Design and Test of a Forward Neutron Calorimeter for the ZEUS Experiment

TL;DR

This paper presents the design, construction, and calibration of a lead scintillator calorimeter for measuring neutrons in the ZEUS experiment, including test results from CERN and analysis of neutron spectra.

Contribution

It introduces a new forward neutron calorimeter for ZEUS, detailing its design, calibration, and performance testing in a CERN beam environment.

Findings

Calorimeter successfully measured neutron energy spectra

Effective separation of electromagnetic and hadronic showers achieved

Energy calibration consistent with direct beam measurements

Abstract

A lead scintillator sandwich sampling calorimeter has been installed in the HERA tunnel 105.6 m from the central ZEUS detector in the proton beam direction. It is designed to measure the energy and scattering angle of neutrons produced in charge exchange ep collisions. Before installation the calorimeter was tested and calibrated in the H6 beam at CERN where 120 GeV electrons, muons, pions and protons were made incident on the calorimeter. In addition, the spectrum of fast neutrons from charge exchange proton-lucite collisions was measured. The design and construction of the calorimeter is described, and the results of the CERN test reported. Special attention is paid to the measurement of shower position, shower width, and the separation of electromagnetic showers from hadronic showers. The overall energy scale as determined from the energy spectrum of charge exchange neutrons is compared to that obtained from direct beam hadrons.