Tanaka E, Nohara N, Murayama H
Radioisotopes. 1980 Jul;29(7):320-5. doi: 10.3769/radioisotopes.29.7_320.
This paper proposes scintillation cameras which can handle input pulse rates beyond 1 Mcps with negligible as spatial resolution and energy resolution at low pulse rates. The cameras are based on the "variable sampling-time technique", in which phototube current pulses are first shortened in width and then selectively integrated by gated integrators followed by sample-and-hold circuits. The period of integration before sampling is not fixed but shortened by the arrival of the following pulse to keep a high pulse-pair time resolution. An approximate expression for the count rate characteristics has been derived, and its validity was confirmed by Monte Carlo simulation. The results indicates that the maximum observed count rate will reach 420-520 kcps with an energy window fraction of 0.5 for typical design parameters.
本文提出了一种闪烁相机，它能够处理超过1兆计数每秒（Mcps）的输入脉冲率，并且在低脉冲率下具有可忽略不计的空间分辨率和能量分辨率。这些相机基于“可变采样时间技术”，在该技术中，光电管电流脉冲首先在宽度上被缩短，然后由门控积分器进行选择性积分，接着是采样保持电路。采样前的积分周期不是固定的，而是会随着下一个脉冲的到来而缩短，以保持高脉冲对时间分辨率。已经推导出了计数率特性的近似表达式，并通过蒙特卡罗模拟证实了其有效性。结果表明，对于典型的设计参数，在能量窗分数为0.5时，观察到的最大计数率将达到420 - 520千计数每秒（kcps）。
