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 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
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
Subjects: Physics >> Nuclear Physics submitted time 2023-09-11
Abstract: A trigger system has been designed and implemented for the HIRFL-CSR external target experiment (CEE), the spectrometer for studying nuclear matter properties with heavy ion collisions in the GeV energy region. The system adopts master-slave structure and serial data transmission mode using optical fiber to deal with different types of detectors and long-distance signal transmission. The trigger logic can be accessed based on command register and controlled by a remote computer. The overall field programmable gate array (FPGA) logic can be flexibly reconfigured online to match the physical requirements of the experiment. The trigger system has been tested in beam experiment. It is demonstrated that the trigger system functions correctly and meets the physical requirements of CEE.
Peer Review Status:Awaiting Review
Subjects: Biology >> Biochemistry submitted time 2020-02-12
Abstract: A recent outbreak of pneumonia in Wuhan, China was caused by 2019 novel coronavirus (2019-nCoV). Here we reported 12 patients with 2019-nCoV infections in Shenzhen, China; all of them developed pneumonia and half developed acute respiratory distress syndrome (ARDS). We demonstrated the plasma cytokine profiles of these 12 patients. Thirty-eight out of 48 cytokines measured in the plasmas of 2019-nCoV infected patients were significantly elevated compared to healthy individuals. Seventeen cytokines were linked to 2019-nCoV load. Fifteen cytokines, M-CSF, IL-10, IFN-2, IL-17, IL-4, IP-10, IL-7, IL-1ra, G-CSF, IL-12, IFN-γ, IL-1, IL-2, HGF, and PDGF-BB, were strongly associated with lung injury Murray score, and could predict disease severity of 2019-nCoV infections according to area under the curve (AUC) of the receiver-operating characteristics (ROC) calculations. Our results suggest that 2019-nCoV infections trigger extensive changes in a wide array of cytokines, some of these cytokines could be potential biomarkers of disease severity of 2019-nCoV infections. These findings improve our understanding of the immunopathologic mechanisms of this emerging and still evolving disease and suggest that modulators of cytokine responses could play a therapeutic role in combating the disease. " "
Peer Review Status:Awaiting Review
Subjects: Biology >> Biochemistry submitted time 2020-02-08
Abstract: The outbreak of the 2019-nCoV infection began in December 2019 in Wuhan, Hubei province, and rapidly spread to many provinces in China as well as other countries. Here we report the epidemiological, clinical, laboratory, and radiological characteristics, as well as potential biomarkers for predicting disease severity in 2019-nCoV-infected patients in Shenzhen, China. All 12 cases of the 2019-nCoV-infected patients developed pneumonia and half of them developed acute respiratory distress syndrome (ARDS). The most common laboratory abnormalities were hypoalbuminemia (ALB), lymphopenia, decreased percentage of lymphocytes (LYM) and neutrophils (NEU), elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH), and decreased CD8 count. The viral load of 2019-nCoV detected from patient respiratory tracts was positively linked to lung disease severity. ALB, LYM, LYM (%), LDH, NEU (%) and CRP were highly correlated to the acute lung injury. Age, viral load, lung injury score, and blood biochemistry indexes, ALB, CRP, LDH, LYM (%), LYM, and NEU (%), may be predictors of disease severity. Moreover, the Angiotensin II level in the plasma sample from 2019-nCoV infected patients was markedly elevated and linearly associated to viral load and lung injury. Our results suggest a number of potential diagnosis biomarkers and angiotensin receptor blocker (ARB) drugs for potential repurposing treatment of 2019-nCoV infection.
Peer Review Status:Awaiting Review