UFCC Calibration Measurements for UO2 Samples

The uranium UF₆ coincidence counter (UFCC) was designed to measure 5A/B cylinders containing UF6 in the passive neutron self-interrogation mode. The purpose of the present report is to extend the UFCC capability to other sample types such as oxides and liquids that might be found during verification activities. A ²⁵²Cf source was introduced into the detector to make the active mode measurements possible, because only the UF₆ samples have adequate neutron emission for self-interrogation. A customized HDPE insert was designed to position the ²⁵²Cf source under the UO₂ sample cans. The sample enrichments varied from depleted to 93% to establish the shape of the calibration curve and the measurement uncertainties.