POWERING OF A CMOS GATE BASED RING OSCILLATOR ONLY BY HIGH ENERGY PROTON IRRADIATION OF A CRYSTALLINE SILICON PHOTODIODE PAIR

It has been shown that a CMOS NAND-gate based ring-oscillator can be operated with the small currents, generated in a stack of 2 commercial Silicon photodiodes only by 65 MeV proton irradiation. The photodiodes have been shown, however, to degrade fast under irradiation, so that the ring-oscillator operation lasted only few seconds. Illuminating the photodiodes with very low ambient light, the same combination of photodiodes with the ring-oscillator could be used to reveal the effect of very small irradiation effects during the proton beam irradiation of neighboring devices. Even if the proton beam did in this case not hit the photodiodes directly, continuous decrease of the oscillation frequency during the beam-on periods is observed, showing a very good sensitivity of the setup to spurious irradiation levels