Measurement of high-energy excitation levels of fission product ¹⁴⁵Ba using a 4π clover detector

This paper reports the measurement method of high energy excitation levels using an entire solid angle type clover detector having four germanium crystal and a through-hole, and the identification of the high-energy excitation level and γ-rays of daughter nucleus ¹⁴⁵La based on the decay γ-ray measurement of fission product ¹⁴⁵Ba (T_1/2 = 4.31 s). For measuring the high-energy excitation level and γ-rays, 3 types of spectra were used for analysis: i.e. add-back spectrum, singles spectrum, and two-step cascade spectrum. First, using the add-back spectrum and singles spectrum of the daughter nuclei ¹⁴⁵La, about 90 of high energy excitation levels up to 3703 keV were identified. Next, using the two-step cascade spectrum, it was possible to identify the γ-rays transited from excited level of 2569 KeV, and for all identified excitation levels, about 300 of γ-rays transited from each level were identified. The excitation level of 2566 keV that has already been reported could be identified. (A.O.)