Micro-Pocket Fission Detector (MPFD) performance characteristics

Micro-Pocket Fission Detectors (MPFDs) show improved performance over typical fission chambers due to their miniature size. With chambers of only 0.5 mm thick, an applied bias of 200 volts will allow pulse mode counting rates in excess of 56,000 counts per second with a dead time of only 1%. The ability to discriminate background induced events from neutron induced events also improves with the miniature chamber width. In-core tests have demonstrated linear pulse mode operation through seven orders of neutron flux magnitude. Specialized neutron reactive coatings have been formulated to maintain less than 1% signal deviation in a neutron flux of 10¹³ n cm^-2 s^-1 for over 58 years.