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Spin Transport in Semiconductor heterostructures

Description: The focus of the research performed under this grant has been the investigation of spin transport in magnetic semiconductor heterostructures. The interest in these systems is motivated both by their intriguing physical properties, as the physical embodiment of a spin-polarized Fermi liquid, as well as by their potential applications as spintronics devices. In our work we have analyzed several different problems that affect the spin dynamics in single and bi-layer spin-polarized two-dimensional … more
Date: February 22, 2011
Creator: Marinescu, Domnita Catalina
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

FINAL SCIENTIFIC/TECHNICAL REPORT

Description: Dynalene Inc has developed and patented a fuel cell coolant with the help of DOE SBIR Phase I and Phase II funding (Project DE-FG02-04ER83884). However, this coolant could only be produced in lab scale (500 ml to 2 L) due to problems in the optimization and scale-up of a nanoparticle ingredient. This project optimized the nanoparticle production process in 10 L and 100 L reactors (which translates to about 5000 gallons of coolant), optimized the filtration process for the nanoparticles, and dev… more
Date: December 21, 2011
Creator: Mohapatra, Satish
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Intial characterization fo a commercial electron gun for profiling high intensity proton beams in Project X

Description: Measuring the profile of a high-intensity proton beam is problematic in that traditional invasive techniques such as flying wires don't survive the encounter with the beam. One alternative is the use of an electron beam as a probe of the charge distribution in the proton beam as was done at the Spallation Neutron Source at ORNL. Here we present an initial characterization of the beam from a commercial electron gun from Kimball Physics, intended for use in the Fermilab Main Injector for Project … more
Date: March 1, 2011
Creator: Thurman-Keup, R.; Johnson, A. S.; Lumpkin, A. H.; Thangaraj, J. C. T.; Zhang, D. & Blokland, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Realizing vector meson dominance with transverse charge densities

Description: The transverse charge density in a fast-moving nucleon is represented as a dispersion integral of the imaginary part of the Dirac form factor in the timelike region (spectral function). At a given transverse distance b the integration effectively extends over energies in a range {radical}t {approx}< 1/b, with exponential suppression of larger values. The transverse charge density at peripheral distances thus acts as a low-pass filter for the spectral function and allows one to select energy … more
Date: October 1, 2011
Creator: Gerald Miller, Mark Strikman, Christian Weiss
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electron Beam Charge Diagnostics for Laser Plasma Accelerators

Description: A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of t… more
Date: June 27, 2011
Creator: Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermodynamic and Transport Properties of YTe3, LaTe3 and CeTe3

Description: Measurements of heat capacity, susceptibility, and electrical resistivity are presented for single crystals of the charge density wave compounds YTe{sub 3}, LaTe{sub 3}, and CeTe{sub 3}. The materials are metallic to low temperatures, but have a small density of states due to the charge density wave gapping large portions of the Fermi surface. CeTe{sub 3} is found to be a weak Kondo lattice, with an antiferromagnetic ground state and T{sub N} = 2.8 K. The electrical resistivity of all three com… more
Date: August 19, 2011
Creator: Ru, N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effects of e-beam parameters on coherent electron cooling

Description: Coherent Electron Cooling (CeC) requires detailed control of the phase between the hadron an the FEL-amplified wave packet. This phase depends on local electron beam parameters such as the energy spread and the peak current. In this paper, we examine the effects of local density variations on the cooling rates for CeC. Coherent Electron Cooling (CeC) [1] is a new concept in intense, high energy hadron beamcooling, in which the Debye screened charge perturbation calculated in [2] is used to seed… more
Date: March 28, 2011
Creator: Webb, S. D.; Litvinenko, V. N. & Wang, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Comment on Particle acceleration by stimulated emission of radiation near a solid-state active medium

Description: In a recent Letter, V. Berezovsky, H. Alam, and L. Schaechter have reported 'acceleration of electrons moving in free space near an active Nd:YAG slab'. The reported mechanism is particle acceleration by stimulated emission of radiation (PASER). The energy of electrons was not measured directly, but instead inferred from measurements of the electron beam current, after it 'interacted' with the Nd:YAG slab. In this Comment I suggest that the authors proposition that the increase in beam current … more
Date: May 1, 2011
Creator: Nagaitsev, Sergei
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Parameter Selection and Longitudinal Phase Space Simulation for a Single Stage X-Band FEL Driver at 250 MeV

Description: Hard x-ray Free electron lasers (FEL) are being built or proposed at many accelerator laboratories as it supports wide range of applications in many aspects. Most of the hard x-ray FEL design is similar with the SLAC Linac Coherent Light Source (LCLS), which features a two (or multiple) stage bunch compression. For the first stage of the bunch compression, usually the beam is accelerated in a lower-frequency RF section (such as S-band for LCLS), and then the longitudinal phase space is lineariz… more
Date: August 19, 2011
Creator: Sun, Yipeng; Raubenheimer, Tor & Wu, Juhao
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Implications of Pulser Voltage Ripple

Description: In a recent set of measurements obtained by G. Kamin, W. Manning, A. Molvik, and J. Sullivan, the voltage waveform of the diode pulser had a ripple of approximately {+-}1.3% of the 65 kV flattop voltage, and the beam current had a larger corresponding ripple of approximately {+-}8.4% of the 1.5 mA average current at the location of the second Faraday cup, approximately 1.9 m downstream from the ion source. The period of the ripple was about 1 {mu}s. It was initially unclear whether this large c… more
Date: December 21, 2011
Creator: Barnard, J J
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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