Relativistic Analysis of Intermediate Energy Proton Inelastic Scatterings from Heavy Deformed Nuclei

심숙이,유신호,김민수 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.2

A relativistic coupled channel analysis based on the Dirac equation is performed for inelastic scattering of an intermediate energy proton from a heavy, deformed nucleus by using an optical potential model. In order to describe the low-lying excited states of the deformed nucleus, we used a rotational collective model to get the transition optical potentials. The Dirac coupled-channel equations are solved numerically to calculate the differential cross sections by using the sequential iteration method. Employing Dirac phenomenology, we vary the optical potential parameters and deformation parameters to reproduce the experimental observables. The theoretical results are observed to agree reasonably well with the inelastic scattering experimental data of 800 MeV p+176Yb, and the importance of the multistep process for inelastic scatterings at a deformed nucleus is confirmed. The effective Schrodinger-equivalent central and spin-orbit potentials are calculated by reducing the Dirac equation to a Schrodinger-like second-order differential equation and by comparison them with those of a Schrodinger calculation in which the spin-orbit potential is not included, showing the relatively large strength of a real central potential. Surface-peaked phenomena are not observed for eective central potentials when the heavy, deformed nucleus of 176Yb is considered.

Microscopic Optical Model Potential of Isospin Dependent Nucleon, Deuteron and Helium-3

Yinlu Han,Hairui Guo,Qingbiao Shen 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

The microscopic optical model potentials for isospin-nucleon, deuteron and helium-3 are obtained by the one-particle, two-particle and the three-particle Green function method through nuclear matter approximation and local density approximation based on the Skyrme interactions. The calculated results are compared with the experimental data by the microscopic optical model potentials. Good agreement is generally obtained for elastic scattering angular distributions. Good agreement is obtained for the reaction cross sections of some nucleus.

실리콘 동위원소에서의 양성자 비탄성 산란의 상대론적 분석

심숙이,김문원 한국물리학회 2017 새물리 Vol.67 No.4

Relativistic Dirac coupled-channel calculations are performed employing an optical potential model for intermediate-energy polarized proton inelastic scatterings from silicon isotopes, and the results are compared with those of nonrelativistic calculations. By using a sequential iteration method to solve the Dirac coupled channel equations phenomenologically, we obtained and analyzed the optical potential and the deformation parameters. The Dirac equations are reduced to second-order differential equations to obtain the Schroedinger-equivalent effective central and spin-orbit optical potentials, and the obtained effective potentials are analyzed by considering the mass number and the energy dependence. The deformation parameters obtained in the Dirac phenomenological calculations for the lowest-lying excited $2^+$ state are found to agree pretty well with those of nonrelativistic calculations where the same Woods-Saxon shape is used for the optical potentials. The smaller deformation parameters for the $2^+$ excited state are obtained when two neutrons are added to the target nucleus or when the energy of the projectile is decreased, indicating weaker couplings to the ground state. 실리콘 동위원소에서의 중간에너지 편극된 양성자 비탄성 산란에 대해 광학 퍼텐셜 모형을 이용하여 상대론적 디랙 채널 결합 계산을 시행하고 그 결과를 비상대론적 계산 결과와 비교하였다. 연속 반복법을 이용하여 디랙 채널 결합 방정식들을 현상론적으로 풀어 광학 퍼텐셜 및 변형변수들을 얻고 분석하였다. 디랙 방정식을 슈뢰딩거 방정식과 같은 2계 미분방정식으로 환원 시켰을 때 얻어지는 유효 중심 및 스핀-궤도 퍼텐셜을 계산하여 유효 퍼텐셜들의 에너지 의존성과 질량수 의존성을 분석하였다. 가장 낮은 들뜬 상태인 $2^+$ 상태에 대해 디랙 현상론적 계산 결과 얻어진 변형변수들은 광학 퍼텐셜에 대해 같은 Woods-Saxon 형태를 사용하는 비상대론적 계산의 결과와 상당히 잘 일치하는 것으로 나타났다. 중성자 2개가 대상핵에 추가될 때, 또는 입사입자의 에너지가 감소할 때 $2^+$ 상태에 대해 더 작은 변형 변수가 얻어져, 바닥상태와 더 약한 결합이 일어난다는 것을 관찰하였다.

