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Study on Compton-suppressed Phoswich Gamma-ray Detector of LaBr3(Ce)-CsI(Tl)
Tianxiao LI, Hongyi WU, Yun ZHENG, Congbo LI, Lihua ZHU, Xiaoguang WU, Jingbin LU, Min ZHENG, Zihao ZHAO, Ruofu CHEN, Jiande WEI
2023, 40(1): 73-77. doi: 10.11804/NuclPhysRev.40.2022021  Published:2023-03-20
Keywords: phoswich gamma-ray detector, LaBr3(Ce), CsI(Tl), pulse shape identification, Monte Carlo simulation
In this work, a compact phoswich detector consisting of a cylindrical LaBr3(Ce) principal crystal and a well-shaped CsI(Tl) sub-crystal was designed and assembled to identify and reject Compton scattering in the LaBr3(Ce). Two different crystals coupled to the same photomultiplier tube (PMT). The energy deposition in each layer from incident radiation is then determined via digital pulse shape analysis of the PMT’s pulses. The results of Geant4 simulations were used to verify the performance of the pulse shape identification and the effect of Compton background suppression. Experimental tests were conducted on the detector prototype using a 60Co gamma source, and the result shown that the detector background suppression coefficient was 2.33(1) which achieved the expected purpose of twice as much as the Compton background was suppressed.
Study of Fusion Reaction Mechanism Induced by Weakly Bound Nuclei
Xuedou SU, Guangxin ZHANG, Shipeng HU, Zhen HUANG, Zhenwei JIAO, Mingli WANG, Gaolong ZHANG, Huanqiao ZHANG, Weiwei QU, Xiaoguang WU, Jingbin LU, Yifeng LÜ, Huibin SUN
2020, 37(2): 119-135. doi: 10.11804/NuclPhysRev.37.2019060  Published:2020-07-15
Keywords: weakly bound nuclei, complete and incomplete fusion, suppression factor, breakup effect, gamma rays, light charged particles
Investigation of fusion reaction mechanism is one of important topics in recent years. In comparison with radioactive ion beam, the beam intensities of weakly bound nuclei are orders of magnitude higher. The study of the reaction mechanism induced weakly bound nuclei can further explore the coupling effect of breakup, transfer and other reaction channels on the fusion process. A lot of experimental data have shown that there are many interesting phenomena in the fusion reaction induced by weakly bound nuclei at energies near the Coulomb barrier, such as "enhancement below the Coulomb barrier'' and "suppression above the Coulomb barrier'' of the complete fusion cross section. In this paper, we mainly review the researches of the suppression phenomenon and discuss the possible reasons for the suppression. The main reason for the suppression phenomenon of the complete fusion cross section is that the weakly bound nuclei break up before entering the fusion barrier, thus reducing the incident flux of the complete fusion reaction channel. At the same time, the experimental results show that the degree of suppression may be related to the mass number and structure of target nuclei. There are three kinds of methods to measure the fusion reaction induced by weakly bound nuclei, which are $\gamma$ ray measurement, charged particle measurement and charged particle -$\gamma$ ray coincidence measurement. The charged particle -$\gamma$ ray coincidence measurement has obvious advantages in reaction channel identification. This paper introduces the three measurement methods and the researches using these three methods at home and abroad, including the researches of our groups. In addition, the recent theoretical research work on fusion reactions induced by weakly bound nuclei is also introduced.