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Correction of dispersion and the betatron functions in the CEBAF accelerator

Description: During the commissioning of the CEBAF accelerator, correction of dispersion and momentum compaction, and, to a lesser extent, transverse transfer matrices were essential for robust operation. With changing machine conditions, repeated correction was found necessary. To speed the diagnostic process the authors developed a method which allows one to rapidly track the machine optics. The method is based on measuring the propagation of 30 Hz modulated betatron oscillations downstream of a point of … more
Date: October 1, 1996
Creator: Lebedev, V. A.; Bickley, M.; Schaffner, S.; Zeijts, J. van; Krafft, G. A. & Watson, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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NIF pointing and centering systems and target alignment using a 351 nm laser source

Description: The operational requirements of the National Ignition Facility (NIF) place tight constraints upon its alignment system. In general, the alignment system must establish and maintain the correct relationships between beam position, beam angle, laser component clear apertures, and the target. At the target, this includes adjustment of beam focus to obtain the correct spot size. This must be accomplished for all beamlines in a time consistent with planned shot rates and yet, in the front end and ma… more
Date: October 1, 1996
Creator: Boege, Steven J.; Bliss, Erlan S.; Chocol, Clifford J.; Holdener, Fred R.; Miller, John L.; Toeppen, John S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Simple X-Ray Focusing Mirror Using Float Glass

Description: In our recent x-ray photon correlation spectroscopy (speckle) experiments at NSLS, one of the challenges is to increase the coherent photon flux through a pinhole, whose size is chosen to match the beam`s horizontal transverse coherence length {ital l{sub h}}. We adopted an approach to vertically focus the x-ray beam so as to match its vertical transverse coherence length {ital l{sub v}}, (at NSLS X13, {ital l{sub v}}{approximately} 50{ital l{sub h}}, {ital l{sub h}}{approximately} 12 {mu}m at … more
Date: October 1, 1996
Creator: Yin, Z.; Berman, L.; Siddons, D. P.; Dierker, S. & Dufresne, E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Transfer matrices of superimposed magnets and RF cavity

Description: Superimposed magnets often occur in accelerators, such as in the interaction regions of colliders. This note presents the linear transfer matrices of various superimposed magnets. Since readers of this note are probably well informed, the authors simply list the results without derivation. The method used to calculate the linear transfer matrices is outlined elsewhere. The authors list the Hamiltonian H and the corresponding matrix e{sup :-sH:} for several combinations of common magnets (only s… more
Date: November 1, 1996
Creator: Wang, Shun-xi & Chao, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Plasma possibilities in the NLC

Description: Substantial progress in plasma based methods of acceleration opens new option for optimization of the design of future colliders. Basic idea and preliminary analysis are presented of a possibility to compensate the energy spread and to collimate beam in the next generation of linear colliders (NLC) using tunneling ionization of a gas by the beam.
Date: December 1, 1996
Creator: Heifets, S. & Raubenheimer, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A pure permanent magnet-two plane focusing-tapered wiggler for a high average power FEL

Description: A high-average power FEL is under construction at Los Alamos. The FEL will have aspects of both an oscillator and a SASE (self-amplified spontaneous emission) device. That is, a high-gain and high- extraction efficiency wiggler will be used with a very low-Q optical resonator. FEL simulations reveal that a tapered wiggler with two- plane focusing is required to obtain desired performance. The wiggler is comprised of a I meter long untapered section followed by a 1 meter tapered section. The tap… more
Date: November 1, 1996
Creator: Fortgang, C.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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First operation of the upgraded SLAC A-Line

Description: The SLAC A-Line has been upgraded to transport electrons to fixed target experiments in End Station A (ESA) with energies up to 50 GeV. From September through November, 1995, this beam line was commissioned and used to deliver 48.36 GeV polarized electrons to Experiment E-154 at 120 pulses/sec and up to 10{sup 11} e{sup {minus}}/pulse. The beam had a full width momentum spread of less than 0.5 percent, and was focused to a small spot ({sigma}=0.7 mm) at the target. In this paper the authors des… more
Date: October 1, 1996
Creator: Erickson, R.; Anderson, S. & Baker, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Suppression of radiation excitation in focusing environment

Description: Radiation damping and quantum excitation in an electron damping ring and a straight focusing channel are reviewed. They are found to be the two limiting cases in the study of a general bending and focusing combined system. In the intermediate regime where the radiation formation length is comparable to the betatron wavelength, quantum excitation can be exponentially suppressed by focusing field. This new regime may have interesting applications in the generation of ultra-low emittance beams.
Date: December 1, 1996
Creator: Huang, Z. & Ruth, R. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluation of the gaussian beam model for prediction of LDV fringe fields

