8 Matching Results

Search Results

Advanced search parameters have been applied.

Muon catalyzed fusion in deuterium at 3 K

Description: Muon catalyzed fusion in deuterium has traditionally been studied in gaseous and liquid targets. The TRIUMF solid hydrogen layer target system has been used to study the fusion reaction rates in the solid phase at a target temperature of 3 K. Both branches of the cycle were observed; neutrons by a liquid organic scintillator, and protons by a silicon detector located inside the target system. The effective molecular formation rate from the upper hyperfine state and the spin exchange rate have been measured, and information on the branching ratio parameters has been extracted.
Date: December 1, 1995
Creator: Knowles, P.E.; Beer, G.A. & Bailey, J.M.
Partner: UNT Libraries Government Documents Department

Relativistic nuclear Hamiltonian and currents to (v/c){sub 2}.

Description: Relativistic Hamiltonians are defines as the sum of relativistic one-body kinetic energies and many-body interactions and their boost corrections. The calculation of the latter from commutation relations of the Poincare group is reviewed. It is shown that the most important terms can be understood from classical relativistic mechanics. The constraints of relativistic covariance on the charge and current densities are examined. Nuclear charge and current operators that satisfy them up to order (1/m){sup 2} are derived.
Date: August 1, 1995
Creator: Schiavilla, R.
Partner: UNT Libraries Government Documents Department

{sup 3}He[pol]({rvec e}, e{prime})X and the neutron electromagnetic form factors

Description: Recent data for the spin-dependent A{sub T}, and A{sub TL}, asymmetries in {sup 3}He[pol]({rvec e}, e{prime}) quasielastic scattering are reviewed. The neutron electric and magnetic form factors are extracted from the data using a plane wave impulse approximation (PWIA) model, and the model uncertainties are estimated. The extracted G{sub M}{sup n} is in agreement with the dipole prediction as well as with other recent experiments. No meaningful result for G{sub E}{sup n} is obtained due to large uncertainties and possible final-state interaction effects. At higher Q{sup 2}, the determination of G{sub E}{sup n} in {sup 3}He[pol]({rvec e},e{prime}) does appear feasible based on the plane wave impulse approximation (PWIA) predictions.
Date: December 31, 1995
Creator: Hansen, J.O.
Partner: UNT Libraries Government Documents Department

Defense, basic, and industrial research at the Los Alamos Neutron Science Center: Proceedings

Description: The Workshop on Defense, Basic, and Industrial Research at the Los Alamos Neutron Science Center gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss the use of neutrons in science-based stockpile stewardship, The workshop began with presentations by government officials, senior representatives from the three weapons laboratories, and scientific opinion leaders. Workshop participants then met in breakout sessions on the following topics: materials science and engineering; polymers, complex fluids, and biomaterials; fundamental neutron physics; applied nuclear physics; condensed matter physics and chemistry; and nuclear weapons research. They concluded that neutrons can play an essential role in science-based stockpile stewardship and that there is overlap and synergy between defense and other uses of neutrons in basic, applied, and industrial research from which defense and civilian research can benefit. This proceedings is a collection of talks and papers from the plenary, technical, and breakout session presentations. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.
Date: October 1, 1995
Creator: Longshore, A. & Salgado, K.
Partner: UNT Libraries Government Documents Department

Nuclear structure studies at intermediate energy. Final report, September 1992--May 1995

Description: This constitutes a final report for a two-year grant ending 31 December, 1993, and an additional grant of $15,000 for the period 1 January 1993 to 30 September 1994. At the beginning of 1993 the group consisted of the Principal Investigator (N.H.), two full-time Research Associates (A.S. and V.S.), one part-time Research Associate (M.F.) and one graduate Research Assistant (D.M.). At present only the Principal Investigator in continuing. This report covers the period from September 1992 to April 1995. During this period experiment E 352, ``{sup 208} Pb and {sup 60} Ni (p,t) reaction at 120 MeV`` was completed at the Indiana University Cyclotron Facility (IUCF). A Ph.D. has been awarded (D.M.) on the basis of this work and LAMPF (Los Alamos Meson Physics Facility) E 1201, ``The {sup 40}Ca, (p,2p) reaction at 800 MeV``. A paper on the {sup 208}Pb (p,t) experiment is being prepared for publication, In addition, five papers by members of this group, and four with other collaborators have been published since our last report (September 1992). At present we have one approved experiment (E 1201 above) in the LAMPF cue, but it is unlikely that it will ever be scheduled.
Date: June 1, 1995
Creator: Hintz, N. M.
Partner: UNT Libraries Government Documents Department

Antiproton catalyzed fusion

Description: Because of the potential application to power production, it is important to investigate a wide range of possible means to achieve nuclear fusion, even those that may appear initially to be infeasible. In antiproton catalyzed fusion, the negative antiproton shields the repulsion between the positively charged nuclei of hydrogen isotopes, thus allowing a much higher level of penetration through the repulsive Coulomb barrier, and thereby greatly enhancing the fusion cross section. Because of their more compact wave function, the more massive antiprotons offer considerably more shielding than do negative muons. The effects of the shielding on fusion cross sections are most predominate, at low energies. If the antiproton could exist in the ground state with a nucleus for a sufficient time without annihilating, the fusion cross sections are so enhanced that at room temperature energies, values up to about 1,000 barns (that for d+t) would be possible. Unfortunately, the cross section for antiproton annihilation with the incoming nucleus is even higher. A model that provides an upper bound for the fusion to annihilation cross section for all relevant energies indicates that each antiproton will catalyze no more than about one fusion. Because the energy required to make one antiproton greatly exceeds the fusion energy that is released, this level of catalysis is far from adequate for power production.
Date: May 15, 1995
Creator: Morgan, D.L. Jr.; Perkins, L.J. & Haney, S.W.
Partner: UNT Libraries Government Documents Department

The temperature dependence of the width of the giant dipole resonance

Description: A systematic study of the full-width-at-half-maximum (FWHM) of the giant-dipole resonance (GDR) as a function of temperature for the nuclei {sup 120}Sn and {sup 208}Pb confirms the overall theoretical picture of the GDR in hot nuclei; in particular, the role played by large-amplitude thermal fluctuations of the nuclear shape. This is confirmed by the good agreement between theory and experiment achieved over a range of temperatures from 1.25--32 MeV and by the differences in the behavior of the FWHM for {sup 120}Sn and {sup 208}Pb, which can be attributed to the presence of strong shell corrections favoring spherical shapes in {sup 208}Pb that are absent in {sup 120}Sn. Finally, the increase in the FWHM over that expected from thermal averaging at temperatures of the order 3.0 MeV is in accordance with the increase expected from the particle evaporation of the compound system.
Date: December 1995
Creator: Ormand, W. E.; Bortignon, P. F. & Broglia, R. A.
Partner: UNT Libraries Government Documents Department

Universal correlations of nuclear observables and new signatures of structure in exotic nuclei: A review

Description: Recently, several nearly universal correlations of nuclear observables, spanning nuclei from singly magic to rotor, have been discovered. The simple global behavior revealed by these correlations discloses new signatures of structure that require a knowledge only of the energies of the first two excited states in even-even nuclei and the B(E2 : 2{sub 1}{sup +} {yields} 0{sub 1}{sup +}) value. Since these are the simplest to-obtain data in new nuclei in unexplored regions, they should be especially valuable in radioactive beam studies of nuclei far from stability where the data will necessarily be sparse compared to that with which is accustomed. This report reviews some of these recent developments.
Date: November 1, 1995
Creator: Casten, R.F. & Zamfir, N.V.
Partner: UNT Libraries Government Documents Department