Neitzert, H.; Landi, G.; Lang, F.; Bundesmann, J.; Denker, A.; Keil, S.; Thewes, R.: Monitoring Proton Beam-induced Photodiode Degradation using Low-voltage Ring Oscillators. In: 2019 IEEE 8th International Workshop on Advances in Sensors and Interfaces (IWASI) : Otranto, Italy. IEEE, 2019. - ISBN 978-1-7281-0557-4, p. 48-52
10.1109/IWASI.2019.8791279

Abstract:
The influence of high energy Proton irradiation on the performance of Silicon photodiodes is investigated using two illuminated devices connected in series as power supply of a ring-oscillator realized with commercially available CMOS NAND gates and monitoring the output frequency. In order to consider the degradation of a single solar cell a 19-stage ringoscillator fabricated in a standard CMOS process is operated. The circuit provides an integrated frequency divider and an output buffer, and stable voltage-to-frequency conversion is obtained for supply voltages provided by the photodiode down to 300mV.