J. J. Melone

Performance of irradiated bulk SiC detectors

Abstract Silicon carbide (SiC) is a wide bandgap material with many excellent properties for future use as a detector medium. We present here the performance of irradiated planar detector diodes made from 100-μm-thick semi-insulating SiC from Cree. Ohmic/Schottky diodes were produced and characterised using Schottky barrier measurements and charge collection efficiency (CCE) measurements were made for 5.48 MeV 241 Am alpha particles. Charge collection of ∼60% was measured initially. Measurements were taken of trap lifetimes in an effort to understand this. Three distinct traps with lifetimes of 4, 16, and 130 s were found. Irradiation took place at Paul Scherrer Institute (PSI) to fluences of 10 12 , 10 13 , and 5×10 14 cm −2 , with 300 MeV /c pions. Changes in the Schottky barrier height, leakage current, trap lifetimes, and CCE measurements give an indication of the possible degradation in performance of detectors of this type over their projected lifetime.

Three-dimensional Medipix-a new generation of X-ray detectors

Three-dimensional (3-D) detectors have many potential advantages over standard planar devices and for a range of applications, e.g., high energy physics, synchrotron radiation detection and medical imaging. One such area is minimizing the effects due to charge sharing between adjacent pixels. Simulations of pixel detector compatible with the Medipix2 chip show that 3-D detectors have significant advantages in this area. In addition, a 64/spl times/64 pixel 3-D detector designed for read-out by the Medipix1 chip has been fabricated. The sensors have been characterized using current-voltage and capacitance measurements. They are currently being bump-bonded to the Medipix1 chip at the University of Freiburg in order for the complete system to be evaluated using a X-ray source.