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Boundary Conditions of Wigner-Seitz Cell in Inner Crust of Neutron Stars with Relativistic Mean Field Approach
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The microscopic structure of the Wigner-Seitz (W-S) cell in the inner crust of neutron stars is investigated with the relativistic mean field (RMF) approach. The W-S cell is composed of a cluster of neutrons and protons localized in a region around the centre and surrounded by a neutron gas of approximately uniform density. In order to generate the density of the W-S cell, appropriate boundary conditions in the calculation of the single-particle wavefunctions are necessary. We emphasize on the choice of the boundary conditions in the RMF approach. Three kinds of boundary conditions are suggested. The properties of the W-S cell with the three kinds of boundary conditions are investigated. The neutron density distributions in the RMF and Hartree-Fock-Bogoliubov (HFB) models are compared. It is found that the neutron gas densities of the W-S cell in the RMF model is higher than those obtained in the HFB model. 相似文献
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基于蒙特卡罗软件Geant4,探讨质子与硅的库仑散射和核反应及中子与硅的核反应产生反冲原子沉积非电离能量的过程,建立质子和中子在硅中的非电离能量阻止本领计算方法。在此方法中,描述了原子间库仑散射的物理过程,模拟带电粒子与晶格原子之间的屏蔽库仑散射。计算得到不同能量质子和中子在硅中因库仑散射和核反应产生反冲原子的非电离能量沉积及阻止本领的等效性,计算结果与中子ASTM标准及文献计算得到的质子数据符合很好。 相似文献
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基于蒙特卡罗软件Geant4,探讨质子与硅的库仑散射和核反应及中子与硅的核反应产生反冲原子沉积非电离能量的过程,建立质子和中子在硅中的非电离能量阻止本领计算方法。在此方法中,描述了原子间库仑散射的物理过程,模拟带电粒子与晶格原子之间的屏蔽库仑散射。计算得到不同能量质子和中子在硅中因库仑散射和核反应产生反冲原子的非电离能量沉积及阻止本领的等效性,计算结果与中子ASTM标准及文献计算得到的质子数据符合很好。 相似文献
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The interchange of superconducting character of protons and neutrons in going from 60Ni to 62Ni indicates that the conventional approach of assuming the pairing correlations only in neutrons with
shell-closure for protons is not valid. 相似文献
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Calculation of double mass differences for near-magic nuclei on the basis of a semimicroscopic model
Double mass differences between nuclei having a magic number of protons (neutrons) and their neighbors differing by one or two protons (neutrons) have been calculated on the basis of a semimicroscopic model that has been proposed recently for the problem of nuclear pairing. A dominant term of the effective nucleonnucleon interaction has been calculated on the basis of the realistic Argonne nucleon-nucleon potential v18. It has been supplemented with a moderately small phenomenological term that contains one universal parameter common to protons and neutrons. Double mass differences have been calculated for proton neighbors of the lead-isotope chain (Z = 82) and for neutron neighbors of N = 82 isotones. Corrections to the model that are caused by the contribution of low-lying surface vibrations (phonons) have been estimated. 相似文献
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H. Fuchs 《Zeitschrift für Physik A Hadrons and Nuclei》1963,171(2):416-423
Water enriched to 97% in O18 and liquid nitrogen were irradiated with 30,5 MeV bremsstrahlung. The energy distribution of emitted neutrons between 2,5 MeV and 20 MeV was measured via the recoil protons in a stilbene scintillator. The energy spectrum of photoneutrons from N14 shows maxima at 3,0, 6,5 and 11 MeV, whereas that of neutrons from O18 contains only indication of structure. For both nuclei emission of neutrons seems to proceed mainly through transitions into excited levels of the final nuclei. 相似文献
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H. Jin M. Cavaioli V. Hajdas A. V. Prokofiev A. N. Smirnov L. Tommasino 《Radiation measurements》1999,31(1-6):459-462
A critical requirement for the 209Bi-fission detector is the knowledge of its response as a function of energy for both neutrons and protons. For this reason, stacks of 209Bi-fission detectors have been exposed to proton beams of 100 and 150 MeV at the Paul Sherrer Institute. Similar stacks have been exposed to neutron beams of 100 and 160 MeV at the Svedberg Laboratory from Uppsala University. The calibrations data with neutrons have been compared with those obtained with protons of the same energies. This comparison has proved that the response of 209Bi-fission detector for neutrons is two to three times smaller than that for protons at least in the range of nucleon energy up to 150 MeV. 相似文献
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The neutrons from a Po-α-Be source were detected via the recoil protons in a stilbene scintillator. The pulse height spectrum of the scintillations produced in the stilbene crystal by the recoil protons is analysed to yield the incident neutron energy distribution. Theγ-ray background was eliminated through pulse shape discrimination. Separately the spectrum of neutrons coincident withγ-rays, i.e. of neutrons from the Be9(α,n)C12* reaction, has been determined. The resulting spectra are compared to previous measurements. The structure of the spectra is not compatible with an isotropic angular distribution of the neutrons relative to theα-direction. Furthermore it could be shown that the fraction of reactions leading to the 7,65 MeV state of C12 is only about 10?3. 相似文献
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D. Polster D. Hilscher H. RossnerW. Schmid P. Baumann H. Daniel T. von Egidy F. J. Hartmann P. Hofmann Y. S. Kim M. S. Lotfranei 《Physics letters. [Part B]》1993,300(4):317-321