Description: A simple model is developed to estimate the fringe field geometry at the intersection of two Gaussian laser beams. Comparison of the model results to experimentally measured fringe spacing demonstrates that while the model predicts the fringe geometry well when the beam waists are far from the intersection volume, it performs poorly under nominally ideal conditions- when the beam waists are located at the intersection. Data obtained with two different laser sources indicate that the discrepanci… more
Date: December 31, 1996
Creator: Miles, P.C. & Witze, P.O.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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2x1 prototype plasma-electrode pockels cell (PEPC) for the National Ignition Facility

Description: A large aperture optical switch based on plasma electrode Pockels cell (PEPC) technology is an integral part of the National Ignition Facility (NIP) laser design. This optical switch will trap the input optical pulse in the NIF amplifier cavity for four gain passes and then switch the high-energy output optical pulse out of the cavity. The switch will consist of arrays of plasma electrode Pockels cells working in conjunction with thin-film, Brewster`s angle polarizes. The 192 beams in the NIF w… more
Date: October 1, 1996
Creator: Rhodes, M. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electron optics in hybrid photodetectors in magnetic fields

Description: The CMS detector design has the hadronic calorimeter immersed in a 4 T magnetic field. The scintillator photon transducer must work reliably in this environment. The baseline phototransducer is the ``hybrid photomultiplier``, which consists of a standard photocathode (S20) followed by a high field acceleration onto the surface of a Si diode. Such a device has a linear response, 1 e out for every 3.6 eV of potential drop in excess of the threshold needed to penetrate the passivation layer of the… more
Date: December 1, 1996
Creator: Green, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Synchrotron light source data book: Version 4, Revision 05/96

Description: This book is as its name implies a collection of data on existing and planned synchrotron light sources. The intention was to provide a compendium of tools for the design of electron storage rings as synchrotron radiation sources. The slant is toward the accelerator physicist as other booklets such as the X-Ray Data Booklet address the use of synchrotron radiation. It is hoped that the booklet serves as a pocket sized reference to facilitate back of the envelope type calculations. It contains s… more
Date: May 1, 1996
Creator: Murphy, J.B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High fluence 1.05 {mu}m performance tests using 20 ns shaped pulses on the Beamlet prototype laser

Description: Beamlet is a single beamline, nearly full scale physics prototype of the 192 beam Nd:Glass laser driver of the National Ignition Facility. It is used to demonstrate laser performance of the NIF multipass amplifier architecture. Initial system characterization tests have all been performed at pulse durations less than 10 ns. Pinhole closure and modulation at the end of long pulses are a significant concern for the operation of NIF. We recently demonstrated the generation, amplification and propa… more
Date: December 1, 1996
Creator: Van Wonterghem, B. M.; Murray, J. E.; Burkhart, S. C.; Penko, F.; Henesian, M. A.; Auerbach, J. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Some recent developments in treatment planning software and methodology for BNCT

Description: Over the past several years/the Idaho National Engineering Laboratory (INEL) has led the development of a unique, internationally-recognized set of software modules (BNCT rtpe) for computational dosimetry and treatment planning for Boron Neutron Capture Therapy (BNCT). The computational capability represented by this software is essential to the proper administration of all forms of radiotherapy for cancer. Such software addresses the need to perform pretreatment computation and optimization of… more
Date: December 31, 1996
Creator: Nigg, D. W.; Wheeler, F. J.; Wessol, D. E.; Wemple, C. A.; Babcock, R. & Capala, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Comparison between various beam steering algorithms for the CEBAF lattice

Description: In this paper the authors describe a comparative study performed to evaluate various beam steering algorithms for CEBAF lattice. The first approach that was evaluated used a Singular Value Decomposition (SVD) based algorithm to determine the corrector magnet setting for various regions of the CEBAF lattice. The second studied algorithm is known as PROSAC (Projective RMS Orbit Subtraction And Correction). This algorithm was developed at TJNAF to support the commissioning activity. The third set … more
Date: December 31, 1996
Creator: Chowdhary, M.; Chao, Y.C. & Witherspoon, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Mode-expanded semiconductor laser with tapered-rib adiabatic-following fiber coupler

Description: Expanded-mode semiconductor lasers are of great interest due to the benefits of reduced far-field divergence and improved coupling efficiency to optical fiber. The authors present a new diode laser using a Tapered-Rib Adiabatic-Following Fiber Coupler (TRAFFiC) to achieve 2D mode expansion without epitaxial regrowth or sharply-defined tips on tapered waveguides. The expanded mode size would allow 0.25 to 1 dB coupling loss to standard telecommunications fiber making smaller-core specialty fiber… more
Date: December 1, 1996
Creator: Vawter, G. A.; Smith, R. E.; Hou, H. & Wendt, J. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Deflection, spraying, and induced scattering of intense laser beams in plasmas

