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Frontiers of particle beam physics

Description: First, a review is given of various highly-developed techniques for particle handling which are, nevertheless, being vigorously advanced at the present time. These include soft superconductor radio frequency cavities, hard superconductor magnets, cooling rings for ions and anti-protons, and damping rings for electrons. Second, attention is focused upon novel devices for particle generation, acceleration, and focusing. These include relativistic klystrons and free electron laser power sources, b… more
Date: November 1, 1989
Creator: Sessler, Andrew M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stability of Resonator Configurations in the Presence of Free-Electron Laser Interactions

Description: The stability of empty resonators (or cold cavities) has been widely studied, and is well understood. Here we consider the stability of symmetric resonator systems when there is a free-electron laser (FEL) interaction present within the cavity. We first construct a linear thick-lens model of the FEL and analytically study the dependence of resonator stability on its geometry. Next, we employ a nonlinear, three-dimensional FEL oscillator code to study the dependence of FEL performance on the cav… more
Date: November 1, 1992
Creator: Krishnagopal, S. & Sessler, Andrew M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Highly Effective Polarized Electron Sources Based on Strained Semiconductor Superlattice with Distributed Bragg Reflector

Description: Resonance enhancement of the quantum efficiency of new polarized electron photocathodes based on a short-period strained superlattice structures is reported. The superlattice is a part of an integrated Fabry-Perot optical cavity. We demonstrate that the Fabry-Perot resonator enhances the quantum efficiency by the order of magnitude in the wavelength region of the main polarization maximum. The high structural quality implied by these results points to the very promising application of these pho… more
Date: November 28, 2007
Creator: Gerchikov, L. G.; Aulenbacher, K.; Clendenin, J. E.; Kuz'michev, V. V.; Mamaev, Yu. A.; Maruyama, T. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Soft X-Ray Magnetic Imaging of Focused Ion Beam Lithographically Patterned Fe Thin Films

Description: We illustrate the potential of modifying the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Ber… more
Date: November 9, 2008
Creator: Cook, Paul J.; Shen, Tichan H.; Grundy, PhilJ.; Im, Mi Young; Fischer, Peter; Morton, Simon A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electrical configuration for magnetic drift pumping on the tandem mirror experiment-upgrade (TMX-U)

Description: Magnetic drift pumping on TMX-U involves driving four antennae through high Q-resonant circuits. One of the key elements in the resonant circuit is a variable inductor able to carry the 3500 amperes through the circuit and maintain its shape and inductance. The eight resonant circuits can be combined to feed the four antennae with one or two frequencies on each antenna, or frequency shift keying between two frequencies. Each resonant circuit is fed by two 10 to 30 kHz exciters capable of delive… more
Date: November 11, 1985
Creator: Jackson, M.C.; Kane, R.J. & Hulsey, S.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Superconducting traveling wave accelerators

Description: This note considers the applicability of superconductivity to traveling wave accelerators. Unlike CW operation of a superconducting standing wave or circulating wave accelerator section, which requires improvement factors (superconductor conductivity divided by copper conductivity) of about 10/sup 6/ in order to be of practical use, a SUperconducting TRaveling wave Accelerator, SUTRA, operating in the pulsed mode requires improvement factors as low as about 10/sup 3/, which are attainable with … more
Date: November 1, 1984
Creator: Farkas, Z. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Design of ferrite-tuned accelerator cavities using perpendicular-biased high-Q ferrites

Description: Microwave ferrites with dc bias fields perpendicular to the rf fields exhibit magnetic and dielectric quality factors 1 order of magnitude above that of ferrites used in ferrite-tuned synchrotron accelerating cavities built in the past. For the LAMPF II project, these ferrites appear to allow the design of synchrotron cavities with high gap voltages and high efficiency. A simple coaxial quarter-wave-resonator geometry, first considered only as a model for preliminary studies, turned out to be a… more
Date: November 1, 1984
Creator: Kaspar, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Some aspects of superconducting accelerator design

