Resistive Plate Chambers for Precise Measurement of High-Momentum Protons in Short Range Correlations at R$^3$B

TL;DR

This paper reports on the development and deployment of a high-precision Resistive Plate Chamber detector at R$^3$B for measuring high-momentum protons in short-range correlations within exotic nuclei, achieving timing precision below 100 ps.

Contribution

The paper introduces a large-area, multi-gap RPC with excellent timing and efficiency, specifically designed for nuclear physics experiments involving exotic nuclei at relativistic energies.

Findings

RPC achieved >95% efficiency in beam tests

Timing precision better than 100 ps in measurements

Successful measurement of proton momentum resolution around 1%

Abstract

The Reactions with Relativistic Radioactive Beams (R$^3$B) collaboration of the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, has constructed an experimental setup to perform fundamental studies of nuclear matter, using as a probe reactions with exotic nuclei at relativistic energies. Among the various detection systems, one of the most recent upgrades consisted on the installation of a large area, around 2 m$^2$, multi-gap Resistive Plate Chamber (RPC), equipped with twelve 0.3 mm gaps and readout by 30 mm pitch strips, exhibiting a timing precision down to 50 ps and efficiencies above 98% for MIPs in a previous characterization of the detector. The RPC was part of the setup of the FAIR Phase 0 experiment that focused on measuring, for the first time, nucleon-nucleon short-range correlations (SRC) inside an exotic nucleus ($^{16}$C) that occurred in Spring 2022. The excellent timing precision of this detector will allow the measurement of the forward emitted proton momentum with a resolution of around 1%. In beam measurements show an RPC efficiency above 95% and a time precision better than 100 ps (including the contribution of a reference scintillator and the momentum spread of the particles) for forward emitted particles.