Occulting Light Concentrators in Liquid Scintillator Neutrino Detectors

TL;DR

This paper introduces Occulting Light Concentrators (OLC), a novel design that enhances light collection efficiency and uniformity in liquid scintillator neutrino detectors like JUNO, potentially reducing costs and improving resolution.

Contribution

The paper presents a new type of light concentrator tailored to PMT efficiency profiles, optimizing light collection and uniformity in large neutrino detectors.

Findings

OLC improves light collection efficiency.

OLC enhances energy resolution.

OLC offers more uniform detector response.

Abstract

The experimental efforts characterizing the era of precision neutrino physics revolve around collecting high-statistics neutrino samples and attaining an excellent energy and position resolution. Next generation liquid-based neutrino detectors, such as JUNO, HyperKamiokande, etc, share the use of a large target mass, and the need of pushing light collection to the edge for maximal calorimetric information. Achieving high light collection implies considerable costs, especially when considering detector masses of several kt. A traditional strategy to maximize the effective photo-coverage with the minimum number of PMTs relies on Light Concentrators (LC), such as Winston Cones. In this paper, the authors introduce a novel concept called Occulting Light Concentrators (OLC), whereby a traditional LC gets tailored to a conventional PMT, by taking into account its single-photoelectron collection efficiency profile and thus occulting the worst performing portion of the photocathode. Thus, the OLC shape optimization takes into account not only the optical interface of the PMT, but also the maximization of the PMT detection performances. The light collection uniformity across the detector is another advantage of the OLC system. By considering the case of JUNO, we will show OLC capabilities in terms of light collection and energy resolution.