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, Update time: , doi: 10.11804/NuclPhysRev.41.2023065
Abstract:
In this work, we presented the test results for a prototype of plastic scintillation detectors for time-of-flight measurement, aiming to provide preliminary research for the future development of time-of-flight detectors for HIAFHFRS facility. Each timing detectors was composed of a fast scintillating plastic and four fast photomultiplier tubes coupled to its four sides. The time performance of the detectors was tested using pico-second pulsed laser, For two plastic scintillation detectors with different sizes, a pico-second pulsed laser was used to simulating the actual ionbeam situation by changing laser’s parameters including spot size, repetition rate, light intensity and hitting position. The data was processed utilizing CAEN-DT5742 digitizer and Mesytec-MCFD16+MTDC32 electronics. When the focused laser hit at the center of the plastic scintillators, the time-of-flight (ToF) resolution of two small-sized (7 cm×7cm)plastic scintillation detectors could reach 8 ps, whereas the ToF resolution of the small and large (26 cm×10 cm) detectors could achieve 12 ps. After varying the parameters of the laser, the corresponding ToF resolutions were found to be in the range of 10–16 ps and 19–46 ps, respectively. The ToF resolutions from the test meets the timing-resolution requirement of the HFRS beamline, thereby establishing a solid foundation for further optimizing the time-of-flight detectors.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC11
Abstract:
Based on the group-algebra theory, we illustrate how to build the quadrupole-quadrupole dynamics for the identical fermion and boson systems within the s, d single-particle orbits, by which the influence of identity principle on the many-body dynamical structures of nuclei is discussed. The results indicate that the dimension of low-spin states in the identical fermion system with a given number of particle is much larger than the corresponding situation in the identical boson system, which means that the former can involve a richer rotational structure than the latter under similar conditions. The present analysis provides an example for analyzing nuclear structural model using the SU(3) group-algebra theory.
Based on the group-algebra theory, we illustrate how to build the quadrupole-quadrupole dynamics for the identical fermion and boson systems within the s, d single-particle orbits, by which the influence of identity principle on the many-body dynamical structures of nuclei is discussed. The results indicate that the dimension of low-spin states in the identical fermion system with a given number of particle is much larger than the corresponding situation in the identical boson system, which means that the former can involve a richer rotational structure than the latter under similar conditions. The present analysis provides an example for analyzing nuclear structural model using the SU(3) group-algebra theory.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC01
Abstract:
Reaction dynamics, especially the breakup mechanisms, induced by proton drip-line nuclei at energies around the Coulomb barrier, is one of the most popular topics in nuclear physics. In order to further investigate the reaction mechanisms of proton drip-line nuclei, we performed the complete-kinematics measurements of 8B+120Sn and 17F+58Ni at CRIB, University of Tokyo. This paper summarizes our research findings and unveils for the first time the fusion cross-section results in the 8B+120Sn measurement. Two detector arrays, i.e., the silicon telescope array of STARE and the ionization chamber array of MITA, were designed respectively for the measurements of 8B and 17F. Reaction products were completely identified with the help of these two arrays. For the 8B+120Sn system, the coincident measurement of the breakup fragments was achieved for the first time. The correlations between the breakup fragments reveal that the prompt breakup occurring on the outgoing trajectory dominates the breakup dynamics of 8B. For 17F+58Ni, the complete reaction channel information, such as quasi-elastic scattering, breakup and total fusion, was derived for the first time. An enhancement of the fusion cross section of 17F+58Ni was observed at the energy below the Coulomb barrier. Theoretical calculations indicate that this phenomenon is mainly due to the coupling to the continuum states. Moreover, different direct reaction dynamics were found in 8B and 17F systems, suggesting the influence of proton-halo structure on the reaction dynamics.
