Charge-Collection and Single-Event Upset Measurements at the ISIS Neutron Source

Charge-collection measurements at the VESUVIO instrument at ISIS are described. Neutron SEU cross sections in SRAM-based FPGAs are measured. Results are compared to equivalent data from Los Alamos Neutron Science Center ICE House. The rate of single-event effects due to fast neutrons at VESUVIO is approximately 15% of that at LANSCE. In addition there is a strong thermal and epithermal component, sufficient to cause many events in devices containing small amounts of
¹⁰
B. The effects of low-energy neutrons on a commercial CCD contaminated with traces of
¹⁰
B are described. Cadmium shielding is found to be incompletely effective in separating the effects of fast and slow neutrons, and the implications for testing protocols and instrument design are discussed.