MEASUREMENTS OF NEUTRON CAPTURE CROSS-SECTIONS OF ~(161)Dy AND ~(163)Dy BETWEEN 0.003 EV AND 10 KEV USING A TOTAL ENERGY ABSORPTION DETECTOR

摘要

The neutron capture cross-sections of ~(161)Dy and ~(163)Dy have been measured in the energy region from 0.003 eV to several tens of keV by using the neutron time-of-flight (TOF) method with a 46 MeV electron linear accelerator (linac) at the Research Reactor Institute, Kyoto University (KURRI). An assembly of twelve Bi_4Ge_3O_(12) (BGO) scintillators (size of each: 5 cm x 5 cm, 7.5 cm long), which was placed at a distance of 12.70+-0.02 m from the neutron source, was employed as a total energy absorption detector for the prompt capture gamma-ray measurement, to obtain the absolute capture cross-sections. The enriched samples of ~(161)Dy and ~(163)Dy are in the form of metallic plates (20 mm in diameter, 0.21 mm in thickness). A ~(10)B sample (18 mm x 18 mm, 4.54 g/cm~2) was employed to monitor the neutron flux of the TOF beam using the standard reference cross-section of the ~(10)B(n,α) reaction. The Dy sample or B-10 capture sample was set at the center of the through hole in the BGO assembly. The current measurement has been compared with the previous measurements and the evaluated data in ENDF/B-VI.