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New Particle-in-Cell Code for Numerical Simulation of Coherent Synchrotron Radiation

Description: We present a first look at the new code for self-consistent, 2D simulations of beam dynamics affected by the coherent synchrotron radiation. The code is of the particle-in-cell variety: the beam bunch is sampled by point-charge particles, which are deposited on the grid; the corresponding forces on the grid are then computed using retarded potentials according to causality, and interpolated so as to advance the particles in time. The retarded potentials are evaluated by integrating over the 2D … more
Date: May 1, 2010
Creator: Balsa Terzic, Rui Li
Partner: UNT Libraries Government Documents Department
open access

BEAM CONTAINMENT SYSTEM FOR NSLS-II

Description: The shielding design for the NSLS-II will provide adequate protection for the full injected beam loss in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of {le} 10% full beam. This will require a system to insure that beam losses don't exceed these levels for a period of time that could cause excessive radiation levels outside the shield walls. This beam containment system will measure, provide a level of control and alarm indicatio… more
Date: May 23, 2010
Creator: Kramer, S. L.; Casey, W. & Job, P. K.
Partner: UNT Libraries Government Documents Department
open access

Novel Geometries for the LHC Crab Cavity

Description: The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the I… more
Date: May 23, 2010
Creator: B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang
Partner: UNT Libraries Government Documents Department
open access

An imaging proton spectrometer for short-pulse laser plasma experiments

Description: Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better characterize these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only measure proton energy distribution with high… more
Date: May 11, 2010
Creator: Chen, H.; Hazi, A.; van Maren, R.; Chen, S.; Fuchs, J.; Gauthier, M. et al.
Partner: UNT Libraries Government Documents Department
open access

RHIC BBLR measurements in 2009

Description: Long range beam-beam experiments were conducted during the Run 2009 in the Yellow and the Blue beams of the RHIC accelerator with DC wires. The effects of a long-range interaction with a DC wire on colliding and non-colliding bunches with the aid of beam losses, orbits, tunes were studied. Results from distance scans and an attempt to compensate a long-range interaction with a DC wire is presented. Two DC wires in the vertical plane were installed in the RHIC accelerator in 2006 with the aim of… more
Date: May 23, 2010
Creator: Calaga, R.; Robert-Demolaize, G. & Fischer, W.
Partner: UNT Libraries Government Documents Department
open access

Electrodeposition of U and Pu on Thin C and Ti Substrates

Description: Physics experiments aimed at deducing key parameters for use in a variety of programs critical to the mission of the National Laboratories require actinide targets placed onto various substrates. The target material quantity and the substrate desired depend upon the type of experiment being designed. The physicist(s) responsible for the experimental campaign will consult with the radiochemistry staff as to the feasibility of producing a desired target/substrate combination. In this report they … more
Date: May 19, 2010
Creator: Henderson, R. A. & Gostic, J. M.
Partner: UNT Libraries Government Documents Department
open access

Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

Description: RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activ… more
Date: May 23, 2010
Creator: Wang, E.; Ben-Zvi, Ilan; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q. et al.
Partner: UNT Libraries Government Documents Department
open access

Task 1—Steam Oxidation (NETL-US)

Description: The proposed steam in let temperature in the Advanced Ultra Supercritical (A·USC) steam turbine is high enough (760°C) Ihat traditional turbine casing and valve body materials such as ferr;tic/manensitic steels will not suffice due to temperature lim itations of this class of materials. Cast versions of three traditionally wrought Ni-based superalloys (Haynes 263. Haynes 282, and Nimonic 105) were evaluated for use as casing or valve components for the next generation of industrial steam turbin… more
Date: May 1, 2010
Creator: Holcomb, G. R.
Partner: UNT Libraries Government Documents Department
open access

Predicting Image Blur in Proton Radiography: Comparisons Between Measurements and Monte Carlo Simulations

Description: Given the cost and lead-times involved in high-energy proton radiography, it is prudent to model proposed radiographic experiments to see if the images predicted would return useful information. We recently modified our raytracing transmission radiography modeling code HADES to perform simplified Monte Carlo simulations of the transport of protons in a proton radiography beamline. Beamline objects include the initial diffuser, vacuum magnetic fields, windows, angle-selecting collimators, and ob… more
Date: May 7, 2010
Creator: Schach von Wittenau, Alexis E.; Aufderheide, Maurice B., III & Henderson, Gary L.
Partner: UNT Libraries Government Documents Department
open access

