PAC07 - List of Keywords (acceleration)

A B C D E F G H I K L M O P Q R S T U V W

acceleration

Paper	Title	Other Keywords	Page
MOPAN028	Current Status of Virtual Accelerator at J-PARC 3 GeV Rapid Cycling Synchrotron	controls, injection, beam-losses, simulation	215
	H. Harada K. Furukawa KEK, Ibaraki H. Hotchi, Y. Irie, F. Noda, H. Sako, H. Suzuki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon K. Shigaki Hiroshima University, Higashi-Hiroshima
	We have developed the logical accelerator called "Virtual Accelerator" based on EPICS for 3 GeV Rapid Cycling Synchrotron (RCS) in J-PARC. The Virtual Accelerator has a mathematical model of the beam dynamics in order to simulate the behavior of the beam and enables the revolutionary commissioning and operation of an accelerator. Additionally, we have constructed the commissioning tool based on the Virtual Accelerator. We will present a current status of the Virtual Accelerator system and some commissioning tool.

MOPAN037	Acceleration of Cold Emission Beam from Carbon Nanotube Cathode in KEKB/PF Linac	gun, linac, cathode, emittance	236
	S. Ohsawa Y. Hozumi Advanced Manufacturing Research Institute, Tsukuba M. Ikeda, T. Sugimura KEK, Ibaraki
	An electron gun with carbon nanotube cathode has been installed in the KEKB/PF linac, and the beam acceleration tests up to 2.5GeV have been performed successfully. The results and performance are presented in details.

MOPAN042	Switching Power Supply for Induction Accelerators	induction, 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.

MOPAN045	Longitudinal Particle Tracking of J-PARC RCS for Synchronization	emittance, synchrotron, simulation, extraction	260
	M. Yamamoto S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Toda, M. Yoshii KEK, Ibaraki K. Hasegawa, M. Nomura, A. Schnase, F. Tamura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	We have performed particle tracking simulation of J-PARC RCS to study the synchronization process. A frequency offset is added to the nominal RF frequency pattern to shift the center of the bunch, under the condition of the offset value should be 'adiabatic' with respect to the synchrotron motion. Since the synchrotron frequency of the J-PARC RCS is substantially changed during acceleration, the particle tracking simulation helps to decide upper limit of the frequency offset which can be employed.

MOPAN067	Transport and Installation of the LHC Cryo-Magnets	factory, dipole, insertion, controls	305
	K. Artoos S. Bartolome-Jimenez, O. Capatina, J. M. Chevalley, K. Foraz, M. Guinchard, C. Hauviller, K. Kershaw, S. Prodon, I. Ruehl, G. Trinquart, S. Weisz CERN, Geneva P. Ponsot DBS, Saint Genis-Pouilly
	Eleven years have passed between the beginning of transport and handling studies in 1996 and the completion of the LHC cryo-magnets installation in 2007. More than 1700 heavy, long and fragile cryo-magnets had to be transported and installed in the 27 km long LHC tunnel with very restricted available space. The size and complexity of the project involved challenges in the field of equipment design and manufacturing, maintenance, training and follow-up of operators and logistics. The paper presents the milestones, problems to be overcome and lessons learned during this project.

MOPAN075	Experimental Modal Analysis of Components of the LHC Experiments	damping, monitoring, resonance, coupling	329
	M. Guinchard K. Artoos, A. Catinaccio, K. Kershaw, A. Onnela CERN, Geneva
	Experimental modal analysis of components of the LHC Experiments is performed with the purpose of determining their fundamental frequencies, their damping and the mode shapes of light and fragile detectors components. This process permits to confirm or replace Finite Element analysis in the case of complex structure (with cables and substructure coupling). It helps solving structural mechanics problems to improve the operational stability and determine the acceleration specifications for transport operations. This paper describes the hardware and software equipments used to perform a modal analysis on particular structures such as a particle detectors and the method of curve fitting to extract the results of the measurements. This paper exposes also the main results obtained for the LHC Experiments.

MOPAN104	Current Monitor for the ISIS Synchrotron RF Cavity Bias Regulator	controls, monitoring, synchrotron, lattice	407
	A. Daly C. W. Appelbee, D. Bayley STFC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the world's most intense pulsed neutron source. The accelerator consists of a 70 MeV H^- Linac and an 800 MeV, 50 Hz, proton Synchrotron. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities each having its own high voltage r.f. drive amplifier and bias system. Each of these cavities is driven as a high Q tuned r.f. circuit; the resonant frequency being controlled by passing a current through a bias winding. This current comes from the Bias Regulator system which consists in part of eight banks of 40 transistors. This paper describes the design of a system which will use digital techniques to monitor and display the current of each of the 320 transistors in the Bias Regulator system.

MOPAS005	System Overview for the Multi-element Corrector Magnets and Controls for the Fermilab Booster	power-supply, booster, controls, monitoring	449
	C. C. Drennan M. Ball, A. R. Franck, D. J. Harding, P. A. Kasley, G. E. Krafczyk, M. J. Kucera, J. R. Lackey, D. McArthur, J. R. Misek, W. Pellico, E. Prebys, A. K. Triplett, D. Wolff Fermilab, Batavia, Illinois
	Funding: Work supported by the U. S. Department of Energy To better control the beam position, tune, and chromaticity in the Fermilab Booster synchrotron, a new package of six corrector elements has been designed, incorporating both normal and skew orientations of dipole, quadrupole, and sextupole magnets. The devices are under construction and will be installation in 48 locations in the Booster accelerator. Each of these 288 corrector magnets will be individually powered. Each of the magnets will be individually controlled using operator programmed current ramps designed specifically for the each type of Booster acceleration cycle. This paper provides an overview of the corrector magnet installation in the accelerator enclosure, power and sensor interconnections, specifications for the switch-mode power supplies, rack and equipment layouts, controls and interlock electronics, and the features of the operator interface for programming the current ramps and adjusting the timing of the system triggers.

TUXKI02	Recommendations from the International Scoping Study for a Neutrino Factory	target, proton, factory, linac	681
	C. R. Prior
	The International Scoping Study (ISS), a one-year review set up at the behest of CCLRC, aimed to lay the foundation for a planned international design study (IDS) for a neutrino factory or superbeam facility over the next three to five years. A team of experienced accelerator physicists were asked to examine the accelerator work carried out to date, identify a fully self-consistent and viable scenario, and specify areas for immediate study and R&D. The ISS Report, published in late 2006, makes recommendations for all parts of a Neutrino Factory complex, from the proton driver, through muon production and acceleration to the final decay ring, which directs the neutrino beams through the earth to far detectors. The paper describes these proposals, explaining the reasoning behind them, and outlines the work currently being undertaken in preparation for the IDS.
	Slides

TUYKI02	Status of the RIKEN RIB Factory	factory, cyclotron, ion, heavy-ion	700
	Y. Yano
	A series of ring cyclotrons have been constructed/under construction to accelerate radioactive ion beams to very high energy, e.g. 350MeV/u for uranium. Status of the project will be reported. Commissioning and/or operational experience with the large superconducting ring cyclotrons will be presented. Experience with the projectile fragment separator (BigRIPS) and two new large spectrometers will also be covered.
	Slides

TUODKI01	Status of J-PARC Main Ring Synchrotron	extraction, septum, injection, synchrotron	736
	T. Koseki
	The J-PARC (Japan Proton Accelerator Research Complex) accelerator facility consists of a 400-MeV linac, a 3.0-GeV rapid cycling synchrotron (RCS), a 50-GeV slow cycling main ring synchrotron (MR). Beam commissioning of the linac has been started from this November and construction of the synchrotrons is now underway. The MR accelerates the 3-GeV beam from the RCS up to 30 - 50 GeV and provides the beam to the hadron beam facility via slow extraction and to the neutrino beam facility via fast extraction. In this paper, we present recent status of the accelerator construction and test operation results for some components of the MR. Beam commissioning scenario and related beam dynamics studies are also discussed.
	Slides

