Realtime calibration of the A4 electromagnetic lead fluoride calorimeter

TL;DR

This paper presents a fast, linear algebra-based calibration method for a large lead fluoride calorimeter used in particle physics, ensuring precise energy measurements during experiments.

Contribution

A novel calibration procedure using matrix inversion for real-time calibration of a segmented electromagnetic calorimeter with 1022 crystals.

Findings

Method effective at beam energies between 300 and 1500 MeV.

Enables continuous, accurate calibration of the calorimeter.

Improves energy resolution for particle detection.

Abstract

Sufficient energy resolution is the key issue for the calorimetry in particle and nuclear physics. The calorimeter of the A4 parity violation experiment at MAMI is a segmented calorimeter where the energy of an event is determined by summing the signals of neighbouring channels. In this case the precise matching of the individual modules is crucial to obtain a good energy resolution. We have developped a calibration procedure for our total absorbing electromagnetic calorimeter which consists of 1022 lead fluoride (PbF_2) crystals. This procedure reconstructs the the single-module contributions to the events by solving a linear system of equations, involving the inversion of a 1022 x 1022-matrix. The system has shown its functionality at beam energies between 300 and 1500 MeV and represents a new and fast method to keep the calorimeter permanently in a well-calibrated state.