Development of the semi conductor imaging spectrometer for hard X-ray and gamma-ray observations

我们一直致力于高能量分辨率碲化镉（CdTe）二极管探测器的研制及其在γ射线成像探测器中的应用。在这项研究中，我们开发了一个大的CdTe二极管探测器，面积为2.15厘米2.15厘米。它在整个探测器区域显示出非常好的均匀性。能量分辨率达到2.7keV（FWHM）。为了在太空中的应用，我们进行了振动测试，辐射测试和气球实验。根据这些实验结果，我们证明了CdTe二极管可以用于空间应用。搭建了一个由10层大尺寸CdTe二极管组成的叠层探测器，并对该探测器的伽马探测性能进行了测试。还构建了像素尺寸为200微米× 200微米和1 mm × 1 mm的原型1024像素探测器。从理论上研究了室温下碲化镉二极管的极化现象。我们发现深受主电离引起的电荷积累是其原因。这很好地解释了温度和偏置电压的依赖性。将用于Swift使命的CdZnTe的特性是另一个议题。我们发展了一种新的方法，通过拟合能谱得到迁移率和寿命积。swift使命的标定过程采用了这种方法。

We have been working on the development of high energy resolution Cadmium Teluride (CdTe) diode detector and its application to the gamma-ray imaging detectors. In this research, we developed a large CdTe diode detector with an area of 2.15 cm by 2.15 cm. It shows very good uniformity throughout the detector area. The energy resolution of 2.7 keV (FWHM) has been achieved. In order for the application in space, we did a vibration test, a radiation test and a balloon experiment. According to the results of these experiments we have proved that CdTe diode can be used in space application. A stack detector with several 10 layers of large CdTe diode was built and tested to prove the performance for the gamma-ray detection. Prototype 1024 pixel detectors with the pixel size of 200 micron by 200 micron and 1 mm by 1 mm are also constructed. From theoretical side, we studied polarization phenomena we often experienced from the CdTe diode in room temperature operation. We found that the charge accumulation due to ionization of deep acceptor is the reason. This explains well about temperature and bias voltage dependence. The characterization of CdZnTe to be used in the Swift mission is another topics. We have developed new method to derive mobility and life time products by fitting energy spectra. This method is adopted by the calibration process of the swift mission.