基于反馈调节的闪烁脉冲稀疏量化电平方法

PET探测器采用SQL采样电路对闪烁脉冲进行处理,可固定量化电平。零点噪声引起的电平翻转导致电压比较器长时间非正常发热,无法设置较低的量化电平,限制了探测器符合时间分辨率的提高。文中提出一种基于反馈调节的闪烁脉冲处理方法,该方法通过使用三极管饱和状态下的开关特性,对SQL量化样本进行反馈调节。利用延迟元件对量化样本进行延迟同步,产生可以随样本逻辑电平变化的量化电平,避免了零点噪声对SQL采样电路的影响。实验结果表明,在相等时间内,优化的SQL采样电路的采样量比原SQL采样电路的采样量减少了29%,符合时间分辨率提升了179.3 ps,有效减少了PET探测器无用功耗,提高了PET系统的符合时间分辨率。

Sparse Quantization Level Method for Scintillation Pulse Based on Feedback Regulation

The PET detector uses SQL sampling circuit to process scintillation pulse and fix the quantization level. The electric flipping caused by zero noise leads to abnormal heat of the voltage comparator for a long time, and the lower quantization level cannot be set, which limits the improvement of the detector's coincidence timing resolution. This study proposes a flicker pulse processing method based on feedback adjustment, which uses the switching characteristics of the transistor in the saturation state to perform feedback adjustment on the SQL quantitative samples. The delay element is used to delay and synchronize the quantized samples to generate a quantized level that can vary with the logic level of the sample, avoiding the influence of zero-point noise on the SQL sampling circuit. The experimental results show that compared with the original SQL sampling circuit, the optimized SQL sampling circuit reduces the amount of samples by 29% in the same time, and coincidence timing resolution is improved by 179.3ps, which reduces the useless power of PET detector and improves the coincidence timing resolution of PET system.