burst of neutrinos from a supernova, originating from our Galaxy, via proton elastic scattering (PES) and inverse beta decay (IBD) interactions within the scintillator. The ratio of PES/IBD interactions, due to supernova neutrinos, is determined by the v_x/v_e flux ratio. This ratio could indicate a preference for the inverted neutrino mass hierarchy, due to a proposed dramatic 'spectral swapping' between v_x and v_e flux distributions caused by neutrino-neutrino interactions from the corecollapse of a supernova. The initial commissioning of the data acquisition (DAQ) and scattering calibration (SMELLIE) systems, during SNO+ data commissioning runs taken in December 2014, is also evaluated in this thesis.