Development of an X-ray Spectrometer with Sub-Micron Spatial Resolution

亚微米空间分辨率 X 射线光谱仪的研制

基本信息

批准号：
12440075
负责人：
DOTANI Tadayasu
金额：
$ 4.93万
依托单位：
Institute of Space and Astronautical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440075/
关键词：
X-ray CCD Spectrometer X-ray detector FPGA 画像処理データ処理

项目摘要

We have studied methods to improve the spatial resolution of the X-ray CCD detector as a spectrometer. The spatial resolution of X-ray CCD is determined mainly by (1) pixel size of the CCD, (2) noise of the measured pulse heights, and (3) data processing algorithm. Among these, we concentrated on items (2) and (3), because the development of CCD with small pixels is beyond the scope of current research.Both the clock signals and the analogue electronics are keys to reduce the noise of the pulse heights. We adjusted the phase of the clock signals and the sampling timing to minimize the interference of the clocking noise to the output. We developed a low-noise preamplifier and an active low-pass filter to improve the signal-to-noise ratio of the analogue circuits. With these modifications, we could reduce the measurement noise significantly. We also studied the best algorithm to determine the incident position of X-ray photons from the distribution of measured charges. We found that just a simple model fitting with a 2-dimensional Gauss function gives a good result.We could determine the incident position of X-ray photons with an accuracy of about 20% of the pixsel size. We estimate that the position error can be reduced to 10% with further improvement of S/N ratio. CCDs with pixel size smaller the 10 μm are now available for X-ray detection. With these CCDs it is possible to achieve a spatial resolution less than 1 μm. This is the goal of our research.

我们研究了改善X射线CCD检测器作为光谱仪的空间分辨率的方法。 X射线CCD的空间分辨率主要由CCD的（1）像素大小，（2）测量的脉冲高度的噪声和（3）数据处理算法确定。其中，我们集中在项目（2）和（3）上，因为带有小像素的CCD的开发超出了当前研究的范围。这是时钟信号和模拟电子设备的关键，旨在降低脉冲高度的噪声。我们调整了时钟信号的阶段和采样时间，以最大程度地减少时钟噪声对输出的干扰。我们开发了一个低噪声前置放大器和一个活跃的低通滤波器，以提高模拟电路的信噪比。通过这些修改，我们可以显着降低测量噪声。我们还研究了最佳算法，以确定来自测量电荷分布的X射线照片的入射位置。我们发现，仅具有二维高斯功能的简单模型拟合可得出良好的结果。我们可以确定X射线照片的入射位置，其精度约为像素大小的20％。我们估计，随着S/N比进一步提高，可以将位置误差降低到10％。具有像素大小的CCD较小10μm现在可用于X射线检测。使用这些CCD，可以实现小于1μm的空间分辨率。这是我们研究的目标。