The Wavelength-shifting Optical Module (WOM) for the IceCube Upgrade

TL;DR

The WOM is a new optical sensor for IceCube that uses wavelength shifting and light guiding to increase detection area, promising improved performance for large-volume Cherenkov detectors.

Contribution

Introduction of the WOM, a novel wavelength-shifting optical module that enhances photosensitive area without increasing dark current, tailored for IceCube and similar detectors.

Findings

WOM design successfully tested with promising performance.

Effective increase in photocathode area without additional dark noise.

Deployment in IceCube Upgrade demonstrates practical applicability.

Abstract

The Wavelength-shifting Optical Module (WOM) is a novel optical sensor that uses wavelength shifting and light guiding to substantially enhance the photosensitive area of UV optical modules. It has been designed for the IceCube Upgrade, a seven-string extension of the IceCube detector planned for the 2022/2023 South Pole deployment season. The WOM consists of a hollow quartz cylinder coated in wavelength shifting paint which serves as detection area and has two photomultipliers (PMTs) attached to the end faces. The light-collecting tube increases the effective photocathode area of the PMTs without producing additional dark current, making it suitable for low-signal, low-noise applications. We report on the design and performance of the WOM with a focus on the 12 modules in production for deployment in the IceCube Upgrade. While the WOM will be deployed in IceCube, its design is applicable to any large-volume particle detector based on the detection of Cherenkov light.