Design and performance of the muon monitor for the T2K neutrino oscillation experiment

TL;DR

This paper details the design, implementation, and testing of a muon monitor for the T2K neutrino experiment, emphasizing its ability to measure beam intensity and direction with high precision.

Contribution

It introduces a novel muon monitor combining ionization chambers and silicon photodiodes, demonstrating its stability and accuracy in beam measurements.

Findings

Detector linearity within 2.4%

Detector stability within 1.5%

Beam direction measurement precision of 0.25 mrad

Abstract

This article describes the design and performance of the muon monitor for the T2K (Tokaito-Kamioka) long baseline neutrino oscillation experiment. The muon monitor consists of two types of detector arrays: ionization chambers and silicon PIN photodiodes. It measures the intensity and profile of muons produced, along with neutrinos, in the decay of pions. The measurement is sensitive to the intensity and direction of the neutrino beam. The linearity and stability of the detectors were measured in beam tests to be within 2.4% and 1.5%, respectively. Based on the test results, the precision of the beam direction measured by the muon monitor is expected to be 0.25 mrad.