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AGS slow extracted beam improvement

Description: The Brookhaven AGS is a strong focusing accelerator which is used to accelerate protons and various heavy ion species to an equivalent proton energy of 29 GeV. Since the late 1960`s it has been serving high energy physics (HEP - proton beam) users of both slow and fast extracted beams. The AGS fixed target program presently uses primary proton and heavy ion beams (HIP) in slowly extracted fashion over spill lengths of 1.5 to 4.0 seconds. Extraction is accomplished by flattoping the main and extraction magnets and exciting a third integer resonance in the AGS. Over the long spill times, control of the subharmonic amplitude components up to a frequency of 1 kilohertz is very crucial. One of the most critical contributions to spill modulation is due to the AGS MMPS. An active filter was developed to reduce these frequencies and it`s operation is described in a previous paper. However there are still frequency components in the 60-720 Hz sub-harmonic ripple range, modulating the spill structure due to extraction power supplies and any remaining structures on the AGS MMPS. A recent scheme is being developed to use the existing tune-trim control horizontal quadrupole magnets and power supply to further reduce these troublesome noise sources. Feedback from an external beam sensor and overcoming the limitations of the quadrupole system by lead/lag compensation techniques will be described.
Date: July 1, 1997
Creator: Marneris, I.; Danowski, G.; Sandberg, J. & Soukas, A.
Partner: UNT Libraries Government Documents Department

Slow extraction from the Fermilab Main Injector

Description: Slow resonant extraction from the Fermilab Main Injector through the extraction channel was achieved in February, 2000, with a spill length of 0.3 sec. Beam losses were small. Excellent wire chamber profiles were obtained and analyzed. The duty factor was not very good and needs to be improved.
Date: July 20, 2001
Creator: al., Craig D. Moore et
Partner: UNT Libraries Government Documents Department

Side extraction duoPIGatron-type ion source.

Description: We have designed and constructed a compact duoPIGatron-type ion source, for possible use in ion implanters, in such the ion can be extracted from side aperture in contrast to conventional duoPIGatron sources with axial ion extraction. The size of the side extraction aperture is 1x40 mm. The ion source was developed to study physical and technological aspects relevant to an industrial ion source. The side extraction duoPIGatron has stable arc, uniformly bright illumination, and dense plasma. The present work describes some of preliminary operating parameters of the ion source using Argon, BF3. The total unanalyzed beam currents are 23 mA using Ar at an arc current 5 A and 13 mA using BF3 gas at an arc current 6 A.
Date: August 26, 2007
Creator: GUSHENETS,V.I.; OKS, E.M.; HERSCHOVITCH, A. & JOHNSON, B.M.
Partner: UNT Libraries Government Documents Department

R_transport_matrices of the Fast Extraction Beam (FEB) of the AGS, and Beam Parameters at the Starting point of the AtR Line

Description: As part of the task to improve and further automate the 'AtR BPM Application' we provide the theoretically calculated R-transport-matrices for the following beam line sections, which are shown schematically in Figure 1: (a) the Fast Extraction Beam section (FEB) of the AGS synchrotron. The FEB section starts at the middle of the GlO-kicker and ends at the middle of the H1 0{_}septum. (b) the Drift Extraction Channel (DEC) section of the AGS synchrotron. The DEC section starts at the middle of the H10{_}septum, continues along the fringe field region of the H11,H12, and H13 AGS main magnets, and ends at the starting point of the AtR line. The knowledge of these R-transport-matrices are needed in order to calculate the beam parameters at the beginning of the AtR line, which in turn, are required to calculate the magnet settings of the U{_}line, that match the U{_}line into the W{_}line. Also by incorporating these R{_}matrices into the model of the AtR line, the G10 kicker and the H10 septum are included in the AtR model therefore one can investigate any 'jitter' of either the GlO{_}kicker or HlO{_}septum by looking at the trajectory of the beam in the AtR line.
Date: January 1, 2008
Creator: Tsoupas,N.; MacKay, W.W.; Satogata, T.; Glenn, W.; Ahrens, L.; Brown, K. et al.
Partner: UNT Libraries Government Documents Department

The Short Circumference Damping Ring Design for the ILC

Description: The ILC damping ring tentative design is driven by the operational scenario of the main linac, the beam-dynamics demand of producing a stable and high-quality beam, the injection/extraction scheme and the kicker performance. In this paper, a short circumference damping ring design based on TME cells is described. The ring accommodates injection kickers which provide a flat top of 280 nsec and a 60 nsec rise and fall time and very fast strip-line kickers for beam extraction with a 2 nsec rise and fall time for 3-MHz operation.
Date: March 14, 2006
Creator: Korostelev, M.; Zimmermann, F.; /CERN; Kubo, K.; Kuriki, M.; Kuroda, S. et al.
Partner: UNT Libraries Government Documents Department

