Temperature dependence of commercially available diode detectors

Temperature dependence of commercially available n- and p-type diodes were studied experimentally under both high instantaneous dose rate (pulsed) and low dose rate (Continuous) radiation, The 2 sensitivity versus temperature was measured at SSD = 80 or 100 cm. 10 x 10 cm(2). and 5 cm depth in a 30 x 30 x 30 cm(3) water phantom between 10 degreesC and 35 degreesC. The response was linear for all the diode detectors. The temperature coefficient (or sensitivity variation with temperature, svwt) was dose rate independent for preirradiated diodes. They were (0.30 +/- 0.01)%/degreesC (0.36 +/- 0.03)%/degreesC. and (0.29 +/- 0.08)%/degreesC for QED p-type. EDP p-type. and Isorad n-type diodes, respectively. The temperature coefficient for unirradiated n-type diodes was different under low dose rate [(0.16 to 0.45)%/degreesC. continuous. cobalt] and high instantaneous dose rate [(0.07 +/-0.02)%/degreesC. pulsed radiation]. Moreover. the temperature coefficient varies among individual diodes. Similarly, the temperature coefficient for a special unirradiated QED p-type diode was different under low dose rate (0.34%/degreesC, cobalt) and high instantaneous, dose rate [(0.26 +/- 0.01)%/degreesC, pulsed radiation]. Sufficient preirradiation can eliminate dose rate dependence Or the temperature coefficient. On the contrary, preirradiation cannot eliminate close rate dependence of the diode sensitivity itself. (C) 2002 American Association of Physicists in Medicine.