TUODKI04	Accelerating Polarized Protons to 250 GeV	resonance, polarization, proton, betatron	745
	M. Bai L. Ahrens, I. G. Alekseev, J. G. Alessi, J. Beebe-Wang, M. Blaskiewicz, A. Bravar, J. M. Brennan, K. A. Brown, D. Bruno, G. Bunce, J. J. Butler, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K. A. Drees, W. Fischer, G. Ganetis, C. J. Gardner, J. Glenn, T. Hayes, H.-C. Hseuh, H. Huang, P. Ingrassia, J. S. Laster, R. C. Lee, A. U. Luccio, Y. Luo, W. W. MacKay, Y. Makdisi, G. J. Marr, A. Marusic, G. T. McIntyre, R. J. Michnoff, C. Montag, J. Morris, P. Oddo, B. Oerter, J. Piacentino, F. C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, M. Wilinski, A. Zaltsman, A. Zelenski, K. Zeno, S. Y. Zhang BNL, Upton, Long Island, New York D. Svirida ITEP, Moscow
	Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA) The Relativistic Heavy Ion Collider~(RHIC) as the first high energy polarized proton collider was designed to provide polarized proton collisions at a maximum beam energy of 250GeV. It has been providing collisions at a beam energy of 100GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during the acceleration from injection to 100GeV with careful control of the betatron tunes and the vertical orbit distortions. However, the intrinsic spin resonances beyond 100GeV are about a factor of two stronger than those below 100GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated to the record energy of 250GeV in RHIC with a polarization of 45\% measured at top energy in 2006. The polarization measurement as a function of beam energy also shows some polarization loss around 136GeV, the first strong intrinsic resonance above 100GeV. This paper presents the results and discusses the sensitivity of the polarization survival to orbit distortions.
	Slides

TUXC02	Induction Synchrotron Experiment in the KEK PS	induction, 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, pick-up, vacuum, induction	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

TUOCC01	Software Tools for Commissioning of the Spallation Neutron Source Linac	linac, proton, quadrupole, optics	883
	J. Galambos A. V. Aleksandrov, C. K. Allen, S. Henderson, T. A. Pelaia, A. P. Shishlo, Y. Zhang ORNL, Oak Ridge, Tennessee P. Chu SLAC, Menlo Park, California
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725. The Accelerator Physics group at the Spallation Neutron Source (SNS) has developed numerous codes to assist in the beam commissioning, tuning, and operation of the SNS Linac. These codes have been key to meeting the beam commissioning milestones. For example, a recently developed code provides for rapid retuning of the superconducting Linac in case of RF stations going offline or coming online. Highlights of these "physics applications" will be presented.
	Slides

TUPMN012	STARS - A Two-Stage High-Gain Harmonic Generation FEL Demonstrator	electron, laser, free-electron-laser, simulation	938
	T. Kamps M. Abo-Bakr, W. Anders, J. Bahrdt, P. Budz, K. B. Buerkmann-Gehrlein, O. Dressler, H. A. Duerr, V. Duerr, W. Eberhardt, S. Eisebitt, J. Feikes, R. Follath, A. Gaupp, R. Goergen, K. Goldammer, S. C. Hessler, K. Holldack, E. Jaeschke, S. Klauke, J. Knobloch, O. Kugeler, B. C. Kuske, P. Kuske, A. Meseck, R. Mitzner, R. Mueller, M. Neeb, A. Neumann, K. Ott, D. Pfluckhahn, T. Quast, M. Scheer, Th. Schroeter, M. Schuster, F. Senf, G. Wuestefeld BESSY GmbH, Berlin D. Kramer GSI, Darmstadt F. Marhauser JLAB, Newport News, Virginia
	Funding: Bundesministerium fur Bildung und Forschung and the Land Berlin BESSY is proposing a demonstration facility, called STARS, for a two-stage high-gain harmonic generation free electron laser (HGHG FEL). STARS is planned for lasing in the wavelength range 40 to 70 nm, requiring a beam energy of 325 MeV. The facility consists of a normal conducting gun, three superconducting TESLA-type acceleration modules modified for CW operation, a single stage bunch compressor and finally a two-stage HGHG cascaded FEL. This paper describes the faciliy layout and the rationale behind the operation parameters.

TUPMN113	A Plasma Channel Beam Conditioner for Free electron Lasers	plasma, emittance, electron, focusing	1176
	G. Penn A. Sessler, J. S. Wurtele LBNL, Berkeley, California
	Funding: Work supported by the U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-05CH11231. By "conditioning" an electron beam, through establishing a correlation between transverse action and energy within the beam, the performance of free electron lasers (FELs) can be dramatically improved. Under certain conditions, the FEL can perform as if the transverse emittances of the beam were substantially lower than the actual values. After a brief review of the benefits of beam conditioning, we present a method to generate this correlation through the use of a plasma channel. The strong transverse focusing produced by a dense plasma (near standard gas density) allows the optimal correlation to be achieved in a reasonable length channel, of order 1 m. This appears to be a convenient and practical method for achieving conditioned beams, especially in comparison with other methods which require either a long beamline or multiple passes through some type of ring.

TUPAN003	Beam Quality and Operational Experience with the Superconducting LINAC at the ISAC II RIB facility	linac, emittance, ion, diagnostics	1392
	M. Marchetto R. E. Laxdal, V. Zviagintsev TRIUMF, Vancouver
	The ISAC II superconducting LINAC is now in the operational phase. The linac was commissioned with stable beams from an off-line source. The commissioning not only proved the integrity of the infrastructure but benchmarked the beam quality and rf cavity performance. Measurements of the transverse and longitudinal emittance are consistent with little or no emittance growth through the acceleration. Transmission near 100% has been achieved though some solenoid steering is evident due to misalignment. The misalignment problem is being evaluated using the beam as diagnostic tool while applying corrections based on the beam measurements. The effectiveness of the corrections will be reported. The machine has been demonstrated to be easy to tune, reliable in restoring beam and flexible enough to accommodate different tuning strategies; software routines have been developed in order to facilitate the tuning process. In this paper the operational routine for tuning and beam delivery will be presented as well as the beam characteristics drawn from the commissioning studies.

TUPAN007	3-D Magnetic Calculation Methods for Spiral Scaling FFAG Magnet Design	magnet-design, lattice, background, extraction	1401
	T. Planche B. Autin, J. Fourrier, E. Froidefond, J. Pasternak LPSC, Grenoble J. L. Lancelot, D. Neuveglise Sigmaphi, Vannes F. Meot CEA, Gif-sur-Yvette
	Funding: ANR (French Research Agency) 2-D and 3-D magnetic calculation tools and methods have been developed at SIGMAPHI, in collaboration with IN2P3/LPSC, to design spiral FFAG magnets. These tools are currently being used for RACCAM spiral scaling FFAG magnet design. In the particular case of a spiral gap shaped magnet, a careful magnetic design has to be realized in order to keep both vertical and horizontal tunes constant during acceleration process. Promising results, obtained from tracking in 3-D field maps, demonstrate the efficiency of the horizontal and vertical tune adjustment methods presented in this paper.

TUPAN044	Acceleration Scheme in the AIA and its Control System	induction, 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

TUPAN046	A Modification Plan of the KEK 500MeV Booster to an All-ion Accelerators (An Injector-free Synchrotron)	ion, kicker, extraction, injection	1490
	E. Nakamura T. Adachi, Y. Arakida, T. Iwashita, M. Kawai, T. Kono, H. Sato, Y. Shimosaki, K. Takayama, M. Wake KEK, Ibaraki T. S. Dixit GUAS/AS, Ibaraki S. I. Inagaki Kyushu University T. Kikuchi Utsunomiya University, Utsunomiya K. Okazaki Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture K. T. Torikai NIRS, Chiba-shi
	A medium-energy synchrotron capable of accelerating all ion species based on a novel technology of the induction synchrotron* has been proposed as an all-ion accelerator (AIA). The AIA without any specific injector employs a strong focusing lattice and induction acceleration, driven by novel switching power supplies. All ions, including cluster ions with any charge state, are accelerated in a single accelerator. A plan to modify the existing KEK 500 MeV Booster to the AIA is under consideration. Its key aspects, such as an ion-source, a low-field injection scheme and induction acceleration, are described. Deep implant of moderate-energy heavy ions provided from the AIA into various materials may create a new alloy in bulk size. Energy deposition caused by the electro-excitation associated with passing of swift ions through the material is known to largely modify its structure. The similar irradiation on metal in a small physical space of less than a mm in diameter and in a short time period less than 100 nsec is known to create a particularly interesting warm dense-matter state. The AIA capable is a quite interesting device as a driver to explore these new paradigms. K. Takayama, et al., "Experimental Demonstration of the Induction Synchrotron", PAC07. K. Takayama, et al., PCT/JP2006/308502 (2006).* T. Dixit, et al., PAC07.

