Investigation of nuclear structure change expected for neutronrich deformed nuclei by means of lifetime measurements in sub-nanosecond region

我们研制了一种由LaBr_3和薄塑料闪烁体组成的光谱仪，旨在用于测量能级寿命。能谱仪对能量在100keV左右的γ射线的时间分辨率为600ps。这意味着光谱仪有足够的能力在时间范围内测量到亚纳秒的寿命。对质量分离的^<93>Sr和^<148>Ce观测到的能级寿命与先前评价良好的值一致。在^<148>Pr的98.2keV能级下，首次成功地获得了8.5(5)ns的寿命。

We have developed a spectrometer consisting of a LaBr_3 and a thin plastic scintillator, aiming for use to measure level lifetimes. The spectrometer showed a good time resolution of 600ps for γ rays with energies around 100keV. This means that the spectrometer is sufficiently capable of measuring lifetimes in a time range down to sub-nanosecond. Level lifetimes observed for mass-separated ^<93>Sr and ^<148>Ce agreed with the well-evaluated previous values. The lifetime of 8.5(5)ns for the 98.2keV level in ^<148>Pr was successfully obtained for the first time.