Scintillation Light in SBND: Simulation, Reconstruction, and Expected Performance of the Photon Detection System

TL;DR

This paper evaluates the expected performance of SBND's photon detection system, combining simulation and innovative design features to improve light yield, timing, and position reconstruction for neutrino detection.

Contribution

It introduces a dual readout photon detection system with novel reflective and wavelength-shifting components, enhancing performance in neutrino experiments.

Findings

High light yield and uniform detection efficiency

Excellent timing resolution with nanosecond accuracy

Independent 3D-position reconstruction using scintillation light

Abstract

SBND is the near detector of the Short-Baseline Neutrino program at Fermilab. Its location near to the Booster Neutrino Beam source and relatively large mass will allow the study of neutrino interactions on argon with unprecedented statistics. This paper describes the expected performance of the SBND photon detection system, using a simulated sample of beam neutrinos and cosmogenic particles. Its design is a dual readout concept combining a system of 120 photomultiplier tubes, used for triggering, with a system of 192 X-ARAPUCA devices, located behind the anode wire planes. Furthermore, covering the cathode plane with highly-reflective panels coated with a wavelength-shifting compound recovers part of the light emitted towards the cathode, where no optical detectors exist. We show how this new design provides a high light yield and a more uniform detection efficiency, an excellent timing resolution and an independent 3D-position reconstruction using only the scintillation light. Finally, the whole reconstruction chain is applied to recover the temporal structure of the beam spill, which is resolved with a resolution on the order of nanoseconds.