MOS-transistor radiation detectors and X-ray dose-enhancement effects

Sandia National Laboratory CMOS IC dose detectors and 3N161 MOS Transistors were evaluated as pulsed X-radiation dosimeters and used as monitors to measure dose-enhancement effects. Measurements were made in the photon environments from the HydraMITE II, SPR III, MBS and PITHON radiation sources. The dosimeter evaluation data suggest that the 3N161 MOS transistors are useful dosimeters for measuring flash X-ray-induced doses in the oxide layers of modern MOS integrated circuits. However, dose-enhancement calculations indicate that Monte Carlo codes, using 1-D geometries and calculated source spectra, consistently overpredict measured dose-enhancement ratios by factors as large as two.