arXiv subjects

Hui-Ling Wei

Publications and source records attributed to Hui-Ling Wei.

11 recordsLinked to original sources

arXiv2025

Improved ion bunch quality of conical target irradiated by ultra-intense and ultra-short laser

We conduct particle-in-cell simulations to estimate the effects of circularly and linearly polarized SEL 100 PW lasers on flat Th targets with thicknesses of 50 nm, 100 nm and 250 nm, as well as easy to manufacture conical Th targets with angularity either on the left or right. As the thickness of the three types of targets increases and under the same polarized laser, the average energy, maximum energy and energy conversion efficiency of Th ions decrease as it is well-known, and except for the circularly polarized laser hit on the conical target with angularity on the left, the Th ion beam emittance also decreases, while its beam intensity increases conversely. The linearly polarized laser, compared to the circularly polarized laser with the same laser intensity, exhibits higher beam intensity, beam emittance and energy conversion efficiency for the same type and thickness of Th target. The conical Th target with angularity on the left and intermediate thickness, compared to the flat target and conical target with angularity on the right of the same thickness, possesses both higher ion average energy up to 7 GeV and virtually the same beam intensity up to 0.8 MA under the linearly polarized laser. The results lead us to an easier way of controlling laser-accelerated high-quality heavy ion beam by switching to an optimal laser-target configuration scheme, which may enable the synthesis of superheavy nuclei in a high-temperature and high-density extreme plasma environment in astronuclear physics.

physics.plasm-ph↗

arXiv2021

Bayesian evaluation of residual production cross sections in proton induced spallation reactions

The Bayesian neural network (BNN) method is used to construct a predictive model for fragment prediction of proton induced spallation reactions with the guidance of a simplified EPAX formula. Compared to the experimental data, it is found that the BNN + sEPAX model can reasonably extrapolate with less information compared with BNN method. The BNN + sEPAX method provides a new approach to predict the energy-dependent residual cross sections produced in proton-induced spallation reactions from tens of MeV/u up to several GeV/u.

nucl-th↗

arXiv2020

A Bayesian-Neural-Network Prediction for Fragment Production in Proton Induced Spallation Reaction

Fragments productions in spallation reactions are key infrastructure data for various applications. Based on the empirical parameterizations {\sc spacs}, a Bayesian-neural-network (BNN) approach is established to predict the fragment cross sections in the proton induced spallation reactions. A systematic investigation have been performed for the measured proton induced spallation reactions of systems ranging from the intermediate to the heavy nuclei and the incident energy ranging from 168 MeV/u to 1500 MeV/u. By learning the residuals between the experimental measurements and the {\sc spacs} predictions, the BNN predicted results are in good agreement with the measured results. The established method is suggested to benefit the related researches in the nuclear astrophysics, nuclear radioactive beam source, accelerator driven systems, and proton therapy, etc.

nucl-th↗

arXiv2017

Experimental Determination of One- and Two-Neutron Separation Energies for Neutron-Rich Copper Isotopes

A method is proposed to determine the one-neutron $S_n$ or two-neutron $S_{2n}$ separation energy of neutron-rich isotopes. Relationships between $S_n$ ($S_{2n}$) and isotopic cross sections have been deduced from an empirical formula, i.e., the cross section of an isotope exponentially depends on the average binding energy per nucleon $B/A$. The proposed relationships have been verified using the neutron-rich copper isotopes measured in the 64$A$ MeV $^{86}$Kr + $^{9}$Be reaction. $S_n$, $S_{2n}$, and $B/A$ for the very neutron-rich $^{77, 78, 79}$Cu isotopes are determined from the proposed correlations. It is also proposed that the correlations between $S_n$, $S_{2n}$ and isotopic cross sections can be used to find the location of neutron drip line isotopes.

nucl-ex↗

arXiv2017

An Empirical Scaling formula for fragments production in projectile fragmentation reactions

A scaling phenomenon in the cross section for fragments has been found in the projectile fragmentation reaction, and an empirical scaling formula is proposed by considering the dependence of cross section on the size and asymmetry of the reaction system and the fragment itself. Furthermore, the empirical scaling formula is used to predict the production of fragment in the $^{68}$Ni/$^{69}$Cu/$^{72}$Zn + $^9$Be reactions around 90$A$ MeV. Compared to the results calculated by the statistical abrasion ablation model and the {\sc epax3} parameterizations, the empirical scaling formula can better reproduce the measured fragments. The empirical scaling formula can be used to predict the yield for fragment in projectile fragmentation reaction.

nucl-th↗

arXiv2015

A Scaling Phenomenon in Shannon Information Uncertainty Difference of fragments in Heavy-ion Collisions

The Shannon information-entropy uncertainty (in brief as "information uncertainty") is used to analyze the fragments in the measured 140$A$ MeV $^{40, 48}$Ca + $^{9}$Be and $^{58, 64}$Ni + $^{9}$Be reactions. A scaling phenomenon is found in the information-uncertainty difference of fragments between the reactions. The scaling phenomenon is explained in a manner of canonical ensemble theory, and is reproduced in the simulated reactions by the antisymmetric molecular dynamics (AMD) and AMD + GEMINI models. The probes based on information uncertainty, requiring no equilibrium state of reaction, can be used in the non-equilibrium system, and bridge the results of the static thermodynamics models and the evolving dynamical transport models.

nucl-ex↗

arXiv2014

Isotopic ratio, isotonic ratio, isobaric ratio and Shannon information uncertainty