500 MW X-BAND RF SYSTEM OF A 0.25 GEV ELECTRON LINAC FOR ADVANCED COMPTON SCATTERING SOURCE APPLICATION

Description: A Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering light source is being developed at LLNL in collaboration with SLAC National Accelerator Laboratory. The electron beam for the Compton scattering interaction will be generated by a X-band RF gun and a X-band LINAC at the frequency of 11.424 GHz. High power RF in excess of 500 MW is needed to accelerate the electrons to energy of 250 MeV or greater for the interaction. Two high power klystron amplifiers, each capable of generating 50 MW, 1.… more
Date: May 12, 2010
Creator: Chu, T S; Anderson, S G; Gibson, D J; Hartemann, F V; Marsh, R A; Siders, C et al.
Partner: UNT Libraries Government Documents Department
open access

Progress of Bep Treatments on Nb at JLAB

Description: Recent experimental results have indicated that Buffered Electropolishing (BEP) is a promising candidate for the next generation of surface treatment technique for Nb superconducting radio frequency (SRF) cavities to be used in particle accelerators. In order to lay the foundation for using BEP as the next generation surface treatment technique for Nb SRF cavities, some fundamental aspects of BEP treatments for Nb have to be investigated. In this report, recent progress on BEP study at JLab is … more
Date: May 1, 2010
Creator: A.T. Wu, S. Jin, R.A. Rimmer,X.Y. Lu, K. Zhao
Partner: UNT Libraries Government Documents Department
open access

Recent Developments on ALICE (Accelerators and Lasers In Combined Experiments) at Daresbury Laboratory

Description: Progress made in ALICE (Accelerators and Lasers In Combined Experiments) commissioning and a summary of the latest experimental results are presented in this paper. After an extensive work on beam loading effects in SC RF linac (booster) and linac cavities conditioning, ALICE can now operate in full energy recovery mode at the bunch charge of 40pC, the beam energy of 30MeV and train lengths of up to 100us. This improved operation of the machine resulted in generation of coherently enhanced broa… more
Date: May 1, 2010
Creator: Saveliev, Y. M.; Buckley, R. K.; Buckley, S. R.; Clarke, J. A.; Corlett, P. A.; Dunning, D. J. et al.
Partner: UNT Libraries Government Documents Department
open access

LHC crab-cavity aspects and strategy

Description: The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity des… more
Date: May 23, 2010
Creator: Calaga, R.; Tomas, R. & Zimmermann, F.
Partner: UNT Libraries Government Documents Department
open access

Novel Geometries for the LHC Crab Cavity

Description: The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the I… more
Date: May 1, 2010
Creator: B. Hall,G. Burt,C. Lingwood,Robert Rimmer,Haipeng Wang; Hall, B.; Burt, G.; Lingwood, C.; Rimmer, Robert & Wang, Haipeng
Partner: UNT Libraries Government Documents Department
open access

Do Heat Pump Clothes Dryers Make Sense for the U.S. Market

Description: Heat pump clothes dryers (HPCDs) can be as much as 50percent more energy-efficient than conventional electric resistance clothes dryers, and therefore have the potential to save substantial amounts of electricity. While not currently available in the U.S., there are manufacturers in Europe and Japan that produce units for those markets. Drawing on analysis conducted for the U.S. Department of Energy's (DOE) current rulemaking on amended standards for clothes dryers, this paper evaluates the cos… more
Date: May 14, 2010
Creator: Meyers, Steve; Franco, Victor; Lekov, Alex; Thompson, Lisa & Sturges, Andy
Partner: UNT Libraries Government Documents Department
open access

Beam Dynamics Studies for the First Muon Linac of the Neutrino Factory

Description: Within the Neutrino Factory Project the muon acceleration process involves a complex chain of accelerators including a (single-pass) linac, two recirculating linacs and an FFAG. The linac consists of RF cavities and iron shielded solenoids for transverse focusing and has been previously designed relying on idealized field models. However, to predict accurately the transport and acceleration of a high emittance 30 cm wide beam with 10 % energy spread requires detailed knowledge of fringe field d… more
Date: May 1, 2010
Creator: C. Bontoiu,M. Aslaninejad,J. Pozimski,Alex Bogacz
Partner: UNT Libraries Government Documents Department
open access

Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry

Description: For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizont… more
Date: May 15, 2010
Creator: Berryman, J.G.
Partner: UNT Libraries Government Documents Department
open access