Dirac Coupled Channel Analyses of the 2− Gamma Vibrational Band Excitation in 20Ne

Sugie Shim 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7

Dirac coupled channel analyses are performed using the optical potential model for the highlyingexcited states that belong to the 2− gamma vibrational band for 800 MeV unpolarized protoninelastic scatterings from 20Ne. First-order vibrational collective models are used to obtain thetransition optical potentials to describe the high-lying excited vibrational collective states, andLorentz-covariant scalar and time-like vector potentials are used as direct optical potentials. Thecomplicated Dirac coupled channel equations are solved phenomenologically to reproduce the differentialcross section data by varying the optical potential and the deformation parameters andby using the minimum chi-square method. Relativistic Dirac coupled channel calculation is ableto describe the excited states of the 2− gamma vibrational band in 20Ne much better than thenonrelativistic coupled channel calculation, especially for the 2− and the 3− states of the band. The multistep excitation process via channel coupling with the 3− state is shown to be essential indescribing the excitation of the 2− state, and the pure direct transition from the ground state isdominant for the excitation of the 3− state at the 2− gamma vibrational band in 20Ne.

Relativistic Dirac analyses of proton scattering from 92Zr

Shim S. 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.3

Relativistic coupled channel analyses based on the Dirac equation are presented for polarized 800-MeV proton inelastic scatterings from an axially symmetric deformed nucleus 92Zr by using an optical potential model and the first-order collective model. The sequential iteration method using a computer program is employed to solve the complicated Dirac coupled channel equations. The optical potential parameters of the Woods–Saxon shape and the deformation parameters of several low-lying excited states are determined phenomenologically and analyzed. The coupled channel effect between the excited states that belong to the ground-state rotational band is investigated.

Theoretical Investigation of 6,8He Halo Nuclei by Using Microscopic Optical Potentials

Wedad R. Alharbi,Awad A. Ibraheem,M. El-Azab Farid 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.5

Recently measured data for elastic scattering angular distributions of 6,8He projectiles on a 65Cu target at three energies above the Coulomb barrier (19.9, 22.6 and 30.6 MeV) have been investigated in the framework of the optical model potential. The real parts are microscopically calculated with the Reid M3Y effective nucleon-nucleon interaction by using the double folding approach. Results comparable to the experimental data were obtained using two different forms of the imaginary part. The total reaction cross sections were successfully reproduced using the extracted potentials.

Dirac Analyses of Proton Inelastic Scatterings from 206Pb

정성현,심숙이 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.11

Polarized 650-MeV proton inelastic scatterings from 206Pb are analyzed phenomenologically in the relativistic Dirac formalism using an optical potential model. The first-order collective model is used to obtain the transition potentials by considering several excited states at the inelastic scatterings. By reducing the Dirac equation to the Schr¨odinger-like second-order differential equation, we obtain and analyze the effective central and spin-orbit optical potentials. The deformation parameters for several excited states are calculated and compared with those obtained from nonrelativistic calculations.

Alternative Potentials Analyzing the Scattering Cross Sections of 7,9,10,11,12,14Be Isotopes from a 12C target: Proximity Potentials

M. Aygun 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.9

In this paper, alternative potentials to explain the scattering cross sections of 7;9;10;11;12;14Be isotopes by a 12C target nucleus at different energies are researched. For this purpose, fourteen different proximity potentials, such as Proximity 1966, Proximity 1976, Proximity 1977, Proximity 1979, Proximity 1984, Proximity 1988, Proximity 1995, Broglia and Winther 1991, Aage Winther, Bass 1973, Bass 1977, Bass 1980, Christensen and Winther 1976, and Ng^o 1980, are used to pro- duce the real potential within the optical model. The imaginary potential is formed by using the Woods-Saxon potential. The theoretical results are compared with both experimental data and data reported in the literature. The results are in good agreement with the data. The proxim- ity potentials are observed to play a significant role in obtaining the scattering cross sections of 7;9;10;11;12;14Be isotopes.

Neutron Cross Section Evaluation on Dy Isotopes

Lee, Y.D.,Chang, J.H. 한국원자력학회 2002 Nuclear Engineering and Technology Vol.34 No.2

Dirac Coupled-channel Analyses of the High-lying Excited States at 22Ne(p,p0)22Ne

Sugie Shim,Moon-Won Kim 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.12

Dirac phenomenological coupled-channel analyses are performed by using an optical potential model for the high-lying excited vibrational states at 800-MeV unpolarized proton inelastic scatterings from 22Ne nucleus. Lorentz-covariant scalar and time-like vector potentials are used as direct optical potentials, and the first-order vibrational collective model is used for the transition optical potentials to describe the high-lying excited vibrational collective states. The complicated Dirac coupled-channel equations are solved phenomenologically by using a sequential iteration method by varying the optical potential and the deformation parameters. Relativistic Dirac coupled-channel calculations are able to describe the high-lying excited states of the vibrational bands in 22Ne clearly better than the nonrelativistic coupled-channel calculations. The channel-coupling effects of the multistep process for the excited states of the vibrational bands are investigated. The deformation parameters obtained from the Dirac phenomenological calculations for the high-lying vibrational excited states in 22Ne are found to agree well with those obtained from the nonrelativistic calculations using the same Woods-Saxon potential shape.