A model for analyzing corrosion data from pulsed proton beam irradiation experiments

A model for analyzing corrosion data from pulsed proton beam irradiation experiments was developed from time-averaged corrosion rate measurements taken as a function of beam duty cycle and peak (instantaneous) beam current. The model assumes that there are two separate processes that control corrosion kinetics at the solution–metal interface: one during proton pulses and one between pulses. The model was evaluated using two techniques: a simulation program with integrated circuit emphasis (an integrated circuit analysis routine) and a numerical method. The model found that the corrosion rate between proton pulses was two orders of magnitude lower than the corrosion rate during a proton pulse. In addition, the model predicts that the corrosion rate during a pulse of protons correlates with peak current and that the time-average corrosion rate is weighted more heavily for duty cycle (repetition rate and gate length) than peak current. These findings explain apparent anomalies in time-averaged corrosion data; it was observed that for a fixed average beam current that the time-averaged corrosion rate for a 16 mA peak current was lower than the time-averaged corrosion rate at a peak current of 1.6 mA. This apparent anomaly is explained in the model by the higher duty cycle for the 1.6 mA case.