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in creator/contributor: "Lawrence Berkeley National Laboratory. Nuclear Science Division."  
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Heavy-Ion Irradiation of Thulium(III) Oxide Targets Prepared by Polymer-Assisted Deposition

Description: Thulium(III) oxide (Tm{sub 2}O{sub 3}) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method's feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 {micro}g/cm{sup 2}) and were irradiated with an {sup 40}Ar beam at laboratory frame energy of {approx}210 MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1 nm for a {approx}250 n… more
Date: September 15, 2008
Creator: Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, Tashi; Ashby, Paul D.; Gates, Jacklyn M. et al.
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Partner: UNT Libraries Government Documents Department
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The IceCube Data Acquisition Software: Lessons Learned during Distributed, Collaborative, Multi-Disciplined Software Development.

Description: In this experiential paper we report on lessons learned during the development ofthe data acquisition software for the IceCube project - specifically, how to effectively address the unique challenges presented by a distributed, collaborative, multi-institutional, multi-disciplined project such as this. While development progress in software projects is often described solely in terms of technical issues, our experience indicates that non- and quasi-technical interactions play a substantial role… more
Date: September 21, 2007
Creator: Beattie, Keith S.; Beattie, Keith; Day, Christopher; Glowacki, Dave; Hanson, Kael; Jacobsen, John et al.
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Partner: UNT Libraries Government Documents Department
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Extraction systems for the study of dubnium

Description: The chemistry of transactinide elements (Z {ge} 104) is a topic of great interest in current nuclear chemistry research. The chemical systems that can be used in these studies are limited by the short half-lives of the isotopes and the small production rates of atoms per minute or even atoms per week. In the initial investigations, the chemistry used had to be very selective to the periodic group of interest to separate the transactinide atom from all the other unwanted nuclear reaction product… more
Date: September 1, 2007
Creator: Gates, J. M.; Sudowe, R.; Ali, M. N.; Calvert, M. G.; Dragojevic, I.; Ellison, P. A. et al.
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Partner: UNT Libraries Government Documents Department
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kt-factorization for Hard Processes in Nuclei

Description: Two widely proposed kt-dependent gluon distributions in the small-x saturation regime are investigated using two particle back-to-back correlations in high energy scattering processes. The Weizsacker-Williams gluon distribution, interpreted as the number density of gluon inside the nucleus, is studied in the quark-antiquark jet correlation in deep inelastic scattering. On the other hand, the unintegrated gluon distribution, defined as the Fourier transform of the color-dipole cross section, is … more
Date: September 13, 2010
Creator: Dominguez, Fabio; Xiao, Bo-Wen & Yuan, Feng
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Partner: UNT Libraries Government Documents Department
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ADIABATICITY CRITERION FOR CHARGE EQUILIBRATION WITH APPLICATION TO FISSION

Description: The dispersion of a quantal oscillator with a time-dependent inertial mass is considered. For a special class of time dependence, an empirical method is formulated for predicting the asymptotic behavior of such a system. This method is then applied to the prediction of charge widths in strongly damped nuclear collisions and in fission.
Date: September 1, 1980
Creator: Myers, W. D.; Mantzouranis, G. & Randrup, J.
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Partner: UNT Libraries Government Documents Department
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Indirect Determination of the 230Th(n,f) and 231Th(n,f) Cross Sections for Thorium-Based Nuclear Energy Systems

Description: The Surrogate Ratio Method (SRM) was employed in the first experimental determination of the 231Th(n,f) cross section, relative to the 235U(n,f) cross section, over an equivalent neutron energy range of 360 keV to 10 MeV. The 230Th(n,f) cross section was also deduced using the SRM, relative to the 234U(n,f) cross section, over an equivalent neutron energy range of 220 keV to 25 MeV. The desired compound nuclei were populated using (3He,3He) and (3He) reactions on targets of 232Th and 236U and r… more
Date: September 11, 2009
Creator: Stroberg, S.R.; Allmond, J.M.; Angell, C.; Bernstein, L.A.; Bleuel, D.L.; Burke, J.T. et al.
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Partner: UNT Libraries Government Documents Department
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MANIFESTATIONS OF EXCITATION ENERGY EQUILIBRIUM IN DEEP-INELASTIC COLLISIONS

