PAC07 - List of Keywords (induction)

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induction

Paper	Title	Other Keywords	Page
MOPAN042	Switching Power Supply for Induction Accelerators	acceleration, power-supply, synchrotron, impedance	251
	M. Wake Y. Arakida, K. Koseki, Y. Shimosaki, K. Takayama, K. T. Torikai KEK, Ibaraki W. Jiang, K. Nakahiro Nagaoka University of Technology, Nagaoka, Niigata A. Sugiyama Shindengen Co., Ltd., Tokyo A. Tokuchi Nichicon (Kusatsu) Corporation, Shiga
	A new particle acceleration method using pulsed induction cavities was introduced in the super-bunch project at KEK. Unlike conventional RF acceleration, this acceleration method separates functions of acceleration and confinement As a result, this acceleration method can be applied for accelerating a wide mass range of particles. However, it is necessary to give a very fast pulsed-excitation to the cavity to perform the induction acceleration. Switching power supplies of high voltage output with very fast pulse-operation is one of the most important key technologies for this new acceleration method. We have developed 20ns rise time pulse at continuous repetition rate of 1MHz using MOS-FET's. Induction cavities were modulated through the 200m long transmission lines. Further development using SI- thyristor achieved 1MHz and 2kV switching in a burst mode operation. SiC devices are also studied for the application and some promising results were obtained. Faster operation will make this new acceleration technology available for small accelerator projects.

MOPAS041	Design of Superferric Magnet for the Cyclotron Gas Stopper Project at the NSCL	cyclotron, ion, simulation, superconducting-magnet	524
	S. Chouhan E. Barzi Fermilab, Batavia, Illinois G. Bollen, C. Guenaut, D. Lawton, F. Marti, D. J. Morrissey, J. Ottarson, G. K. Pang, S. Schwarz, B. Sherrill, A. Zeller NSCL, East Lansing, Michigan
	Funding: Michigan State University, Cyclotron-1, East Lansing, MI-48824 We present the design of a superferric cyclotron gas stopper magnet that has been proposed for use at the NSCL/MSU to stop the radioactive ions produced by fragmentation at high energies (~140 MeV/u). The magnet is a gradient dipole with three sectors ( B~2.7 T at the center and 2 T at the pole-edge. The magnet outer diameter is 3.8 m, with a pole radius of 1.1 m and Brho=1.7 T-m). The field shape is obtained by extensive profiles in the iron. The coil cross-section is 64 cmcm and peak field on the conductor is about 1.6 T. The upper and lower coils are in separate cryostat and have warm electrical connections. We present the coil winding and protection schemes. The forces are large and the implication on the support structure is presented.

TUXC01	Status of DARHT 2nd Axis Accelerator at the Los Alamos National Laboratory	target, electron, kicker, beam-transport	831
	R. D. Scarpetti J. Barraza, C. Ekdahl, E. Jacquez, S. Nath, K. Nielsen, G. J. Seitz LANL, Los Alamos, New Mexico F. M. Bieniosek, B. G. Logan LBNL, Berkeley, California G. J. Caporaso, Y.-J. Chen LLNL, Livermore, California
	This presentation will provide a status report on the 2kA, 17MeV, 2-microsecond Dual-Axis Radiographic Hydrotest electron beam accelerator at Los Alamos National Laboratory, and will cover results from the cell refurbishment effort, commissioning experiments on beam transport and stability through the accelerator, and experiments exercising the beam chopper.
	Slides

TUXC02	Induction Synchrotron Experiment in the KEK PS	acceleration, synchrotron, proton, controls	836
	K. Takayama
	We report an experimental demonstration of the induction synchrotron, the concept of which has been proposed as a future accelerator for the second-generation of neutrino factory or hadron collider. The induction synchrotron supports a super-bunch and a super-bunch permits more charge to be accelerated while observing the constraints of the transverse space-charge limit. By using a newly developed induction acceleration system instead of radio-wave acceleration devices, a single proton bunch injected from the 500 MeV Booster ring and captured by the barrier bucket created by the induction step-voltages was accelerated to 6 GeV in the KEK proton synchrotron. A specific feature of the beam handling, such as the DR feedback, and a beam-dynamical property, such as the temporal evolution of the bunch size, are described. Beyond the demonstration, an injector-free induction synchrotron is under designing at KEK as a driver of all species of ion*. It will be briefly described. K. Takayama, published in Phys. Rev. Lett. soon. K. Takayama and J. Kishiro, N. I.M. A 451, 304-317 (2000).* K. Takayama, K. Torikai, Y. Shimosaki, and Y. Arakida, PCT/JP2006/308502
	Slides

