Subjects: Physics >> Nuclear Physics submitted time 2023-12-29
Dawei Si
Yan Zhou
Sheng Xiao
Zhi Qin
Dong Guo
Yuhao Qin
Yijie Wang
Boyuan Zhang
Baiting Tian
Zhigang Xiao
Abstract： The energetic bremsstrahlung photons up to 100 MeV produced in heavy ion collisions can be used as a
sensitive probe to the short range correlation in atomic nuclei. The energy of the γ-rays can be measured
by collecting theˇCerenkov light in medium induced by the fast electrons generated in Compton scattering or
electromagnetic shower of the incident γ ray. Two types of detectors, based on pure water and lead glass as
the sensitive material respectively, are designed for the above purpose. The γ response and optical photon
propagation in detectors have been simulated based on the electromagnetic and optical processes in Geant4.
The inherent energy resolution of 0.022(4) + 0.51(2)/Eγ 1/2 for water and 0.0026(3) + 0.446(3)/Eγ 1/2 for
lead glass are obtained. The geometry size of lead glass and water are optimized at 30 × 30 × 30 cm3 and
60 × 60 × 120 cm3 , respectively, for detecting high energy γ-rays at 160 MeV. Hough transform method has
been applied to reconstruct the direction of the incident γ-rays, giving the ability to distinguish experimentally
the high-energy γ rays produced in the reactions on the target from the random background cosmic ray muons.
Subjects: Physics >> Nuclear Physics submitted time 2023-11-25
Yijie Wang
Fenhai Guan
Qianghua Wu
Xinyue Diao
Yan Huang
Liming Lyu
Yuhao Qin
Zhi Qin
Dawei Si
Zhen Bai
Fangfang Duan
Limin Duan
Zhihao Gao
Qiang Hu
Rongjiang Hu
Genming Jin
Shuya Jin
Junbing Ma
Peng Ma
Jiansong Wang
Abstract： The intensity interferometry is applied as a chronometer of the particle emission of hydrogen isotopes from the intermediate velocity source formed in $^{40}$Ar+$^{197}$Au reactions at 30 MeV/u. The dynamic emission order of $ tau_{ rm p}> tau_{ rm d}> tau_{ rm t}$ is evidenced via the correlation functions of nonidentical particle pairs. Assuming the similar source size, the same emission order is inferred from the correlation functions of identical particle pairs, where $ tau_{ rm p} approx 100 { rm ~fm/c}$ is extracted by the fit of Koonin-Pratt equation to p-p correlation function. Transport model simulations demonstrate that the dynamic emission order of light charged particles depends on the stiffness of the nuclear symmetry energy.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2023-11-15
Yijie Wang
Mengting Wan
Xinyue Diao
Sheng Xiao
Yuhao Qin
Zhi Qin
Dong Guo
Dawei Si
Boyuan Zhang
Baiting Tian
Fenhai Guan
Qianghua Wu
Xianglun Wei
Herun Yang
Peng Ma
Rongjiang Hu
Limin Duan
Fangfang Duan
Junbing Ma
Shiwei Xu
Abstract： The neutron rich neck zone created in heavy ion reaction is experimentally probed by the production of the $A=3$ isobars. The energy spectra and angular distributions of triton and $^3$He are measured with the CSHINE detector in $^{86}$Kr +$^{208}$Pb reactions at 25 MeV/u. While the energy spectrum of $^{3}$He is harder than that of triton, known as "$^{3}$He-puzzle", the yield ratio $R({ rm t/^3He})$ presents a robust rising trend with the polar angle in laboratory. Using the fission fragments to reconstruct the fission plane, the enhancement of out-plane $R({ rm t/^3He})$ is confirmed in comparison to the in-plane ratios. Transport model simulations reproduce qualitatively the experimental trends, but the quantitative agreement is not achieved. The results demonstrate that a neutron rich neck zone is formed in the reactions. Further studies are called for to understand the clustering and the isospin dynamics related to neck formation.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2023-11-14
Yijie Wang
Fenhai Guan
Dawei Si
Sheng Xiao
Boyuan Zhang
Yaopeng Zhang
Baiting Tian
Xianglun Wei
Herun Yang
Peng Ma
Rongjiang Hu
Limin Duan
Fangfang Duan
Qiang Hu
Junbing Ma
Shiwei Xu
Zhen Bai
Yanyun Yang
Jiansong Wang
Wenbo Liu
Abstract： Two-body correlations of the isotope-resolved light and heavy clusters are measured in 86Kr+ 208Pb reactions at 25 MeV/u. The yield and kinetic variables of the A = 3 isobars, triton and 3He, are analyzed in coincidence with the heavy clusters of 7 ≤ A ≤ 14 emitted at the earlier chance. While the velocity spectra of both triton and 3He exhibit scaling behavior over the type of the heavy clusters, the yield ratios of t/ 3He correlate reversely to the neutron-to-proton ratio N/Z of the latter, showing the ping-pong modality of the N/Z of emitted clusters. The commonality that the N/Z of the residues keeps the initial system value is extended to the cluster emission in heavy ion reactions. The comparison of transport model calculations to the data is discussed.
Peer Review Status:Awaiting Review
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