Nuclear physics and its applications (original) (raw)
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1.1 General survey It is customary to regard nuclear physics as the field of study that includes the structure of atomic nuclei, the reactions that take place between them, and the techniques, both experimental and theoretical, that shed light on these subjects. Rigid adherence to such limits would, however, exclude much that is both exciting and informative. The nucleus entered physics as a necessary component of the atomic model and nuclear effects in spectroscopy and solid state physics now provide not only elegant methods for determination of nuclear properties but also convincing demonstrations of the powers of quantum mechanics. Equally, those particles sometimes described as elementary or fundamental, although first recognized in the cosmic radiation, soon assumed a role of importance in nuclear problems, especially in the understanding of the forces between neutrons and protons. Advances in the study of particles, or sub-nuclear physics, besides leading to the discovery of new and previously unsuspected physical laws, have frequently stimulated back-reference to complex nuclei
Fundamentals of Nuclear Physics
2012
Use in any way except education purpose is prohibited. Every student may print out no more than one copy for personal use. 11. Nuclear physics 11.1. Internal structure of an atomic nucleus All nuclei (besides the ordinary hydrogen nucleus which is a single proton) are composed of two types of particles: protons and neutrons. Some of the properties of nuclei, such as their charge, structure and composition, radius and symbols are shown by the following scheme: Symbols of nucleus X : Nucleons proton 1p 1 number of protons Z Q=Z|e| neutron 0n 1 number of neutrons N (charge) ZX A radius 10-15 m A-atomic mass
Physical Review, 1958
The properties of nuclear matter have been determined by the solution of the nuclear many-body problem, using the reaction matrix theory of Brueckner. The nonlinear integral equations characteristic of the theory have been solved with the aid of the fast electronic computer IBM 704. The two-body interaction assumed is the phenomenological potential of Gammel, Christian, and Thaler. It is found that the binding energy of nuclear matter, neglecting Coulomb forces, is 14.6 Mev per particle at a density corresponding to a radius parameter ro-1. 00&(10 " cm. The Coulomb repulsion in a heavy nucleus is shown to drop the density by approximately 15%. The tensor force is shown to give approximately 6-Mev binding energy. The results are found to be very sensitive to the self-consistency requirements of the theory, the binding energy shifting from 14.6 Mev to 34.4 Mev if the velocity dependence of the single-particle potential is neglected. The actual solutions were made self-consistent by an iteration procedure which converged in five or six iterations, the final results being self-consistent to one part in 10' or 10'. The effective mass for nucleon motion in the Fermi sea is found to vary from 0.56M for slow particles to 0.66M for particles near the Fermi surface. This velocity dependence of the potential is closely related to the symmetry energy which also depends, however, on the shifting in the spin populations as the neutronproton ratio is changed from unity. The symmetry energy computed is 10 to 15/z larger than that deduced from experiment. I. INTRODUCTION ' 'N previous papers, ' ' one of us (K. A. B.) and others~h ave developed a method for determining the properties of extended nuclear matter. This theory was first used to make an approximate study of the equilibrium density and binding energy of nuclear matter' ' and to develop a theory of high-energy nuclear reactions,ẽ nergy-level fine structure, and conlguration mixing, ' and neutron reactions with nuclei at low energy. " Later studies, " " particularly that by Bethe, ' have made further analyses of the theoretical foundation of the method and also examined the problems which arise in applying the method to finite systems. Thus in this paper, it is not necessary to review the'foundations of the method. The purpose of this paper is to give the details" of *Work performed under the auspices of the U. S. Atomic Energy Commission.
Anatomy of nuclear matter fundamentals
The bridge between finite and infinite nuclear system is analyzed for the fundamental quantities like binding energy, density, compressibility, giant monopole excitation energy and effective mass of both nuclear matter and finite nuclei systems. It is shown quantitatively that by knowing one of the fundamental property of one system one can estimate the same in its counter part, only approximately.
It is more than a century since the discovery by J. J. Thomson of the electron. The electron is still thought to be a structureless point particle, and one of the elementary particles of Nature. Other particles that were subsequently discovered and at firstthought to be elementary, like the proton and the neutron, have since been found to have a complex structure. What then are the ultimate constituents of matter? How are they categorised? How do they interact with each other? What, indeed, should we ask of a mathematical theory of elementary particles? Since the discovery of the electron, and more particularly in the last sixty years, there has been an immense amount of experimental and theoretical effort to determine answers to these questions. The present Standard
Hypotheses on Nuclear Physics and Quantum Mechanics: A New Perspective
The purpose of this study is to bring out new approach for determining the distance between each nucleon in a nucleus, explain why nuclear force is a short range force, and why electrostatic force has greater range than magnetic force, predict the structure of Helium-4 nucleus through different tests, and combine four different energies equations—nuclear energy equation, magnetic potential energy equation, electrostatic energy equation, and gravitational energy equation to form one energy equation, which is the net energy of the nucleus.In this study mathematical models were used to arrive at various experimental results, and new equations were developed, which can be used to predict the net energy of the nucleus, the self energy of every nucleon, the energy released during nuclear fission, the size of the atom, and the contraction of the nucleons in any nucleus.
