Due to pulse pileup, photon counting detectors (PCDs) suffer from count loss and energy distortion when operating in high count rate environments. In this paper, we studied the pulse pileup of a double-sided silicon strip detector (DSSSD) to evaluate its potential application in a mammography system. We analyzed the pulse pileup using pulses of varied shapes, where the shape of the pulse depends on the location of photon interaction within the detector. To obtain the shaped pulses, first, transient currents for photons interacting at different locations were simulated using a Technology Computer-Aided Design (TCAD) software. Next, the currents were shaped by a CR–RC² shaping circuit, calculated using Simulink. After obtaining these pulses, both the different orders of pileup and the energy spectrum were calculated by taking into account the following two factors: 1) spatial distribution of photon interactions within the detector and 2) time interval distribution between successive photons under a given photon flux. We found that for a DSSSD with a thickness of $300~\mu \text{m}$ , a pitch of $25~\mu \text{m}$ , and a strip length of 1 cm, under a bias voltage of 50 V, the variable pulse shape model predicts that the fraction free of pileup can be >90% under a photon flux of 3.75 Mcps/mm² (million counts per second per square mm). The DSSSD is a promising candidate for digital mammography applications.

中文翻译：

---

使用可变脉冲形状对双面硅带探测器进行脉冲堆积分析

由于脉冲堆积，光子计数探测器 (PCD) 在高计数率环境中运行时会遭受计数损失和能量失真。在本文中，我们研究了双面硅条探测器 (DSSSD) 的脉冲堆积，以评估其在乳腺 X 线摄影系统中的潜在应用。我们使用不同形状的脉冲分析了脉冲堆积，其中脉冲的形状取决于探测器内光子相互作用的位置。为了获得整形脉冲，首先，使用技术计算机辅助设计（TCAD）软件模拟在不同位置相互作用的光子的瞬态电流。接下来，电流被塑造为CR–RC²整形电路，利用Simulink计算。获得这些脉冲后，通过考虑以下两个因素来计算不同阶的堆积和能谱：1）探测器内光子相互作用的空间分布；2）给定光子通量下连续光子之间的时间间隔分布。我们发现对于厚度为 $300~\mu \text{m}$，节距为 $25~\mu \text{m}$^{，条带长度为 1 cm，在 50 V 偏置电压下，可变脉冲形状模型预测，在 3.75 Mcps/mm 2}（每秒百万次计数）的光子通量下，无堆积的分数可 >90%平方毫米）。DSSSD 是数字乳腺 X 线摄影应用的一个有前途的候选者。