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Radiation and Health Technology Laboratory Capabilities

Description: The Radiological Standards and Calibrations Laboratory, a part of Pacific Northwest National Laboratory (PNNL)(a) performs calibrations and upholds reference standards necessary to maintain traceability to national standards. The facility supports U.S. Department of Energy (DOE) programs at the Hanford Site, programs sponsored by DOE Headquarters and other federal agencies, radiological protection programs at other DOE and commercial nuclear sites and research and characterization programs sponsored through the commercial sector. The laboratory is located in the 318 Building of the Hanford Site's 300 Area. The facility contains five major exposure rooms and several laboratories used for exposure work preparation, low-activity instrument calibrations, instrument performance evaluations, instrument maintenance, instrument design and fabrication work, thermoluminescent and radiochromic Dosimetry, and calibration of measurement and test equipment (M&TE). The major exposure facilities are a low-scatter room used for neutron and photon exposures, a source well room used for high-volume instrument calibration work, an x-ray facility used for energy response studies, a high-exposure facility used for high-rate photon calibration work, a beta standards laboratory used for beta energy response studies and beta reference calibrations and M&TE laboratories. Calibrations are routinely performed for personnel dosimeters, health physics instrumentation, photon and neutron transfer standards alpha, beta, and gamma field sources used throughout the Hanford Site, and a wide variety of M&TE. This report describes the standards and calibrations laboratory.
Date: July 9, 2005
Creator: Bihl, Donald E.; Lynch, Timothy P.; Murphy, Mark K.; Myers, Lynette E.; Piper, Roman K. & Rolph, James T.
Partner: UNT Libraries Government Documents Department

Multi-neutron transfer reactions at sub-barrier energies.

Description: The optimum conditions for multi-neutron transfer have been studied in the system {sup 58}Ni + {sup 124}Sn at bombarding energies at and below the Coulomb barrier. The experiments were performed in inverse kinematics with a {sup 124}Sn beam bombarding a {sup 58}Ni target. The particles were identified with respect to mass and Z in the split-pole spectrograph with a hybrid focal plane detector with mass and Z-resolutions of A/{Delta}A = 150 and Z/{Delta}Z = 70. At all energies the transfer of up to 6 neutrons was observed. The yields for these transfer reactions are found to decrease by about a factor of four for each transferred neutron.
Date: January 20, 1998
Creator: Rehm, K. E.
Partner: UNT Libraries Government Documents Department

Neutron transfer kernels in the resonance domain in the harmonic crystal model.

Description: To describe neutron scattering the resonance domain of the nuclear fuel isotopes, the static model is widely in use in nuclear data processing codes. With this model the influence of chemical binding on the transfer cross section is not taken into account since the nucleus is considered to be in rest and isolated in the laboratory system. Further, the application of the free gas model to the resonant scattering of neutrons shows that the up-scattering probability is strongly dependent on the incident neutron energy. If the latter is smaller than the resonance energy then the free gas model predicts an enormous chance for the neutron to gain energy after collision. Neither the static nor free gas model is adequate to describe the resonant scattering of neutrons in a crystal. This fact can induce non-negligible errors in reactor calculations and, in particular, in the estimation of the Doppler coefficient. In the present paper the author proposes the theoretical study of the possibility to estimate the neutron transfer cross sections in the harmonic crystal approximation.
Date: December 21, 1999
Creator: Naberejnev, D. G.
Partner: UNT Libraries Government Documents Department

Physics with Heavy Neutron-Rich RIBs at the HRIBF*

Description: The Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge is the first ISOL-type facility to provide beams of accelerated radioactive fission products. To generate these beams, products of fission induced by proton bombardment of a uranium carbide target are ionized, charge-exchanged in Cs vapor, and injected into the HRIBF tandem. Using a single stripper foil in the terminal, they can be accelerated to about 3 MeV per nucleon, ideal for Coulomb Excitation studies. Alternatively, they can be accelerated to energies above the Coulomb barrier by means of double-stripping, at the expense of a factor of about five in lost beam intensity. This paper reports on recent experiments using neutron-rich radioactive ion beams (RIBs) from the HRIBF facility. They have performed Coulomb excitation measurements of B(E2; 0{sup +} {yields} 2{sup +}) in {sup 126,128}Sn and {sup 132,134,136}Te, neutron transfer to single-particle states in {sup 135}Te, and fusion-evaporation reactions on light targets to study evaporation residues with {gamma}-{gamma}-recoil coincidence spectroscopy.
Date: August 14, 2001
Creator: Radford, D.C.
Partner: UNT Libraries Government Documents Department

