AI 中文总结
本文报告T2K ND280升级中飞行时间探测器的设计与调试，其实现约130 ps时间分辨率，并成功同步束流结构，助力减少系统误差并提升CP破坏灵敏度。
AI 中文摘要
T2K ND280升级旨在减少中微子振荡参数测量中的系统不确定性，并提高对电荷-宇称（CP）破坏相位$\delta_{\mathrm{CP}}$的灵敏度。其关键组成部分是飞行时间（ToF）探测器，由六个面板组成，包含118根EJ-200塑料闪烁体条，环绕超级细粒度探测器（SuperFGD）和两个高角度时间投影室（HA-TPC）。每根闪烁体条两端由硅光电倍增管阵列读出，并使用SAMPIC波形电子学进行数字化。ToF提供精确的时间和粒子方向信息，用于粒子识别和拒绝从外部进入跟踪器的本底。本文介绍了探测器的设计、建造、信号重建、集成、调试和性能。专用的单条测量实现了约130 ps的时间分辨率和2.6 cm的纵向位置分辨率。在安装到ND280后，宇宙射线校准得出自上而下穿越事件的原位单条时间分辨率为$169 \pm 1$ ps。束流数据清晰分辨出八束团T2K脉冲结构，确认了与ND280触发和数据采集系统的同步。ToF已成功完成调试，并在升级后的ND280探测器中稳定运行。
英文摘要
The T2K ND280 Upgrade aims to reduce systematic uncertainties in measurements of neutrino oscillation parameters and improve sensitivity to the charge-parity (CP)-violating phase, $δ_{\mathrm{CP}}$. A key component is the Time-of-Flight (ToF) detector, comprising six panels with 118 EJ-200 plastic-scintillator bars surrounding the Super Fine-Grained Detector (SuperFGD) and two High-Angle Time Projection Chambers (HA-TPCs). Each bar is read out at both ends by silicon photomultiplier arrays and digitised using SAMPIC waveform electronics. The ToF provides precise timing and particle-direction information for particle identification and rejection of backgrounds entering the tracker from outside. This article presents the detector design, construction, signal reconstruction, integration, commissioning, and performance. Dedicated single-bar measurements achieve a time resolution of approximately 130 ps and a longitudinal position resolution of 2.6 cm. After installation in ND280, cosmic-ray calibration yields an in situ single-bar time resolution of $169 \pm 1$ ps for Top-Bottom crossing events. Beam data clearly resolve the eight-bunch T2K spill structure, confirming synchronisation with the ND280 trigger and data-acquisition systems. The ToF has been successfully commissioned and operates stably within the upgraded ND280 detector.
Comments40 pages, 28 figures, 3 tables. Prepared for submission to JINST