TUPAN050	Status of the Induction Acceleration System	induction, power-supply, 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.

TUPAN055	Present Status of J-PARC Ring RF Ring RF Systems	power-supply, synchrotron, radio-frequency, controls	1511
	M. Yoshii S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Toda KEK, Ibaraki K. Haga, K. Hasegawa, M. Nomura, A. Schnase, F. Tamura, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	The RCS high frequency accelerating systems are prepared for beam commissioning in September 2007. Installations of cavities, power supplies and amplifiers have been carried out. The systems have been checked for operation and interoperability. For the MR high frequency accelerating system, the examination of the whole system and its final adjustment are done aiming at installation in October 2007. Here, we report on various issues which had been found and solved during the examination and installation period. masahito.yoshii@kek.jp

TUPAN058	High Power Conditioning of the DTL for J-PARC	vacuum, klystron, linac, pick-up	1517
	T. Ito H. Ao JAEA/LINAC, Ibaraki-ken H. Asano, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken T. Kato, F. Naito, E. Takasaki, H. Tanaka KEK, Ibaraki
	For the J-PARC, DTL (Drift Tube Linac) is used to accelerate an H^- ion beam from 3MeV to 50MeV. The DTL consists of 3 tanks and the all tanks were installed in the accelerator tunnel for J-PARC. After the installation, the high power conditioning has been started in Oct. 2006. The required rf power levels for beam acceleration are about 1.08MW, 1.2MW and 1.03MW (the pulse length is 600μsec and the pulse repetition is 25Hz) for the 1st, 2nd and 3rd tanks, respectively. As a result of the conditioning, we have been achieved that the rf power levels are about 1.3MW, 1.45MW and 1.23MW of 1.2 times required power levels (the pulse length is 650μsec and the pulse repetition is 25Hz). In this paper, the results of the high power conditioning of the DTL tanks are described.

TUPAN063	High Power Test of MA Cavity for J-PARC RCS	impedance, linac, synchrotron, power-supply	1532
	M. Yamamoto S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Toda, M. Yoshii KEK, Ibaraki K. Hasegawa, M. Nomura, A. Schnase, F. Tamura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	We have been testing the RF cavities for the J-PARC RCS, we can operate the cavities without sever problems. Before some MA cores were damaged, then we found such cores have low ribbon resistance. After that we have tested the cavities loaded with improved ribbon resistance.

TUPAN083	Space-Charge Neutralization in Ion Undulator Linear Accelerator	ion, simulation, undulator, linac	1565
	E. S. Masunov S. M. Polozov MEPhI, Moscow
	RF undulator accelerator (UNDULAC-RF) is suggested as an initial part of high intensity ion linac. Such accelerator can be realized in periodical IH structure where a field has no spatial harmonics in synchronism with the beam. Ion beam is accelerated by the combined field of two non-synchronous harmonics. Accelerating force value is proportional to squared particle charge. Transmission coefficient and accelerating gradient for low velocity ions with the identical sign of charge are the same as in RFQ. The limit beam current can be larger in this type accelerator. Its value was calculated earlier in paper . But the beam intensity can be substantially increased in UNDULAC by using space charge neutralization of positive and negative charged ions. In UNDULAC positive and negative ions can be accelerated simultaneously within the same bunch. The process of acceleration and focusing of oppositely charged ions with the identical charge-to-mass ratio is discussed in this paper. E. S. Masunov, Technical Physics, V. 46, 11, 2001, pp. 1433-1436.**E. S. Masunov, S. M. Polozov, NIM., A 558, 2006, pp. 184-187.

TUPAN084	Using Smooth Approximation for Beam Dynamics Investigation in Superconducting Linac	linac, ion, focusing, proton	1568
	E. S. Masunov A. V. Samoshin MEPhI, Moscow
	The superconducting linac consists of some different classes of the identical cavities. The each cavity based on a superconducting structure with a high accelerating gradient. The distance between the cavities is equal to acceleration structure period L. By specific phasing of the RF cavities one can provide a stable particle motion in the whole accelerator. The ion dynamics in such periodic structure is complicated. The reference particle coordinate and momentum can be represented as a sum of a smooth motion term and a fast oscillation term, a period of which is equal to L. Three dimensional equation of motion for ion beam in the Hamiltonian form is derived in the smooth approximation for superconducting linac. The longitudinal acceptance and maximum energy width in a bunch are found by means of the effective potential function. The general conditions applicability of a smooth approximation to given electrodynamic problem is formulated. The nonlinear ion beam dynamics is investigated in such accelerated structure.

TUPAN117	Progress on Dual Harmonic Acceleration on the ISIS Synchrotron	synchrotron, beam-losses, proton, power-supply	1649
	A. Seville D. J. Adams, C. W. Appelbee, D. Bayley, N. E. Farthing, I. S.K. Gardner, M. G. Glover, B. G. Pine, J. W.G. Thomason, C. M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the most intense pulsed, spallation, neutron source. The accelerator consists of a 70 MeV H^- linac and an 800 MeV, 50 Hz, rapid cycling, proton synchrotron. The synchrotron beam intensity is 2.5·10¹³ protons per pulse, corresponding to a mean current of 200 μA. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities with harmonic number 2. Four additional, harmonic number 4, cavities have been installed to increase the beam bunching factor with the potential of raising the operating current to 300μA. The dual harmonic system has now been used operationally for the first time, running reliably throughout the last ISIS user cycle of 2006. This paper reports on the hardware commissioning, beam tests and improved operational results obtained so far with dual harmonic acceleration.

TUPAS005	Accelerators for the Advanced Exotic Beam Facility in the U. S.	linac, ion, target, heavy-ion	1664
	P. N. Ostroumov J. D. Fuerst, M. P. Kelly, B. Mustapha, J. A. Nolen, K. W. Shepard ANL, Argonne, Illinois
	Funding: This work was supported by the U. S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC-02-06CH11357 The Office of Science of the Department of Energy is currently considering options for an advanced radioactive beam facility in the U. S. The U. S. facility will complement capabilities both existing and planned elsewhere. As envisioned at ANL, the facility, called the Advanced Exotic Beam Laboratory (AEBL), would consist of a heavy-ion driver linac, a post-accelerator and experimental areas. The proposed design of the AEBL driver linac is a cw, fully superconducting, 833 MV linac capable of accelerating uranium ions up to 200 MeV/u and protons to 580 MeV with 400 kW beam power. An extensive research and development effort has resolved many technical issues related to the construction of the driver linac and other systems required for AEBL. This paper presents the status of planning, some options for such a facility, as well as, progress in related R&D.

TUPAS007	The Investigation of Injection Timing for the IPNS RCS	injection, proton, space-charge, simulation	1667
	S. Wang F. R. Brumwell, J. C. Dooling, R. Kustom, G. E. McMichael, M. E. Middendorf ANL, Argonne, Illinois
	Funding: This work is supported by the U. S. Department of Energy under contract no. W-31-109-ENG-38. The Intense Pulsed Neutron Source (IPNS) Rapid Cycling Synchrotron (RCS) accelerates 3.2x 10¹² protons from 50 MeV to 450 MeV at 30 Hz. During the 14.2 ms acceleration period, the RF frequency varies from 2.21 MHz to 5.14 MHz. In order to improve capture efficiency, we varied the injection timing and the early RF voltage profiles. The experimental results are compared with similar studies at ISIS and calculation done with the 1-D tracking code, Capture-SPC. This allowed us to optimize injection time and the RF voltage profile for better capture efficiency. An optimized injection time and RF voltage profile was found that resulted in raising the capture efficiency from 85.1% to 88.6%. These studies have now also been expanded to included 2nd harmonic RF during the capture and initial acceleration cycle in the RCS.

TUPAS014	Fast Beam Stacking using RF Barriers	injection, booster, simulation, proton	1682
	W. Chou D. Capista, E. Griffin, K. Y. Ng, D. Wildman Fermilab, Batavia, Illinois
	Funding: Work supported by Universities Research Association, Inc. under contract No. DE-AC02-76CH03000 with the U. S. Dept. of Energy. Two barrier rf systems were fabricated, tested and installed in the Fermilab Main Injector.* Each can provide 8-10 kV rectangular pulses (the rf barriers) at 90 kHz. When a stationary barrier is combined with a moving barrier, injected beams from the Booster can be continuously deflected, folded and stacked in the Main Injector (MI), which leads to doubling of the beam intensity. This paper gives a report on the beam experiment using this novel technology. * W. Chou, D. Wildman and A. Takagi, "Induction Barrier RF and Applications in Main Injector," Fermilab-Conf-06-227 (2006).

