CMOS current source based radiation sensors

This paper presents a comparison of two gamma radiation sensors intended to be embedded in CMOS integrated circuits. Both sensors are based on a current source, whose output depends upon the cumulated radiation dose, followed by a current-frequency converter. The two sensors differ in the sensing elements: one uses conventional transistors and the other a floating gate transistor. Results are discussed in terms of sensitivity to radiation dose, and supply voltage and temperature dependence.