The Topmetal detector, utilized in this investigation, is a direct-type CMOS pixel sensor known for its distinctive feature of employing exposed metal at the top of each pixel to directly capture external charged particles. This method generates electrical signals through the induction of charge. At present, it is mainly used in gas pixel detector(GPD) and particle beam monitoring. In this paper, we present a new front-end design aimed at enhancing the capabilities of the Topmetal pixel detector. The focus is on incorporating a Time-Digital Conversion (TDC) ASIC into the front-end, with the objective of achieving high-precision time measurement in addition to superior position resolution. The function of the TDC is achieved by the two reverse delay chains, 11 edge acquisition circuits Time-to-Amplitude Converter (TAC), analog gate, weight count module, and Wilkinson Analog-to-Digital Converter (ADC). Coarse time measurement is implemented based on a counter with a working frequency of 500 MHz, and fine time measurement is implemented by the combination of TAC and ADC. The design prototype was taped out with the GSMCR130 nm technology. Test results show that this circuit can handle up to 11 consecutive cases, with the minimum time interval of adjacent cases being 500 ps and the bin size up to 2 ps. The time measurement precision is better than 50.3 ps RMS and the PVT(Process Voltage Temperature) robustness of the input delay chain circuit is validated, showing the stable performance of the design.

中文翻译：

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适用于 Topmetal 探测器的 50.3 ps 时间分辨率和 11 通道时间测量芯片

本次研究中使用的 Topmetal 探测器是一种直接型 CMOS 像素传感器，以其独特的特点而闻名，即在每个像素的顶部采用暴露的金属来直接捕获外部带电粒子。该方法通过电荷感应产生电信号。目前主要应用于气体像素探测器（GPD）和粒子束监测。在本文中，我们提出了一种新的前端设计，旨在增强 Topmetal 像素探测器的功能。重点是将时间数字转换 (TDC) ASIC 集成到前端，目的是实现高精度时间测量以及卓越的位置分辨率。 TDC的功能由两个反向延迟链、11边沿采集电路时间幅度转换器(TAC)、模拟门、重量计数模块和威尔金森模数转换器(ADC)来实现。粗时间测量基于工作频率为500 MHz的计数器实现，细时间测量通过TAC和ADC结合实现。该设计原型采用 GSMCR130 nm 技术流片。测试结果表明，该电路最多可以处理 11 个连续情况，相邻情况的最小时间间隔为 500 ps，bin 大小高达 2 ps。时间测量精度优于50.3 ps RMS，并且验证了输入延迟链电路的PVT（过程电压温度）鲁棒性，表明该设计性能稳定。