The isoscaling and the isobaric yield ratio difference (IBD) probes, which both are constructed by yield ratio of fragment, provide cancelation of parameters. The information entropy theory is introduced to explain the physical meaning of the isoscaling and IBD probes. The similarity between the isoscaling and IBD results is found, i.e., the information uncertainty determined by the IBD method equals to $β-α$ determined by the isoscaling [$α$ ($β$) is the parameter fitted from the isotopic (isotonic) yield ratio].

nucl-th↗

arXiv2014

Neutron Density Distributions of Neutron-Rich Nuclei Studied with the Isobaric Yield Ratio Difference

The isobaric yield ratio difference (IBD) between two reactions of similar experimental setups is found to be sensitive to nuclear density differences between projectiles. In this article, the IBD probe is used to study the density variation in neutron-rich $^{48}$Ca. By adjusting diffuseness in the neutron density distribution, three different neutron density distributions of $^{48}$Ca are obtained. The yields of fragments in the 80$A$ MeV $^{40, 48}$Ca + $^{12}$C reactions are calculated by using a modified statistical abrasion-ablation model. It is found that the IBD results obtained from the prefragments are sensitive to the density distribution of the projectile, while the IBD results from the final fragments are less sensitive to the density distribution of the projectile.

nucl-th↗

arXiv2014

Residue Coulomb interaction among isobars and its influence in symmetry energy of neutron-rich fragment

The residue Coulomb interaction (RCI), which affects the results of symmetry energy of neutron-rich nucleus in isobaric yield ratio (IYR) methods, is difficult to be determined. Four RCI approximations are investigated: (1) the M1--RCI adopting the $a_{c}/T$ (the ratio of Coulomb energy coefficient to temperature) determined from the IYR of mirror-nuclei fragment; (2) the M2--RCI by fitting the difference between IYRs; (3) the M3--RCI by adopting the standard Coulomb energy at a temperature $T=2$MeV; and (4) neglecting the RCI among the three isobars. The M1--, M2-- and M3--RCI is found to no larger than 0.4. In particular, the M2--RCI is very close to zero. The effects of RCI in the $a_{sym}/T$ of fragment are also studied. The M1-- and M4--$a_{sym}/T$ are found to be the lower and upper limitations of $a_{sym}/T$, respectively. The M2--$a_{sym}/T$ overlaps the M4--$a_{sym}/T$, which indicates that the M2--RCI is negligible, at the same time the RCI among the three isobars can be neglected. A relative consistent low values of M3--$a_{sym}/T$ ($7.5\pm2.5$) are found in very neutron-rich isobars.

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arXiv2013

Chemical Property of Colliding Sources in 124,136Xe and 112,124Sn Induced Collisions in Isobaric Ratio Difference and Isoscaling Methods

The isoscaling and isobaric ratio difference (IBD) methods are used to study the $Δμ/T$ ($Δμ$ being the difference between the chemical potentials of neutron and proton, and $T$ being the temperature) in the measured 1$A$ GeV $^{124}$Sn + $^{124}$Sn, $^{112}$Sn + $^{112}$Sn, $^{136}$Xe + Pb and $^{124}$Xe + Pb reactions. The isoscaling phenomena in the $^{124}$Sn/$^{112}$Sn and the $^{136}$Xe/$^{124}$Xe reactions pairs are investigated, and the isoscaling parameter $α$ and $β$ are obtained. The $Δμ/T$ determined by the isoscaling method (IS--$Δμ/T$) and IBD method (IB--$Δμ/T$) in the measured Sn and Xe reactions are compared. It is shown that in most of fragments, the IS-- and IB-- $Δμ/T$ are consistent in the Xe reactions, while the IS-- and IB-- $Δμ/T$ are only similar in the less neutron-rich fragments in the Sn reactions. The shell effects in IB--$Δμ/T$ are also discussed.

nucl-ex↗

arXiv2013

Isobaric Yield Ratio Difference in Heavy-ion Collisions, and Comparison to Isoscaling

An isobaric yield ratio difference (IBD) method is proposed to study the ratio of the difference between the chemical potential of neutron and proton to temperature ($Δμ/T$) in heavy-ion collisions. The $Δμ/T$ determined by the IBD method (IB-$Δμ/T$) is compared to the results of the isoscaling method (IS-$Δμ/T$), which uses the isotopic or the isotonic yield ratio. Similar distributions of the IB- and IS-$Δμ/T$ are found in the measured 140$A$ MeV $^{40,48}$Ca + $^{9}$Be and the $^{58,64}$Ni + $^{9}$Be reactions. The IB- and IS-$Δμ/T$ both have a distribution with a plateau in the small mass fragments plus an increasing part in the fragments of relatively larger mass. The IB- and IS-$Δμ/T$ plateaus show dependence on the $n/p$ ratio of the projectile. It is suggested that the height of the plateau is decided by the difference between the neutron density ($ρ_n$) and the proton density ($ρ_p$) distributions of the projectiles, and the width shows the overlapping volume of the projectiles in which $ρ_n$ and $ρ_p$ change very little. The difference between the IB- and IS-$Δμ/T$ is explained by the isoscaling parameters being constrained by the many isotopes and isotones, while the IBD method only uses the yields of two isobars. It is suggested that the IB-$Δμ/T$ is more reasonable than the IS-$Δμ/T$, especially when the isotopic or isotonic ratio disobeys the isoscaling. As to the question whether the $Δμ/T$ depends on the density or the temperature, the density dependence is preferred since the low density can result in low temperature in the peripheral reactions.

nucl-ex↗