First results of the deployment of a SoLid detector module at the SCK-CEN BR2 reactor

TL;DR

The paper reports on the initial deployment and performance of a novel, highly segmented scintillator detector at the BR2 reactor, aiming to investigate the reactor neutrino anomaly through sterile neutrino oscillation searches.

Contribution

It introduces a new detector design for reactor neutrino experiments and presents initial performance results from its first deployment at the BR2 reactor.

Findings

Successful deployment of the 288 kg detector module

Effective neutron-gamma discrimination achieved

Promising initial detector performance results

Abstract

The SoLid experiment aims to resolve the reactor neutrino anomaly by searching for electron-to-sterile anti-neutrino oscillations. The search will be performed between 5.5 and 10 m from the highly enriched uranium core of the BR2 reactor at SCK-CEN. The experiment utilises a novel approach to anti-neutrino detection based on a highly segmented, composite scintillator detector design. High experimental sensitivity can be achieved using a combination of high neutron-gamma discrimination using 6 LiF:ZnS(Ag) and precise localisation of the inverse beta decay products. This compact detector system requires limited passive shielding as it relies on spacial topology to determine the different classes of backgrounds. The first full scale, 288 kg, detector module was deployed at the BR2 reactor in November 2014. A phased three tonne experimental deployment will begin in the second half of 2016, allowing a precise search for oscillations that will resolve the reactor anomaly using a three tonne detector running for three years. In this talk the novel detector design is explained and initial detector performance results from the module level deployment are presented along with an estimation of the physics reach of the next phase.