Reaction dynamics, especially the breakup mechanisms, induced by proton drip-line nuclei at energies around the Coulomb barrier, is one of the most popular topics in nuclear physics. In order to further investigate the reaction mechanisms of proton drip-line nuclei, we performed the complete-kinematics measurements of 8B+120Sn and 17F+58Ni at CRIB, University of Tokyo. This paper summarizes our research findings and unveils for the first time the fusion cross-section results in the 8B+120Sn measurement. Two detector arrays, i.e., the silicon telescope array of STARE and the ionization chamber array of MITA, were designed respectively for the measurements of 8B and 17F. Reaction products were completely identified with the help of these two arrays. For the 8B+120Sn system, the coincident measurement of the breakup fragments was achieved for the first time. The correlations between the breakup fragments reveal that the prompt breakup occurring on the outgoing trajectory dominates the breakup dynamics of 8B. For 17F+58Ni, the complete reaction channel information, such as quasi-elastic scattering, breakup and total fusion, was derived for the first time. An enhancement of the fusion cross section of 17F+58Ni was observed at the energy below the Coulomb barrier. Theoretical calculations indicate that this phenomenon is mainly due to the coupling to the continuum states. Moreover, different direct reaction dynamics were found in 8B and 17F systems, suggesting the influence of proton-halo structure on the reaction dynamics.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC05
Abstract:
In this work, the Gamow-like model for calculating the one-proton radioactivity half-life is improved by introducing the deformation of the nucleus. The calculations show that the deformed Gamow-like model can reproduce the experimental data better than the Gamow-like model. In addition, the reliability of the deformed Gamow-like model is confirmed by studying the linear relationship between the logarithmic form of the experimental half-life and the logarithmic form of the theoretical penetration probability. As an application, the one-proton radioactivity half-life of the deformed nucleus is predicted using the deformed Gamow-like model, and the predictions are able to comply well with the Geiger-Nuttall law. Finally, by studying the relationship between the orbital angular momentum and the calculated half-life, the reference values of the orbital angular momentum of 109I and 131Eu are given to obtain a more accurate theoretical half-life for one-proton radioactivity.
In this work, the Gamow-like model for calculating the one-proton radioactivity half-life is improved by introducing the deformation of the nucleus. The calculations show that the deformed Gamow-like model can reproduce the experimental data better than the Gamow-like model. In addition, the reliability of the deformed Gamow-like model is confirmed by studying the linear relationship between the logarithmic form of the experimental half-life and the logarithmic form of the theoretical penetration probability. As an application, the one-proton radioactivity half-life of the deformed nucleus is predicted using the deformed Gamow-like model, and the predictions are able to comply well with the Geiger-Nuttall law. Finally, by studying the relationship between the orbital angular momentum and the calculated half-life, the reference values of the orbital angular momentum of 109I and 131Eu are given to obtain a more accurate theoretical half-life for one-proton radioactivity.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC07
Abstract:
Relativistic Brueckner-Hartree-Fock(RBHF) theory is one of the most important ab initio methods in the relativistic framework, where the saturation properties of nuclear matter could be described satisfactorily with only considering two-body forces. By achieving the self-consistent solution of the RBHF equations for nuclear matter in the full Dirac space, the scalar and vector components of the single-particle potential have been determined uniquely, the uncertainties caused by the neglect of negative-energy states(NESs) have been avoided, and the long-standing problem over 40 years of not being able to uniquely determine the single-particle potential has been solved. The history of the RBHF theory is briefly reviewed, and the necessity of considering NESs is illustrated. The latest results of nuclear matter and neutron star matter by the RBHF theory in the full Dirac space are discussed, including the effective mass, the binding energy per particle of pure neutron matter, the pressure of symmetric nuclear matter and pure neutron matter, the particle fractions as well as the equation of state for neutron star matter, and the mass-radius relation as well as the tidal deformability of a neutron star. Possible applications of the RBHF theory in the full Dirac space are also discussed, including the calibration of the parameters in density functional theory, the microscopic description of nucleon-nucleus elastic scattering, and the research on the hadron-quark transition inside neutron stars.
