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Experimental Research on the Laser Cyclotron Auto-Resonance Accelerator “LACARA”

Description: The Laser Cyclotron Auto-Resonant Accelerator LACARA has successfully operated this year. Results are summarized, an interpretation of operating data is provided in the body of the report, and recommendations are made how the experiment should be carried forward. The Appendix A contains a description of the LACARA apparatus, currently installed at the Accelerator Test Facility, Brookhaven National Laboratory. This report summarizes the project, extending over three grant-years.
Date: November 11, 2008
Creator: Marshall, T C
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fast Ignition relevant study of the flux of high intensity laser generated electrons via a hollow cone into a laser-imploded plasma

Description: An integrated experiment relevant to fast ignition is described. A Cu doped CD spherical shell target is imploded around an inserted hollow Au cone by a six beam 600J, 1ns laser to a peak density of 4gcm{sup -3} and a diameter of 100 {micro}m. A 10 ps, 20TW laser pulse is focused into the cone at the time of peak compression. The flux of high-energy electrons through the imploded material is determined from the yield of Cu K{alpha} fluorescence by comparison with a Monte Carlo model and is esti… more
Date: October 11, 2005
Creator: Key, M.; Adam, J.; Akli, K.; Borgheshi, M.; Chen, M.; Evans, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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On the electronic configuration in Pu: spectroscopy and theory

Description: Photoelectron spectroscopy, synchrotron-radiation-based x-ray absorption, electron energy-loss spectroscopy, and density-functional calculations within the mixed-level and magnetic models, together with canonical band theory have been used to study the electron configuration in Pu. These methods suggest a 5f{sup n} configuration for Pu of 5 {le} n < 6, with n {ne} 6, contrary to what has recently been suggested in several publications. We show that the n = 6 picture is inconsistent with the … more
Date: October 11, 2006
Creator: Tobin, J G; Soderlind, P; Landa, A; Moore, K T; Schwartz, A J; Chung, B W et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Study of Bunch Instabilities By the Nonlinear Vlasov-Fokker-Planck Equation

Description: Instabilities of the bunch form in storage rings may be induced through the wake field arising from corrugations in the vacuum chamber, or from the wake and precursor fields due to coherent synchrotron radiation (CSR). For over forty years the linearized Vlasov equation has been applied to calculate the threshold in current for an instability, and the initial growth rate. Increasing interest in nonlinear aspects of the motion has led to numerical solutions of the nonlinear Vlasov equation, augm… more
Date: July 11, 2006
Creator: Warnock, Robert L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Transverse momentum and centrality dependence of high-ptnon-photonic electron suppression in Au+Au collisions at $\sqrt{s_{NN}}$= 200 GeV

Description: The STAR collaboration at RHIC reports measurements of theinclusive yield of non-photonic electrons, which arise dominantly fromsemi-leptonic decays of heavy flavor mesons, over a broad range oftransverse momenta (1.2<pt<10 gevc) in pp, dAu, and AuAucollisions at sqrt sNN = 200 GeV. The non-photonic electron yieldexhibits unexpectedly large suppression in central AuAu collisions athigh pt, suggesting substantial heavy quark energy loss at RHIC. Thecentrality and \pt dependences of the suppressi… more
Date: July 11, 2006
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Initial Self-Consistent 3D Electron-Cloud Simulations of the LHC Beam with the Code WARP+POSINST

Description: We present initial results for the self-consistent beam-cloud dynamics simulations for a sample LHC beam, using a newly developed set of modeling capability based on a merge [1] of the three-dimensional parallel Particle-In-Cell (PIC) accelerator code WARP [2] and the electron-cloud code POSINST [3]. Although the storage ring model we use as a test bed to contain the beam is much simpler and shorter than the LHC, its lattice elements are realistically modeled, as is the beam and the electron cl… more
Date: October 11, 2005
Creator: Vay, J; Furman, M A; Cohen, R H; Friedman, A & Grote, D P
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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SOME PHOTOCHEMICAL AND PHOTOPHYSICAL REACTIONS OP CHLOROPHYLL ANDITS RELATIVES

Description: The solution photochemistry of chlorophyll and chlorophyll analogs is described. Many cases of electron transfer to or from the porphyrin macrocycle have been found, but in no case has any very large degree of energy storage been achieved. Because of the very rapid back-reaction for products with a {Delta}F of approximately -30 kcal, some solid state models in which such an energy storage might be achieved are described and their possible relation to the natural photosynthetic apparatus is give… more
Date: April 11, 1960
Creator: Calvin, Melvin
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Beam energy spread in FERMI@elettra gun and linac induced by intrabeam scattering

Description: Intrabeam scattering (IBS) of electrons in the pre-cathode area in the electron guns know in the literature as Boersh effect is responsible for a growth of the electron beam energy spread there. Albeit most visible within the electron gun where the electron beam density is large and the energy spread is small, the IBS acts all along the entire electron beam pass through the Linac. In this report we calculate the energy spread induced by IBS in the FERMI@elettra electron gun.
Date: July 11, 2008
Creator: Zholents, Alexander A.; Zolotorev, Max S. & Penco, Giuseppe
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Filling in the Roadmap for Self-Consistent Electron Cloud and Gas Modeling

