All Results

Subjects: Physics >> Nuclear Physics

本文分析讨论了加速器的百年历史， 从思想的萌芽、理论的突破与准备、技术的准备与储存、实验的成功、加速器的未来与展望等几个方面进行了论述。 |

submitted time
2018-07-10
Hits*2606*，
Downloads*1319*，
Comment
*1*

On the analytical solution of accelerating structure

朱雄伟Subjects: Physics >> Nuclear Physics

本文讨论了加速结构中的解析求解问题， 主要讨论了场和等效电路两种求解方法。 |

submitted time
2018-06-20
Hits*10527*，
Downloads*903*，
Comment
*0*

Progress of beam diagnosis system for EAST neutral beam injector.pdf

Xu,YongjianSubjects: Physics >> Nuclear Physics

Neutral beam injection has been recognized as one of the most effective means for plasma heating.According to the research plan of the EAST physics experiment, two sets of neutral beam injector were built and operational in 2014. The paper presents the development of beam diagnosis system for EAST neutral beam injector (NBI) and the latest experiment results obtained on the test-stand and EAST-NBI-1 and 2. The results show that the optimal divergence angle is (0.62°, 1.57°) and the full energy particle is up to 77%. They indicate that EAST NBI work properly and all targets reach or almost reach the design targets. All these lay a solid foundation for the achievement of high quality plasma heating for EAST. |

Analysis of beam optics for a high power ion source

谢亚红Subjects: Physics >> Nuclear Physics

The high power ion source is the key parts of neutral beam injector. Generally speaking, the beam power should matching the extraction voltage for a given accelerator. In order to get higher beam power with lower beam extraction voltage, the beam optics of accelerator was analyzed based on the structure of EAST-NBI tetrode accelerator. The beam optics of a tetrode accelerator and a new designed three-electrode accelerator was analyzed with beam energy of 50 keV. The results shown that, the two types of accelerator can get high beam perveance (4.6μp) with lower beam divergence angle compare to the EAST-NBI accelerator (2.8μp). And the tetrode accelerator can gets lower beam divergence angle compare to the three-electrode accelerator, but the electric field between two electrode is much higher than three-electrode accelerator. The results can help for the ion source design of high power ion source. |

Calorimetric Power Measurements in the EAST ECRH System

Weiye XuSubjects: Physics >> Nuclear Physics

In this paper, the calorimetric power measurement method for electron cyclotron resonance heating system on EAST are presented. This method requires measurement of the water flow through the cooling circuits and the input and output water temperatures in each cooling circuit. Usually, the inlet water temperature is controlled to be stable to get more accurate results. The influence of the inlet water temperature change on the measurement results is analyzed for the first time in this paper. A novel temperature calibration method is proposed also. This kind of calibration method is accurate and effective, and can be easily implemented. |

submitted time
2017-08-28
Hits*2846*，
Downloads*1337*，
Comment
*0*

Subjects: Physics >> Nuclear Physics

The ground state properties including radii, density distribution and one neutron separation energy for C, N, O and F isotopes up to the neutron drip line are systematically studied by the fully self-consistent microscopic Relativistic Continuum Hartree-Bogoliubov (RCHB) theory. With the proton density distribution thus obtained, the charge-changing cross sections for C, N, O and F isotopes are calculated using the Glauber model. Good agreement with the data has been achieved. The charge changing cross sections change only slightly with the neutron number except for proton-rich nuclei. Similar trends of variations of proton radii and of charge changing cross sections for each isotope chain is observed which implies that the proton density plays important role in determining the charge-changing cross sections. |

Isospin and Z1/3 Dependence of the Nuclear Charge Radii

S.Q. Zhang; J. Meng; S.-G. Zhou; J.Y. ZengSubjects: Physics >> Nuclear Physics

Based on the systematic investigation of the data available for A ≥ 40, a Z1/3 dependence for the nuclear charge radii is shown to be superior to the generally accepted A1/3 law. A delicate scattering of data around Rc/Z1/3 is infered as owing to the isospin effect and a linear dependence of Rc/Z1/3 on N/Z ( or (N ? Z)/2 ) is found. This inference is well supported by the microscopic Relativistic Continuum Hartree-Bogoliubov (RCHB) calculation conducted for the proton magic Ca, Ni, Zr, Sn and Pb isotopes including the exotic nuclei close to the neutron drip line. With the linear isospin dependence provided by the data and RCHB theory, a new isospin dependent Z1/3 formula for the nuclear charge radii is proposed. |

Pseudospin symmetry and its approximation in real nuclei

T.S. Chen; H.F. Lu; J. Meng; and S.-G. ZhouSubjects: Physics >> Nuclear Physics

The origin of pseudospin symmetry and its broken in real nuclei are discussed in the relativistic mean field theory. In the exact pseudospin symmetry, even the usual intruder orbits have degenerate partners. In real nuclei, pseudospin symme- try is approximate, and the partners of the usual intruder orbits will disappear. The difference is mainly due to the pseudo spin-orbit potential and the transition between them is discussed in details. The contribution of pseudospin-orbit potential for intruder orbits is quite large, compared with that for pseudospin doublets. The disappearance of the pseu- dospin partner for the intruder orbit can be understood from the properties of its wave function. |

Splitting of the π ? ρ spectrum in a renormalized light-cone QCD-inspired model

T. Frederico; Hans-Christian Pauli; Shan-Gui ZhouSubjects: Physics >> Nuclear Physics

We show that the splitting between the light pseudo-scalar and vector meson states is due to the strong short-range attraction in the 1S0 sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudo-scalar ground state mass fixes the renormalized strength of the Dirac-delta interaction. |