Surface and depth dose measurement with photodiode BPW-34

In recent years the application of semiconductor detectors in radiation dosimetry has increased due to its advantages. In fact, the current produced by the diode is approximately 18,000 times that produced by an ionisation chamber of equal sensitive volume. Since the junction characteristics of semiconductor detectors and commercial photodiodes are similar, the instrumentation laboratory of DEN/UFPE developed a dosimeter using the photodiode BPW-34 as a detector. Surface and depth doses were measured with this photodiode in x-ray of 6MV and 10MV and sup(60)Co gamma fields. The results obtained were compared with the response of a plate ionisation chamber and with a tabulated data. Differences smaller than 1% were observed among these values. (author)