SUBMET 实验的读出电子学

中文摘要 AI 辅助

为日本质子加速器研究综合体（J-PARC）的亚毫电荷实验（SUBMET）开发了一套专用数据采集（DAQ）系统，该实验旨在寻找携带分数电荷 $Q = \epsilon e$（其中 $\epsilon$ 低于 $\mathcal{O}(10^{-3})$，以下称为毫电荷粒子（mCPs））的粒子。由于此类粒子预计最多产生少量闪烁光子，该系统针对光电倍增管（PMTs）的单光电子探测进行了优化，将高速波形数字化与精确计时相结合。为了在单次触发内捕获 30 GeV J-PARC 束流的八个连续质子束团，Domino Ring Sampler 4（DRS4）芯片的八个通道按每组四个级联，形成两个读出输入，每个输入以 820.5 MHz 的频率连续采样 4096 个点，有效时间窗口为 5 微秒。校准后，同一 DRS4 芯片上通道间的计时差异在 1 ns 以内，同一板卡上在 2 ns 以内，不同板卡之间在 8 ns 以内，完全满足实验的 30 ns 符合窗口要求。前端电子学的均方根（RMS）噪声低于 0.4 mV。基线被有意向上偏移，使得负向脉冲占据数字化仪量程的更大比例，从而提高了电压分辨率和动态范围。触发控制板汇总来自多个读出板的数据，并维持束流运行所需的数据传输速率。实测性能证实，该 DAQ 系统满足实验的计时、噪声和吞吐量要求。

英文摘要

A dedicated data acquisition (DAQ) system has been developed for the SUB-Millicharge ExperimenT (SUBMET) at the Japan Proton Accelerator Research Complex (J-PARC), a search for particles carrying a fractional electric charge $Q = εe$ with $ε$ below $\mathcal{O}(10^{-3})$, hereafter referred to as millicharged particles (mCPs). Because such particles are expected to produce at most a few scintillation photons, the system is optimized for single-photoelectron detection from the photomultiplier tubes (PMTs), combining high-speed waveform digitization with precise timing. To capture eight consecutive proton bunches of the 30 GeV J-PARC beam within a single trigger, the eight channels of the Domino Ring Sampler 4 (DRS4) chip are cascaded in groups of four to form two readout inputs, each sampling 4096 points continuously at 820.5 MHz over an effective time window of 5 us. After calibration, timing differences between channels are within 1 ns on the same DRS4 chip, 2 ns on the same board, and 8 ns across different boards, well within the 30 ns coincidence window of the experiment. The front-end electronics achieve an RMS noise below 0.4 mV. The baseline is deliberately offset upward such that the negative-going pulses span a larger fraction of the digitizer range, improving voltage resolution and dynamic range. A trigger control board aggregates data from multiple readout boards and sustains the data-transfer rate required for beam operation. The measured performance confirms that the DAQ system meets the timing, noise, and throughput requirements of the experiment.

发表机构

• University of California, Santa Barbara（加州大学圣塔芭芭拉分校）
• Korea University（高丽大学）
• Columbia University（哥伦比亚大学）
• CERN（欧洲核子研究组织）
• New York University（纽约大学）
• The Ohio State University（俄亥俄州立大学）
• Boston University（波士顿大学）

机构由 AI 辅助整理，请以论文原文为准。