On-site Background Measurements for the J-PARC E56 Experiment: A Search for Sterile Neutrino at J-PARC MLF

TL;DR

This paper reports on background measurements at J-PARC MLF to assess the feasibility of the E56 experiment searching for sterile neutrinos, focusing on gamma, neutron, and cosmic ray backgrounds at candidate detector sites.

Contribution

It provides the first detailed background rate measurements at the E56 detector sites, essential for evaluating the experiment's sensitivity.

Findings

Measured gamma and neutron backgrounds at the detector sites.

Quantified cosmic ray background levels.

Assessed the impact of backgrounds on sterile neutrino search sensitivity.

Abstract

The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The result of the measurements is described in this article. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured.