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Abstract

A method of obtaining a relative calibration of Si photodiodes for the spectral range of soft X-rays (1-30 keV) is presented. A simple mathematical model of the p-n diode is adopted which allows the response to be described in terms of a small set of parameters. The diffusion length as well as the thickness of a dead layer below the front surface of the diodes are obtained from measurements of angular dependences of the photoinduced current. It is shown that a precise characterisation of the diode response and an accurate relative calibration can be obtained using this method. However, it was found that the presence of a dead layer a few tenths of a micrometre thick can pose severe restrictions on the use of planar diode arrays in X-ray tomography systems where uniformity of response is crucial. The method has been applied to the diode arrays equipping the X-ray tomography system built for the TCV tokamak, a magnetic fusion research device.

Additional information

Authors: ANTON M, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH);DUTCH M J, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH);WEISEN H, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH)
Bibliographic Reference: Article: Review Scientific Instrumentation, Vol. 66 (1995) No. 7, pp. 3762-3769
Record Number: 199511448 / Last updated on: 1995-11-03
Category: PUBLICATION
Original language: en
Available languages: en