TUPAS058	Electromagnetic Simulations of Linear Proton Accelerator Structures Using Dielectric Wall Accelerators	proton, simulation, impedance, controls	1784
	S. D. Nelson G. J. Caporaso, B. R. Poole 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. Proton accelerator structures for medical applications using Dielectric Wall Accelerator (DWA) technology allows for the utilization of high field gradients on the order of 100 MV/m to accelerate the proton bunch. Medical applications involving cancer therapy treatment usually desire short bunch lengths on the order of hundreds of picoseconds in order to limit the extent of the energy deposited in the tumor site (in 3D space, time, and deposited proton charge). Electromagnetic simulations of the DWA structure, in combination with injections of proton bunches, have been performed using 3D finite difference codes in combination with particle pushing codes. Electromagnetic simulations of DWA structures includes these effects and also includes the details of the switch configuration and how that switch time affects the electric field pulse which accelerates the particle beam. Design trade-offs include the driving switch effects, layer-to-layer coupling analysis and its affect on the pulse rise time.

TUPAS060	Particle Simulations of a Linear Proton Dielectric Wall Accelerator	injection, simulation, proton, focusing	1790
	B. R. Poole D. T. Blackfield, S. D. Nelson 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. The dielectric wall accelerator (DWA) is a compact induction accelerator structure that incorporates the accelerating mechanism, pulse forming structure, and switch structure into an integrated module. The DWA consists of stacked stripline Blumlein assemblies, which can provide accelerating gradients in excess of 100 MeV/meter. Blumleins are switched sequentially according to a prescribed acceleration schedule to maintain synchronism with the proton bunch as it accelerates. A finite difference time domain code (FDTD) is used to determine the applied acceleration field to the proton bunch. Particle simulations are used to model the injector as well as the accelerator stack to determine the proton bunch energy distribution, both longitudinal and transverse dynamic focusing, and emittance associated with various DWA configurations.

TUPAS104	Heavy Ion Driver with the Non-Scaling FFAG	injection, ion, lattice, emittance	1880
	A. G. Ruggiero J. G. Alessi, E. N. Beebe, A. I. Pikin, T. Roser, D. Trbojevic BNL, Upton, Long Island, New York
	Funding: Supported by the U. S. Department of Energy under Contract No. DE-AC02-98CH10886. * Work supported by the U. S. Department of Energy under Contract No. DE-AC02-05CH11231* We explore the possibility of using two non-scaling FFAG with a smaller number of distributed RF cavities for a high power heavy ion driver. The pulsed heavy ion source would consist of an Electron Beam Ion Source (EBIS), fed continuously from a high charge state Electron Cyclotron Resonance (ECR) source. The Radio Frequency Quadrupole (RFQ) and a short 10 MeV/u linac would follow the ion source. Microseconds long heavy ion beam bunches from the EBIS would be injected in a single turn into a multi-pass small aperture non-scaling Fixed Field Alternating Gradient (FFAG) accelerator. The heavy ion maximum kinetic energy is assumed to be 400 MeV/u with a total of 400 kW power for uranium ion beams. Partially stripped heavy ions would be accelerated from 10 MeV/u to 67 MeV/u with a first non-scaling FFAG, while, after further stripping, a second non-scaling FFAG would accelerate from 67 to 400 MeV/u.

WEXKI01	First Experimental Evidence for PASER: Particle Acceleration by Stimulated Emission of Radiation	electron, laser, radiation, resonance	1889
	S. Banna V. Berezovsky, L. Schachter Technion, Haifa
	Funding: Israel Science Foundation - ISF and United States Department of Energy -DoE Franck and Hertz in 1914 were the first to demonstrate that free electrons can be decelerated by mercury atoms in discrete energy quanta. In 1930 Latyscheff and Leipunsky have demonstrated the inverse effect namely; free electrons can be accelerated by energy stored in the mercury atoms (collision of the second kind). It was only in 1958 that Townes has used multiple collisions between photons and excited atoms to amplify radiation (MASER & LASER). In 1995 Schachter suggested to use excited atoms for coherently accelerate particles. The results of a proof-of-principle experiment (2006) demonstrating the PASER scheme are reported here. Performed at the BNL-ATF, the essence of the experiment is to inject a 45MeV density modulated beam into an excited CO2 gas mixture. Resonance is insured by having the beam bunched by its interaction with a high-power CO2 laser pulse within a wiggler. The electrons experienced 0.15% relative change in their kinetic energy, in less than 40cm long interaction region. The experimental results indicate that a fraction of these electrons have gained 200keV each, implying that such an electron has undergone 2,000,000 collisions of the second kind.
	Slides

WEXKI02	Demonstration of Optical Microbunching and Net Acceleration at 0.8 microns	laser, electron, simulation, undulator	1894
	C. M.S. Sears R. L. Byer, T. Plettner Stanford University, Stanford, Califormia E. R. Colby, R. Ischebeck, C. Mcguinness, R. Siemann, J. E. Spencer, D. R. Walz SLAC, Menlo Park, California
	Formation, diagnosis, and acceleration of electron microbunches from an rf linac generated beam is presented. A PM-EM hybrid IFEL/chicane buncher was designed and commissioned to produce optical bunch trains suitable for injection into solid-state laser accelerators. Microbunching is independently diagnosed via coherent optical tranisition radiation (COTR). Net acceleration is obtained by splitting the laser power between the IFEL and an inverse transition radiation (ITR) accelerator.
	Slides

WEXKI03	Survey of Advanced Dielectric Wakefield Accelerators	electron, gun, simulation, linac	1899
	M. E. Conde
	Funding: Work supported by the US Department of Energy under contract # DE-AC02-06CH11357. There has been continued interest in the development of dielectric-loaded wakefield structures that can be used to accelerate particle beams. The present search for materials able to withstand very intense RF fields has renewed this interest. Recent experiments at the Argonne Wakefield Accelerator have generated short RF pulses with accelerating fields in excess of 80 MV/m. These experiments used ceramic-lined cylindrical waveguides, operating at frequencies between 10 and 15 GHz. Other important experiments, at different RF frequencies and using planar or cylindrical geometries, have been carried out at various other facilities. A number of new experiments are planned in the near future to explore the capabilities of this class of structures. This presentation will provide an up-to-date survey of the activities in this area of research.
	Slides

WEOBC02	Vertical Instability at IPNS RCS	synchrotron, proton, beam-losses, extraction	2022
	S. Wang F. R. Brumwell, J. C. Dooling, K. C. Harkay, R. Kustom, G. E. McMichael, M. E. Middendorf, A. Nassiri ANL, Argonne, Illinois
	Funding: This work is supported by the U. S. Department of Energy under contract no. W-31-109-ENG-38. The Intense Pulsed Neutron Source (IPNS) Rapid Cycling Synchrotron (RCS) accelerates 3.2x 10¹² protons from 50 MeV to 450 MeV at 30 Hz. During the 14.2 ms acceleration period, the RF frequency varies from 2.21 MHz to 5.14 MHz. The beam current is limited by a vertical instability. By analyzing turn-by-turn Beam Position Monitor (BPM) data, large amplitude mode 0 and mode 1 vertical beam centroid oscillations were observed in the later part of the acceleration cycle. The oscillations develop in the tail of the bunch, build up and remain localized in the later part of the bunch. This vertical instability was compared with a head-tail instability that was intentionally induced in the RCS by adjusting the trim-sextupoles to make the horizontal chromaticity positive (below transition). It appears that our vertical instability is not typical head-tail instability. More data analysis and experiments were performed to characterize the instability.
	Slides

