Modeling, calibration, and verification of a fission chamber for ACRR experimenters

For past experiments at the Annular Core Research Reactor (ACRR), the neutron fluence was calculated by integrating the response of a fission chamber rate detection signal and then normalizing this integral to fluence determined from passive dosimetry. An alternative method of directly measuring neutron flux is desired; the new methodology described here, provides a complete neutron flux profile after a reactor pulse, utilizing fission chamber physics in combination with a compensating ion chamber to extract and convert a current signal to neutron flux as a function of time. Experimenters at the ACRR facility can now gather data on the neutron flux profile of future pulsed or steady-state experiments, just a few minutes after data collection. Experimenters will be able to immediately determine if the desired neutron fluence or flux was achieved for each experiment