Subjects: Physics >> Nuclear Physics submitted time 2024-05-24
Abstract： The recently discovered, extremely proton-rich nuclide 18Mg exhibits ground-state decay via two sequential two-proton (2p) emissions through the intermediate nucleus, 16Ne. This study investigates the structure and the initial 2p decay mechanism of 18Mg by examining the density and correlations of the valence protons using a three-body Gamow-coupled-channel method. The results show that the ground state of 18Mg is significantly influenced by the continuum, resulting in a significant s-wave component. However, based on the current frame- work, this does not lead to a significant deviation in mirror symmetry in either the structure or spectroscopy of the 18Mg-18C pair. Additionally, the time evolution analysis of the 18Mg ground state suggests a simultaneous 2p emission during the first step of decay. The observed nucleon–nucleon correlations align with those of the light–mass 2p emitters, indicating a consistent decay behavior within this nuclear region.
Subjects: Physics >> Nuclear Physics submitted time 2024-03-19
Abstract： The exploration of exotic shapes and properties of atomic nuclei, e.g., α cluster and toroidal shape, is a
fascinating field in nuclear physics. To study the decay of these nuclei, a novel detector aimed at detecting
multiple alpha-particle events was designed and constructed. The detector comprises two layers of double-sided
silicon strip detectors (DSSD) and a cesium iodide scintillator array coupled with silicon photomultipliers array
as light sensors, which has the advantages of their small size, fast response, and large dynamic range. DSSDs
couple with cesium iodide crystal arrays are used to distinguish multiple alpha hits. The detector array has a
compact and integrated design that can be adapted to different experimental conditions. The detector array was
simulated using Geant4, and the excitation energy spectra of some alpha-clustering nuclei were reconstructed
to demonstrate the performance. The simulation results show that the detector array has excellent angular
and energy resolutions, enabling effective reconstruction of the nuclear excited state by multiple alpha particle
events. This detector offers a new and powerful tool for nuclear physics experiments and has the potential to
discover interesting physical phenomena related to exotic nuclear structures and their decay mechanisms
Subjects: Physics >> Nuclear Physics submitted time 2024-03-19
Abstract： In recent years, the gap between the supply and demand of medical radioisotopes has increased, necessitating new methods for producing medical radioisotopes. Photonuclear reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical radioisotopes. However, the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical radioisotopes. In this study, the entire process of the generation, decay, and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gammaray spectrometer. Based on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source (SLEGS), the feasibility of the measurement of production cross section for surveyed medical isotopes was simulated, and specific solutions for measuring medical radioisotopes with low production cross sections were provided. The feasibility of this method for high precision measurements of the reaction cross section of medical radioisotopes was demonstrated.
Subjects: Physics >> Nuclear Physics submitted time 2023-09-07
Abstract： In this study, we developed a neural network that incorporates a fully connected layer with a convolutional layer to predict the nuclear charge radii based on the relationships between four local nuclear charge radii.
The convolutional neural network (CNN) combines the isospin and pairing effects to describe the charge radii of nuclei with $A geq $ 39 and $Z geq $ 20. The developed neural network achieved a root--mean--square (RMS) deviation of 0.0195 fm for a dataset with 928 nuclei. Specifically, the CNN reproduced the trend of the inverted parabolic behavior and odd--even staggering observed in the calcium isotopic chain, demonstrating reliable predictive capability.
Subjects: Physics >> Nuclear Physics submitted time 2022-01-21 Cooperative journals: 《Nuclear Science and Techniques》
Abstract：
By implementing an additional heavy quark–antiquark pair production trigger in a multiphase transport (AMPT) model, we study the effect on anisotropy flows of identified particles with a focus on charged particles and quarkonium (J/Ψ and Υ). A systematic increase in the collision rate for active partons in the AMPT model with such an implementation has been observed. It leads to a slight increase of identified particles anisotropy flows as a function of transverse momentum (pT ) and rapidity, and gives a better description of the experimental data of elliptic flow toward larger pT . Our approach provides an efficient way to study the heavy quark dynamics in the AMPT model at LHC energies.
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