TUYC01	Studies of the Pulse Line Ion Accelerator	ion, acceleration, pick-up, vacuum	852
	W. L. Waldron R. J. Briggs SAIC, Alamo, California A. Friedman LLNL, Livermore, California E. Henestroza, L. R. Reginato LBNL, Berkeley, California
	Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U. S. Department of Energy under Contracts No. DE-AC02-05CH11231 and W-7405-Eng-48. The Pulse Line Ion Accelerator concept was motivated by the need for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied to one end of a helical pulse line creates a traveling wave that accelerates and axially confines the heavy ion beam pulse. The concept has been demonstrated with ion beams at modest acceleration gradients. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/m acceleration gradients. This method has the potential to reduce the length of an equivalent induction accelerator by a factor of 6-10 while simplifying the pulsed power systems. The performance of prototype hardware has been limited by high voltage flashover across the vacuum insulator. Bench tests and analysis have led to significantly improved flashover thresholds. Further studies using a variety of experimental configurations are planned.
	Slides

TUYC02	High Gradient Induction Accelerator	proton, electron, vacuum, linac	857
	G. J. Caporaso D. T. Blackfield, Y.-J. Chen, J. R. Harris, S. A. Hawkins, L. Holmes, S. D. Nelson, A. Paul, B. R. Poole, M. A. Rhodes, S. Sampayan, M. Sanders, S. Sullivan, L. Wang, J. A. Watson LLNL, Livermore, California M. L. Krogh University of Missouri - Rolla, Rolla, Missouri C. Nunnally University of Missouri, Columbia, Columbia, Missouri K. Selenes TPL, Albuquerque, NM
	Funding: This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. Progress in the development of compact induction accelerators employing advanced vacuum insulators and dielectrics will be described. These machines will have average accelerating gradients at least an order of magnitude higher than existing machines and can be used for a variety of applications including flash x-ray radiography and medical treatments. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described.
	Slides

TUOBC02	A New Type High Voltage Fast Rise/Fall Time Solid State Marx Pulse Modulator	controls, power-supply, electron, damping	865
	R. L. Cassel S. Hitchcock Stangenes Industries, Palo Alto, California
	A new type of solid state Marx modulator developed by Stangenes Industries has the capability of producing high voltage pulses with fast rise and fall time at high repetition rates. In addition it has the ability to produce dynamically flexible output amplitude and pulse width. The pulse modulator was developed for the Fermi Labs Tevatron Electron Lens Tune Compensation System. It can produce a 14kV pulse with 200 nanosecond rise time and 600 nanosecond full pulse width at a 25 kilohertz repetition rate. It has no overshot or reverse voltage, making it ideal for beam bunch manipulation. It is designed to operate into a 200 pfd, 800 Ω load. This design permits all of the sources of power including the 1kV charging power supply to be connected at the grounded end of the pulser. A second generation pulser is under development to operate at above 50 kHz repetition rate with an arbitrary voltage waveform and faster rise/fall time. The pulser can accommodate load arcing and incorporates built in redundancy to insure high availability. The paper delineates the unique design of the modulator and its performance.
	Slides

TUPAN044	Acceleration Scheme in the AIA and its Control System	acceleration, injection, ion, simulation	1484
	T. Iwashita Y. Arakida, T. Kono, Y. Shimosaki, K. Takayama KEK, Ibaraki T. S. Dixit GUAS/AS, Ibaraki K. Okazaki Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture
	An All Ion Accelerator (AIA), an injector-free induction synchrotron (IS) is proposed as a modification of the KEK booster. The Booster is a rapid cycle synchrotron operating at a repetition rate of 20Hz. The AIA based on the booster requires more flexible trigger generation for the acceleration or confinement system than the one used for the IS POP experiment. Assuming Ar+18 injection from a 200 kV ion source, the revolution period changes from 9.08usec to 333nsec at the end, and the required acceleration voltage changes from few tens of volts to 6.4kV at the middle of acceleration.　Since a number of available acceleration cells is finite and their maximum pulse width and output voltage are limited to 500 nsec and 2 kV/cell, respectively, the dynamic allocation of acceleration cells in real time is indispensable, where a trade-off between the voltage amplitude and integrated pulse-length is realized. The acceleration scheme employing fast DSPs and a trigger control system is designed so as to meet the above requirement. Its whole story will be presented, including beam simulation results in the proposed AIA. E. Nakamura et al., in PAC07** K. Takayama et al., "Experimental Demonstration of the Induction Synchrotron" appeared in Phys. Rev. Lett. soon and in PAC07