Relativistic Brueckner-Hartree-Fock(RBHF) theory is one of the most important ab initio methods in the relativistic framework, where the saturation properties of nuclear matter could be described satisfactorily with only considering two-body forces. By achieving the self-consistent solution of the RBHF equations for nuclear matter in the full Dirac space, the scalar and vector components of the single-particle potential have been determined uniquely, the uncertainties caused by the neglect of negative-energy states(NESs) have been avoided, and the long-standing problem over 40 years of not being able to uniquely determine the single-particle potential has been solved. The history of the RBHF theory is briefly reviewed, and the necessity of considering NESs is illustrated. The latest results of nuclear matter and neutron star matter by the RBHF theory in the full Dirac space are discussed, including the effective mass, the binding energy per particle of pure neutron matter, the pressure of symmetric nuclear matter and pure neutron matter, the particle fractions as well as the equation of state for neutron star matter, and the mass-radius relation as well as the tidal deformability of a neutron star. Possible applications of the RBHF theory in the full Dirac space are also discussed, including the calibration of the parameters in density functional theory, the microscopic description of nucleon-nucleus elastic scattering, and the research on the hadron-quark transition inside neutron stars.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC17
Abstract:
In heavy ion collisions(HICs), the production of light particles plays an important role in extracting information about the equation of state(EoS) of nuclear matter. Based on the Ultra-relativistic Quantum Molecular Dynamics(UrQMD) model, the effect of the sequential decay on the collective flows and the nuclear stopping power of light particles in Au+Au collisions at intermediate energies were investigated, with the statistical decay model GEMINI++ is used to process the secondary decay of the primary fragments. It is found that due to the memory effect and the daughter nuclei produced by decay inherent part of the dynamic information of the parent nucleus, the experimental data can be better described by considering the sequential decay. And the influence of the sequential decay on the observables weakens with the increase of the collision energy. The results highlight that the sequential decay and the production of light particles in HICs have an obvious effect on the observables sensitive to the EoS, and these effects should be considered when adopting these observables to extract the information of the EoS.
In heavy ion collisions(HICs), the production of light particles plays an important role in extracting information about the equation of state(EoS) of nuclear matter. Based on the Ultra-relativistic Quantum Molecular Dynamics(UrQMD) model, the effect of the sequential decay on the collective flows and the nuclear stopping power of light particles in Au+Au collisions at intermediate energies were investigated, with the statistical decay model GEMINI++ is used to process the secondary decay of the primary fragments. It is found that due to the memory effect and the daughter nuclei produced by decay inherent part of the dynamic information of the parent nucleus, the experimental data can be better described by considering the sequential decay. And the influence of the sequential decay on the observables weakens with the increase of the collision energy. The results highlight that the sequential decay and the production of light particles in HICs have an obvious effect on the observables sensitive to the EoS, and these effects should be considered when adopting these observables to extract the information of the EoS.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC18
Abstract:
The nucleon-nucleon short-range correlation(NN-SRC) is one of the key issues in nuclear physics that cause high-momentum tails in the nucleon momentum distributions. In this paper, the nuclear spectral functions are constructed based on the axially deformed relativistic mean-field model, and the correction of the short-range correlation effect is introduced. Then, the inclusive scattering cross sections are calculated using the nuclear spectral function and the framework of the plane wave impulse approximation, including both the quasielastic and Δ resonance parts. In particular, in the Δ resonance region, the electromagnetic structure of the nucleon resonance state Δ(1232) is reconsidered, which effectively improves the theoretical calculations that can be in better agreement with experimental data. The paper further divides the inclusive scattering cross sections into the contributions of NN-SRC and mean-field. It is found that, the quasielastic peak and Δ resonance peak not only reflect the mean-field structure but also are sensitive to NN-SRC information. Finally, we propose a method for extracting the NN-SRC strength of nuclei from experimental cross-section data.
