Letter of Intent: The Accelerator Neutrino Neutron Interaction Experiment (ANNIE)

TL;DR

ANNIE aims to measure neutron yields from atmospheric neutrino interactions in gadolinium-doped water using innovative timing techniques with LAPPDs, enhancing background reduction in neutrino detection.

Contribution

This paper introduces the ANNIE experiment, the first application of LAPPDs in water Cherenkov detectors for precise neutron tagging and vertex localization.

Findings

Design of the ANNIE detector with Gd-doping and LAPPDs

Feasibility demonstration of LAPPDs for vertex localization

Expected improvements in neutron tagging efficiency

Abstract

Neutron tagging in Gadolinium-doped water may play a significant role in reducing backgrounds from atmospheric neutrinos in next generation proton-decay searches using megaton-scale Water Cherenkov detectors. Similar techniques might also be useful in the detection of supernova neutrinos. Accurate determination of neutron tagging efficiencies will require a detailed understanding of the number of neutrons produced by neutrino interactions in water as a function of momentum transferred. We propose the Atmospheric Neutrino Neutron Interaction Experiment (ANNIE), designed to measure the neutron yield of atmospheric neutrino interactions in gadolinium-doped water. An innovative aspect of the ANNIE design is the use of precision timing to localize interaction vertices in the small fiducial volume of the detector. We propose to achieve this by using early production of LAPPDs (Large Area Picosecond Photodetectors). This experiment will be a first application of these devices demonstrating their feasibility for Water Cherenkov neutrino detectors.