摘要
A LaBr3：Ce scintillator has a high light output （～60000 p.e/MeV） and a short decay constant （25 ns）, which makes it good for time spectrometry. Compared with a BaF2 scintillator, it can bear a much higher count rate, and can be coupled to photomultipliers without using a quartz window. In this work, a positron annihilation lifetime spectrometer （PALS） consisting of two bulks of φ25 mm×25 mm LaBr3：Ce scin- tillator coupled to two XP20D0 photomultipliers, respectively, was built. A time resolution of FWHM=206 ps was measured for the PALS with a 60Co source at the energy window for 22Na. With this spectrometer, a reasonable lifetime value τ =221±4 ps in a pure Si sample is obtained, which means that the utilization of LaBr3：Ce as the detector for a PALS is feasible.
A LaBr3：Ce scintillator has a high light output （～60000 p.e/MeV） and a short decay constant （25 ns）, which makes it good for time spectrometry. Compared with a BaF2 scintillator, it can bear a much higher count rate, and can be coupled to photomultipliers without using a quartz window. In this work, a positron annihilation lifetime spectrometer （PALS） consisting of two bulks of φ25 mm×25 mm LaBr3：Ce scin- tillator coupled to two XP20D0 photomultipliers, respectively, was built. A time resolution of FWHM=206 ps was measured for the PALS with a 60Co source at the energy window for 22Na. With this spectrometer, a reasonable lifetime value τ =221±4 ps in a pure Si sample is obtained, which means that the utilization of LaBr3：Ce as the detector for a PALS is feasible.
基金
Supported by National Natural Science Foundation of China(10805049,10775149)
