Timepix, a 65k programmable pixel readout chip for arrival time, energy and/or photon counting measurements
Timepix, a 65k programmable pixel readout chip for arrival time, energy and/or photon counting measurements
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DOI：
10.1016/j.nima.2007.08.079
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发表时间：
2007-10-21
影响因子：
1.4
通讯作者：
Wong, W.
中科院分区：
文献类型：
--
作者：
Llopart, X.;Ballabriga, R.;Wong, W.
在未来的直线对撞机上，一种新的TPC读出方法是使用CMOS像素探测器结合某种气体增益栅。第一次测试使用光子计数芯片Medipix2与GEM或Micromegas证明了这种方法的可行性。尽管该实验证明可以检测单个初级电子，但芯片没有提供关于电子在敏感气体体积中的到达时间的信息，也没有给出检测到的电荷量的任何指示。Timepix芯片使用频率高达100MHz的外部时钟作为时间基准。每个像素包含一个ADC、一个具有迟滞的ADC和一个用于阈值调整的4位DAC、同步逻辑和一个具有溢出控制的14位计数器。此外，每个像素可以在四种不同模式中的一种中独立地配置：掩蔽模式：像素关闭，计数模式：对于超过阈值的每个信号计数1，TOT模式：只要信号高于阈值，计数器就连续递增，以及到达时间模式：计数器从第一次撞击到达的时间连续递增，直到快门结束。该芯片在物理上与Medipix2芯片非常相似，可以使用各种现有系统的略微修改版本进行读取。本文介绍了新设计的主要特点，电气测量和一些第一图像。(C)2007 Elsevier B.V.保留所有权利。
A novel approach for the readout of a TPC at the future linear collider is to use a CMOS pixel detector combined with some kind of gas gain grid. A first test using the photon counting chip Medipix2 with GEM or Micromegas demonstrated the feasibility of such an approach. Although this experiment demonstrated that single primary electrons could be detected the chip did not provide information on the arrival time of the electron in the sensitive gas volume nor did it give any indication of th e quantity of charge detected. The Timepix chip uses an external clock with a frequency of up to 100MHz as a time reference. Each pixel contains a preamplifier, a discriminator with hysteresis and 4-bit DAC for threshold adjustment, synchronization logic and a 14-bit counter with overflow control. Moreover, each pixel can be independently configured in one of four different modes: masked mode: pixel is off, counting mode: 1-count for each signal over threshold, TOT mode: the counter is incremented continuously as long as the signal is above threshold, and arrival time mode: the counter is incremented continuously from the time the first hit arrives until the end of the shutter. The chip resembles very much the Medipix2 chip physically and can be readout using slightly modified versions of the various existing systems. This paper presents the main features of the new design, electrical measurements and some first images. (C) 2007 Elsevier B.V. All rights reserved.