Heat load of a P-doped GaAs photocathode in SRF electron gun

Description: Many efforts were made over the last decades to develop a better polarized electron source for the high energy physics. Several laboratories operate DC guns with the Gallium-Arsenide photo-cathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved using a Superconducting RF electron gun, which delivers beams of higher brightness than DC guns does, because the field gradient at the cathode is higher. SRF guns with metal cathodes and CsTe cathodes … more
Date: May 23, 2010
Creator: Wang, E.; Ben-Zvi, Ilan; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q. et al.
Partner: UNT Libraries Government Documents Department
open access

Electron-cloud Build-up Simulations in the Proposed PS2: Status Report

Description: A replacement for the PS storage ring is being considered, in the context of the future LHC accelerator complex upgrade, that would likely place the new machine (the PS2) in a regime where the electron-cloud (EC) effect might be significant. We report here our current estimate of the EC density ne in the bending magnets and the field-free regions at injection and extraction beam energy, for both proposed bunch spacings, tb = 25 and 50 ns. The primary model parameters exercised are the peak seco… more
Date: May 5, 2010
Creator: Furman, M. A.; De Maria, R.; Papaphilippou, Y. & Rumolo, G.
Partner: UNT Libraries Government Documents Department
open access

The MuCool Test Area and RF Program

Description: The MuCool RF Program focuses on the study of normal conducting RF structures operating in high magnetic field for applications in muon ionization cooling for Neutrino Factories and Muon Colliders. This paper will give an overview of the program, which will include a description of the test facility and its capabilities, the current test program, and the status of a cavity that can be rotated in the magnetic field which allows for a more detailed study of the maximum stable operating gradient v… more
Date: May 1, 2010
Creator: Bross, A. D.; Jansson, A.; Moretti, A.; Yonehara, K.; Huang, D.; Torun, Y. et al.
Partner: UNT Libraries Government Documents Department
open access

Muon Acceleration with RLA and Non-scaling FFAG Arcs

Description: Recirculating Linear Accelerators (RLA) are the most likely means to achieve the rapid acceleration of shortlived muons to multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper, we present a novel return-arc optics design based on a Non Scaling Fixed Field Alternating Gradient (NS-FFAG) lattice that allows 5 and 9 GeV/c muons of both charges to be transported in the same string of magnets. The return arcs are made up of super cells with e… more
Date: May 1, 2010
Creator: Vasiliy Morozov,Alex Bogacz,Dejan Trbojevic
Partner: UNT Libraries Government Documents Department
open access

THE JLAMP VUV/SOFT X-RAY USER FACILITY AT JEFFERSON LABORATORY

Description: Jefferson Lab (JLab) is proposing JLAMP (JLab Amplifier), a 4th generation light source covering the 10-100 eV range in the fundamental mode with harmonics stretching towards the oxygen k-edge. The new photon science user facility will feature a two-pass superconducting LINAC to accelerate the electron beam to 600MeV at repetition rates of 4.68MHz continuous wave. The average brightness from a seeded amplifier free electron laser (FEL) will substantially exceed existing light sources in this de… more
Date: May 1, 2010
Creator: Benson, S. V.; Douglas, D.; Evtushenko, P.; Gubeli, J.; Hannon, F. E.; Jordan, K. et al.
Partner: UNT Libraries Government Documents Department
open access

ELECTROSTATIC MODELING OF THE JEFFERSON LABORATORY INVERTED CERAMIC GUN

Description: Jefferson Laboratory (JLab) is currently developing a new 500kV DC electron gun for future use with the FEL. The design consists of two inverted ceramics which support a central cathode electrode. This layout allows for a load-lock system to be located behind the gun chamber. The electrostatic geometry of the gun has been designed to minimize surface electric field gradients and also to provide some transverse focusing to the electron beam during transit between the cathode and anode. This pape… more
Date: May 1, 2010
Creator: P. Evtushenko ,F.E. Hannon, C. Hernandez-Garcia
Partner: UNT Libraries Government Documents Department
open access

Target Diagnostic Control System Implementation for the National Ignition Facility

Description: The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics. Many diagnostics are being developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. A Diagnostic Control System (DCS) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other… more
Date: May 12, 2010
Creator: Shelton, R T; Kamperschroer, J H; Lagin, L J; Nelson, J R & O'Brien, D W
Partner: UNT Libraries Government Documents Department
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