Measurement of Total Cross Sections at Pohang Neutron Facility

Abstract

The Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled Ta target with a water moderator, and a time-of-flight path with an 11 m length has been operated since 2000. We report the status activities on the neutron total cross-section measurements in the neutron energy region from 0.01 eV to 100 eV by the neutron time-of-flight method at Pohang Neutron Facility. A 6

Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a

thickness of 1.5 cm has been used as a neutron detector. The background level has been determined by using notch- filters of Co, In, and Cd sheets. In order to reduce the gamma rays from Bremsstrahlung and that from neutron capture,

we have employed a neutron-gamma separation system based on their different pulse shape. The present measurements for Ag, Hf, and Ta samples are compared with the previous ones and the evaluated data in ENDF/B-VI. The resonance parameters for Ag and Hf samples have been extracted from the transmission data by using the SAMMY code.