Description: Electron clouds and gas pressure rise limit the performance of many major accelerators. A multi-laboratory effort to understand the underlying physics via the combined application of experiment, theory, and simulation is underway. We present here the status of the simulation capability development, based on a merge of the three-dimensional parallel Particle-In-Cell (PIC) accelerator code WARP and the electron cloud code POSINST, with additional functionalities. The development of the new capabi… more
Date: October 11, 2005
Creator: Vay, J; Furman, M A; Seidl, P A; Cohen, R H; Friedman, A; Grote, D P et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Density and Temperature Profile Modifications with Electron Cyclotron Power Injection in Quiescent Double Barrier Discharges on DIII-D

Description: Quiescent double barrier (QDB) conditions often form when an internal transport barrier is created with high-power neutral-beam injection into a quiescent H-mode (QH) plasma. These QH-modes offer an attractive, high-performance operating scenario for burning plasma experiments due to their quasi-stationarity and lack of edge localized modes (ELMs). Our initial experiments and modeling using ECH/ECCD in QDB shots were designed to control the current profile and, indeed, we have observed a strong… more
Date: October 11, 2005
Creator: Casper, T. A.; Burrell, K. H.; Doyle, E. J.; Gohil, P.; Lasnier, C. J.; Leonard, A. W. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Melting of Copper and Nickel at high pressure: the role of d-electrons

Description: Melting curves of Cu and Ni were measured to 97 GPa (3800 K) and 60 GPa (2970 K), respectively, in the laser-heated diamond cell. The measured melting temperatures of Cu are in good agreement with recent theoretical calculations. The melting slope (dT/dP) of Cu, which has a filled d-electron band, is about 2.5 times steeper than for Ni, which with one less electron, has a partially unfilled d-electron band. The relatively low melting slope obtained for Ni, measured using identical experimental … more
Date: April 11, 2005
Creator: Japel, S; Boehler, R & Ross, M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HUNTING THE QUARK GLUON PLASMA.

Description: The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been… more
Date: April 11, 2005
Creator: LUDLAM, T. & ARONSON, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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100-keV Faraday cup design: materials and structure

Description: A Faraday cup design for a 1 mA.cm/sup -2/ 100-keV, light-ion-beam measurement in background plasma is proposed. Features of this shielded, three-grid structure with deep target are described, and a mechanical draft is included. In the appendix, we reference and survey results of experiments reporting the number and energy range of secondary electrons and back-scattered ions originating on various metal surfaces bombarded with approximately 100-keV hydrogen and deuterium ions. Choice of target … more
Date: October 11, 1976
Creator: Jones, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Heteroepitaxial Perovskite Metal-Base Transistor

Description: 'More than Moore' captures a concept for overcoming limitations in silicon electronics by incorporating new functionalities in the constituent materials. Perovskite oxides are candidates because of their vast array of physical properties in a common structure. They also enable new electronic devices based on strongly-correlated electrons. The field effect transistor and its derivatives have been the principal oxide devices investigated thus far, but another option is available in a different ge… more
Date: August 11, 2011
Creator: Yajima, T.; Hikita, Y. & Hwang, H. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Indirect Dark Matter Detection Limits from the Ultra-Faint Milky Way Satellite Segue 1

Description: We use new kinematic data from the ultra-faint Milky Way satellite Segue 1 to model its dark matter distribution and derive upper limits on the dark matter annihilation cross-section. Using gamma-ray ux upper limits from the Fermi satellite and MAGIC, we determine cross-section exclusion regions for dark matter annihilation into a variety of different particles including charged leptons. We show that these exclusion regions are beginning to probe the regions of interest for a dark matter interp… more
Date: August 11, 2011
Creator: Essig, Rouven; Sehgal, Neelima; Strigari, Louis E.; Geha, Marla & Simon, Joshua D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Short Pulse Laser Applications Design

Description: We are applying our recently developed, LDRD-funded computational simulation tool to optimize and develop applications of Fast Ignition (FI) for stockpile stewardship. This report summarizes the work performed during a one-year exploratory research LDRD to develop FI point designs for the National Ignition Facility (NIF). These results were sufficiently encouraging to propose successfully a strategic initiative LDRD to design and perform the definitive FI experiment on the NIF. Ignition experim… more
Date: February 11, 2008
Creator: Town, R J; Clark, D S; Kemp, A J; Lasinski, B F & Tabak, M
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fermi Surface of Superconducting LaFePO Determined by Quantum Oscillations

