31st International Seminar on Interaction of Neutrons with Nuclei: Fundamental Interactions & Neutrons, Nuclear Structure, Ultracold Neutrons, Related Topics (ISINN-31)

Measurement of Neutron Total Cross Section of 169Tm at Back-n

27 May 2025, 16:05

20m

Room V6 (4th floor)

Parallel session 1 Parallel Session 1: Fundamental interactions & symmetries in neutron induced reactions/Properties of compound states, nuclear structure/Intermediate and fast neutron induced reactions/Nuclear fission

Speaker

Jie Ren (China Institute of Atomic Energy)

Description

The neutron total cross sections ( σtot ) are of great value in nuclear reactor design, nuclear theory models, nuclear applications and other fields. Thulium ( 169Tm ) is a crucial neutron absorbing material, and the σtot of 169Tm are highly useful for nuclear reactor design. However, there are only a few experimental σtot of 169Tm in EXFOR and no data in the energy between 10 keV and hundreds keV. Besides, the evaluated σtot of 169Tm in ENDF/B-VIII.1, JENDL, and TENDL show significant discrepancies within the 10 keV and 100 keV energy region. To determine the σtot of 169Tm in the energy between 10 keV and 100 keV, a wing-shaped lithium glass detector was designed in this work， and a measurement was carried out with this lithium glass scintillation detector at the Back-n facility. The experimental backgrounds induced by gamma rays were measured with lithium-7 enriched scintillator and “black resonance filter” method. The corrections for dead time, beam stability, and self-shielding were taken into consideration in the data analysis. The σtot of 169Tm in the energy between 5 keV and 100 keV was obtained and compared with the evaluated data from ENDF/B-VIII.1, JENDL, and TENDL. The comparison result indicated that the σtot of 169Tm measured by this work is more consistent with the evaluated data of JENDL-5.