WEZC02	Extreme Compression of Heavy Ion Beam Pulses: Experiments and Modeling	plasma, ion, simulation, focusing	2030
	A. B. Sefkow J. J. Barnard LLNL, Livermore, California J. E. Coleman, P. K. Roy, P. A. Seidl LBNL, Berkeley, California R. C. Davidson, P. Efthimion, E. P. Gilson, I. Kaganovich PPPL, Princeton, New Jersey D. R. Welch Voss Scientific, Albuquerque, New Mexico
	Funding: Research supported by the U. S. Department of Energy. Intense heavy ion beam pulses need to be compressed in both the transverse and longitudinal directions for warm dense matter and heavy ion fusion applications. Previous experiments and simulations utilized a drift region filled with high-density plasma in order to neutralize the space-charge and current of a 300 keV K⁺ beam, and achieved transverse and longitudinal focusing separately to a radius < 2 mm and pulse width < 5 ns, respectively. To achieve simultaneous beam compression, a strong solenoid is employed near the end of the drift region in order to transversely focus the beam to the longitudinal focal plane. Simulations of near-term experiments predict that the ion beam can be focused to a sub-mm spot size coincident with the longitudinal focal plane, reaching a peak beam density in the range 10¹² - 10¹³ cm^-3, provided that the plasma density is large enough for adequate neutralization. Optimizing the compression under the appropriate experimental constraints offers the potential of delivering higher intensity per unit length of accelerator to the target, thereby allowing more compact and cost-effective accelerators and transport lines to be used as ion beam drivers.
	Slides

WEPMN036	High Field Performance in Reduced Cross-sectional X-Band Waveguides Made of Different Materials	laser, linac, simulation	2119
	K. Yokoyama Y. Higashi, T. Higo, N. K. Kudo, S. Ohsawa KEK, Ibaraki
	To study the characteristics of different materials on high-field rf breakdown we designed a simplified waveguide, where the field of 200MV/m is realized at rf power of 100MW. The geometry is transformed from the WR90, where the height and the width are reduced from 10.16 mm to 1mm and from 22.86mm to 14mm, respectively. This paper reports on the high-gradient testing of copper and stainless-steel waveguides. We have observed rf breakdowns by bursts of x-rays, flashes of visible lights and acoustic signals. Frequent breakdowns are observed at about 100MV/m level in copper case and the study on the stainless-steel waveguide will be performed to be compared to that of copper case.

WEPMN040	MA Cavities for J-PARC with Controlled Q-value by External Inductor	impedance, vacuum, resonance, controls	2131
	A. Schnase S. Anami, E. Ezura, K. Hara, K. Hasegawa, C. Ohmori, A. Takagi, M. Toda, M. Yoshii KEK, Ibaraki M. Nomura, F. Tamura, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	The original J-PARC RCS cavity design* used cut-cores to control the Q-value. Adjusting the distance between the C-shaped core parts the optimum Q=2 is reached. Because of problems related to the cut-core surfaces, the "hybrid cavity" was introduced, using tanks with uncut cores (Q=0.6) in parallel to tanks with cut cores with a wider gap (Q=4), resulting in total Q=2. This was successfully tested. The manufacturing procedure for cut-cores involves more steps than for uncut cores. To reduce risks for long-term operation, the RCS cavities will be loaded with uncut cores for day-1 operation. With uncut cores (Q=0.6) the maximum beam power is limited. Therefore we introduce a parallel inductor, placed in the push-pull tube amplifier driving the cavity, to adjust the Q-value to 2. Parallel vacuum capacitors shift the resonance near to 1.7 MHz. Each of the 10 cavity systems for RCS, necessary for day-1 operation, is tested for at least 300 hours to detect initial problems before installation into the RCS tunnel. We report the results of cavity performance tests with external inductor, which simulate 25Hz operation and the optimization of the combined system of cavity and amplifier. * C. Ohmori at. al, "High Field-Gradient Cavity for J-PARC 3 GeV RCS", PAC 2004

WEPMN066	Progress Towards Development of a Superconducting Traveling Wave Accelerating Structure	feedback, coupling, linac, collider	2182
	P. V. Avrakhov A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio S. Kazakov KEK, Ibaraki N. Solyak Fermilab, Batavia, Illinois V. P. Yakovlev Omega-P, Inc., New Haven, Connecticut
	In the ILC project the required accelerating gradient is higher than 35 MeV/m. For current technology the maximum acceleration gradient in SC structures is limited mainly by the value of the surface RF magnetic field. In order to increase the gradient, the RF magnetic field is distributed homogeneously over the cavity surface (low-loss structure), and coupling to the beam is improved by introducing aperture ?noses? (re-entrant structure). These features allow gradients in excess of 50 MeV/m to be obtained for a singe-cell cavity. Further improvement of the coupling to the beam may be achieved by using a TW SC structure with small phase advance per cell. Calculations show that an additional gradient increase by up to 40% is possible if a p/2 TW SC structure is employed. However, a TW SC structure requires a SC feedback waveguide to return the few GW of circulating RF power from the structure output back to the structure input. We describe a single-cell test TW SC structure with a feedback waveguide. The test cavity is designed to demonstrate the possibility of achieving a significantly higher gradient than existing SC structures.

WEPMN088	The IPNS Second Harmonic RF Upgrade	injection, controls, extraction, proton	2233
	M. E. Middendorf F. R. Brumwell, J. C. Dooling, D. Horan, R. Kustom, M. K. Lien, G. E. McMichael, M. R. Moser, A. Nassiri, S. Wang ANL, Argonne, Illinois
	Funding: This work is supported by the U. S. Department of Energy under contract no. W-31-109-ENG-38. The Intense Pulsed Neutron Source (IPNS) rapid cycling synchrotron (RCS) is used to accelerate protons from 50 MeV to 450 MeV, at a repetition rate of 30 Hz. The original ring design included two identical RF systems, each consisting of an accelerating cavity, cavity bias supply, power amplifiers and low level analog electronics. The original cavities are located 180 degrees apart in the ring, and provide a total peak accelerating voltage of ~21 kV over the 2.21 MHz to 5.14 MHz revolution frequency sweep. A third RF system has been constructed and installed in the RCS. The third RF system is capable of operating at the fundamental revolution frequency for the entire acceleration cycle, providing an additional peak accelerating voltage of up to ~11kV, or at the second harmonic of the revolution frequency for the first ~4 ms of the acceleration cycle, providing an additional peak voltage of up to ~11kV for bunch shape control, resulting in a modest increase in bunch length. We describe here to date, the hardware implementation and operation of the third RF cavity in the second harmonic mode.

WEPMS007	Manufacture and Performance of Superconducting RF Cavities for Cornell ERL Injector	emittance, electron, gun, superconducting-RF	2340
	R. L. Geng P. Barnes, B. Clasby, J. Kaminski, M. Liepe, V. Medjidzade, D. Meidlinger, H. Padamsee, J. Sears, V. D. Shemelin, N. Sherwood, M. Tigner CLASSE, Ithaca
	Funding: Work supported by NSF Six 1300 MHz superconducting niobium 2-cell cavities are manufactured for the prototype of Cornell ERL injector to boost the energy of a high current, low emittance beam produced by a DC gun. Designed for high current beam acceleration, these cavities have new characteristics as compared to previously developed low-current cavities such as those for TTF. Precision manufacture is emphasized for a better straightness of the cavity axis so as to avoid unwanted emittance dilution. We present the manufacturing, processing and vertical test performance of these cavities. We also present the impact of new cavity characteristics to the cavity performance as learnt from vertical tests. Solutions for improving cavity performance are discussed.

WEPMS033	LANSCE 201 MHz and 805 MHz RF System Experience	klystron, linac, vacuum, cathode	2412
	K. A. Young G. O. Bolme, J. T.M. Lyles, M. T. Lynch, E. P. Partridge, D. Rees LANL, Los Alamos, New Mexico
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396 The LANSCE RF system consists of four RF stations at 201 MHz and 44 klystrons at 805 MHz. In the LANSCE accelerator, the beam source is injected into the RF system at 0.75 MeV. The beam is then accelerated to 100 MeV in four drift tube linac (DTL) tanks, driven at 201.25 MHz. Each 201 MHz RF system consists of a train of amplifiers, including a solid state amplifier, a tetrode, and then at triode. After the DTL, the beam is accelerated from 100 MeV to 800 MeV in the forty-four coupled cavity linac (CCL) tanks at 805 MHz. The machine operates with a normal RF pulse width of 835 microseconds at a repetition rate up to 120 Hz, and sometimes operates with a pulse width up to 1.2 microseconds for single pulses. This RF system has been operating for about 37 years. This paper summarizes the recent operational experience. The reliability of the 805 MHz and 201 MHz RF systems is discussed, and a summary the lifetime data of the 805 MHz klystrons and 201 MHz triodes is presented.

