Application of Imaging Systems to Characterization of Single-Event Effects in High-Energy Neutron Environments

We use charge-coupled devices (CCDs) to characterise the single-event effect (SEE) inducing properties of high-energy neutron beams, including the spatial distribution of induced charge. Three representative CCD types are evaluated for this purpose. We study the significance of anti-blooming structures and pixel size. Anti-blooming structures are found to suppress event rates and corrupt event statistics. Devices without such structures are preferred and anti-blooming correction is performed in software. A CCD with 9 mum pixels is chosen for an Imaging SEE Monitor, which is currently being deployed in a variety of natural and synthetic neutron fields. Comparison is made between effects observed in neutron beams at LANSCE and TRIUMF accelerator facilities. Cross-sections for all events at the two facilities agree, providing independent confirmation of dosimetry. Cross-sections for more intense events disagree, with about a factor of 5 difference (LANSCE more effective) at 1 pC deposited charge. We attribute this discrepancy to the harder neutron spectrum at LANSCE, and conclude that predictions of SEE cross-sections in devices of interest, as measured at the two facilities, are liable to differ for this reason. Predictions of SEE rates in the field may also be in doubt. Charge collection measurements are recommended for adoption in test protocols for accelerated testing for neutron SEE