Photon Detection in the Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN)

TL;DR

CAPTAIN is a cryogenic detector using a liquid argon TPC to test photon detection methods for neutrino interactions, serving as a test bed for future neutrino experiments.

Contribution

This paper describes the design and current implementation of the photon detection system in the CAPTAIN detector, including testing options for future neutrino experiments.

Findings

Photon detection system with 16 Hamamatsu PMTs and wavelength shifting coatings.

Evaluation of different wavelength shifting coatings for photon detection.

System readiness for testing photon detection options in neutrino interactions.

Abstract

The Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN) is being built at Los Alamos National Laboratory. A hexagonal time projection chamber (TPC) with a 1 m drift length will be constructed inside a cryostat containing 7,700L of liquid argon. CAPTAIN will be used to test interactions using beams of neutrons and neutrinos. It will serve as a test bed for various options for the Long Baseline Neutrino Experiment (LBNE) including in the photon detection system. The current photon detection system will be described and future options discussed. The system is composed of sixteen R8520-500 Hamamatsu photomultiplier tubes with a wavelength shifting coating on acrylic in front of the PMT. Various wavelength shifting coatings can be examined with the current default of tetraphenyl butadiene.