Description: The consequences of excitation energy equilibrium between the two partners in a deep-inelastic collision are explored. In this work we calculate the second moment of the excitation energy distribution and demonstrate the effects of the fluctuations on evaporated particle spectra and the correlation created in the numbers of evaporated particles from the deep-inelastic fragments.
Date: September 1, 1980
Creator: Morrissey, D. J. & Moretto, L. G.
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Partner: UNT Libraries Government Documents Department
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Transverse momentum dependent quark distributions and polarized Drell-Yan processes

Description: We study the spin-dependent quark distributions at large transverse momentum. We derive their transverse momentum behaviors in the collinear factorization approach in this region. We further calculate the angular distribution of the Drell-Yan lepton pair production with polarized beams and present the results in terms of the collinear twist-three quark-gluon correlation functions. In the intermediate transverse momentum region, we find that the two pproaches: the collinear factorization and the… more
Date: September 11, 2009
Creator: Zhou, J.; Yuan, F. & Liang, Z.-T.
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Partner: UNT Libraries Government Documents Department
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Collins Mechanism Contributions to Single Spin Asymmetry

Description: We present recent developments on the single transverse spin physics,in particular, the Collins mechanism contributions in various hadronic reactions,such as semi-inclusive hadron production in DIS process, azimuthal distributionof hadron in high energy jet in pp collisions. We will demonstrate thatthe transverse momentum dependent and collinear factorization approaches areconsistentwith each other in the description of the Collins effects in the semi-inclusivehadron production in DIS process.
Date: September 11, 2009
Creator: Yuan, Feng
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Partner: UNT Libraries Government Documents Department
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System-size independence of directed flow at the RelativisticHeavy-Ion Collider

Description: We measure directed flow (v{sub 1}) for charged particles in Au + Au and Cu + Cu collisions at {radical}s{sub NN} = 200 GeV and 62.4 GeV, as a function of pseudorapidity ({eta}), transverse momentum (p{sub t}) and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragm… more
Date: September 20, 2008
Creator: STAR Collaboration
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Partner: UNT Libraries Government Documents Department
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Extraction of niobium and tantalum isotopes using organophosphorus compounds - Part I - Extraction of 'carrier-free' metal concentrations from HCl solutions

Description: The extraction of niobium (Nb) and tantalum (Ta) from hydrochloric acid media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) was studied. The goal of the experiments is to find a system that demonstrates selectivity between the members of group five of the Periodic Table and is also suitable for the study of dubnium (Db, Z = 105). Experiments were performed at the trace level (10-16 M Nb or Ta) using hydrochloric acid with concentrations ranging … more
Date: September 1, 2008
Creator: Gates, Jacklyn; Sudowe, Ralf; Stavsetra, Liv; Ali, Mazhar; Calvert, Michael; Dragojevic, Irena et al.
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Partner: UNT Libraries Government Documents Department
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TIME-WALK CHARACTERISTICS OF AN IMPROVED CONSTANT FRACTION DISCRIMINATOR

Description: A modification to a constant fraction discriminator design published earlier makes the observed time walk less than 30 ps over an input voltage range of 0.15 to 2.5 V. This performance makes time-walk corrections unnecessary in many situations.
Date: September 1, 1980
Creator: Wozniak, G. J.; Richardson, L. W. & Maier, M. R.
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Partner: UNT Libraries Government Documents Department
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MICROSCOPIC CALCULATIONS OF FISSION BARRIERS AND CRITICAL ANGULAR MOMENTA FOR EXCITED HEAVY NUCLEAR SYSTEMS