The nucleon-nucleon short-range correlation(NN-SRC) is one of the key issues in nuclear physics that cause high-momentum tails in the nucleon momentum distributions. In this paper, the nuclear spectral functions are constructed based on the axially deformed relativistic mean-field model, and the correction of the short-range correlation effect is introduced. Then, the inclusive scattering cross sections are calculated using the nuclear spectral function and the framework of the plane wave impulse approximation, including both the quasielastic and Δ resonance parts. In particular, in the Δ resonance region, the electromagnetic structure of the nucleon resonance state Δ(1232) is reconsidered, which effectively improves the theoretical calculations that can be in better agreement with experimental data. The paper further divides the inclusive scattering cross sections into the contributions of NN-SRC and mean-field. It is found that, the quasielastic peak and Δ resonance peak not only reflect the mean-field structure but also are sensitive to NN-SRC information. Finally, we propose a method for extracting the NN-SRC strength of nuclei from experimental cross-section data.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC04
Abstract:
The recent progresses on the wobbling motion are briefly introduced. So far 17 wobbling candidates have been reported in odd-A and even-even nuclei that spread over A≈100, 130, 160 and 190 mass regions. The two-quasiparticle configuration wobbling in 130Ba and the wobbling motion in a triaxial rotor are taken as examples in this paper to show the wobbling motion in even-even nuclei. For the 130Ba, the wobbling are investigated based on the combination of the covariant density functional theory (CDFT) and the particle rotor model (PRM). The CDFT provides crucial information on the configuration and deformation parameters of observed bands, serving as input for PRM calculations. The corresponding experimental energy spectra and electromagnetic transition probabilities are reproduced. An analysis of the angular momentum geometry reveals the enhanced stability of transverse wobbling of a two-quasiparticle configuration compared to a single-quasiparticle one. For the triaxial rotor, the time evolution of wobbling motion is explored through the solution of Euler equations. This investigation yields valuable insights into the evolution of orientation angles (\begin{document}$\phi $\end{document} ![]()
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\begin{document}$\theta $\end{document} ![]()
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The recent progresses on the wobbling motion are briefly introduced. So far 17 wobbling candidates have been reported in odd-A and even-even nuclei that spread over A≈100, 130, 160 and 190 mass regions. The two-quasiparticle configuration wobbling in 130Ba and the wobbling motion in a triaxial rotor are taken as examples in this paper to show the wobbling motion in even-even nuclei. For the 130Ba, the wobbling are investigated based on the combination of the covariant density functional theory (CDFT) and the particle rotor model (PRM). The CDFT provides crucial information on the configuration and deformation parameters of observed bands, serving as input for PRM calculations. The corresponding experimental energy spectra and electromagnetic transition probabilities are reproduced. An analysis of the angular momentum geometry reveals the enhanced stability of transverse wobbling of a two-quasiparticle configuration compared to a single-quasiparticle one. For the triaxial rotor, the time evolution of wobbling motion is explored through the solution of Euler equations. This investigation yields valuable insights into the evolution of orientation angles (
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC24
Abstract:
Based on the self-consistent RBUU transport theory, the isospin-dependent in-medium\begin{document}$ {\rm{N}} \Delta \rightarrow {\rm{N}} \Delta$\end{document} ![]()
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\begin{document}$ {\rm{N}} \Delta $\end{document} ![]()
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\begin{document}$\sigma-\delta$\end{document} ![]()
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\begin{document}$\sigma-\rho$\end{document} ![]()
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\begin{document}$\omega-\delta$\end{document} ![]()
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\begin{document}$\omega-\rho$\end{document} ![]()
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Based on the self-consistent RBUU transport theory, the isospin-dependent in-medium
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC20
Abstract:
Nuclear mass plays an important role in both nuclear physics and astrophysics. While the theoretical accuracy of masses has reached quite astonishing accuracy, their extrapolations have been conflicting, especially in neutron-rich regions. This paper reviews the main results of the extrapolations of nuclear mass models in recent years. By using a rigorous multi-objective optimization on mass models, we take the mass differences α decay energy and the Garvey-Kelson relations as multiple physical constraints to reduce the degree of overfitting phenomenon, resulting that the predictive power of models was improved in some degree. In addition, we use the improved mass data for the rapid neutron capture processes in nuclear astrophysics, further validating the reliability of the extrapolations.
