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in subjects: "Beam Currents"

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Development of a low intensity current monitor system

This report documents the development of a current transformer system used to measure pulsed ion beam currents with a wide dynamic intensity range (nA to mA, and factor of 10{sup 6}). Peak beam currents at the LAMPF accelerator typically range from 100 to nA to 40 mA with pulse widths varying from 30 to 1000 {mu}s. Signal conditioning of the peak current output provides an average current readout with a range of 1 nA to 2 mA, noise of approximately {plus minus}0.5 nA, and accuracy of {plus minu… more

Date: January 1, 1991

Creator: Gallegos, F.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Radially resolved measurements of ''q'' on the ATC tokamak

This paper describes a new technique for directly measuring the safety factor, or q, profile in a tokamak. A tightly collimated neutral beam capable of injecting approximately 100 mA of 30 keV deuterium atoms was mounted on the ATC tokamak. By proper tangential aiming of the beam a strong concentration of circulating fast ions was created at a chosen plasma minor radius. By examining the orbits of these ions with a multi-sight-line charge exchange detector, it was possible to measure the shifts… more

Date: April 1, 1978

Creator: Goldston, R.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Noninterceptive beam diagnostics

The need for accurate real-time diagnostics is critical for high-power particle beams. This paper describes the present level of development of noninterceptive devices for these beams. Discussion will be related to diagnostic measurements as they occur along the beamline, from ion-source performance through presentation to an RFQ and measures of the RFQ output, using the cw beam at Los Alamos as a guide. 23 refs.

Date: January 1, 1985

Creator: Chamberlin, D.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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New newtron time-of-flight (NTOF) facilities at the Brookhaven 200-MeV Linac

The installation of a new beam chopper and radio-frequency quadrupole (RFQ) preinjector (750 keV) at the Brookhaven National Laboratory (BNL) 200-MeV Linac will enable single micropulse selection (pulse width <1 ns) with periods ranging from 400 ns to 10 ..mu..s. The standard micropulse intensity is 1.2 X 10/sup 9/ p..mu.. pulse with dc-average beam currents of 50 nA-1 ..mu..A routinely available. The NTOF facilities consists of 30-100 meter flight paths at angles of 0, 12, 30, 45, 90, and 135/… more

Date: January 1, 1988

Creator: Ward, T.E.; Alessi, J.; Brennan, J.; Grand, P.; Lankshear, R.; Snead, C.L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Review of induction LINACS

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design cho… more

Date: October 1, 1981

Creator: Faltens, A. & Keefe, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Negative ion-based neutral injection on DIII-D

High energy negative ion-based neutral beam injection is a strong candidate for heating and non-inductive current drive in tokamaks. Many of the questions related to the physics and engineering of this technique remain unanswered. In this paper, we consider the possibility of negative ion-based neutral beam injection on DIII-D. We establish the desired parameter space by examining physics trades. This is combined with potential design constraints and a survey of component technology options to … more

Date: January 1, 1990

Creator: Stewart, L. D.; Bhadra, D. K.; Colleraine, A. P. & Kim, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Informal workshop on intense polarized ion sources: a summary

An Informal Workshop on Intense Polarized Ion Sources was held on March 6, 1980, at the O'Hare Hilton Hotel, Chicago, Illinois. The purpose of the Workshop was to discuss problems in developing higher-intensity polarized proton sources, particularly the optically-pumped source recently proposed by L.W. Anderson of the University of Wisconsin. A summary of the discussions is reported.

Date: January 1, 1980

Creator: Schultz, P.F. (ed.)

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Guiding center simulations of strong ion beams with applications to the Counterstreaming Ion Torus

In the proposed Counterstreaming Ion Torus (CIT) steady state rather than pulsed operation may be possible if all of the plasma power density is provided by neutral beam injection. After the neutral beams have penetrated the magnetic field, strong ion beam currents are produced. A major concern with the relatively strong counterstreaming ion currents is the effect of the beam self-magnetic fields on the macroscopic equilibrium of the system. Pinching and self focusing of the individual beams ma… more

Date: March 1, 1978

Creator: Tull, C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Applications of the MEVVA high current metal ion source

A new kind of ion source has been developed in which a metal vapor vacuum arc (MEVVA) is used to produce the plasma from which the ion beam is extracted. The novel and exciting feature of this source is the very high metal ion beam current attainable. A total ion beam current of over 1 Ampere has been extracted from the embodiment of the concept that we're presently using, and this is not a limit of the method. The source was developed to upgrade the uranium ion beam intensity of the Bevatron, … more

Date: August 1, 1986

Creator: Brown, I.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Pressure bump instability in very large cold bore storage rings

Calculations have been done to estimate the circulating current necessary to induce the onset of a pressure bump instability in a cold bore storage ring. For a wide range of storage ring parameters, the instability threshold current is more than an order of magnitude higher than the operating current. 4 references, 2 tables.

Date: December 1, 1983

Creator: Limon, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Volume H/sup -/ ion production experiments at LBL

H/sup -/ ions formed by volume processes have been extracted from a multicusp ion source. It is shown that a permanent magnet filter together with a small positive bias voltage on the plasma grid can produce a very significant reduction in electron drain as well as a sizable increase in H/sup -/ ions available for extraction. A further reduction in electron current is achieved by installing a pair of small magnets at the extraction aperture. An H/sup -/ ion current density of 38 mA/cm/sup 2/ wa… more

Date: November 1, 1983

Creator: Leung, K. N. & Ehlers, K. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Summary from working group on multiple beams and funneling

The working group on Multiple Beams and Funneling discussed various topics related to multiple beams and funneling, including (1) design considerations for multiple-beam accelerators; (2) scaling of current, emittance, and brightness for multiple-beam systems; (3) funneling lines using either discrete components or a radiofrequency quadrupole (RFQ) funneling structure; and (4) alternatives to funneling.