Radiation and Health Technology Laboratory Capabilities

Description: The Radiological Standards and Calibrations Laboratory, a part of Pacific Northwest National Laboratory (PNNL)(a) performs calibrations and upholds reference standards necessary to maintain traceability to national standards. The facility supports U.S. Department of Energy (DOE) programs at the Hanford Site, programs sponsored by DOE Headquarters and other federal agencies, radiological protection programs at other DOE and commercial nuclear sites and research and characterization programs sponsored through the commercial sector. The laboratory is located in the 318 Building of the Hanford Site's 300 Area. The facility contains five major exposure rooms and several laboratories used for exposure work preparation, low-activity instrument calibrations, instrument performance evaluations, instrument maintenance, instrument design and fabrication work, thermoluminescent and radiochromic Dosimetry, and calibration of measurement and test equipment (M&TE). The major exposure facilities are a low-scatter room used for neutron and photon exposures, a source well room used for high-volume instrument calibration work, an x-ray facility used for energy response studies, a high-exposure facility used for high-rate photon calibration work, a beta standards laboratory used for beta energy response studies and beta reference calibrations and M&TE laboratories. Calibrations are routinely performed for personnel dosimeters, health physics instrumentation, photon and neutron transfer standards alpha, beta, and gamma field sources used throughout the Hanford Site, and a wide variety of M&TE. This report describes the standards and calibrations laboratory.
Date: July 15, 2003
Creator: Goles, Ronald W.; Johnson, Michelle Lynn; Piper, Roman K.; Peters, Jerry D.; Murphy, Mark K.; Mercado, Mike S. et al.
Partner: UNT Libraries Government Documents Department

From simple to complex reactions: Nuclear collisions near the Coulomb barrier

Description: Collisions between two heavy nuclei produce a diverse spectrum of reaction modes which is much wider than that observed in light ion studies. For the latter case, two processes are observed: direct reactions and compound nucleus formation. Heavy ion reaction studies on the other hand have identified additional processes such as deep-inelastic scattering, incomplete fusion and quasi-fission reactions. While the boundaries between the various processes are usually not well defined, it is generally accepted that with increasing overlap of the two nuclei the interaction evolves from distant collisions where only elastic scattering and Coulomb excitation processes occur, through grazing-type collisions associated with quasi-elastic reactions to deep-inelastic and fusion-fission processes requiring a substantial nuclear overlap. Varying the bombarding energy is a convenient way to change the overlap of the two nuclei. Measurements of excitation functions can thus probe the onset and the interplay of the various reaction modes. Experiments at bombarding energies in the vicinity of the Coulomb barrier are particularly suited for comparisons with theoretical predictions since the small number of degrees of freedom involved in the interaction greatly simplifies the calculations. In the first part of this contribution a short overview is given on the status of heavy ion reaction studies at energies in the vicinity of the Coulomb barrier. In the second part two experiments, one involving simple and the other studying complex reactions, are discussed in more detail.
Date: December 1, 1992
Creator: Rehm, K. E.
Partner: UNT Libraries Government Documents Department

Coherent and semi-coherent neutron transfer reactions

Description: Neutron transfer reactions are proposed to account for anomalies reported in Pons-Fleischmann experiments. The prototypical reaction involves the transfer of a neutron (mediated by low frequency electric or magnetic fields) from a donor nucleus to virtual continuum states, followed by the capture of the virtual neutron by an acceptor nucleus. In this work we summarize basic principles, recent results and the ultimate goals of the theoretical effort.
Date: December 31, 1992
Creator: Hagelstein, P. L.
Partner: UNT Libraries Government Documents Department

