A Cost Effective Optimization of the hybrid-DOM Design for TRIDENT

TL;DR

This paper optimizes the design of TRIDENT's hybrid Digital Optical Modules by comparing 3-inch and 4-inch PMTs, demonstrating that 4-inch PMTs can reduce costs and power while maintaining or improving detection performance.

Contribution

It introduces a cost-effective optimization of the hybrid DOM design for TRIDENT, evaluating the performance of 4-inch PMTs with high QE as a scalable alternative to 3-inch PMTs.

Findings

4-inch PMTs with high QE match or outperform 3-inch PMTs in detection efficiency.

Using 4-inch PMTs reduces channel count, power, and cost.

Performance is maintained or improved with 4-inch PMTs if QE is comparable.

Abstract

TRIDENT is a planned multi-cubic-kilometer deep-sea neutrino telescope to be built in the South China Sea, designed to rapidly discover high-energy astrophysical neutrino sources with sensitivity to all neutrino flavors. Achieving this at scale requires a detector design that balances performance with power, cost, and mechanical simplicity. This study presents a cost-effective optimization of TRIDENT's hybrid Digital Optical Module (hDOM) design, comparing configurations using high-quantum-efficiency (QE) 3-inch PMTs and larger 4-inch PMTs, the latter evaluated with both baseline and enhanced QE assumptions. Using full-chain detector simulations incorporating site-specific seawater optical properties and realistic backgrounds, we assess performance in all-flavor neutrino detection efficiency, directional reconstruction, and tau neutrino flavor identification from 1 TeV to 10 PeV. We find that if 4-inch PMTs can achieve QE comparable to 3-inch PMTs, their performance matches or improves upon that of the 3-inch design, while significantly reducing channel count, power consumption, and cost. These findings support the 4-inch PMT hDOM as a promising and scalable choice for TRIDENT's future instrumentation.