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in subjects: "Particle Beams 430200* -- Particle Accelerators-- Beam Dynamics, Field Calculations, & Ion Optics"  
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Relativistic electron beam cyclotron wave growth in helical slow wave structures

Description: One of the more promising and thoroughly studied proposals for high energy collective ion acceleration is Autoresonant Acceleration: Ions trapped in the electrostatic wells of large amplitude slow cyclotron waves in an unneutralized intense relativistic electron beam are accelerated by the increase of wave phase velocity as the beam propagates along a magnetic guide field of decreasing strength. A critical component of this scheme is growth of coherent, large amplitude waves. A discussion is gi… more
Date: January 1, 1977
Creator: Godfrey, B.B.; Faehl, R.J.; Newberger, B.S.; Shanahan, W.R. & Thode, L.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Collective ion acceleration

Description: Progress achieved in the understanding and development of collective ion acceleration is presented. Extensive analytic and computational studies of slow cyclotron wave growth on an electron beam in a helix amplifier were performed. Research included precise determination of linear coupling between beam and helix, suppression of undesired transients and end effects, and two-dimensional simulations of wave growth in physically realizable systems. Electrostatic well depths produced exceed requirem… more
Date: January 1, 1977
Creator: Godfrey, B.B.; Faehl, R.J.; Newberger, B.S.; Shanahan, W.R. & Thode, L.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electron trajectory program

Description: The SLAC Electron Trajectory Program is described and instructions and examples for users are given. The program is specifically written to compute trajectories of charged particles in electrostatic and magnetostatic focusing systems including the effects of space charge and self-magnetic fields. Starting options include Child's Law conditions on cathodes of various shapes. Either rectangular or cylindrically symmetric geometry may be used. Magntic fields may be specified using arbitrary config… more
Date: November 1, 1979
Creator: Herrmannsfeldt, W.B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Formulary for MEQALAC design

Description: From the space-charge limits for quadrupole transport systems discussed in an earlier report, some simple relations are obtained that will assist in the design of practical systems.
Date: November 27, 1979
Creator: Maschke, A.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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MEQATRON: a high-power high-frequency rf source

Description: MEQATRON is an acronym for a multiple-beam electrostatic-quadrupole-focused array of electron beams. Conventional electron beam devices consist principally of single electron beams. In this paper the single-beam space-charge limitations are discussed, and a relationship for power flux (W/m/sup 2/) is obtained. Several features of the multiple-beam approach become clear at once. Because the multiple-beam approach removes the current limitation on performance, it is possible to design high-curren… more
Date: September 28, 1979
Creator: Maschke, A W
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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New method for positron production at SLAC

Description: The focusing system for the positron beam at SLAC makes use of an adiabatically tapered solenoid whose transverse acceptance remains high over a broad energy band. From the computed distribution in energy of the accepted positrons, one can estimate that approximately one-half of the total number of positrons lies within the energy band from 2 - 4 MeV. Due to the debunching effect over the drift space following the target, only the high energy part (from 4.5 MeV to 10 MeV or more) of the accepte… more
Date: September 1, 1979
Creator: Aune, B. & Miller, R. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Beam tomography in two and four dimensions. [100 MeV H/sup +/ beams and 750 keV H/sup -/ beams]

Description: The coming generations of high beam-power accelerators require new techniques to monitor the emittance and the shape of the beam; in particular, measurements that do not interfere with the beam itself are necessary. A new computational algorithm, MENT (Maximum ENTropy), will be presented that combines nondestructive profile measurements taken from a number of stations along the beam line with beam-dynamics calculations to compute a four-dimensional phase-space distribution. A version of MENT ha… more
Date: January 1, 1979
Creator: Sander, O. R.; Minerbo, G. N.; Jameson, R. A. & Chamberlin, D. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electron cooling of high energy beams

Description: A short note is presented to clarify the relationship between electron cooling time and beam energy and also to see how the nature of the electron beam enters. In particular, whether it is electron total current or current density that is significant is considered. There is no attempt to include any measure of sophistication, such as the effect of a solenoid field, but simply to use Coulomb scattering and statistical equilibrium. For simplicity, the 3 phase spaces (horizontal, vertical and mome… more
Date: January 1, 1978
Creator: Month, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calculations Pertaining to the Design of a Prebuncher for a 150-MeV Electron Linear Accelerator. [Part] 2. Radial Motion

Description: In the previous paper, calculated results based on a one-dimensional ballistic model were presented to indicate the extent to which a current pulse of 150-keV electrons containing 1 ..mu..C of charge and having a duration of 15 nsec (FWHM) could be bunched by a combination of accelerating and decelerating voltage gaps followed by a drift space. A very approximate perturbation model is used here to determine the extent to which the prebuncher performance determined previously is modified by radi… more
Date: May 1979
Creator: Alsmiller, R. G., Jr.; Alsmiller, F. S. & Barish, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Beam voltage and current parameter study for the autoresonant acceleration proof-of-principle experiment

Description: Due to flashover problems, Austin Research Associates, Inc. may be forced to perform its proof-of-principle autoresonant collective ion acceleration experiment at electron beam parameters of 2.25 MeV and 15 kA rather than the intended 3.0 MeV and 30 kA. We show that the original experimental goals still can be achieved provided the beam radius is reduced by a factor of two and a thinner anode foil is employed. More generally, our parameter study suggests that operating with beams of smaller rad… more
Date: November 1, 1978
Creator: Godfrey, B.B. & Faehl, R.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Beam tomography or ART in accelerator physics. [Current density profiles]

