Subjects: Physics >> Nuclear Physics submitted time 2023-12-29
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
Abstract: The Compact Spectrometer for Heavy Ion Experiment (CSHINE) is under construction for the study of isospin chronology via the Hanbury Brown$-$Twiss (HBT) particle correlation function and the nuclear equation of state of asymmetrical nuclear matter. The CSHINE consists of silicon strip detector (SSD) telescopes and large-area parallel plate avalanche counters, which measure the light charged particles and fission fragments, respectively. In phase I, two SSD telescopes were used to observe 30 MeV/u $^{40}$Ar +$^{197}$Au reactions. The results presented here demonstrate that hydrogen and helium were observed with high isotopic resolution, and the HBT correlation functions of light charged particles could be constructed from the obtained data.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2023-11-15
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
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