An alternative methodology for high counting-loss corrections in neutron time-of-flight measurements

摘要

In counting experiments associated with pulsed sources, a high data collection rate can lead to considerably large counting losses, especially in the case of spallation Time-of-Flight facilities equipped with medium and short flight paths where the research interest is focused on higher neutron energies where counting losses can be quite large due to the higher neutron flux, the more compressed time frame compared to the one on lower energies and the higher cross-section depending on the reaction. Examples of such measurements are the neutron induced fission experiments at the new experimental area EAR-2 at the n_TOF facility at CERN. Although analytical expressions to account for this inefficiency exist in literature, the introduced corrections are not always sufficient to retrieve the true reaction rate, therefore a different approach is mandatory. This work explores the possibility to quantify the counting losses using detector emulation devices and exponential fits in waiting time distributions. The methodology is benchmarked in the test case of the standard U-238(n,f) cross-section with reference to U-235(n,f) for bandwidths up to 1.9 MHz and counting losses that exceed 60%.