Investigation of temperature dependence of semiconductor detectors used in medicine for radiation measurements


ALTUNKOK S. O. , TUNÇEL N., UÇAR N.

International Workshop on Theoretical and Experimental Studies in Nuclear Applications and Technology (TESNAT), Osmaniye, Türkiye, 23 - 26 Nisan 2015, cilt.100 identifier identifier

Özet

In this study, the temperature dependence of p-type semiconductor diodes that are a part of in-vivo dosimetry system was assessed in Co-60 photon energy. The collimator and gantry angle on zero degree, SSD 100 cm, field size 20x20 cm(2) was selected. The IBA EDP-5, EDP-10 and EDP-20 diode types that included in this study have different thickness of build-up material so the depth of measurements at water equivalent phantom by FC65-p ion chamber was selected at 5, 10 and 20 mm. Along the process the room and phantom temperature was measured and recorded (19 degrees C). The special water filled PMMA phantom was used for diode set-up on its surface and a thermometer for determine phantom temperature was employed. Each type of diodes irradiated separately for one minute and the signal to dose sensitivity and calibration was performed at room temperature (19 degrees C) by OmniPro-InViDos software with DPD-12 electrometer. Examination was repeated from 33 degrees C to 20 degrees C temperatures. The temperature correction factors were found from slope of the linear drawings for each diode types. The obtained correction factor for EDP-5 and EDP-10 was 0.29 %degrees C/cGy and 0.30 %degrees C/cGy respectively, that higher than recommended factor (%0.25 C/cGy). While the more fluctuation for EDP-20 was realized.