Description: An extended version of Strutinsky's macro~microscopic method is used to calculate effective potential energies for rotating, excited heavy compound nuclei undergoing fission. Nuclear deformation is parameterized in terms of Lawrence's family of shapes. A two-center single-particle potential corresponding to these shapes is employed, with BCS pairing added. Statistical excitation is introduced by temperature-dependent occupation of (quasi-) particle energy levels. We calculate shell co… more
Date: September 1, 1980
Creator: Diebel, Michael; Albrecht, Klaus & Hasse, Rainer W.
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Partner: UNT Libraries Government Documents Department
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FISSION OF {sup 238}U INDUCED BY INELASTIC SCATTERING OF 120 MeV {alpha}-PARTICLES

Description: The fission decay of {sup 238}U has been measured as function of excitation energy in inelastic scattering of 120 MeV {alpha}-particles. Total kinetic energies and masses of fission fragments were measured by the double energy method. It is observed that the total kinetic energy E{sub K} decreases and that the valley in the mass distribution is reduced when the excitation energy of the system is increased. No indication of anomalous total kinetic energy release in the region of the giant quadru… more
Date: September 1, 1980
Creator: Back, B.B.; Shotter, A.C.; Symons, T.J.M.; Bice, A.; Gelbke, C.K.; Awes, T.C. et al.
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Partner: UNT Libraries Government Documents Department
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Effects of particle evaporation on the angular momentum of the emitting nucleus for deep inelastic and compound nuclear reactions

Description: A model is developed which allows one to calculate analytically the angular momentum removed, and the angular momentum misalignment created by the evaporation of light particles from an excited nucleus. The mass, temperature, and angular momentum of the emitting nucleus are explicitly considered. The formalism applies equally well to heavy ion and compound nuclear reactions.
Date: September 1, 1980
Creator: Blau, S. K. & Moretto, L. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Entrance-channel effects in odd-Z tranactinide compound nucleus reactions

Description: Swiatecki, Siwek-Wilczynska, and Wilczynski's 'Fusion By Diffusion' description [1] of transactinide (TAN) compound nucleus (CN) formation utilizes a three-step model. The first step is the 'sticking', or capture, which can be calculated relatively accurately. The second step is the probability for the formation of a CN by 'diffusion' analogous to that of Brownian motion. Lastly, there exists the probability of the CN 'surviving' deexcitation by neutron emission, which competes with fission and… more
Date: September 1, 2007
Creator: Nelson, S. L.; Gregorich, K. E.; Dragojevic, I.; Dullmann, Ch. E.; Eichler, R.; Folden, C. M., III et al.
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Partner: UNT Libraries Government Documents Department
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Influence of projectile neutron number on cross section in cold fusion reactions

Description: Elements 107-112 [1,2] have been discovered in reactions between {sup 208}Pb or {sup 209}Bi targets and projectiles ranging from {sup 54}Cr through {sup 70}Zn. In such reactions, the compound nucleus can be formed at excitation energies as low as {approx}12 MeV, thus this type of reaction has been referred to as 'cold fusion'. The study of cold fusion reactions is an indispensable approach to gaining a better understanding of heavy element formation and decay. A theoretical model that successfu… more
Date: September 1, 2007
Creator: Dragojevic, Irena; Dragojevic, I.; Gregorich, K. E.; Dullmann, Ch. E.; Folden, C. M., III; Garcia, M. A. et al.
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Partner: UNT Libraries Government Documents Department
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Comparison of reactions for the production of 258,257Db: 208Pb(51V,xn) and 209Bi(50Ti,xn)

Description: Excitation functions for the 1n and 2n exit channels of the 208Pb(51V,xn)259-xDb reaction were measured. A maximum cross section of the 1n exit channel of 2070+1100/-760 pb was measured at an excitation energy of 16.0 +- 1.8 MeV. For the 2n exit channel, a maximum cross section of 1660+450/-370 pb was measured at 22.0 +- 1.8 MeV excitation energy. The 1n excitation function for the 209Bi(50Ti,n)258Db reaction was remeasured, resulting in a cross section of 5480+1750/-1370 pb at an excitation en… more
Date: September 29, 2008
Creator: Gates, Jacklyn M.; Nelson, Sarah L.; Gregorich, Kenneth E.; Dragojevic, Irena; Dullmann, Christoph E.; Ellison, Paul A. et al.
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Partner: UNT Libraries Government Documents Department
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