Nuclear mass plays an important role in both nuclear physics and astrophysics. While the theoretical accuracy of masses has reached quite astonishing accuracy, their extrapolations have been conflicting, especially in neutron-rich regions. This paper reviews the main results of the extrapolations of nuclear mass models in recent years. By using a rigorous multi-objective optimization on mass models, we take the mass differences α decay energy and the Garvey-Kelson relations as multiple physical constraints to reduce the degree of overfitting phenomenon, resulting that the predictive power of models was improved in some degree. In addition, we use the improved mass data for the rapid neutron capture processes in nuclear astrophysics, further validating the reliability of the extrapolations.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC03
Abstract:
The diamond-like carbon(DLC) stripper foils with ~5 μg/cm2 in thickness were produced by using the composite technology of the filtered cathodic vacuum arc(FCVA)- alternating current carbon arc(ACCA)-relaxation technique. The uniformity of the DLC foils were measured by the XP2U balance. The results show that the maximum inhomongeneity of DLC foils in the range of Φ100 mm is 8.82%. The microstructure of the DLC foils were measured by the scanning electron microscopy(SEM), Raman spectroscopy and X-ray photoelectron spectroscopy(XPS). The SEM images show that the DLC foils are smooth, and contain hardly droplets through the double 90° filters. The Raman spectrum indicates that the DLC foils are amorphous carbon films. The X-ray photoelectron spectrum indicates the sp3 bonds of the DLC foils exceed 70%. The irradiation lifetimes of the DLC stripper foils were tested with the heavy ion beams at the Beijing HI-13 Tandem Accelerator. The results indicate that the lifetime of the DLC stripper foils after relaxation is ~3 times of the DLC stripper foils before relaxation. The lifetime of DLC stripper foil is respectively 4 and 13 times of the carbon stripper foil for the 197Au− and 63Cu− ion beams(~9 MV, ~1 μA). The lifetime of DLC stripper foil is 2.6~10.0 times of the carbon stripper foil for the 107Ag−、70Ge−、48Ti−、28Si− and 127I− ion beams. The heavier ions and the stronger beam current, the longer lifetime of DLC stripper foil compared with that of carbon stripper foil. The lifetime of the DLC stripper foils is related to the substrate bias voltage, and increases at first and then decreases with the increasing of the substrate bias voltage. The lifetime reaches the peak value when the substrate bias voltage is −400 V.
The diamond-like carbon(DLC) stripper foils with ~5 μg/cm2 in thickness were produced by using the composite technology of the filtered cathodic vacuum arc(FCVA)- alternating current carbon arc(ACCA)-relaxation technique. The uniformity of the DLC foils were measured by the XP2U balance. The results show that the maximum inhomongeneity of DLC foils in the range of Φ100 mm is 8.82%. The microstructure of the DLC foils were measured by the scanning electron microscopy(SEM), Raman spectroscopy and X-ray photoelectron spectroscopy(XPS). The SEM images show that the DLC foils are smooth, and contain hardly droplets through the double 90° filters. The Raman spectrum indicates that the DLC foils are amorphous carbon films. The X-ray photoelectron spectrum indicates the sp3 bonds of the DLC foils exceed 70%. The irradiation lifetimes of the DLC stripper foils were tested with the heavy ion beams at the Beijing HI-13 Tandem Accelerator. The results indicate that the lifetime of the DLC stripper foils after relaxation is ~3 times of the DLC stripper foils before relaxation. The lifetime of DLC stripper foil is respectively 4 and 13 times of the carbon stripper foil for the 197Au− and 63Cu− ion beams(~9 MV, ~1 μA). The lifetime of DLC stripper foil is 2.6~10.0 times of the carbon stripper foil for the 107Ag−、70Ge−、48Ti−、28Si− and 127I− ion beams. The heavier ions and the stronger beam current, the longer lifetime of DLC stripper foil compared with that of carbon stripper foil. The lifetime of the DLC stripper foils is related to the substrate bias voltage, and increases at first and then decreases with the increasing of the substrate bias voltage. The lifetime reaches the peak value when the substrate bias voltage is −400 V.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC12
Abstract:
High-spin level structure of 95Nb has been investigated using the multi-detector array of the conjoint gamma array in China via the 82Se(18O, p4n)95Nb. Based on γ-γ coincidence relationships, the level scheme of 95Nb has been modified and extended with 25 new γ rays and 15 new levels. The new level structure of 95Nb has been compared with the shell model calculations. It is suggested that the proton core excitation(f5/2→g9/2) across\begin{document}$Z = 38 $\end{document} ![]()