A new approach to physics of nuclei
Physics of Atomic Nuclei, 2012
We employ the QCD sum rules method for description of nucleons in nuclear matter. We show that this approach provides a consistent formalism for solving various problems of nuclear physics. Such nucleon characteristics as the Dirac effective mass m * and the vector self-energy Σ V are expressed in terms of the in-medium values of QCD condensates. The values of these parameters at saturation density and the dependence on the baryon density and on the neutron-to-proton density ratio is in agreement with the results, obtained by conventional nuclear physics method. The contributions to m * and Σ V are related to observables and do not require phenomenological parameters. The scalar interaction is shown to be determined by the pion-nucleon σ-term. The nonlinear behavior of the scalar condensate may appear to provide a possible mechanism of the saturation. The approach provided reasonable results for renormalization of the axial coupling constant, for the contribution of the strong interactions to the neutron-proton mass difference and for the behavior of the structure functions of the in-medium nucleon. The approach enables to solve the problems which are difficult or unaccessible for conventional nuclear physics methods. The method provides guide-lines for building the nuclear forces. The threebody interactions emerge within the method in a natural way. There rigorous calculation will be possible in framework of self-consistent calculation in nuclear matter of the scalar condensate and of the nucleon effective mass m * .
A Molecular-Orbital Model of the Atomic Nuclei
Progress of Theoretical Physics, 1973
A new nuclear model is proposed that describes the cluster and the shell structures unifiedly. By the present model one can investigate characteristics of one-particle orbitals in clustering states and also polarizations of constituent clusters. The model has its base on the Hartree-Fock (H.F.) approximation for nuclear intrinsic states. The basis wave functions used in the present H.F. calculations are constructed from single-particle wave functions around each "cluster center", which can well describe possible large eccentric nuclear deformations in light nuclei. The model is analogous to the LCAO-MO-SCF method in the molecular physics. Numerical calculations are performed using an effective twonucleon force (Volkov No. 1) for the ground states of 8B e and 12 C nuclei, and interesting results are obtained about the stability of a-cluster structures. Polarizations are smallest at the equilibrium distance between a-clusters, determined by Brink's a-particle model. An artificial collapse or an extreme decomposition of the a-cluster structures brings about large polarizations. By those polarizations of constituent a-clusters themselves, the a-cluster structure recovers their density distributions. Comparisons of the results are made with those of two-center shell model, usual H. F. calculation and a-particle model. § I. Introduction Molecular viewpoints in nuclear structure were first introduced by Wheeler m 1937. 8 l He studied the usefulness and the limitations of the concept of molecular structure in the atomic nuclei; the division of the constituent particles into more or less well-defined groups. Furthermore he made qualitative discussions on the excitation modes associated with molecular structure and also proposed the method of the resonating groups as the mathematical description. Following him, simple analyses with a-particle model were applied to self-conjugated 4n nuclei. 4 l After about two decades Wildermuth and Kanellopoulos 5 l proposed a cluster model, making a careful reference to the oscillator shell model and performed a number of variational calculations. Smirnov et al. 6 l investigated physical properties of cluster wave functions, the extent of isolation of a-clusters, etc. By the resonating group method a-a scattering phase shifts were very well reproduced and the validity of effective a-a potentials was shown. 7 l Based on this result, an a-particle model of 9 Be nucleus was studied dynamically by Shimodaya *> The preliminary results were reported at the International Conference on Clustering Phenomena in Nuclei,ll Bochum, Germany, 1969 and also published in the Progress of Theoretical Physics.s>
The purpose of the following study is to build up a nucleus model – based on the symmetries of atomic shell – where the density of nucleons is constant. And which gives enough space for zero point quantum motion in a way that the collision of identical particles is excluded. Electrons flowing as superfluids in supraconductive crystals are suitable analogies. Its condition, the most symmetric cubic lattice can be realized by the strict self-organization and harmonized movement of nucleons. Continuing with the process, we will arrive at the magic numbers, the shell structure of nuclei, which logically derive from the above mentioned symmetry. We get a clear explanation of the role classical spin plays in nuclear physics, and a simple method to describe nuclear spin. Binding energies of certain nuclei can be calculated with proper approach.