TUPAN050	Status of the Induction Acceleration System	power-supply, acceleration, synchrotron, ion	1502
	Y. Shimosaki Y. Arakida, T. Iwashita, T. Kono, E. Nakamura, K. Takayama, M. Wake KEK, Ibaraki T. S. Dixit GUAS/AS, Ibaraki N. Nagura, K. Okazaki, K. Otsuka Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture K. T. Torikai NIRS, Chiba-shi
	Single proton bunch confined by the barrier voltage was accelerated by the induction step-voltage from 500 MeV to 6 GeV at the KEK-PS on March 2006. We will present the status with the information about troubles and counter-measures for the induction acceleration system. K. Takayama, presented in PAC07.

TUPAS061	Electromagnetic and Thermal Simulations for the Switch Region of a Compact Proton Accelerator	simulation, proton	1793
	L. Wang G. J. Caporaso, S. Sullivan LLNL, Livermore, California
	Funding: This work was performed under the auspices of the U. S. Department of Energy, the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. A compact proton accelerator for medical applications is being developed at Lawrence Livermore National Laboratory. The accelerator architecture is based on the dielectric wall accelerator (DWA) concept. One critical area to consider is the switch region. Electromagnetic field simulations and thermal calculations of the switch area were performed to help determine the operating limits of the SiC switches. Different geometries were considered for the field simulation including the shape of the thin indium solder meniscus between the electrodes and SiC, and possible misalignment of electrodes and SiC during manufacturing. Electromagnetic field simulations were also utilized to demonstrate how the field stress could be reduced. Both transient and steady-state thermal simulations were analyzed to find the average power capability of the switches.

WEPMS001	Application of Induction Module for Energy Perturbations in the University of Maryland Electron Ring	space-charge, electron, simulation, impedance	2322
	B. L. Beaudoin S. Bernal, I. Haber, R. A. Kishek, P. G. O'Shea, M. Reiser, J. C.T. Thangaraj, K. Tian, M. Walter, C. Wu UMD, College Park, Maryland
	Funding: Work supported by the U. S. Department of Energy grant numbers: DE-FG02-94ER40855 and DE-FG02-92ER54178, ONR and Joint Technology Office The University of Maryland Electron Ring (UMER) is a scaled storage ring using low-energy electrons to inexpensively model beams with high-space-charge. With the ability to inject such beams comes the problem of longitudinal end erosion of both the head and tail. It is important therefore to apply suitably designed longitudinal focusing forces to confine the beam and prevent it from its normal expansion. This paper presents the design and prototyping of an induction cell for this purpose. Successful operation of the induction cell would push the achievable number of turns and also enable us to perform studies of the longitudinal physics of such highly space-charge dominated beams. The pulsed voltage requirements for such a system on UMER would require ear-fields that switch 3kV in about 8ns or so for the most intense flat-top rectangular beam injected into the ring. This places a considerable challenge on the electronics used to deliver ideal waveforms with a compact module. Alternate waveforms are also being explored for other various injected beam shapes into UMER.

WEPMS015	An Improved SF6 System for the FXR Induction Linac Blumlein Switches	linac, pulsed-power, electron, controls	2361
	W. J. DeHope K. L. Griffin, R. Kihara, M. M. Ong, O. Ross LLNL, Livermore, California
	Funding: This work was performed under the auspices of the US Department of Energy by the University of California, Lawrence Livermore National Laboratory, under Contract W-7405-Eng-48. The now-mature FXR (Flash X-Ray) radiographic facility at Lawrence Livermore National Laboratory will be briefly described with emphasis on its pulsed power system. The heart of each accelerating cell's pulse-forming Blumlein is it's sulfur hexafluoride-based triggered closing switch. FXR's recent upgrade to a recirculating SF6 gas reclamation system will be described and the resulting accelerator performance and reliability improvements documented. This was accompanied by a detailed switch breakdown study on FXR's Test Stand* and the recent analysis of the resulting statistics will be shown. * W. DeHope, D. Goerz, R. Kihara, M. Ong, G. Vogtlin, J. Zentler, "An Induction Linac Test Stand", 21st Particle Accelerator Conference, Knoxville, TN, May 20, 2005

