Timing performance of the Timepix4 front-end
Timing performance of the Timepix4 front-end
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DOI：
10.1088/1748-0221/17/07/p07006
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发表时间：
2022-07-01
影响因子：
1.3
通讯作者：
Cudie, X. Llopart
中科院分区：
文献类型：
--
作者：
Heijhoff, K.;Akiba, K.;Cudie, X. Llopart
对Timepix4像素前端的时序性能进行了分析。外部产生的测试脉冲用于探测每像素时间-数字转换器（TDC），并通过精确控制测试脉冲到达时间（10 ps）来测量时间箱大小。结果表明，如果进行校准以补偿像素TDC的电压控制振荡器的频率变化，TDC可以实现60 ps的时间分辨率。Timepix4内部时钟分配系统用于控制内部生成的模拟测试脉冲的到达时间，其步长约为20ps。模拟测试脉冲机制将受控量的电荷直接注入像素的模拟前端（AFE），并用于测量作为信号电荷函数的时间分辨率，而不依赖于TDC。结果表明，在默认配置下，空穴采集模式下的AFE时间分辨率限制为105ps。然而，通过增加前置放大器偏置电流，以增加功耗为代价，可以将其提高到60ps左右。对于电子收集模式，在信号电荷为21克时，对裸Timepix4器件测量了47 ps的AFE时间分辨率。观察到，来自键合传感器的额外输入电容将该数字降低到62 ps。
A characterisation of the Timepix4 pixel front-end with a strong focus on timing performance is presented. Externally generated test pulses were used to probe the per-pixel time-to-digital converter (TDC) and measure the time-bin sizes by precisely controlling the test-pulse arrival time in steps of 10 ps. The results indicate that the TDC can achieve a time resolution of 60 ps, provided that a calibration is performed to compensate for frequency variation in the voltage controlled oscillators of the pixel TDCs. The internal clock distribution system of Timepix4 was used to control the arrival time of internally generated analog test pulses in steps of about 20 ps. The analog test pulse mechanism injects a controlled amount of charge directly into the analog front-end (AFE) of the pixel, and was used to measure the time resolution as a function of signal charge, independently of the TDC. It was shown that for the default configuration, the AFE time resolution in the hole-collecting mode is limited to 105 ps. However, this can be improved up to about 60 ps by increasing the preamplifier bias-current at the cost of increased power dissipation. For the electron-collecting mode, an AFE time resolution of 47 ps was measured for a bare Timepix4 device at a signal charge of 21 ke. It was observed that additional input capacitance from a bonded sensor reduces this figure to 62 ps.