Inclusive energy spectra of neutrons, protons, deuterons, tritons, charged kaons and pions following antiproton annihilation at rest in copper and uranium have been measured. The determined multiplicity charged kaons is compared to recent measurements and indicates an enhancement of strangeness production. Ratios of directly emitted neutrons and protons have been determined for copper and uranium to 3.0±0.6 and 3.2±0.5, respectively. 相似文献
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Yu. P. Gangrskiĭ S. G. Zemlyanoi D. V. Karaivanov N. N. Kolesnikov K. P. Marinova B. N. Markov V. S. Rostovskii 《Optics and Spectroscopy》2002,92(5):658-663
Hyperfine-splitting constants in the optical spectra of rare-earth elements, Nd, Eu, Gd, and Lu, were measured using the laser-induced resonance fluorescence in a low-divergence atomic beam. Values of the hyperfine magnetic anomaly for different atomic levels were determined by comparing the ratios of the magnetic dipole constants of neighboring isotopes with odd numbers of protons or neutrons. The relation of these values to the special features of the atomic and nuclear structure of the investigated elements is discussed. 相似文献
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We have performed an analysis of data from electron, neutrino and antineutrino scattering experiments on hydrogen and deuterium within the framework of the quark-parton model. The data indicate that the distortion of the structure functions of the neutrons and protons in the deuteron are small. This is in contrast with the observed distortion of the structure functions of nucleons bound in a heavy nucleus such as iron. These results support the hypothesis that the “EMC Effect” is related to the density of nucleons in a nucleus. 相似文献
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Yu. V. Ryabov G. K. Matushko V. N. Slastnikov 《Zeitschrift für Physik A Hadrons and Nuclei》1983,311(4):363-365
Neutron yield from 250 MeV protons accelerated by the ITEPh synchrotron was measured in a lead target 5 cm diameter and 10 cm long. The observed total yield is 2.56±0.27 neutrons/proton, where the evaporation and cascade components are 2.30±0.25 and 0.26±0.11 neutrons/proton respectively. 相似文献
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We present a mean-field quantum calculation of the specific heat in the inner crust of neutron stars, taking into account the inhomogeneous character of the system, in which a lattice of neutron-rich nuclei coexists with a gas of unbound neutrons.Received: 10 December 2002, Published online: 24 February 2004PACS:
21.60.-n Nuclear structure models and methods - 26.60. + c Nuclear matter aspects of neutron stars - 97.60.Jd Neutron stars 相似文献
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Double mass differences between nuclei with a magic number of protons (neutrons) and their neighbors differing from them by one or two protons (neutrons) are calculated within the semimicroscopic model proposed recently for the nuclear pairing problem. The main term in the effective nucleon interaction is calculated on the basis of the realistic Argonne nucleon-nucleon potential v18. This term is supplemented with a small phenomenological term involving one universal parameter common to protons and neutrons. The double mass differences are calculated for the proton neighbors of the Z = 82, 50, 28, and 20 lead, tin, nickel, and calcium isotopic chains and for the neutron neighbors of the N = 126, 82, 50, and 20 isotonic chains. The corrections to the model that are induced by the contribution of low-lying surface vibrations (phonons) are discussed. 相似文献
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Baillie N Tkachenko S Zhang J Bosted P Bültmann S Christy ME Fenker H Griffioen KA Keppel CE Kuhn SE Melnitchouk W Tvaskis V Adhikari KP Adikaram D Aghasyan M Amaryan MJ Anghinolfi M Arrington J Avakian H Baghdasaryan H Battaglieri M Biselli AS Branford D Briscoe WJ Brooks WK Burkert VD Carman DS Celentano A Chandavar S Charles G Cole PL Contalbrigo M Crede V D'Angelo A Daniel A Dashyan N De Vita R De Sanctis E Deur A Dey B Djalali C Dodge G Domingo J Doughty D Dupre R Dutta D Ent R Egiyan H 《Physical review letters》2012,108(14):142001
We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ?100 MeV/c and their angles to ?100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65
相似文献
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We study the role played by the protons clustered in non-spherical neutron star crust nuclei in terms of contribution to the total fermionic specific heat. We find that in the deeper part of the crust protons play a non marginal role on the thermodynamical properties of the crust.Communicated by: B. Povh 相似文献
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M.G. Albrow M. BorghiniB. Bosnjakovic F.C. Erné Y. Kimura J.P. Lagnaux J.C. Sens F. Udo 《Physics letters. [Part B]》1971
By using a polarized deuteron target we have measured the asymmetry in the differential cross section for elastic scattering of protons on deuterons and for quasi-elastic scattering of protons on protons bound in deuterons between the two states of opposite polarization, normal to the scattering plane of the initial deuteron. The beam momentum was 1.21 GeV/c. It is checked that the neutrons bound in the deuterons are polarized to approximately 20%. 相似文献
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J. Kasagi S. Saini T.C. Awes A. Galonsky C.K. Gelbke G. Poggi D.K. Scott K.L. Wolf R.L. Legrain 《Physics letters. [Part B]》1981,104(6):434-438
The emission of energetic neutrons and protons in coincidence with fission fragments was measured for the reactions 238U(16O, nf) and 238U(16O, pf). Larger cross sections were observed for the emission of high-energy protons than for the emission of high-energy neutrons. The differences in spectral shapes and the implications for the coalescence model are discussed. 相似文献