Test of the CLAS12 RICH large scale prototype in the direct proximity focusing configuration

TL;DR

This paper reports on the testing of a large-scale RICH detector prototype designed for hadron identification in CLAS12 experiments, demonstrating effective pion-kaon separation across the target momentum range.

Contribution

It presents the first large-scale prototype test of a hybrid optics RICH detector with novel design features for high-energy physics applications.

Findings

Achieved pion-to-kaon rejection factor of 1:500

Validated the detector's performance in the 3-8 GeV/c momentum range

Confirmed the effectiveness of the hybrid optics design

Abstract

A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and high-packed and high-segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). We report here the results of the tests of a large scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1:500 in the whole momentum range.