RESPONSE OF SILICON DETECTOR FOR HIGH-ENERGY X-RAY COMPUTED-TOMOGRAPHY

The suitability of Si-SSD as a detector for high energy X-ray CT has been investigated. Two types of Si-SSDs which can take the place of ordinary scintillation detectors were proposed. Their predicted responses were compared with that of a CWO scintillation detector of almost the same dimensions by using the EGS4 Monte Carlo simulation code. The sensitivities of the sole-silicon detector and the metal-sandwiched detector were about ten times higher than that of the CWO scintillation detector at X-ray energies above 1 MeV. The metal-sandwiched detector was judged more useful than the sole Si-SSD when the width of X-ray beam was less than about 0.2 mm. Then the silicon semiconductor detector for high energy X-ray CT was fabricated and actual measurements of the depletion layer width and the electronic noise contribution were made.