Description: The performance of an accelerator can be characterized by the efficiency with which electrical energy, the minimumm energy needed to generate a given beam voltage. The current accelerator improvement program at SLAC aims at raising the beam voltage to 50 GV which will use 240 klystrons each capable of producing a pulse 5 ..mu..s in length at a peak power of 36 MW. The Linear Collider requires 50 MW klystrons to achieve 60 GV which will raise the concomittant power consumption to 32.3 MW. We sho… more
Date: November 1, 1982
Creator: Farkas, Z. D. & St. Lorant, S. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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RF cavity development for the PEP-II B factory

Description: This paper describes the development of an RF cavity design for the proposed PEP-II asymmetric B factory. The high luminosity required of PEP-II provides challenges in the design of the RF cavities, most notably in the reduced higher-order mode (HOM) impedances that must be attained and in the power that must be dissipated in the cavity walls. This paper outlines the goals set in these regards, describes how the cavity has been developed to meet them, and presents the results of measurements on… more
Date: November 1, 1992
Creator: Rimmer, R.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Accelerator technology program. Progress report, January-December 1979

Description: The activities of Los Alamos Scientific Laboratory's (LASL) Accelerator Technology (AT) Division during the calendar year 1979 are highlighted, with references to more detailed reports. This report is organized around the major projects of the Division, reflecting a wide variety of applications and sponsors. The first section covers the Fusion Materials Irradiation Test program, a collaborative effort with the Hanford Engineering Development Laboratory; the second section summarizes progress on… more
Date: November 1, 1980
Creator: Knapp, E.A. & Jameson, R.A. (comps.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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LABCOM resonator Phase 3

Description: The purpose of this project was to develop quartz crystal resonator designs, production processes, and test capabilities for 5-MHz, 6.2-MHz, and 10-MHz resonators for Tactical Miniature Crystal Oscillator (TMXO) applications. GE Neutron Devices (GEND) established and demonstrated the capability to produce and test quartz crystal resonators for use in the TMXO developed by the US Army ERADCOM (now LABCOM). The goals in this project were based on the ERADCOM statement of work. The scope of work i… more
Date: November 1, 1990
Creator: Keres, L.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Focused ion beam patterned Fe thin films A study by selective area Stokes polarimetry and soft x-Ray microscopy

Description: We demonstrate the potential to modify the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berke… more
Date: November 14, 2010
Creator: Cook, P. J.; Shen, T. H.; Grundy, P. J.; Im, M.-Y.; Fischer, P.; Morton, S. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Hole Coupling Resonator for Free Electron Lasers

Description: The performance of two mirror resonators with holes for output coupling is studied for free electron laser application using a Fox-Li type code. The mode profiles inside and outside the cavity, the diffraction losses at the mirror edges and apertures, the amount of useful power coupled through the hole, e.t.c., are calculated for the dominant mode for different hole and mirror dimensions. It is found that resonators in near concenoic geometry can develop a mode degeneracy in certain cases, whic… more
Date: November 1, 1990
Creator: Xie, M. & Kim, K. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Beam dynamics studies of the 8 GeV Linac at FNAL

Description: The proposed 8-GeV proton driver (PD) linac at FNAL includes a front end up to {approx}420 MeV operating at 325 MHz and a high energy section at 1300 MHz. A normal conducting RFQ and short CH type resonators are being developed for the initial acceleration of the H-minus or proton beam up to 10 MeV. From 10 MeV to {approx}420 MeV, the voltage gain is provided by superconducting (SC) spoke-loaded cavities. In the high-energy section, the acceleration will be provided by the International Linear … more
Date: November 1, 2008
Creator: Ostroumov, P.N.; Mustapha, B.; /Argonne; Carneiro, J.-P. & /Fermilab
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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LDRD final report on using chaos for ultrasensitive coherent signal detection.