Description: Projections of charged particle beam current density have been used for many years as a measure of beam position and size. The conventional practice of obtaining only two projections, usually in the horizontal and vertical planes, puts a severe limit on the detail that can be recovered from the projections. A third projection provides sufficient improvement to justify the addition of a wire to the conventional wire scanner in certain cases. A group of programs using algebraic reconstruction tec… more
Date: November 1, 1978
Creator: Fraser, J.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Computer simulation of collective ion acceleration by discrete cyclotron modes

Description: Extensive analytical studies suggest that significant currents of high energy ions can be obtained by collective acceleration via large amplitude cyclotron waves in a non-neutral intense relativistic electron beam. This acceleration mechanism was previously demonstrated in fully self-consistent two-dimensional computer simulations for low ion current and energy. However, the simulations employed a packet of cyclotron waves created ad hoc upstream of the acceleration region. Acceleration was lim… more
Date: January 1, 1977
Creator: Faehl, R. J.; Godfrey, B. B.; Newberger, B. S.; Shanahan, W. R. & Thode, L. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Secondary yield enhancement from current-carrying target

Description: Monte Carlo calculations of relative yield of ..pi../sup -/, K/sup -/ and anti p secondaries from cylindrical current-carrying production targets in high energy proton beams are presented. The results show that the expected focusing effect can increase the secondary intensity within the acceptance of a secondary beam by significant factors--in some cases two or more--with currents in the 15 to 25 kA range. These currents are readily obtainable from pulsed power supplies. For dc operation curren… more
Date: January 1, 1977
Creator: Blumberg, L. N. & Webster, A. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Choice of initial operating parameters for high average current linear accelerators

Description: Recent emphasis on alternative energy sources together with the need for intense neutron sources for testing of materials for CTR has resulted in renewed interest in high current (approximately 100 mA) c.w. proton and deuteron linear accelerators. In desinging an accelerator for such high currents, it is evident that beam losses in the machine must be minimized, which implies well matched beams, and that adequate acceptance under severe space charge conditions must be met. An investigation is p… more
Date: January 1, 1976
Creator: Batchelor, K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Workshop on phase space cooling

Description: A two-day workshop was held on August 5 and 6, 1976, to discuss phase space damping (''cooling'') of particle beams. Two cooling techniques have been developed: in stochastic cooling the spread of amplitudes in a beam is reduced by a feedback signal derived from the statistical fluctuations in the beam; in electron cooling an electron beam having the same mean velocity as the heavy particle (proton or antiproton) beam coincides with the heavy beam in part of the orbit. Viewed in the center-of-m… more
Date: January 1, 1976
Creator: Courant, E. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Reduction of losses in linacs for protons or heavy ions

Description: It is necessary to minimize the beam losses in linacs for high average currents in order to avoid serious problems due to radiation damage, dissipation and radio activation of the accelerator structure. A large part of the losses in existing linacs is due to incomplete bunching of the injected beam. Proposed improvements generally appear to be deficient in one or more respects if applied to linacs with conventional frequencies, injection energies and current densities. By preceding the linac pr… more
Date: January 1, 1977
Creator: Claus, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Progress in space charge lens development

Description: A number of space charge lens electrode geometries have been studied for use at very high beam currents at low energy, and for precision optics at MeV energies. One such lens mounted very near a Duo-plasmatron extractor delivered a 30-keV beam of H/sup +/ ions through an analyzing magnet at a current of 175 mA for a period of six hours. Another produced a focal spot of diameter 0.2 mm when a 1-cm diameter beam of 1.2-MeV protons was focussed 90 cm from the lens. This paper also describes observ… more
Date: March 1, 1979
Creator: Lefevre, H. W. & Booth, Rex
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Report of group I: e/sup +/e/sup -/ colliders

Description: The important parameters which relate the beam dynamics and performance in a system of colliding linacs were identified. These are: the disruption parameter D which describes the strength of the beam-beam interaction, and hence replaces the beam-beam tune shift ..delta..Q familiar in storage rings; and the relative energy loss due to synchrotron radiation emitted by the particles of one beam in the collective electromagnetic field of the other beam. (GHT)
Date: January 1, 1979
Creator: Amaldi, U.; Balakin, V.; Hutton, A.; Pellegrini, C.; Richter, B.; Saxon, G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theory of longitudinal instability for bunched electron and proton beams

Description: A discussion is given of an original approach for the treatment of the longitudinal stability of high-intensity proton and electron bunches. The general analysis is divided in three steps. First, a search is made for a stationary bunch distribution which is matched to the external rf forces as well as to the current dependent induced fields. The existence of such distribution is questioned. Second, the stability of the stationary solution is checked by applying a small perturbation and observin… more
Date: January 1, 1977
Creator: Ruggiero, Alessandro G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Computer simulation of the electron-bunch widening as due to self-bunching

Description: Several theories have been proposed to explain anomalous bunch lengthening and widening in particle storage rings. All these theories either assume a modification of the accelerating potential well or a high frequency self-bunching mechanism similar to the one proposed for proton bunches. Some of the theories assume interaction between several modes of self-bunching which leads then to ''turbulence.'' In most cases it is possible to derive a stability condition in terms of bunch current and imp… more
Date: January 1, 1977
Creator: Ruggiero, Alessandro G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Single bunch fast longitudinal instability

Description: Single bunch longitudinal instability producing an increase of the bunch area have been observed in proton synchrotron and storage rings. Signals at microwave frequencies are observed during the bunch blow-up and because of this the effect has been called the microwave instability. A similar increase in bunch area is observed also in electron storage rings, where it is usually referred to as the bunch lengthening effect. This paper is an attempt to obtain a more general theory of this effect. H… more
Date: January 1, 1979
Creator: Wang, J. M. & Pellegrini, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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