Noise degradation induced by γ-rays on P- and N-channel junction field-effect transistors

This paper compares the effects of γ-rays on the noise behaviour of P- and N-channel JFETs intended as front-end elements in radiation detector preamplifiers. It will be shown that exposure to γ-rays affects the noise spectral density in a way which is substantially different for the two types of devices. As a result of the noise analysis it is suggested that in preamplifiers exposed to γ-rays the P-channel JFET should be preferred at processing times in the 1-to-10 μs range, while the N-channel device remains superior in applications involving processing times below 0.1 μs