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High-spin level structure of 95Nb has been investigated using the multi-detector array of the conjoint gamma array in China via the 82Se(18O, p4n)95Nb. Based on γ-γ coincidence relationships, the level scheme of 95Nb has been modified and extended with 25 new γ rays and 15 new levels. The new level structure of 95Nb has been compared with the shell model calculations. It is suggested that the proton core excitation(f5/2→g9/2) across
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC23
Abstract:
The Lanzhou Heavy Ion Accelerator Cooling Storage Ring(HIRFL-CSR) is an ideal device for studying the decay of highly charged and short-lived isomers. In the lifetime measurement experiment of the short-lived highly charged ion\begin{document}$^{94m}{\rm{Ru}}^{44+}$\end{document} ![]()
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\begin{document}$^{94}{\rm{Ru}}$\end{document} ![]()
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\begin{document}$^{94m}{\rm{Ru}}^{44+}$\end{document} ![]()
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The Lanzhou Heavy Ion Accelerator Cooling Storage Ring(HIRFL-CSR) is an ideal device for studying the decay of highly charged and short-lived isomers. In the lifetime measurement experiment of the short-lived highly charged ion
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC14
Abstract:
There must be electromagnetic fields created during high-energy heavy-ion collisions. Although the electromagnetic field may become weak with the evolution of the quark-gluon plasma (QGP), compared to the energy scales of the strong interaction, they are potentially important to some electromagnetic probes. In this work, we propose the coupled effect of the weak magnetic field and the longitudinal dynamics of the background medium for the first time. We demonstrate that the induced photon spectrum can be highly azimuthally anisotropic when the quark-gluon plasma is in the presence of a weak external magnetic field. On the other hand, the weak magnetic photon emission from quark-gluon plasma only leads to a small correction to the photon production rate. After hydrodynamic evolution with a tilted fireball configuration, the experimentally measured direct photon elliptic flow is well reproduced. Meanwhile, the used time-averaged magnetic field in the hydrodynamic stage is found no larger than a few percent of the pion mass square.
There must be electromagnetic fields created during high-energy heavy-ion collisions. Although the electromagnetic field may become weak with the evolution of the quark-gluon plasma (QGP), compared to the energy scales of the strong interaction, they are potentially important to some electromagnetic probes. In this work, we propose the coupled effect of the weak magnetic field and the longitudinal dynamics of the background medium for the first time. We demonstrate that the induced photon spectrum can be highly azimuthally anisotropic when the quark-gluon plasma is in the presence of a weak external magnetic field. On the other hand, the weak magnetic photon emission from quark-gluon plasma only leads to a small correction to the photon production rate. After hydrodynamic evolution with a tilted fireball configuration, the experimentally measured direct photon elliptic flow is well reproduced. Meanwhile, the used time-averaged magnetic field in the hydrodynamic stage is found no larger than a few percent of the pion mass square.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC19
Abstract:
The number of constituent quark(NCQ) scaling of elliptic flow in heavy-ion collisions is one of the important signals of parton anisotropic degrees of freedom. In this work, we systematically study the\begin{document}$\upsilon_{2}^{}$\end{document} ![]()
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\begin{document}$p_{\mathrm{T}}^{}$\end{document} ![]()
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\begin{document}$\upsilon_{2}^{}$\end{document} ![]()
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\begin{document}$\upsilon_{2}^{}$\end{document} ![]()
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The number of constituent quark(NCQ) scaling of elliptic flow in heavy-ion collisions is one of the important signals of parton anisotropic degrees of freedom. In this work, we systematically study the
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC16
