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 b een investigated. Two types of Si-SSDs which can take the place of ord inary 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 se nsitivities of the sole-silicon detector and the metal-sandwiched dete ctor were about ten times higher than that of the CWO scintillation de tector at X-ray energies above 1 MeV. The metal-sandwiched detector wa s 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 f or high energy X-ray CT was fabricated and actual measurements of the depletion layer width and the electronic noise contribution were made.