An experiment of neutron resonances in
159Tb was carried out using the Japan Atomic Energy Research Institute linac time-of-flight facility. Transmission and capture measurements were made on terbium samples of two thicknesses, using
6Li-glass and Moxon-Rae detectors at the 47 m station ; the neutron flux was monitored with a
6Li-glass transmission type flux monitor. Transmission data were analyzed with an area program up to 1.2 keV, and capture data with Monte-Carlo program CAFIT, to obtain 2gΓ
0n, Γ and Γ
γ. Resonance parameters of 209 levels below 1.2 keV are obtained, and 52 levels between 754 eV and 1.2 keV are new ones. The results are ; average level spacing <D> = 4.4 ± 0.4 eV below 600 eV, s-wave strength function S
0 = (1.55 ± 0.15)10
-4 below 1.2 keV, and average radiation width <Γ
γ> = 107 ± 7 meV for lower 25 levels. Average capture cross section <σ
c> were obtained from 50 eV to 30 keV.
View full abstract