Relative calibration of photodiodes in the soft-X-ray spectral rangeFunded under: EAEC-FUSION 12C
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 pn-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. A precise characterisation of the diode response and an accurate relative calibration can be obtained using this method. The presence of a dead layer a few tenths of a micron 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.
Bibliographic Reference: Report: LRP 515/95 EN (1995) 34 pp.
Availability: Available from Confédération Suisse, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, 21 avenue des Bains, 1007 Lausanne (CH)
Record Number: 199510595 / Last updated on: 1995-05-03
Original language: en
Available languages: en