Computer calculation of angular momentum coupling coefficients and of (d,p) stripping reaction cross section. Technical report No. 14. [B53 DWC, B53GOR, B53RIM, B53SIX, in FORTRAN]

Description: A theoretical expression for the stripping differential cross section is derived and prepared for computer evaluation. Input information is provided for the code B53DWC, which calculates this cross section, and the codes B53GOR, B53SIX, and B53RIM, which evaluate 3-J, 6-J, and 9-J coefficients. (RWR)
Date: February 1, 1965
Creator: Strobel, G.L.
Partner: UNT Libraries Government Documents Department

From Simple to Complex Reactions: Nuclear Collisions Near the Coulomb Barrier

Description: Collisions between two heavy nuclei produce a diverse spectrum of reaction modes which is much wider than that observed in light ion studies. For the latter case, two processes are observed: direct reactions and compound nucleus formation. Heavy ion reaction studies on the other hand have identified additional processes such as deep-inelastic scattering, incomplete fusion and quasi-fission reactions. While the boundaries between the various processes are usually not well defined, it is generally accepted that with increasing overlap of the two nuclei the interaction evolves from distant collisions where only elastic scattering and Coulomb excitation processes occur, through grazing-type collisions associated with quasi-elastic reactions to deep-inelastic and fusion-fission processes requiring a substantial nuclear overlap. Varying the bombarding energy is a convenient way to change the overlap of the two nuclei. Measurements of excitation functions can thus probe the onset and the interplay of the various reaction modes. Experiments at bombarding energies in the vicinity of the Coulomb barrier are particularly suited for comparisons with theoretical predictions since the small number of degrees of freedom involved in the interaction greatly simplifies the calculations. In the first part of this contribution a short overview is given on the status of heavy ion reaction studies at energies in the vicinity of the Coulomb barrier. In the second part two experiments, one involving simple and the other studying complex reactions, are discussed in more detail.
Date: January 1, 1992
Creator: Rehm, K. E.
Partner: UNT Libraries Government Documents Department

Coherent and semi-coherent neutron transfer reactions

Description: Neutron transfer reactions are proposed to account for anomalies reported in Pons-Fleischmann experiments. The prototypical reaction involves the transfer of a neutron (mediated by low frequency electric or magnetic fields) from a donor nucleus to virtual continuum states, followed by the capture of the virtual neutron by an acceptor nucleus. In this work we summarize basic principles, recent results and the ultimate goals of the theoretical effort.
Date: January 1, 1992
Creator: Hagelstein, P.L.
Partner: UNT Libraries Government Documents Department

Quasimolecular single-nucleon effects in heavy-ion collisions

Description: Several experimental examples are discussed to illustrate that single-particle molecular orbital behavior has become an established reality in nuclear physics over the last several years. Measurements and analyses of inelastic scattering in the /sup 13/C + /sup 12/C and /sup 17/O + /sup 12/C systems, and of neutron transfer in the /sup 13/C(/sup 13/C, /sup 12/C)/sup 14/C reaction, show that the motion of valence nucleons can be strongly and simultaneously influenced by both collision partners in heavy-ion collisions. This bvehavior is characteristic of a molecular (single-particle) rather than a direct (DWBA) mechanism: it demonstrates that the single-particle analog of atomic molecular motion plays an important role in nuclear reactions at bombarding energies near the Coulomb barrier. Such behavior may be even more pronounced in the collisions of massive nuclei that will be studied with the new generation of heavy-ion accelerators. 19 references.
Date: January 1, 1984
Creator: Erb, K.A.
Partner: UNT Libraries Government Documents Department