WEPMS039	High Power Tests of Normal Conducting Single-Cell Structures	klystron, vacuum, radiation, impedance	2430
	V. A. Dolgashev Y. Higashi, T. Higo KEK, Ibaraki C. D. Nantista, S. G. Tantawi SLAC, Menlo Park, California
	Funding: This work was supported by the U. S. Department of Energy contract DE-AC02-76SF00515. We report results of the first high power tests of single-cell traveling-wave and standing-wave accelerating structures. These tests are part of an experimental and theoretical study of RF breakdown in normal conducting structures at 11.4 GHz. The goal of this study is to determine the gradient potential of normal conducting, RF powered particle beam accelerators. The test setup consists of reusable mode converters and short test structures powered by SLAC?s XL-4 klystron. This setup was created for economic testing of different cell geometries, cell materials and preparation techniques with short turn-around time. The mode launchers and structures were manufactured at SLAC and KEK and tested in the klystron test laboratory at SLAC. V. A. Dolgashev et al., "RF Breakdown In Normal Conducting Single-Cell Structures," SLAC-PUB-11707, Particle Accelerator Conference (PAC 05), Knoxville, Tennessee, 16-20 May 2005, pp. 595- 599.

WEPMS087	Conceptual Design of an L-Band Recirculating Superconducting Traveling Wave Accelerating Structure	coupling, feedback, collider, simulation	2538
	A. Kanareykin P. V. Avrakhov, Z. Liu Euclid TechLabs, LLC, Solon, Ohio W. Gai ANL, Argonne, Illinois S. Kazakov KEK, Ibaraki N. Solyak Fermilab, Batavia, Illinois V. P. Yakovlev Omega-P, Inc., New Haven, Connecticut
	Funding: This research is supported by the US Department of Energy We describe a conceptual design for a superconducting traveling wave accelerator for the ILC. The RF feedback system plus phase shifter can redirect the accelerating wave that passed through the STWA section back to the input of the accelerating structure. In this paper, the STWA cell shape optimization, coupler cell design and rat race ring coupler in the feedback loop are presented. The STWA cell shape is similar to the LL cavity with a 60 mm disk diameter. A 9-cell STWA operates at the mode with group velocity as low as 0.0106 c. Both the ratio of peak electric field and magnetic field to the axial electric field are smaller than in the TESLA 9-cell cavity. The STWA structure has more cells per unit length than a TESLA structure but provides an accelerating gradient higher than a TESLA structure, consequently reducing the cost. The designed rat race directional coupler with four ports has ?3 dB direct coupling coefficients, 16.5 MHz bandwidth between ?30 dB isolations and 1.1 MHz bandwidth between ?30 dB reflection coefficients. Effects of the mechanical tolerances are also discussed.

THXKI01	R&D in RF Superconductivity to Support the International Linear Collider	linear-collider, collider, insertion, superconductivity	2559
	L. Lilje
	ILC-related R&D in SRF spans a broad range of topics, ranging from the search for high gradients through improved processes and cavity geometries, through the use of new materials (large-grain and single-crystal niobium metal) and development of superconducting joints to enable superstructure concepts and minimum length vacuum joints. This talk will review the status of the global ILC SRF R&D program and discuss plans for the future.
	Slides

THYKI01	Ultra-High Intensity Laser Acceleration of Ions to Mev/Nucleon Energies	laser, ion, target	2581
	B. M. Hegelich
	Advances have been made in using ultra-high intensity lasers to directly produce high-current beams of MeV/nucleon ions in solid targets. Experimental results using the LANL Trident Laser will be discussed including beam quality and possible applications.
	Slides

THXAB01	Commissioning and Early Experiments with ISAC II	linac, ion, emittance, vacuum	2593
	R. E. Laxdal
	The first phase of the ISAC-II superconducting accelerator has recently been commissioned. The heavy ion linac adds 20MV to the 1.5MeV/u beam injected from the ISAC post accelerator. The linac is composed of five cryomodules; each cryomodule housing four 106 MHz quarter wave resonators and one 9T superconducting solenoid. On-line performance has confirmed cw operation at a peak surface field in excess of 35MV/m. The talk will describe the very successful commissioning and the early operation with both stable and radioactive beams.
	Slides

THYAB01	Muon Accelerators	emittance, linac, factory, proton	2614
	S. Machida
	Funding: The work is supported by the UK Neutrino Factory/Particle Physics and Astronomy Research Council (PPARC) under Contract No. 2054. Accelerator of muon has to have very large acceptance and very quick acceleration. Recent study shows that FFAGs (in particular non-scaling) are one of the most promising candidates for muon accelerators as building block for a neutrino factory. There are, however, some unresolved problems which should be studied in more detail. We will talk about mostly beam dynamics issues of the muon accelerators, not only FFAG, but other candidates such as linac and RLA and compare their performance.
	Slides

THYAB02	Commissioning of the J-PARC Linac	linac, rfq, klystron, proton	2619
	K. Hasegawa
	The J-PARC (Japan Proton Accelerator Research Complex?is a joint project between the Japan Atomic Energy Agency (JAEA) and the High Energy Accelerator Research Organization (KEK) to construct and operate the high-intensity proton accelerator facility. The J-PARC comprises a 400 MeV linac, a 3 GeV rapid-cycling synchrotron (RCS), a 50 GeV main ring synchrotron (MR) and experimental facilities. The energy of the linac is reduced to 181 MeV for the time being, and it will be increased to 400 MeV in the near future. The 3 MeV RFQ, which is a front end of the linac, has been beam commissioned since November 2006, and we will continue to work on the rest of the linac such as a 50 MeV DTL and a 181 MeV Separated-type DTL. The results and status of the J-PARC linac beam commissioning will be presented.
	Slides

THOBAB01	EMMA - the World's First Non-scaling FFAG	extraction, diagnostics, injection, factory	2624
	T. R. Edgecock
	EMMA - the Electron Model of Muon Acceleration - is to be built at the CCLRC Daresbury Laboratory in the UK. It will demonstrate the principle of non-scaling FFAGs and be used to study the features of this type of accelerator in detail. Although a model of the muon accelerators in a Neutrino Factory, EMMA will have sufficient flexibility to study a variety of applications. It has been designed by an international collaboration of accelerator physicists and will be built as part of the CONFORM project using funds recently approved in the UK.
	Slides

THPMN002	Nonlinear Dynamics of Electromagnetic Pulses in Cold Relativistic Plasmas	plasma, electron, resonance, radiation	2707
	A. Bonatto R. Pakter, F. B. Rizzato IF-UFRGS, Porto Alegre
	Funding: CNPq, Brasil In the present analysis we study the self consistent propagation of nonlinear electromagnetic pulses in a one dimensional relativistic electron-ion plasma, from the perspective of nonlinear dynamics. We show how a series of Hamiltonian bifurcations give rise to the electric fields which are of relevance in the subject of particle acceleration. Nonlinear coupling of plasma waves and electromagnetic pulses triggers strong chaotic dynamics which may detrap the plasma wave from the electromagnetic pulse, leading to wave breaking. Connections with results of earlier analysis are discussed.

THPMN026	C-band Linac in SCSS Prototype Accelerator of the Japanese X-FEL Project	klystron, linac, power-supply, electron	2766
	T. Inagaki H. Baba, H. Matsumoto KEK, Ibaraki A. Miura Nihon Koshuha Co., Ltd., Yokohama S. Miura MHI, Hiroshima T. Shintake, K. Shirasawa RIKEN Spring-8 Harima, Hyogo
	Funding: RIKEN-JASRI Joint-Project for SPring-8 XFEL C-band (5712-MHz) linac is used as the main accelerator of the Japanese X-FEL facility in SPring-8. Since the C-band linac has high acceleration gradient, our 8-GeV accelerator is compact rather than a conventional S-band accelerator. The system consists of following components; two choke-mode-type 1.8-m accelerating structures, an rf pulse compressor (SLED), a 50-MW klystron, a 100-MW compact modulator, and an rf digital control system. We will use 60 to 70 units for the X-FEL accelerator. Since November 2005, we have operated two C-band units in the 250-MeV FEL prototype accelerator (SCSS). After rf conditioning, the accelerating gradient was achieved to 35-MV/m. We successfully accelerated the electron beam by this gradient of electrical field. In this presentation, we will report the detail of each component and its operation status of the SCSS prototype accelerator.

