Background Reduction of Cosmic X-ray Detector By Means of High Speed Pulse Shape Processing

利用高速脉冲整形处理降低宇宙X射线探测器的本底

• 批准号: 03640249
• 负责人: HAYASHIDA Kiyoshi
• 金额: $ 0.13万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03640249/
• 关键词: X-ray Polarimetry; X-ray Astronomy; Proportional Countor; CCD; Digital Processing; Radiation Facility; X線偏光; X線検出器; 偏光度検出器; 波形処理; デジテル波形処理

We have studied digital processing techniques for the pulse shapes of the output signals from X-ray counters. Our first motivation was to reduce particle backgrounds in the proportional counter more efficiently than with usual rise time discrimination method. However, in the course of the study, we noticed that polarimetry of X-ray photons can be done by means of the pulse shape processing (analysis). The basic idea was due to the fact that photoelectrons are preferentially emitted to the direction parallel to the electric vector of the incoming photons. If energy of photoelectron is high enough to reflect its direction of emission to the elongation of the primary electron cloud, pulse shape would be different depending on the geometry between the emission direction and the anode wire. It is expected that for X-ray photons with electric vector parallel to the anode wire the output pulse rises more rapidly than for the vertical case, on average.To examine the idea of "pulse shape (or ri … More se time) X-ray polarimetor", we performed experiments at the synchrotron facility in the Institute for High Energy Physics, Tsukuba, Japan. We irradiated a Xe filled proportional counter against the monochromatic X-ray beam there. Output signals from the preamplifier of the counter were sampled using a Digital Storage Scope. The pulse shape data stored in a personal computer system were analyzed. Rise time of the pulse was investigated, and for X- ray energy from 20 keV to 40 keV, it was found that the average rise time (10%-50% of the pulse peak) was shorter for the parallel (electric vector // anode wire) case. One problem was that reproducibility of the absolute values of the rise time was not good.There are handful of techniques for X-ray poralimetry. To get higher sensitivity for polarization, scattering methods (e. g. Bragg crystal) would be better. However, as for X-ray astronomy use, polarimetry with proportional counter and pulse shape analysis have advantages of 1) photons in wide energy bands can be measured, 2) spectral & timing information is obtained at the same time. Thus further study will enable this technique for actual use. Less

我们研究了 X 射线计数器输出信号脉冲形状的数字处理技术。我们的第一个动机是比通常的上升时间辨别方法更有效地减少正比计数器中的粒子背景。然而，在研究过程中，我们注意到X射线光子的偏振测量可以通过脉冲形状处理（分析）来完成。基本思想是由于光电子优先发射到与入射光子的电矢量平行的方向。如果光电子的能量足够高以将其发射方向反映到初级电子云的伸长，则脉冲形状将根据发射方向和阳极线之间的几何形状而不同。平均而言，对于电矢量平行于阳极线的 X 射线光子，输出脉冲的上升速度比垂直情况更快。为了检验“脉冲形状（或 ri … More se 时间）X 射线偏振计”的想法，我们在日本筑波高能物理研究所的同步加速器设施中进行了实验。我们用 Xe 填充正比计数器照射单色 X 射线束。使用数字存储示波器对计数器前置放大器的输出信号进行采样。对存储在个人计算机系统中的脉冲形状数据进行了分析。研究了脉冲的上升时间，对于从 20 keV 到 40 keV 的 X 射线能量，发现并联（电矢量/阳极线）情况下的平均上升时间（脉冲峰值的 10%-50%）较短。一个问题是上升时间绝对值的再现性不好。X 射线偏振测定技术有几种。为了获得更高的偏振灵敏度，散射方法（例如布拉格晶体）会更好。然而，对于X射线天文学用途，采用正比计数器和脉冲形状分析的偏振测量具有以下优点：1）可以测量宽能带中的光子，2）同时获得光谱和定时信息。因此，进一步的研究将使该技术能够实际使用。较少的

项目成果

H. Tsunemi et al: "Detection of X-ray polarization with a charge coupled device" Numclear Instruments and Methods in Physics Research. A321. 629-631 (1992)

H. Tsunemi 等人：“用电荷耦合器件检测 X 射线偏振”Numclear 物理研究仪器和方法。

H.TSUNEMI et al.: "Detction of X-ray polarization with a charge coupled device" Nucler Instruments and Methods in Physics Research. A321. 629-631 (1992)

H.TSUNEMI 等人：“用电荷耦合器件检测 X 射线偏振”核子仪器和物理研究方法。