Fast Pulsing Neutron Generators for Security Application

Description: Active neutron interrogation has been demonstrated to be an effective method of detecting shielded fissile material. A fast fall-time/fast pulsing neutron generator is needed primarily for differential die-away technique (DDA) interrogation systems. A compact neutron generator, currently being developed in Lawrence Berkeley National Laboratory, employs an array of 0.6-mm-dia apertures (instead of one 6-mm-dia aperture) such that gating the beamlets can be done with low voltage and a small gap to achieve sub-microsecond ion beam fall time and low background neutrons. Arrays of 16 apertures (4x4) and 100 apertures (10x10) have been designed and fabricated for a beam extraction experiment. The preliminary results showed that, using a gating voltage of 1200 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is approximately 0.15 mu s at beam energies of 1000 eV.
Date: April 24, 2009
Creator: Ji, Q.; Regis, M. & Kwan, J. W.
Partner: UNT Libraries Government Documents Department

Simulation Studies on the Vertical Emittance Growth in the ATF Extraction Beamline

Description: Significant dependence of the vertical emittance growth on the beam intensity was experimentally observed at the ATF/KEK extraction beamline. This technical note describes the simulations of possible vertical emittance growth sources, particularly in the extraction channel, where the magnets are shared by both the ATF extraction beamline and its damping ring. The vertical emittance growth is observed in the simulations by changing the beam orbit in the extraction channel even with all optics corrections. The possible reasons for the experimentally observed dependence of the vertical emittance growth on the beam intensity are discussed. An experiment to measure the emittance vs beam orbit at the existing ATF extraction beamline is proposed.
Date: December 18, 2007
Creator: Zhou, F.; Amann, J.; Selestiky, S.; Seryi, A.; Spencer, C.; Woodley, M. et al.
Partner: UNT Libraries Government Documents Department

Bunching for shorter damping rings for the ILC

Description: A variant rearrangement of the bunch trains for the ILC that enables much shorter damping rings is presented. In a particular example the {approx}2820 bunches are regrouped into {approx}550 subtrains of five adjacent bunches. These subtrains are extracted from the damping rings at {approx}1.8 {micro}s intervals, obtaining the 1ms macrobunch length of the baseline TESLA collider scenario. If the baseline damping rf frequency is 325 MHz and the kicker rise and fall times are {approx}20 ns, a ring circumference of {approx}5.8km is required. Variations of the scheme could easily reduce the circumference to {approx}4km, and faster kickers could reduce it even further.
Date: May 1, 2005
Creator: Neuffer, D.
Partner: UNT Libraries Government Documents Department

Development of a Fast High-Power Pulser and ILC DR Injection/Extraction Kicker

Description: Kicker is an efficient HOM power extractor. Peak HOM voltage and average power at the feeder may be sufficient to act on the kicker pulser. Feeder imperfections (real cable, feedthroughs, kicker electrodes, loads) is one source of residual energy between bunches. HOM spectrum is broad.
Date: October 16, 2007
Creator: Krasnykh, A.
Partner: UNT Libraries Government Documents Department

A coaxial ring-sidearm power extraction design

Description: We report a successful klystron power extraction design, in which a TEM coaxial mode is transmitted into TE10 mode of a WR90 rectangular waveguide at 11.42 GHz, with very little TEM reflection and almost vanishing asymmetric (TEM {r_arrow} TE11, or monopole to dipole) reflectance. Our coupler consists of a ring (disk) around the coaxial waveguide, and a coax-WR90 sidearm junction. The methods used in the design are numerical simulation, performed on the MAFIA3 T3 time- domain module and on the High Frequency Structure Simulator, and analytical treatment to guide the numerical runs. The demerit parameters (dipole reflectance and TEM reflection) can be reduced as much as desired (to zero in principle), the only limitation being computer run time and memory. Results are accurate to a few percent.
Date: January 1, 1996
Creator: Ben-Menahem, S. & Yu, D.
Partner: UNT Libraries Government Documents Department

Klystron power specifications based on transient beam loading analysis in damping rings

Description: A useful diagram is presented and used to study rf cavity voltage regulation in a damping ring or other circular accelerator where large beam currents are injected and extracted rapidly. With conventional feedback systems and high particle beam currents, the maximum beam current can be limited by the ability of the klystron to maintain constant gap voltage at high currents, low currents, or in the absence of beam. Techniques for storing high current beams are suggested when the maximum klystron output power is predetermined. Alternately, these techniques may be applied and used to specify the performance requirements of the klystron if the desired particle beam current and nominal rf cavity voltage are known.
Date: June 1, 1995
Creator: Minty, M.G. & Siemann, R.H.
Partner: UNT Libraries Government Documents Department

High intensity performance and upgrades at the Brookhaven AGS

Description: For the last two years the Brookhaven AGS has operated the slow extracted beam program at record proton intensities. This high beam intensity allowed for the simultaneous operation of three high precision rare kaon decay experiments. The record beam intensities were achieved after the 1.5 GeV Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. Recently even higher intensity proton synchrotrons are studied for neutron spallation sources or proton driver for a muon collider. Implications of the experiences from the AGS to these proposals and also possible future upgrades for the AGS are discussed.
Date: December 31, 1996
Creator: Roser, T.
Partner: UNT Libraries Government Documents Department

