Beam test results of 3D fine-grained scintillator detector prototype for a T2K ND280 neutrino active target

TL;DR

This paper reports on the beam test results of a prototype 3D scintillator detector designed for the T2K ND280 neutrino experiment upgrade, focusing on light yield, timing, and optical cross-talk performance.

Contribution

It introduces a novel 3D fine-grained scintillator detector prototype with WLS fiber readout and provides empirical test results from CERN tests.

Findings

High light yield observed in prototype

Good timing resolution achieved

Optical cross-talk within acceptable limits

Abstract

An upgrade of the long baseline neutrino experiment T2K near detector ND280 is currently being developed with the goal to reduce systematic uncertainties in the prediction of number of events at the far detector Super-Kamiokande. The upgrade program includes the design and construction of a new highly granular fully active scintillator detector with 3D WLS fiber readout as a neutrino target. The detector of about $200\times 180\times 60~cm^3$ in size and a mass of $\sim$2.2~tons will be assembled from about $2\times10^6$ plastic scintillator cubes of $1\times1\times1~cm^3$. Each cube is read out by three orthogonal Kuraray Y11 Wave Length Shifting (WLS) fibers threaded through the detector. A detector prototype made of 125 cubes was assembled and tested in a charged particle test beam at CERN in the fall of 2017. This paper presents the results obtained on the light yield and timing as well as on the optical cross-talk between the cubes.