Muon Detection and Direction Reconstruction with the Upgraded 1-ton Water Cherenkov Prototype Detector at CJPL-I

By Wang, Yang, Chen +35Sep 28, 2026

Score████░░░░░░4.2

Key numbers

59% higher than that of
30% of its previous value
85 days

VerdictWorth a reader's time today.

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Abstract

The 1-ton prototype detector for Jinping neutrino experiment (JNE-1ton) has completed its hardware upgrade and has been successfully operated in both water and liquid-scintillator modes at CJPL-I, which is situated under a 2400-m rock overburden. During the upgrade, the detector's mechanical support structure and PMT layout were redesigned. The original Hamamatsu PMTs were replaced with 8-inch MCP-PMTs from North Night Vision, increasing the PMT count from 30 to 60. The detector was then operated in water mode for 85 days (Water-I) and 79 days (Water-II). From the accumulated water-mode data, we derive a muon detection efficiency (Water-II) that is approximately 59% higher than that of the pre-upgrade liquid scintillator detector. The measured muon flux is $φ_{I+II} = (3.55 ± 0.43_{stat}± 0.28_{syst}) × 10^{-10}~cm^{-2}s^{-1}$, which is consistent with the previous measurement. Owing to the characteristic angular dependence of Cherenkov radiation and the increased PMT coverage, the uncertainty in muon direction reconstruction is approximately 6^°, which corresponds to a reduction to 30% of its previous value. Notably, one rare up-going muon event was clearly identified. It is excluded from the cosmic-ray muon flux sample and opens a new window for neutrino-induced event studies in the deepest underground laboratory in China. This work marks the first time that CJPL has employed a cost-effective water detector for muon flux measurement.

Yapeng Wang, Yuzi Yang, Shaomin Chen, Wei Dou, Haoyang Fu, Guanghua Gong, Lei Guo, Ziyi Guo, XiangPan Ji, Jianmin Li, Jinjing Li, Bo Liang, Ye Liang, Ling Liu, Qian Liu, Zhiyi Liu, Wentai Luo, Ming Qi, Wenhui Shao, Haozhe Sun, Jian Tang, Yuyi Wang, Zhe Wang, Changxu Wei, Jun Weng, Yiyang Wu, Benda Xu, Chuang Xu, Tong Xu, Tao Xue, et al.

The editor's rubric

Heuristic review

Dimension	Level	Weight	What that level means
Leverage	██░░░ 2	18%	Reusable within one subfield (a technique, dataset, or protocol a few groups will adopt).
Magnitude	███░░ 3	20%	Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem.
Evidence	███░░ 3	22%	Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.
Novelty	███░░ 3	22%	A genuinely new approach to an open problem.
Trajectory	██░░░ 2	10%	Some room to improve with obvious engineering.
Stakes	██░░░ 2	8%	Benefits a professional community (practitioners, clinicians, engineers).

Editor’s rationale

Heuristic triage from title and abstract text only, not a reading of the paper. Cues found: gains (relative gain); firsts (first); novelty (new kind); verification (error bars); scale (efficient).

How the score was computed

rank-2026-09-29

Score████░░░░░░4.2

Score = 10 × (75% × adjusted merit / 10 + 15% × attention + 10% × freshness)

Merit: 5.3 / 10; Weighted rubric, evidence-gated.
Adjusted merit: 4.5 / 10; Shrunk toward the desk prior by editor confidence (40%).
Attention: 0%; Citations, upvotes, points, mentions.
Freshness: 83%; Half-life decay since publication.

Citations0 (reference 20, via semantic-scholar, Sep 29, 2026, 23:37 UTC)

The record

Reviewed by heuristic-v2 on Sep 29, 2026, 23:53 UTC. Paper type: theory.
Categories: hep-ex
BRIEF, No.7 in the Physics edition of September 29, 2026.