Upgraded photon calorimeter with integrating readout for Hall A Compton Polarimeter at Jefferson Lab

TL;DR

This paper describes an upgrade to the photon calorimeter and data acquisition system of the Hall A Compton polarimeter at Jefferson Lab, enabling more accurate electron beam polarization measurements with reduced systematic uncertainties.

Contribution

The paper introduces a new integrating readout mode and a Ce-doped GSO crystal calorimeter, improving measurement accuracy and reducing systematic errors in polarization experiments.

Findings

Achieved better than 1% accuracy in polarization measurements.

Successfully implemented integrating mode in the DAQ system.

Demonstrated effective operation of the new calorimeter at 1-6 GeV energies.

Abstract

The photon arm of the Compton polarimeter in Hall A of Jefferson Lab has been upgraded to allow for electron beam polarization measurements with better than 1% accuracy. The data acquisition system (DAQ) now includes an integrating mode, which eliminates several systematic uncertainties inherent in the original counting-DAQ setup. The photon calorimeter has been replaced with a Ce-doped GSO crystal, which has a bright output and fast response, and works well for measurements using the new integrating method at electron beam energies from 1 to 6 GeV.