The SLAC NLC extraction & diagnostic line

Description: A prototype extraction line for the Next Linear Collider is discussed that has several important functions that include optimizing luminosity, characterizing beam properties at the Interaction Point and transporting beams from the IP to a dump. Beam characterization includes measurements of current, position, profile, energy, polarization and low-order correlations on a bunch-to-bunch basis for feedback and stabilization. Prototype optical and diagnostic layouts are described that provide such functions. The authors also consider possibilities for e, {mu} and {gamma} secondary beam lines and dump experiments as well as energy recovery and local reuse of an assumed 10MW in each 500 GeV beam.
Date: May 1, 1995
Creator: Spencer, J.; Irwin, J.; Walz, D. & Woods, M.
Partner: UNT Libraries Government Documents Department

Multi-pulse extraction from Los Alamos Proton Storage Ring for radiographic applications

Description: In Proton Radiography, one of the goals is a motion picture of a rapidly moving object. The Los Alamos Proton Storage Ring (PSR) in its normal operating mode, delivers a single pulse approximately 120 ns wide (fwhm). In development runs at the PSR, the authors successfully demonstrated operation of a technique to deliver two pulses, each 40 nsec wide, with adjustable spacing.
Date: August 1, 1997
Creator: Thiessen, H.A.; Neri, F.; Rust, K. & Redd, D.B.
Partner: UNT Libraries Government Documents Department

The BNL AGS accelerator complex status and future plans

Description: This paper describes the present performance and capability of the BNL AGS accelerator complex and possible future intensity upgrade plans. In 1995, the AGS reached its design upgrade goal of 6.0 x 10(exp 13) ppp with the Booster. The AGS with a new fast extracted beam (FEB) system is able to perform single bunch multiple extraction at 30 Hz per AGS cycle for the g-2 experiment and for RHIC injection.
Date: May 1, 1997
Creator: Tanaka, Mitsuyoshi
Partner: UNT Libraries Government Documents Department

Analytical theory of multipass crystal extraction

Description: An analytical theory for the efficiency of particle extraction from an accelerator by means of a bent crystal is proposed. The theory agrees with all the measurements performed in the broad energy range of 14 to 900 GeV, where the efficiency range also spans over two decades, from {approximately}0.3% to {approximately}30%.
Date: October 1, 1997
Creator: Biryukov, V. & Murphy, C.T.
Partner: UNT Libraries Government Documents Department

High energy implantation with high-charge-state ions in a vacuum arc ion implanter

Description: Ion implantation energy can in principal be increased by increasing the charge states of the ions produced by the ion source rather than by increasing the implanter operating voltage, providing an important savings in cost and size of the implanter. In some recent work the authors have shown that the charge states of metal ions produced in a vacuum arc ion source can be elevated by a strong magnetic field. In general, the effect of both high arc current and high magnetic field is to push the distribution to higher charge states--the mean ion charge state is increased and new high charge states are formed. The effect is significant for implantation application--the mean ion energy can be about doubled without change in extraction voltage. Here they describe the ion source modifications, the results of time-of-flight measurements of ion charge state distributions, and discuss the use and implications of this technique as a means for doing metal iron implantation in the multi-hundreds of keV ion energy range.
Date: August 1, 1996
Creator: Oks, E. M.; Anders, A.; Brown, I. G.; Dickinson, M. R. & MacGill, R. A.
Partner: UNT Libraries Government Documents Department

Design and test results of kicker units for the positron accumulator ring at the APS

Description: Three fast kicker units have been designed, tested, and installed in the positron accumulator ring (PAR) at the Advanced Photon Source (APS) for beam injection and extraction. The performance of these kicker units has been satisfactory. This presents the design and test results.
Date: June 1, 1995
Creator: Wang, J.
Partner: UNT Libraries Government Documents Department

Beam size versus intensity for resonant extracted beam at the Brookhaven AGS

Description: Transverse beam sizes were measured in the AGS prior to the initiation of the third order resonance ({nu}{sub H} = 8 2/3; driven by sextupoles) used for the slow extraction and again in the external beam lines. The measurements were made using the AGS Ionization Profile Monitor (IPM) and an External Profile Monitor (EPM). Both of these monitors use the ionized residual gas to image the beam on arrays of wires that are aligned parallel to the direction of the beam. The effects of space charge on the IPM are significant at the intensities measured, but the EPM measurements are not affected by space charge. Two measurements are reported. First is the intensity dependence of the resonant beam size, and secondly, an indirect measure of the space charge effect on the IPM. A differential comparison of the two monitors in the vertical plane allows unfolding the effect of the space charge on the measurements. These measurements were made over an intensity range between 15 {times} 10{sup 12} and 36 {times} 10{sup 12} protons per AGS pulse.
Date: May 1, 1995
Creator: Brown, K.A.; Thern, R. & Huang, H.
Partner: UNT Libraries Government Documents Department