Semiconductor detectors with high energy efficiency in the range at several 10 keV are now playing an important role in various research fields; from X-ray astronomy to non-destructive material analysis and in vivo medical imaging. We have been working on a double-sided strip detector based on high energy resolution Cadmium Telluride (CdTe) diode.
In this presentation, we will present the performance of a 60 μm pitch CdTe Double-sided Strip Detector (CdTe-DSD), which was originally developed for the focal plane detector of hard X-ray telescope to observe the Sun. The detector has a thickness of 750 μm and has 128 strip electrodes orthogonally placed on both sides of the detector and covers energy range from 4 keV to 80 keV. The width of the strip electrode is 50 μm and the gap between the strips is 10 μm. Studies of uniformity and effects of charge sharing are of importance in order to provide accurate imaging. For this, we constructed a simple imaging system using a 5 mm thick Tungsten plate that has a pinhole collimator with a diameter of 100 μm and an opening angle of 40 degrees. In order to make evaluation of the detector in a laboratory easy, we have developed a new type of sealed radioisotope (RI) in collaboration with the Japan Radioisotope Association. The RI is mixed with resin and injected into micro tubes with different diameters ranging from 0.167 mm to 1 mm with a pattern that is suitable for testing how accurately we can reconstruct the fine structure of target sources. By using these setups, we obtained 1.3 keV energy resolution at 59.5 keV peak (FWHM). In terms of position resolution, after applying depth corrections of interaction and charge sharing between strips, we obtained a position resolution smaller than the strip pitch of 60 μm.
|Submission declaration||Original and unpublished|