Description: We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (T{sub c} {approx} 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that the Fermi surface is in broad agreement with the band-structure calculations with the quasiparticle mass enhanced by a factor {approx}2. The quasi-two dimensional Fermi surface consist of nearly-nested electron and hole pockets, suggesting proximity t… more
Date: January 11, 2010
Creator: Coldea, A. I.; Fletcher, J. D.; Carrington, A.; U., /Bristol; Analytis, J. G.; /Stanford U., Geballe Lab. /Stanford U., Appl. Phys. Dept. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Space-charge effects in ultra-high current electron bunches generated by laser-plasma accelerators

Description: Recent advances in laser-plasma accelerators, including the generation of GeV-scale electron bunches, enable applications such as driving a compact free-electron-laser (FEL). Significant reduction in size of the FEL is facilitated by the expected ultra-high peak beam currents (10-100 kA) generated in laser-plasma accelerators. At low electron energies such peak currents are expected to cause space-charge effects such as bunch expansion and induced energy variations along the bunch, potentially … more
Date: February 11, 2009
Creator: Grinner, F. J.; Schroeder, C. B.; Maier, A. R.; Becker, S. & Mikhailova, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Operational Radiation Protection in Synchrotron Light and Free Electron Laser Facilities

Description: The 3rd generation synchrotron radiation (SR) facilities are storage ring based facilities with many insertion devices and photon beamlines, and have low injection beam power (&lt; few tens of watts), but extremely high stored beam power ({approx} 1 GW). The 4th generation x-ray free electron laser (FEL) facilities are based on an electron Linac with a long undulator and have high injection beam power (a few kW). Due to its electron and photon beam characteristics and modes of operation, storag… more
Date: December 11, 2009
Creator: Liu, James C.; Rokni, Sayed H. & Vylet, Vaclav
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theory of Fine-scale Zonal Flow Generation From Trapped Electron Mode Turbulence

Description: Most existing zonal flow generation theory has been developed with a usual assumption of qrρθ¡ << 1 (qr is the radial wave number of zonal flow, and ρθ¡ is the ion poloidal gyrora- dius). However, recent nonlinear gyrokinetic simulations of trapped electron mode (TEM) turbulence exhibit a relatively short radial scale of the zonal flows with qrρθ¡ ~ 1 [Z. Lin et al., IAEA-CN/TH/P2-8 (2006); D. Ernst et al., Phys. Plasmas 16, 055906 (2009)]. This work reports an extension of zonal flow growth ca… more
Date: June 11, 2009
Creator: Hahm, Lu Wang and T.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Gyrokinetic Electron and Fully Kinetic Ion Particle Simulation of Collisionless Plasma Dynamics

Description: Fully kinetic-particle simulations and hybrid simulations have been utilized for decades to investigate various fundamental plasma processes, such as magnetic reconnection, fast compressional waves, and wave-particle interaction. Nevertheless, due to disparate temporal and spatial scales between electrons and ions, existing fully kinetic-particle codes have to employ either unrealistically high electron-to-ion mass ratio, me/mi, or simulation domain limited to a few or a few ten's of the ion La… more
Date: August 11, 2009
Creator: Lin, Yu; Wang, Xueyi; Chen, Liu & Lin, Zhihong
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Solar Energetic Particle Spectrum on 13 December 2006 Determined by IceTop

Description: The IceTop air shower array now under construction at the South Pole as the surface component of the IceCube neutrino telescope (Achterberg et al. 2006) detected an unusual near-solar-minimum Ground Level Enhancement (GLE) after a solar flare on 13 December 2006. Beginning at 0220 UT, the 4B class flare occurred at solar coordinates S06 W24, accompanied by strong (X3.4) X-ray emission and type II and IV radio bursts. The LASCO coronagraph on the SOHO spacecraft observed a halo CME launch from t… more
Date: October 11, 2008
Creator: Collaboration, IceCube & Klein, Spencer
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Betatron radiation from density tailored plasmas

Description: In laser wakefield accelerators, electron motion is driven by intense forces that depend on the plasma density. Transverse oscillations in the accelerated electron orbits produce betatron radiation. The electron motion and the resulting betatron radiation spectrum can therefore be controlled by shaping the plasma density along the orbit of the electrons. Here, a method based on the use of a plasma with a longitudinal density variation (density depression or step) is proposed to increase the tra… more
Date: April 11, 2009
Creator: Ta Phuoc, Kim; Esarey, E.; Leurent, V.; Cormier-Michel, E.; Geddes, C. G. R.; Schroeder, C. B. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Defect Measurements of CdZnTe Detectors Using I-DLTS, TCT, I-V and Gamma-ray Spectroscopy

Description: In this work we measured the crystal defect levels and tested the performance of CdZnTe detectors by diverse methodologies, viz., Current Deep Level Transient Spectroscopy (I-DLTS), Transient Current Technique (TCT), Current and Capacitance versus Voltage measurements (I-V and C-V), and gamma-ray spectroscopy. Two important characteristics of I-DLTS technique for advancing this research are (1) it is applicable for high-resistivity materials (&gt;10{sup 6} {Omega}-cm), and, (2) the minimum temp… more
Date: August 11, 2008
Creator: Gul,R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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