Characterization of an INVS Model IV Neutron Counter for High Precision ($\gamma,n$) Cross-Section Measurements

摘要

A neutron counter designed for assay of radioactive materials has beenadapted for beam experiments at TUNL. The cylindrical geometry and 60% maximumefficiency make it well suited for ($\gamma,n$) cross-section measurements nearthe neutron emission threshold. A high precision characterization of thecounter has been made using neutrons from several sources. Using a combinationof measurements and simulations, the absolute detection efficiency of theneutron counter was determined to an accuracy of $\pm$ 3% in the neutron energyrange between 0.1 and 1 MeV. It is shown that this efficiency characterizationis generally valid for a wide range of targets.