Undersea Background Characterization for the Pacific Ocean Neutrino Experiment

Synopsis

Telescopes, as we often think of them, use light as the primary messenger for their observations. However, in recent years, using alternative messengers to study the cosmos has become increasingly popular. These alternatives to photons include cosmic rays, gravitational waves, and neutrinos, which each come with its own advantages but requires special telescopes to be observed. The Pacific Ocean Neutrino Experiment (P-ONE) is a proposed initiative to construct one of the largest neutrino telescopes deep in the northern Pacific Ocean off the coast of British Columbia. The detector itself will consist of an array of digital optical modules (DOMs) that detect Cherenkov light produced by neutrino interactions within the detector volume. To date, two pathfinder missions have been deployed to study the optical properties and ambient background of Pacific Ocean seawater. This background is composed of bioluminescent light and light from undersea radioactivity. The radioactive background is attributed to the decay of natural radioactive isotopes, primarily 40K, in sea salt. I will present my research in modeling the response of a pathfinder DOM to the 40K background. In addition, I will discuss how I intend to use my characterization of 40K to develop a noise model for the full-scale detector. Matching my simulation to data from the pathfinder confirms the accuracy of not only the background data that I will discuss, but also the general optical measurement parameters. My analysis confirms that the ambient background noise at the proposed site is suitably low for P-ONE.