WEPMS024	Upgrades to the DAHRT Second Axix Induction Cells	vacuum, target, cathode, kicker	2385
	K. Nielsen J. Barraza, M. Kang LANL, Los Alamos, New Mexico F. M. Bieniosek, K. Chow, W. M. Fawley, E. Henestroza, L. R. Reginato, W. L. Waldron LBNL, Berkeley, California R. J. Briggs, B. A. Prichard SAIC, Alamo, California T. E. Genoni, T. P. Hughes Voss Scientific, Albuquerque, New Mexico
	The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two perpendicular electron Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. The second axis, DARHT II, features a 3-MeV injector and a 15-MeV, 2-kA, 1.6-microsecond accelerator consisting of 74 induction cells and drivers. Major induction cell components include high flux swing magnetic material (Metglas 2605SC) and a MycalexTM insulator. The cell drivers are pulse forming networks (PFNs). The DARHT II accelerator cells have undergone a series of test and modeling efforts to fully understand their operational parameters. Physical changes in the cell oil region, the cell vacuum region, and the cell drivers, together with different operational and maintenance procedures, have been implemented in the prototype. A series of prototype acceptance tests have demonstrated that the required cell lifetime is met at the increased performance levels. Shortcomings of the original design are summarized and improvements to the design, their resultant enhancement in performance, and various test results are discussed.

WEPMS045	Power Modulators for FERMI Linac's Klystrons.	klystron, controls, linac, vacuum	2448
	G. C. Pappas G. D'Auria, P. Delgiusto, L. Veljak ELETTRA, Basovizza, Trieste
	The conventional line type modulators used for ELETTRA will have to be replaced for FERMI due to the increase in the pulse repetition frequency (PRF) from 10 to 50 Hz. The requirements for the FERMI modulator are as follows. The klystron used is a Thales TH2132 with a microperviance of 1.9-2.1 uA/V(3/2). The peak voltage from the modulator is 320 kV, and the current is 350 A. The pulse width is 4.5 us, with a PRF of 50 Hz. Flat top should be better than ?0.5 % of the peak voltage. Prototypes for an upgraded line type modulator and a solid state induction type modulator[1] are in fabrication. The solid state design uses eight induction cells, each cell driven by two parallel Insulated Gate Bipolar Transistors (IGBT). Each IGBT will power a METGLAS 2605CO core with 4 kV and 3 kA for up to 5 us. A single turn is passed through the aperture of each of the cells, inductively adding the pulse voltages. The output from the modulator is then fed to a conventional pulse transformer to reach the 320 kV requirement. This paper presents the system design of both modulator types as well as details of the IGBT drivers, control electronics, IGBT and klystron protection and test data. 1. "NLC Hybrdi Solid State Induction Modulator" R. L. Cassel, etal, Lubeck, Germany, Linac 2004.**

THPAN082	Implementation of Spread Mass Model of Ion Hose Instability in Lamda	ion, simulation, acceleration, target	3408
	Y. Tang C. Ekdahl LANL, Los Alamos, New Mexico T. C. Genoni, T. P. Hughes Voss Scientific, Albuquerque, New Mexico M. E. Schulze SAIC, Los Alamos, New Mexico
	Funding: Work supported by Los Alamos National Laboratory. The ion-hose instability sets limits on the allowable vacuum in the DARHT-2 linear induction accelerator (2kA, 18.6MeV, 2μs). Lamda is a transport code which advances the beam centroid and envelope in a linear induction accelerator from the injector to the final focus region. The code computes the effect of magnet misalignments, beam breakup instability, image-displacement instability, and gap voltage fluctuation on the beam. In this work, we have implemented the Spread Mass (SM) model of ion-hose instability into Lamda so that we can examine quickly the operating parameters for the experiments. Unlike the ordinary SM ion-hose code which assumes the uniform axial magnetic field, Lamda ion-hose calculation includes varying axial magnetic field, accelerating beam, gas pressure file, varying beam radius and elliptical beam. The benchmarks against a semi-analytical SM code and the particle-in-cell code Lsp, and a prediction of ion-hose instability for a 2.5MeV-1.4kA beam in the DARHT-2 are presented.