In-beam studies of high-spin states of actinide nuclei

Description: High-spin states in the actinides have been studied using Coulomb- excitation, inelastic excitation reactions, and one-neutron transfer reactions. Experimental data are presented for states in {sup 232}U, {sup 233}U, {sup 234}U, {sup 235}U, {sup 238}Pu and {sup 239}Pu from a variety of reactions. Energy levels, moments-of-inertia, aligned angular momentum, Routhians, gamma-ray intensities, and cross-sections are presented for most cases. Additional spectroscopic information (magnetic moments, M{sub 1}/E{sub 2} mixing ratios, and g-factors) is presented for {sup 233}U. One- and two-neutron transfer reaction mechanisms and the possibility of band crossings (backbending) are discussed. A discussion of odd-A band fitting and Cranking calculations is presented to aid in the interpretation of rotational energy levels and alignment. In addition, several theoretical calculations of rotational populations for inelastic excitation and neutron transfer are compared to the data. Intratheory comparisons between the Sudden Approximation, Semi-Classical, and Alder-Winther-DeBoer methods are made. In connection with the theory development, the possible signature for the nuclear SQUID effect is discussed. 98 refs., 61 figs., 21 tabs.
Date: November 15, 1990
Creator: Stoyer, M.A. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div. California Univ., Berkeley, CA (USA). Dept. of Chemistry)
Partner: UNT Libraries Government Documents Department

Two-neutron transfer in Pt and Os nuclei and the IBA

Description: Two-neutron transfer studies in Pt and Os were investigated. The extracted relative enhancement factors in Pt were found to be in excellent agreement with the 0(6) limit predictions. The differences in transfer strength between Pt and Os (t,p) could not be reproduced within the present framework of the Interacting Boson Approximation Model. 3 figures.
Date: January 1, 1980
Creator: Cizewski, J.A.
Partner: UNT Libraries Government Documents Department

Tests of dynamical supersymmetries via charged particle transfer reactions

Description: The (t,p) and (t/sup ..-->../,..cap alpha..) reactions on enriched /sup 191/ /sup 193/Ir targets were investigated. The resultant spectroscopic strengths are compared and contrasted with the expectations of the dynamical supersymmetry scheme proposed for the Pt-Ir region. 1 figure, 2 tables.
Date: January 1, 1980
Creator: Cizewski, J.A.
Partner: UNT Libraries Government Documents Department

Cross section and analyzing power in the /sup 206/Pb(. -->. t,p) /sup 208/Pb(4/sup -/) reaction. [17 MeV, mechanism study]

Description: Cross sections and analyzing powers were measured in the /sup 206/Pb(..-->..t,p) /sup 208/Pb reaction leading to the 4/sup -/, 5/sup -/ states of the (p/sub 1/2//sup -1/ g/sub 9/2/) doublet. Standard DWBA calculations reproduce the cross section but not the analyzing power for the 5/sup -/ state. The opposite is true for a sequential transfer (t,d) (d,p) calculation for the 4/sup -/ state. 1 figure, 1 table.
Date: January 1, 1980
Creator: Alford, W.P.; Boyd, R.N.; Sugarbaker, E.; deBoer, F.; Brown, R.E. & Flynn, E.R.
Partner: UNT Libraries Government Documents Department

Heavy ion induced transfer reactions: a spectroscopic tool for high spin states

Description: By selectively choosing the appropriate heavy ion transfer reaction one can access high spin states. As a demonstration of the technique two proton and two neutron states of high spin (both yrast and non-yrast) in Nd nuclei have been identified. These spectroscopic results have yielded the first direct information about the configuration of some of these states. 11 refs., 6 figs. (WRF)
Date: January 1, 1985
Creator: Bond, P.D.
Partner: UNT Libraries Government Documents Department

Two-neutron transfer study on /sup 195/Pt

Description: The /sup 195/Pt(t,p)/sup 197/Pt reaction was investigated. Three states below 1 MeV are populated with a large fraction of the L = 0 strength, which is seen in the even-to-even cases. This is in contrast to other (p,t) and (t,p) studies on Pt targets, where the L = 0 strength is concentrated in the ground state. 1 figure, 1 table.
Date: January 1, 1980
Creator: Cizewski, J.A.; Flynn, E.R.; Brown, R.E. & Sunier, J.W.
Partner: UNT Libraries Government Documents Department