Ph.d. degree
University of Sussex, UK, 2105

J. R. Sinclair

Supervisor: Simon Peeters

Positioning and Timing Calibration of SNO+

Keywords:

• Neutrino
• Calibration
• SNO+
• Double-Beta

Abstract:

The Sudbury Neutrino Observatory solved the solar neutrino problem, confirming neutrinos have non-zero masses. Massive neutrinos raise questions about the nature of neutrinos, implying physics beyond the standard model and potentially a solution to the observed matter-antimatter asymmetry in the universe. The Sudbury Neutrino Observatory is being upgraded, with the goal of probing the nature of neutrino masses. The experiment will also study reactor, geo, supernovae and solar neutrinos. The upgrade is characterised by changing the target mass from heavy water to scintillator. Using scintillator allows for the lowering of the energy threshold, but this increases sensitivity to backgrounds. To meet the requirements of the physics on detector performance, a detailed optical calibration is needed. Due to increased background sensitivity, a new external LED-based calibration system has been developed and the existing laser calibration system has been modified to meet radiopurity requirements. This thesis describes the the development and implementation of both of these calibration systems. With a study of the potential use of the LED system to monitor the detector's structure, enabling a better definition of the fiducial volume by reducing the effects of external backgrounds. An assessment of the impact of these systems on the detector performance will be presented.