Measurement of neutron total cross section of Ag and Sm at Pohang Neutron Facility

The neutron total cross section of natural Ag and Sm has been measured in the energy region from 0.1 eV to 100 eV by the neutron time-of-flight method at Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled Ta target with a water moderator, and an 11 m long time-of-flight path. A ⁶Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm has been used as a neutron detector and metallic plates of Ag and Sm samples have been used for the neutron transmission measurement. 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 shapes. The present measurements are in general agreement with the previous ones and the evaluated data in ENDF/B-VI. The resonance parameters of Ag isotopes (¹⁰⁷Ag and ¹⁰⁹Ag) have been extracted from the transmission data by using the SAMMY code. (author)