Measurements of the T2K neutrino beam properties using the INGRID on-axis near detector

TL;DR

This paper reports precise measurements of the T2K neutrino beam's direction and intensity using the modular INGRID detector, achieving high accuracy in beam monitoring for neutrino oscillation experiments.

Contribution

Introduction of a modular on-axis detector system that accurately measures neutrino beam properties for the first time in T2K.

Findings

Beam direction measured with better than 0.4 mrad accuracy.

Neutrino event rate normalized with 4% precision.

Effective monitoring of beam profile and intensity.

Abstract

Precise measurement of neutrino beam direction and intensity was achieved based on a new concept with modularized neutrino detectors. INGRID (Interactive Neutrino GRID) is an on-axis near detector for the T2K long baseline neutrino oscillation experiment. INGRID consists of 16 identical modules arranged in horizontal and vertical arrays around the beam center. The module has a sandwich structure of iron target plates and scintillator trackers. INGRID directly monitors the muon neutrino beam profile center and intensity using the number of observed neutrino events in each module. The neutrino beam direction is measured with accuracy better than 0.4 mrad from the measured profile center. The normalized event rate is measured with 4% precision.