Description: Investigations into laser beam spraying, deflection, and induced scattering in plasmas are presented. Recent calculations and experiments on beam spraying due to filamentation are discussed. A simple model is presented for an enhanced beam deflection associated with nearly sonic plasma flow transverse to the beam. This model provides useful insights on the laser beam deflection, its scaling and the importance of self-consistent profile modifications. Finally, some discussion is given of recent … more
Date: September 1, 1996
Creator: Kruer, W.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An energy upgrade from TESLA to a high-energy {mu}{sup +}{mu}{sup {minus}} collider

Description: We discuss the possible extension of a TESLA 250X250 GeV SRF e{sup +}e{sup -} linear collider to a multi-TeV {mu}{sup +}{mu}{sup -} collider, by future addition of a muon source, return arcs for recirculation and a collider ring. The TESLA SRF systems are potentially also suitable for multiturn acceleration of muon bunches, and could be adapted for use in a recirculating {mu}-linac. Many problems and design issues would need to be resolved, and further study is needed.
Date: October 1, 1996
Creator: Neuffer, D.; Edwards, H. & Finley, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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3-D electromagnetic modeling of wakefields in accelerator components

Description: We discuss the use of 3-D finite-difference time-domain (FDTD) electromagnetic codes for modeling accelerator components. Computational modeling of cylindrically symmetric structures such as induction accelerator cells has been very successful in predicting the wake potential and wake impedances of these structures, but full 3-D modeling of complex structures has been limited due to substantial computer resources required for a full 3-D model. New massively parallel 3-D time domain electromagne… more
Date: September 18, 1996
Creator: Poole, B.R.; Caporaso, G.J.; Ng, Wang C.; Shang, C.C. & Steich, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Lattices for a high-field 30 TeV hadron collider

Description: Long arc cells would lead to major cost savings in a high field high T{sub c} hadron collider, operating in the regime of significant synchrotron radiation. Two such lattices, with half cell lengths of 110 and 260 m, are compared. Both allow flexible tuning, and have large dynamic apertures when dominated by chromatic sextupoles. Lattices with longer cells are much more sensitive to systematic magnet errors, which are expected to dominate.
Date: December 1, 1996
Creator: Peggs, S.; Dell, F.; Harrison, M.; Syphers, M. & Tepikian, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Gaussian laser beam shaping: Test and evaluation

Description: A method for converting single mode Gaussian beams into beams with uniform irradiance profiles is described. This technique has application to laser cutting and welding, laser ablation, semiconductor mask fabrication, and other tasks. Currently, designs for rectangular and circular flat top profiles have been investigated. Experimental results are presented for an element that converts a single mode Gaussian beam into a square, flat top spot. The design is based on a Fourier transform relation … more
Date: August 1, 1996
Creator: Holswade, S.C. & Dickey, F.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Optimization of laser scribing for thin-film PV modules. Annual technical progress report, 12 April 1995--11 April 1996

Description: One of the most important aspects in moving from the cell level to the integrated module level in thin-film photovoltaics is to achieve reliable and reproducible cell interconnects having low series resistance and high shunt resistance, and to do this with a minimum of dead area between cells. It is known that mechanical scribing often produces considerable damage (e.g., film tearing) surrounding the scribe. Laser scribing has shown the potential for superior scribe widths and profiles for many… more
Date: October 1, 1996
Creator: Compaan, A. D.; Jayamaha, U.; Matulionis, I. & Miller, M. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Impact of beam smoothing method on direct drive target performance for the NIF

Description: The impact of smoothing method on the performance of a direct drive target is modeled and examined in terms of its l-mode spectrum. In particular, two classes of smoothing methods are compared, smoothing by spectral dispersion (SSD) and the induced spatial incoherence (ISI) method. It is found that SSD using sinusoidal phase modulation (FM) results in poor smoothing at low l-modes and therefore inferior target performance at both peak velocity and ignition. Modeling of the hydrodynamic nonlinea… more
Date: November 1, 1996
Creator: Rothenberg, J.E. & Weber, S.V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Brown-Servranckx matching transformer for simultaneous RFQ to DTL H{sup +} and H{sup {minus}} matching

Description: The issue involved in simultaneous matching of H{sup +} and H{sup -} beams between an RFQ and DTL lies in the fact that both beams experience the same electric-field forces at a given position in the RFQ. Hence, the two beams are focused to the same correlation. However, matching to a DTL requires correlation of the opposite sign. The Brown-Servranckx quarter-wave ({lambda}/4) matching transformer system, which requires four quadrupoles, provides a method to simultaneously match H{sup +} and H{… more
Date: September 1, 1996
Creator: Wadlinger, E. A. & Garnett, R. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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