Abstract:
The investigation of the equation of state(EoS) of nuclear matter, especially at high baryon densities is one of the hot topics in the frontier of nuclear physics. The impact of the EoS at 2~5 times saturation density\begin{document}$\rho_{0}$\end{document} ![]()
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\begin{document}$\sim5 \rho_{0}$\end{document} ![]()
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The investigation of the equation of state(EoS) of nuclear matter, especially at high baryon densities is one of the hot topics in the frontier of nuclear physics. The impact of the EoS at 2~5 times saturation density
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC09
Abstract:
\begin{document}$ C_I $\end{document} ![]()
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\begin{document}$ {{M}}_\odot $\end{document} ![]()
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\begin{document}$ 70 \leqslant \varLambda_{1.4} \leqslant 580 $\end{document} ![]()
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\begin{document}$ C_I $\end{document} ![]()
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Research performed during the past decade revealed an important role of symmetry energy in the equation of state of quark matter. By introducing an isospin-dependent term into the quark mass scaling, the stability window of quark matter was studied in the equivparticle model. The results show that a sufficiently strong isospin dependence
can significantly widen the absolute stable region of strange quark matter, yielding results that simultaneously satisfy the constraints of the astrophysical observations of PSR J1614-2230 with (1.928 ± 0.017)
and tidal deformability
measured in the event GW170817. Contrary to the case of strange quark matter, the stable region of u-d quark matter narrows with isospin dependence
, leading to inconsistency with astrophysical observations. Finally, we found that the symmetry energy of strange quark matter is much larger than that of u-d quark matter, and one-gluon exchange interaction between quarks causes the symmetry energy of strange quark matter to become softer.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC08
Abstract:
Schottky diodes are fabricated using 100 µm thick 4H-SiC epitaxial wafers with Ohmic and Schottky contacts, and packaged as SiC detectors to meet the requirements of high temperature and radiation environments. The current-voltage (I-V) curves are measured in the range of 25 to 150 ºC. The experimental results show that the leakage current changes very little when the temperature is less than or equal to 105 ºC. The change rate of leakage current is 0.33%/ºC, when the reverse bias is −500 V and the temperature rises from 25 to 105 ºC. The SiC detector is irradiated by 60Co source in Peking University. The I-V characteristics of the SiC detector are compared before and after the irradiation experiment with total dose of 1 Mrad. The experimental data indicates that the leakage current has almost no significant change.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC22
Abstract:
The space charge effect is the core problem of high intensity proton accelerator, especially at injection and initial acceleration stages. Using the phase space painting with optimized process, will effectively reduce the influence of space charge effect on injection and acceleration efficiency, and emittance increase. Transverse phase space painting methods can be divided into correlated painting and anti-correlated painting. In this paper, firstly, the transverse phase space paintings for the high intensity proton synchrotron are discussed in detail, including different painting methods and different implementation methods. Secondly, based on the injection system of the China Spallation Neutron Source (CSNS), the beam injection process and anti-correlated painting design scheme are studied in detail. The reasons for the reduction of the actual vertical painting range and the influence of edge focusing effects of the bump magnets on the painting and beam dynamics are deeply explored. In addition, the method to perform the correlated painting based on the mechanical structure of the anti-correlated painting scheme and its key role in realizing the CSNS design goal are briefly introduced. Finally, according to the requirement of switching between different painting methods online in future accelerators, a new injection scheme that can realize correlated and anti-correlated painting simultaneously has been proposed. The new painting injection scheme has been demonstrated, simulated and optimized in detail.