THPMN027	Status of C-band Accelerator Module in the KEKB Injector Linac	linac, positron, electron, klystron	2769
	T. Kamitani T. Higo, M. Ikeda, K. Kakihara, N. Kudoh, S. Ohsawa, T. Sugimura, T. T. Takatomi, K. Yokoyama KEK, Ibaraki
	For future upgrade of the KEKB injector linac, components of C-band accelerator module have been developed since 2002. A prototype C-band accelerator module composed of a 50-MW klystron, an RF-pulse compressor and four 1-m long accelerating sections, has been constructed in the present S-band injector linac. It has been operated for 14 months. In a recent beam-acceleration study, it has achieved an energy gain of 151 MeV, which corresponds to an average acceleration field of 39 MV/m.

THPMN034	Manipulation of Electron Beam Generation with Modified Magnetic Circuit on Laser-wakefield Acceleration	electron, laser, plasma, cathode	2790
	A. Yamazaki T. Hosokai, K. Kinoshita, A. Maekawa, R. Tsujii, M. Uesaka, A. G. Zhidkov UTNL, Ibaraki
	Electron beam injection triggered by intense ultrashort laser pulses, which is called as plasma cathode, is presented. We have studied generation of relativistic electrons by interaction between a high intensity ultra-short laser pulse and gas jet. When a static magnetic field of 0.2 T is applied, the modification of the preplasma cavity, and significant enhancement of emittance and an increase of the total charge of electron beams produced by a 12 TW, 40 fs laser pulse tightly focused in a He gas jet, were observed. And very high stability and reproducibility of the characteristics and position of well-collimated electron beams was detected. Now we are planning to experiment with a magnetic circuit that has more intense magnetic field of 1 T. The present report aims at presenting these experimental and analytical results.

THPMN055	Effect of Amplification of Cherenkov Radiation in an Active Medium with Two Resonant Frequencies	radiation, plasma, resonance, laser	2829
	A. V. Tyukhtin S. N. Galyamin Saint-Petersburg State University, Saint-Petersburg
	Funding: Russian Foundation for Basic Research; Ministry of Education and Science of Russian Federation. The possibility of using an active medium to amplify the generated wakefield of an electron beam and employing the amplified wakefield to accelerate a second beam has been recognized recently. This acceleration scheme is one of several related methods referred to as the Particle Acceleration by Stimulated Emission of Radiation (PASER). However, only the case of an active medium with a single resonant frequency has been analyzed until now. In this paper we present the results of analytical and numerical studies of Cherenkov radiation (CR) in an active medium with two resonant frequencies. We show that this medium can amplify CR even in the case of a purely real refractive index. In contrast to a medium with a single resonant frequency the amplification effect takes place in the absence of metal boundaries but only for sufficiently strong restrictions on the parameters of the medium. The amplification can be effective even for a medium with a relatively small inversion. Examples of CR amplification are given for several active materials. The effect may be useful both for wakefield accelerators and Cherenkov detectors. L. Schachter, Phys. Rev., E, 62, 1252 (2000); N. V.Ivanov, A. V.Tyukhtin, Tech. Phys. Lett., 32, 449 (2006).

THPMN076	PAMELA - A Model for an FFAG based Hadron Therapy Machine	proton, ion, rfq, hadron	2880
	J. K. Pozimski R. J. Barlow UMAN, Manchester J. Cobb, T. Yokoi OXFORDphysics, Oxford, Oxon B. Cywinski University of Leeds, Leeds T. R. Edgecock STFC/RAL, Chilton, Didcot, Oxon A. Elliott Beatson Institute for Cancer Research, Glasgow M. Folkard, B. Vojnovic Gray Cancer Institute, Northwood I. S.K. Gardner STFC/RAL/ISIS, Chilton, Didcot, Oxon B. Jones University Hospital Birmingham, Edgbaston, Birmingham K. Kirkby, R. Webb UOSIBS, Guildford G. McKenna University of Oxford, Oxford K. J. Peach JAI, Oxford M. W. Poole STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	Approximately one third of the world?s 15000 accelerators are used for tumour therapy and other medical applications. Most of these are room temperature cyclotrons: a few are synchrotrons. Neither of these have ideal characteristics for a dedicated medical accelerator. The characteristics of FFAGs make them ideally suited to such applications, as the much smaller magnet size, greater compactness and variable energy offers considerable cost and operational benefits especially in a hospital setting. In the first stage the work on PAMELA will focus on the optimization of the FFAG design to deliver the specific machine parameters demanded by therapy applications. In this phase of the PAMELA project the effort will concentrate on the design of a semi-scaling type FFAGs to deliver a 450 MeV/u carbon ion beam, including detailed lattice and tracking studies. The second stage will use the existing expertise in the BASROC consortium to undertake a design of the magnets and RF system for PAMELA. An outline of the overall concept of PAMELA will be discussed and the actual status of the work will be presented.

THPMN078	The CONFORM Project: Construction of a NonScaling FFAG and its Applications	proton, hadron, radiation, extraction	2886
	R. J. Barlow N. Bliss STFC/DL, Daresbury, Warrington, Cheshire T. R. Edgecock STFC/RAL, Chilton, Didcot, Oxon N. Marks, H. L. Owen, M. W. Poole STFC/DL/ASTeC, Daresbury, Warrington, Cheshire K. J. Peach JAI, Oxford J. K. Pozimski Imperial College of Science and Technology, Department of Physics, London
	The CONFORM project, recently funded as part of the UK 'Basic Technology' initiative, will build a 20 MeV Non-Scaling FFAG (EMMA) at Daresbury. The experience gained will be used for the design of a proton machine (PAMELA) for medical research, and other applications for Non-Scaling FFAGs in different regimes will be explored. The successful development of this type of accelerator will provide many opportunities for increased exploitation, especially for hadron therapy for treatment of tumours, and the project provides a framework where machine builders will work with potential user communities to maximise the synergies and help this to happen successfully.

THPMN082	Beam Injection Into EMMA Non-scaling FFAG	injection, kicker, septum, extraction	2898
	T. Yokoi S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon
	FFAG accelerators have been getting attention as promising candidates for the muon accelerators of a neutrino factory due to their large transverse acceptance and the capability of fast particle acceleration. Non-scaling FFAGs, which are a variation of FFAGs, are nowadays being intensively studied for their simple structure and operational flexibility. To demonstrate the technical feasibility of non-scaling FFAGs and to investigate their beam dynamics, a project to construct a small electron non-scaling FFAG (EMMA) has been proposed in the UK. In EMMA the injection and extraction energies must be arbitrarily changed for a beam with emittance of 3 mm to study the beam dynamics in detail for the entire range of operating energy. In addition, in the planned machine the betatron tunes vary more than a factor of two during acceleration. The requirement of variable injection or extraction energy requires careful optimisation of the of injection elements and operational conditions. The details and design status of the scheme will be described in this paper.

THPMN088	C-Band High Power RF Generation and Extraction Using a Dielectric Loaded Waveguide	linac, insertion, extraction, vacuum	2912
	F. Gao M. E. Conde, W. Gai, R. Konecny, W. Liu, J. G. Power, Z. M. Yusof ANL, Argonne, Illinois C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio T. Wong Illinois Institute of Technology, Chicago, Illinois
	Funding: Department of Energy We report on the fabrication, simulation, and high-power testing of a C-band RF power extractor recently conducted at the Argonne Wakefield Accelerator (AWA) facility. Dielectric loaded accelerating (DLA) structures can be used for high-power RF generation [,] when a high-current electron beam passes through a DLA structure and loses energy into the modes of the structure due to self-wakefields. The AWA generates high charge (up to 100nC), short bunch length (1.5mm~2.5mm) electron beams, which is ideal for high-power RF generation. The generated RF power can be subsequently extracted with a properly designed extraction coupler in order to accelerate a second beam, or for other high power purposes. In this paper, the detailed design of a 7.8 GHz DLA power extractor, MAFIA simulations, and results of the high-power test are presented. Simulation predictions of an 79 MW, 2.2 ns long RF pulse (generated by a single 100 nC electron bunch) and a longer RF pulse of the same power (obtained from a 35 nC periodic bunch train) will be compared to experimental results. W. Gai, et al, Experimental Demonstration of Two Beam Acceleration Using Dielectric Step-up Transformer, PAC01, pp.1880-1882.** D. Yu, et al, 21GHz Ceramic RF Power Extractor, AAC02, pp.484-505.

