Precision Light Yield and Crosstalk Characterization for the SuperFGD scintillator cubes

TL;DR

This study characterizes the light yield, uniformity, and crosstalk of a SuperFGD scintillator cube prototype using a pion beam, providing data crucial for detector performance and simulation accuracy.

Contribution

It offers detailed measurements of light yield and crosstalk in a SuperFGD prototype, enhancing understanding for detector optimization and modeling.

Findings

Average light response map obtained from 27 cubes.

Position-dependent crosstalk ranges from 2% to 6%.

Results align well with a simple Monte Carlo model.

Abstract

A detailed study of a $5\times5\times5$ cube prototype of the SuperFGD detector was performed using a 730 MeV/$c$ pion beam at the SC-1000 synchrocyclotron (PNPI, Gatchina, Russia). The detector, based on plastic scintillation cubes with orthogonal wavelength-shifting (WLS) fiber readout and silicon photomultipliers (SiPMs), was tested to evaluate its performance in terms of light yield, spatial uniformity, and optical crosstalk. Using high-resolution tracking, the spatial distribution of light yield was mapped with a granularity of 0.5 mm. An average light response map was obtained by combining data from 27 cubes. Optical crosstalk between adjacent cubes was also measured and characterized in four directions (left, right, up, down). Position-dependent crosstalk values ranged from 2% to 6%, with the highest levels observed near cube interfaces. These results confirm the excellent performance and scalability of the SuperFGD design, and provide valuable input for simulation tuning and reconstruction algorithms in the ND280 upgrade of the T2K experiment. The obtained result on the response uniformity and crosstalk are reasonably well described by simple MC model of the setup.