The space charge effect is the core problem of high intensity proton accelerator, especially at injection and initial acceleration stages. Using the phase space painting with optimized process, will effectively reduce the influence of space charge effect on injection and acceleration efficiency, and emittance increase. Transverse phase space painting methods can be divided into correlated painting and anti-correlated painting. In this paper, firstly, the transverse phase space paintings for the high intensity proton synchrotron are discussed in detail, including different painting methods and different implementation methods. Secondly, based on the injection system of the China Spallation Neutron Source (CSNS), the beam injection process and anti-correlated painting design scheme are studied in detail. The reasons for the reduction of the actual vertical painting range and the influence of edge focusing effects of the bump magnets on the painting and beam dynamics are deeply explored. In addition, the method to perform the correlated painting based on the mechanical structure of the anti-correlated painting scheme and its key role in realizing the CSNS design goal are briefly introduced. Finally, according to the requirement of switching between different painting methods online in future accelerators, a new injection scheme that can realize correlated and anti-correlated painting simultaneously has been proposed. The new painting injection scheme has been demonstrated, simulated and optimized in detail.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC72
Abstract:
This study establishes a novel high-resolution fast magnetic resonance imaging(MRI) method that incorporates Beam Eye View(BEV) and Beam Path View(BPV) fusion information. Three liver metastasis patients undergoing MRI guided radiotherapy(MRgRT) were selected. A total of 31 200 frames of MRI images were acquired from each patient using two motion patterns: restricted abdominal motion using an abdominal compression belt(RAM group) and free breathing(FB group). Tumor tracking was performed using nearby vessels with clear boundaries, and the radial vector motion amplitude difference(∆R95) within the 95% confidence interval was calculated. The differences in ΔR95 between the RAM and FB groups in all fractions on the BEV/BPV plane were as follows: for Patient 1, they were all less than 0.58 mm; for Patient 2, they were greater than 2.57 mm; for Patient 3, they were 0.71 mm and 1.05 mm, respectively. The results indicate that the abdominal compression technique can effectively reduce tumor motion magnitude, and the tumor motion magnitude ΔR95 variation is highly individual-specific. This method can serve as an imaging basis for the tumor margin reduction in MRgRT.
This study establishes a novel high-resolution fast magnetic resonance imaging(MRI) method that incorporates Beam Eye View(BEV) and Beam Path View(BPV) fusion information. Three liver metastasis patients undergoing MRI guided radiotherapy(MRgRT) were selected. A total of 31 200 frames of MRI images were acquired from each patient using two motion patterns: restricted abdominal motion using an abdominal compression belt(RAM group) and free breathing(FB group). Tumor tracking was performed using nearby vessels with clear boundaries, and the radial vector motion amplitude difference(∆R95) within the 95% confidence interval was calculated. The differences in ΔR95 between the RAM and FB groups in all fractions on the BEV/BPV plane were as follows: for Patient 1, they were all less than 0.58 mm; for Patient 2, they were greater than 2.57 mm; for Patient 3, they were 0.71 mm and 1.05 mm, respectively. The results indicate that the abdominal compression technique can effectively reduce tumor motion magnitude, and the tumor motion magnitude ΔR95 variation is highly individual-specific. This method can serve as an imaging basis for the tumor margin reduction in MRgRT.
, Update time: , doi: 10.11804/NuclPhysRev.41.2023CNPC06
Abstract:
Multi-Wire gaseous detectors have been widely used in the fields of nuclear physics and nuclear technology since they have the advantages of radiation hardness, fast response, large sensitive area, low cost and convenient fabrication. First, the electric field calculation theories for multi-wire gaseous detectors were introduced, and then the electric field calculations and the structure design for the drift region and avalanche region of a multi-wire gaseous detector had been carried out with ANSYS and GARFIELD. Next, the designed detector had been simulated in the case of cosmic ray irradiation with GEANT4, and the output results of current pulses, voltage pulses, the integrated charge for each event and the overall statistic results of the integrated charge were obtained. Furthermore, the multi-wire gaseous detector had been built and was used to measure the cosmic rays. The experiment results agree well with the previous simulation results. The simulation methods and the related experiment technologies in this study can be used to do design optimizations and experiment evaluations for gaseous detectors.
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