Performance test of wavelength-shifting acrylic plastic Cherenkov detector

TL;DR

This study evaluates the efficiency of a wavelength-shifting acrylic Cherenkov detector through beam tests, measuring photon collection rates and response efficiencies for different light sources to assess detector performance.

Contribution

It provides the first detailed measurement of collection efficiency and response of a WLS-based Cherenkov detector using beam tests at KEK.

Findings

Photon collection efficiency for internally generated light is approximately 62%.

Collection efficiency for light from the radiator is about 41%.

The measured efficiencies align with prior estimations, confirming detector performance.

Abstract

The collection efficiency for Cherenkov light incident on a wavelength shifting plate (WLS) has been determined during a beam test at the Proton Synchrotron facility located in the National Laboratory for High Energy Physics (KEK), Tsukuba, Japan. The experiment was conducted in order to determine the detector's response to photoelectrons converted from photons produced by a fused silica radiator; this allows for an approximation of the detector's quality. The yield of the photoelectrons produced through internally generated Cherenkov light as well as light incident from the radiator was measured as a function of the momentum of the incident hadron beam. The yield is proportional to sin$^2$$\theta_c$, where $\theta_{c}$ is the opening angle of the Cherenkov light created. Based on estimations and results from similarly conducted tests, where the collection efficiency was roughly 39%, the experimental result was expected to be around 40% for internally produced light from the WLS. The results of the experiment determined the photon collection response efficiency of the WLS to be roughly 62% for photons created in a fused silica radiator and 41% for light created in the WLS.