THPAS015	Three-Dimensional Integrated Green Functions for the Poisson Equation	space-charge, simulation, linac, accelerator-theory	3546
	D. T. Abell P. J. Mullowney, K. Paul, V. H. Ranjbar Tech-X, Boulder, Colorado J. Qiang, R. D. Ryne LBNL, Berkeley, California
	Funding: Supported by US DOE Office of Science: Offices of Nuclear Physics, grant DE-FG02-03ER83796; High Energy Physics; and Advanced Scientific Computing Research, SciDAC Accelerator Science and Technology. The standard implementation of using FFTs to solve the Poisson equation with open boundary conditions on a Cartesian grid loses accuracy when the change in G rho (the product of the Green function and the charge density) over a mesh cell becomes nonlinear; this is commonly encountered in high aspect ratio situations and results in poor efficiency due to the need for a very large number of grid points. A modification which solves this problem, the integrated Green function (IGF), has been implemented in two dimensions using linear basis functions and in three dimensions using constant basis functions. But, until recently, it has proved to be very difficult to implement IGF in three dimensions using linear basis functions. Recently significant progress has been made. We present both the implementation and test results for the three-dimensional extension.

FRPMN033	Adiabatic Damping During Acceleration in the Induction Synchrotron	acceleration, synchrotron, damping, beam-losses	4009
	T. S. Dixit Y. Shimosaki, K. Takayama KEK, Ibaraki
	Damping in a bunch length during the acceleration in the induction synchrotron experiment , where a single proton bunch injected from the KEK 500 MeV Booster and trapped by the barrier voltages is accelerated to 6 GeV, has been observed. Such a damping may be regarded as the adiabatic damping, as found in a conventional RF synchrotron. A technique to analytically deal with this phenomenon is well established in the RF synchrotron. A WKB solution is employed for the small amplitude synchrotron oscillation. However, a simple WKB approach is not available for the present barrier bucket acceleration, because longitudinal motion always depends on the oscillation amplitude. This paper discusses a novel technique capable of quantitatively predicting the adiabatic phenomenon which has been newly developed. The analytical results were worked out and verified using simulations for ideal conditions. Theoretical approach tells us that a bunch length in the barrier bucket acceleration never continues to shrink but achieves a constant value corresponding to the time duration between the barrier voltage pulses. K. Takayama et al., "Experimental Result of the Induction Synchrotron", appear in Phys. Rev. Lett. (2007) and in this conference.

FRPMN053	Beam Instability and Correction for "DRAGON-I"	electron, simulation, impedance, laser	4114
	W. W. Zhang Y. Li CAEP, Mainyang, Sichuan
	'Dragon-I' is a high current pulse electron linear induction accelerator designed and constructed in IFP/CAEP. It generates a 20MeV, 2.5kA, 60ns pulse electron beam. The whole facility has three parts: injector; accelerator and beam focus system. The accelerator consists of 72 induction cells and 18 connection cells. A solenoid was installed inside each cell forming beam transport sysem. During the initial beam test both high frequency and low frequency oscillation were found. A lot of simulation and experiment investigations were done to get the transverse impedance of the cells and the corkscrew motion of the electron beam. Details of both the simulation and the experimental methods to correct the instability are presented.

FRPMS048	Characterization of a High Current Induction Accelerator Electron Beam via Optical Transition Radiation from Dielectric Foils	diagnostics, electron, radiation, simulation	4087
	V. Tang C. G. Brown, T. L. Houck LLNL, Livermore, California
	Funding: This work was performed under the auspices of the U. S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. Traditionally, thin metal foils are employed for optical transition radiation (OTR) beam diagnostics but the possibility of plating or shorting accelerator insulating surfaces precludes their routine use on high-demand machines. The successful utilization of dielectric foils in place of metal ones would alleviate this issue but necessitates more modeling and understanding of the OTR data for inferring desired beam parameters because of the dielectric's finite permittivity. Additionally, the temperature dependence of the relevant foil parameters must be accounted for due to instantaneous beam heating. Here, we analyze quartz and kapton foil OTR data from the Flash X-Ray (FXR) induction linear accelerator using a model that includes these effects and discuss the resultant FXR beam profiles.