Date: January 1, 1985

Creator: Wangler, T. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Application of the Argonne Advanced Acceleration Test Facility to development for conventional accelerators

The Argonne Advanced Acceleration Test Facility is designed as a powerful tool to test ideas for very high gradient acceleration schemes based on direct beam excitation of plasmas, metal structures, dielectrics, etc. The characteristic size in these systems is )approximately) 1 cm, corresponding to frequencies )approximately) 10 GHz. The question addressed here is whether the special features of this facility have application as well to the development of components for the more conventional, l… more

Date: April 7, 1988

Creator: MacLachlan, J.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Model equations for high current transport

The use of distribution functions to model transverse beam dynamics is discussed. Emphasis is placed on envelope equations, moments, the Vlasov equation, and the Kapchinski-Vladimirskij distribution. 10 refs.

Date: June 1, 1985

Creator: Lee, Edward P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Operational experience with the BNL magnetron H/sup -/ source

A magnetron H/sup -/ source with a grooved cathode has been in operation at the BNL Linac for over 18 months. The source has run at 5 pps with a 600 ..mu..sec pulse width for periods as long as 5 months. Its development and performance will be discussed.

Date: January 1, 1983

Creator: Witkover, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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High current beam transport with multiple beam arrays

Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple bea… more

Date: May 1, 1985

Creator: Kim, C.H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Scheme to funnel ion beams with a radio-frequency quadrupole

We describe a proposed method to funnel ion beams using a new form of the radio-frequency quadrupole (RFQ) structure. This RFQ accepts two bunched ion beams and combines them into a single final beam with interlaced microstructure pulses. It also provides uninterrupted periodic transverse focusing to facilitate the funneling of beams with high current and low emittance.

Date: January 1, 1985

Creator: Stokes, R.H. & Minerbo, G.N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Low Energy Ring issues

The Low Energy Ring (LER) in an Asymmetric B Factory is always too large in circumference. The requirements for the LER in a B Factory are developed, including, damping, emittance and power density, and some examples of technical solutions are given. The main emphasis is on ensuring flexibility of operation.

Date: April 1, 1992

Creator: Hutton, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Design study for a high-current, steady-state autoresonant accelerator. Final report, July 14-November 14, 1979

During the past year and a half, both theoretical and engineering investigations have been carried forward in a research program to assess the feasibility, and provide conceptual designs and engineering design studies for high current, steady state Auto-Resonant Accelerators. The behavior of each of the various components of an Auto-Resonant Accelerator has been carefully examined for the case of moderately relativistic electron energy and high electron current which will be appropriate for ste… more

Date: December 1, 1979

Creator: Drummond, W. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Broad-beam multi-ampere metal ion source

An embodiment of the MEVVA (metal vapor vacuum arc) high current metal ion source has been developed in which the beam is formed from a 10-cm diameter set of extractor grids and which produces a peak beam current of up to several Amperes. The source, MEVVA V, operates in a pulsed mode with a pulse width at present 0.25 ms and a repetition rate of up to several tens of pulses per second (power supply limited). The multicathode feature that was developed for the prior source version, MEVVA IV, ha… more

Date: June 1, 1989

Creator: Brown, I.G.; Galvin, J.E.; MacGill, R.A.; Paoloni, F.J. (Lawrence Berkeley Lab., CA (USA) & Engineering), Wollongong Univ. (Australia). Dept. of Electrical

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Linear Accelerator for Radioisotope Production

A 200- to 500-..mu..A source of 70- to 90-MeV protons would be a valuable asset to the nuclear medicine program. A linear accelerator (linac) can achieve this performance, and it can be extended to even higher energies and currents. Variable energy and current options are available. A 70-MeV linac is described, based on recent innovations in linear accelerator technology; it would be 27.3 m long and cost approx. $6 million. By operating the radio-frequency (rf) power system at a level necessary… more

Date: February 1, 1982

Creator: Hansborough, L. D.; Hamm, R. W. & Stovall, J. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Metal vapor vacuum arc (MEVVA) high current ion source

An ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ions are extracted. Beams of a variety of ions have been produced, ranging from lithium up to uranium. At an extraction voltage of 25 kV we've measured an ion beam current of over 1 Ampere, with over 550 ema of the beam in an emittance of 0.07..pi.. cm. mradians (normalized). The ion charge state distribution varies with cathode material and with arc power; for uranium a typical distribution… more

Date: May 1, 1985

Creator: Brown, I.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Simulation of power flow in magnetically insulated convolutes for pulsed modular accelerators

Two distinct simulation approaches for magnetic insulation are developed which can be used to address the question of nonsimultaneity. First, a two-dimensional model for a two-module system is simulated using a fully electromagnetic, two-dimensional, time-dependent particle code. Next, a nonlinear equivalent circuit approach is used to compare with the direct simulation for the two module case. The latter approach is then extended to a more interesting three-dimensional geometry with several MI… more

Date: January 1, 1980

Creator: Seidel, D. B.; Goplen, B. C. & VanDevender, J. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Development of high current and high brightness negative hydrogen ion sources

Negative hydrogen ions have found important applications in particle accelerators and in fusion research. These ions can be generated from two different types of ion sources---the surface conversion source and the volume production source. Recent experiments demonstrate that H/sup /minus// current exceeding 1 A can be obtained from both types of ion sources. Because of the lower H/sup /minus// ion temperature and the fact that they can be operated without cesium, volume H/sup /minus// sources a… more

Date: April 1, 1988

Creator: Leung, K. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department