Commissioning of ELLIE for SNO+

TL;DR

The paper discusses the commissioning of ELLIE, an optical calibration system with three modules, for SNO+ to monitor detector properties and improve neutrino detection accuracy.

Contribution

It introduces the design and planned commissioning of ELLIE, a novel in-situ optical calibration system with three specialized modules for SNO+.

Findings

ELLIE's modules are designed to monitor optical attenuation, scattering, and timing.

Commissioning of ELLIE began in early 2017.

The system aims to enhance understanding of detector systematics.

Abstract

SNO+ is a neutrinoless double beta decay and low energy neutrino experiment located in Sudbury, Canada. To improve our understanding of the detector energy resolution and systematics, calibration systems have been developed to continuously monitor the optical properties of the detector, such as: absorption, re-emission, scattering and timing. A part of this in-situ optical calibration system is the Embedded LED/Laser Light Injection Entity (ELLIE). It consists of three subsystems: AMELLIE, SMELLIE, TELLIE. The attenuation module (AMELLIE) is designed to monitor the total optical attenuation, whereas the optical scattering over a wavelength range of 375nm -- 700nm will be characterized by the scattering module (SMELLIE). The timing module (TELLIE) aims to measure the timing characteristics of the photomultiplier tubes. We present the planned commissioning of these three systems, the running of which began early 2017.