Description: A quantum optical approach is proposed and analyzed as a solution to the problem of detecting weak coherent radiation in the presence of a strong incoherent background. The approach is based on the extreme sensitivity of laser dynamical nonlinearities to the coherence of external perturbation. This sensitivity leads to dynamical phase transitions that may be employed for detecting the presence of external coherent radiation. Of particular interest are the transitions between stable and chaotic … more
Date: November 1, 2006
Creator: Chow, Weng Wah; Wieczorek, Sebastian Maciej & Torrington, Geoffrey Kenneth
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

User's guide for New ABCI version 6. 2: Azimuthal Beam Cavity Interaction

Description: ABCI described here is a computer program which solves the Maxwell equations directly in the time domain when a Gaussian beam goes through an axi-symmetrical structure on or off axis. Many new features have been implemented in this version of ABCI, including the moving mesh'' and Napoly's method of calculation of wake potentials. The mesh is now generated only for the part of the structure inside a window, and moves together with the window frame. This moving mesh option drastically reduces the… more
Date: November 1, 1992
Creator: Chin, Yong Ho.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Numerical Modeling of Left-Handed Metamaterials

Description: The EIGER method of moments program with periodic Green's function was used to model a periodic array of strips and split-ring resonators. Left-handed propagation due to negative index of refraction is demonstrated in a frequency band. The effective material parameters versus frequency are extracted from the EIGER solution.
Date: November 6, 2001
Creator: Burke, G J; Champagne, N J & Sharpe, R M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Coarse-Grained Molecular Dynamics for Computer Modeling of Nanomechanical Systems

Description: Unique challenges for computer modeling and simulation arise in the course of the development and design of nanoscale mechanical systems. Materials often exhibit unconventional behavior at the nanoscale that can affect device operation and failure. This uncertainty poses a problem because of the limited experimental characterization at these ultra-small length scales. In this Article we give an overview of how we have used concurrent multiscale modeling techniques to address some of these issue… more
Date: November 2, 2003
Creator: Rudd, R E
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Equivalent performance in different helical resonator plasma polymerization coater platforms

Description: Plasma polymerization is used in fabricating target mandrels for implosion experiments on the NOVA laser. As part of effort to translate the theoretical aspects of plasma polymerization fundamentals into practical improvements in a production oriented environment, a study was done to determine the cause of differences in polymer deposition characteristics between two similar plasma polymerization devices. Full characterization of the coating system parameters revealed differences in the flow ra… more
Date: November 1, 1993
Creator: Brusasco, R. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Compact QEPAS sensor for trace methane and ammonia detection in impure hydrogen

Description: A compact two-gas sensor based on quartz enhanced photoacoustic spectroscopy (QEPAS) was developed for trace methane and ammonia quantification in impure hydrogen. The sensor is equipped with a micro-resonator to confine the sound wave and enhance QEPAS signal. The normalized noise-equivalent absorption coefficients (1{sigma}) of 2.45 x 10{sup -8} cm{sup -1}W/{radical}Hz and 9.1 x 10{sup -9} cm{sup -1}W/{radical}Hz for CH{sub 4} detection at 200 Torr and NH{sub 3} detection at 50 Torr were demo… more
Date: November 2, 2011
Creator: Wright, J.; Ferguson, B.; Peters, B. & Mcwhorter, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Advanced methods for the computation of particle beam transport and the computation of electromagnetic fields and beam-cavity interactions

Description: The University of Maryland Dynamical Systems and Accelerator Theory Group carries out research in two broad areas: the computation of charged particle beam transport using Lie algebraic methods and advanced methods for the computation of electromagnetic fields and beam-cavity interactions. Important improvements in the state of the art are believed to be possible in both of these areas. In addition, applications of these methods are made to problems of current interest in accelerator physics in… more
Date: November 1, 1990
Creator: Dragt, Alex J. & Gluckstern, Robert L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Drabkin energy filter for experiments at a spallation neutron source.

Description: We present a new approach for dynamic monochromatization of neutrons suitable for time-of-flight experiments at spallation neutron sources. The method requires polarized neutrons and is based on the Drabkin energy filter. In its initial application, this magnetic resonator device, consisting of a polarizer/analyzer system and a wavelength-dependent spin flipper, was proposed for extracting a narrow bandwidth from a broad bandwidth polarized neutron beam. At a spallation neutron source, waveleng… more
Date: November 21, 2000
Creator: Parizzi, A. A.; Felcher, G. P. & Klose, F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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