In the Implantable Silicon Dosimeter (SiDO) project, an in vivo dosimeter was developed and built that can measure radiation exposure in the immediate vicinity of a carcinoma during radiation therapy.
Through simulation calculations, it was first shown that oxide charges on p-type materials have a decisive influence on the breakdown behavior of the diode current. In addition, the effect of an epilayer thickness on the degradation behavior under radiation exposure was determined.
Until now, in radiation therapy, the measurement signals are acquired by measuring the photocurrent generated in a silicon diode by X-ray radiation with an electrometer. The pulse-sensitive electronics developed at the CiS Research Institute takes advantage of the fact that in radiation therapy the X-rays hit the human body in pulses lasting about 3 µs by converting the pulses into staircase pulses with a decay time of 50 µs. During two measurement campaigns at PTB Braunschweig, it was shown that the influence of dark current and background light has been largely reduced so that they no longer appear during a dose determination and low beam intensities and variations can be measured accurately.
The research and development work in the “Implantable Silicon Dosimeter” (SiDo) project was funded by the German Federal Ministry of Economic Affairs and Climate Action.
Funding code: 49MF190105
