Demonstration of particle tracking with scintillating fibres read out by a SPAD array sensor and application as a neutrino active target

TL;DR

This paper demonstrates a novel particle tracking method using scintillating fibres read out by SPAD array sensors, enabling high-resolution, noise-free imaging suitable for neutrino detection and low-momentum proton tracking.

Contribution

It introduces a new configuration for reading scintillating fibres with SPAD arrays, allowing individual fibre readout regardless of size, enhancing neutrino active target capabilities.

Findings

Successful demonstration with SwissSPAD2 sensor

Potential for high-resolution neutrino tracking

Simulation studies show impact on GeV-neutrino experiments

Abstract

Scintillating fibre detectors combine sub-mm resolution particle tracking, precise measurements of the particle stopping power and sub-ns time resolution. Typically, fibres are read out with silicon photomultipliers (SiPM). Hence, if fibres with a few hundred $\mu$m diameter are used, either they are grouped together and coupled with a single SiPM, losing spatial resolution, or a very large number of electronic channels is required. In this article we propose and provide a first demonstration of a novel configuration which allows each individual scintillating fibre to be read out regardless of the size of its diameter, by imaging them with Single-Photon Avalanche Diode (SPAD) array sensors. Differently from SiPMs, SPAD array sensors provide single-photon detection with single-pixel spatial resolution. In addition, O(us) or faster coincidence of detected photons allows to obtain noise-free images. Such a concept can be particularly advantageous if adopted as a neutrino active target, where scintillating fibres alternated along orthogonal directions can provide isotropic, high-resolution tracking in a dense material and reconstruct the kinematics of low-momentum protons (down to 150 MeV/c), crucial for an accurate characterisation of the neutrino nucleus cross section. In this work the tracking capabilities of a bundle of scintillating fibres coupled to SwissSPAD2 is demonstrated. The impact of such detector configuration in GeV-neutrino experiments is studied with simulations and reported. Finally, future plans, including the development of a new SPAD array sensor optimised for neutrino detection, are discussed.