THPMN099	Plans for a 750 MeV Electron Beam Test Facility at Fermilab	gun, electron, diagnostics, controls	2942
	M. Church S. Nagaitsev, P. Piot Fermilab, Batavia, Illinois
	A 750 MeV electron beam test facility at Fermilab is in the planning and early construction phase. An existing building is being converted for this facility. The photoinjector currently in use at the Fermilab NICADD Photoinjector Laboratory (FNPL) will be moved to the new facility and upgraded to serve as an injector for a beam acceleration section consisting of 3 Tesla or ILC-type cryomodules. A low energy off-axis beam will be constructed to test ILC crab cavity designs and provide opportunities for other tests. Downstream beamlines will consist of a diagnostic section, a beam test area for additional beam experiments, and a high power beam dump. The initial program for this facility will concentrate on testing ILC-type cryomodules and RF control with full ILC beam intensity. A future building expansion will open up further possibiliities for beam physics and beam technology experiments.

THPMN103	New Nonscaling FFAG for Medical Applications	focusing, extraction, quadrupole, synchrotron	2951
	C. Johnstone S. R. Koscielniak TRIUMF, Vancouver
	Funding: Work supported by by the Fermilab Research Association, Inc., under contract DE-AC02-76CH00300 with the U. S. Department of Energy. Fixed Field Alternating Gradient (FFAG) machines have been the subject of recent international activity due to their potential for medical applications and accelerator-based technologies. In particular, nonscaling FFAGs (where the optics are not constant and therefore do not scale with momentum) stand to offer the high current advantage of the cyclotron combined with the smaller radial aperture of the synchrotron plus variable extraction energy. Here, a hybrid design for a nonscaling FFAG accelerator has been invented which uses both edge and alternating-gradient focusing principles applied to a combined-function magnet applied in a specific configuration to stabilize tunes through an acceleration cycle which extends over a factor of 2-6 in momentum. Using normal conducting magnets, the final, extracted energy from this machine attains 400 MeV/nucleon and a normalized emittance of ~10 - 20π, and thus supports a carbon ion beam in the energy range of interest for cancer therapy.

THPMS006	Photonic Bandgap (PBG) Accelerator Structure Design	simulation, damping, higher-order-mode, lattice	3005
	R. A. Marsh M. A. Shapiro, R. J. Temkin MIT/PSFC, Cambridge, Massachusetts
	Funding: Work supported by the Department of Energy, High Energy Physics, under contract DE-FG02-91ER40648. High gradient structure design entails optimization of the gradient, while minimizing surface electric fields (associated with breakdown) and surface magnetic fields (associated with pulsed heating). Design studies are reported comparing metallic and dielectric PBG structures and standard disk-loaded waveguide. Operation in a higher order mode is considered. A variety of codes; HFSS, CST MWS, and Superfish have been used to compare and refine designs. Final design work is in preparation for a structure to be cold tested, tuned, and then processed to high gradient operation at the MIT HRC 17 GHz accelerator facility.

THPMS017	Design of Muon Accelerators for an Advanced Muon Facility	rfq, linac, proton, target	3032
	H. M. Miyadera A. J. Jason LANL, Los Alamos, New Mexico K. Nagamine UCR, Riverside, California
	Muon beams are produced at Muon Facilities all over the world. They are commonly used in condensed matter physics with mSR (Muon Spin Rotation / Relaxation / Resonance) spectroscopy. Up to today, the applications of mSR are limited by the large sizes of the muon beams (typically 10 cm²). We carried out design works of an Advanced Muon Facility at LANSCE that produces a 'muonμbeam'. The muonμbeam improves beam brightness by three orders of magnitude from that at conventional Muon Facilities and would revolutionize not only material research using mSR spectroscopy but also numerous applications in nano-technology, high-pressure science and bioscience. The designed facility mainly consists of a large acceptance muon channel 'LA Omega' followed by novel muon linear accelerators. This equipment is capable of producing the world?s most intense muon beam of ~10⁹ muon/s at LANSCE. The intense muon beam of LA Omega will be cooled and accelerated with the muon linear accelerators to produce a 50-keV and a separate 10-MeV muonμbeam. The unique time structure of the muon beam produced by the LANSCE linear accelerator optimally matches the muon accelerator.

THPMS018	High Average Current Betatrons for Industrial and Security Applications	betatron, focusing, electron, injection	3035
	S. Boucher R. B. Agustsson, P. Frigola, A. Y. Murokh, M. Ruelas RadiaBeam, Los Angeles, California F. H. O'Shea, J. B. Rosenzweig, G. Travish UCLA, Los Angeles, California
	Funding: DOE Grant DE-FG02-04ER84051 The fixed-field alternating-gradient (FFAG) betatron has emerged as a viable alternative to RF linacs as a source of high-energy radiation for industrial and security applications. For industrial applications, high average currents at modest relativistic electron beam energies, typically in the 5 to 10 MeV range, are desired for medical product sterilization, food irradiation and materials processing. For security applications, high power x-rays in the 3 to 20 MeV range are needed for rapid screening of cargo containers and vehicles. In a FFAG betatron, high-power output is possible due to high duty factor and fast acceleration cycle: electrons are injected and accelerated in a quasi-CW mode while being confined and focused in the fixed-field alternating-gradient lattice. The beam is accelerated via magnetic induction from a betatron core made with modern low-loss magnetic materials. Here we present the design and status of a prototype FFAG betatron, called the Radiatron, as well as future prospects for these machines.

THPMS023	Designing LWFA in the Blowout Regime	laser, plasma, electron, injection	3050
	W. Lu S. Fonseca, L. O. Silva, J. H. Vieira Instituto Superior Tecnico, Lisbon C. Joshi, W. B. Mori, F. S. Tsung, M. Tzoufras UCLA, Los Angeles, California
	Funding: This work was supported by DOE and NSF under grant Nos. DE-FG03-92ER40727, DE-FC02-01ER41179, DE-FG02-03ER54721, and NSF-Phy-0321345. The extraordinary ability of space-charge waves in plasmas to accelerate charged particles at gradients that are orders of magnitude greater than that in current accelerators has been well documented. We develop a phenomenological framework for Laser Wakefield Acceleration (LWFA) in the 3D nonlinear regime, in which the plasma electrons are expelled by the radiation pressure of a short pulse laser, leading to nearly complete blowout. This theory provides a recipe for designing a LWFA for given laser and plasma parameters and estimates the number and the energy of the accelerated electrons whether self-injected or externally injected. These formulas apply for self-guided as well as externally guided pulses (e.g. by plasma channels). Based on this theory, we will present scenarios on how to build a single stage accelerator with output energies from GeV to TeV. Particle-In-Cell (PIC) simulations are used to verify our theory. This work was supported by DOE and NSF under grant Nos. DE-FG03-92ER40727, DE-FC02-01ER41179, DE-FG02-03ER54721, and NSF-Phy-0321345.

THPMS027	Dielectric Wakefield Accelerator Experiments at the SABER Facility	simulation, radiation, electron, emittance	3058
	G. Travish H. Badakov, A. M. Cook, J. B. Rosenzweig, R. Tikhoplav UCLA, Los Angeles, California M. K. Berry, I. Blumenfeld, F.-J. Decker, M. J. Hogan, R. Ischebeck, R. H. Iverson, N. A. Kirby, R. Siemann, D. R. Walz SLAC, Menlo Park, California A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio P. Muggli USC, Los Angeles, California M. C. Thompson LLNL, Livermore, California
	Funding: Work supported in part by Department of Energy contracts DE-AC02-76SF00515, DE-FG02-92-ER40745, DE-FG03-92ER40693 and W-7405-ENG-48 Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC FFTB, are foreseen to be produced soon at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of >10 GV/m. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 μm and 200 μm ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in excess of 4 GV/m (2 GV/m accelerating field) in fused silica. With the construction and commissioning of the SABER facility at SLAC, new experiments are made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. The E169 collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures.

THPMS031	Plasma Wakefield Acceleration Utilizing Multiple Electron Bunches	plasma, electron, single-bunch, linac	3070
	E. K. Kallos T. C. Katsouleas, P. Muggli USC, Los Angeles, California W. D. Kimura STI, Washington P. I. Pavlishin, I. Pogorelsky, D. Stolyarov, V. Yakimenko BNL, Upton, Long Island, New York
	Funding: DoE contract # DE-FG02-92-ER40745 We investigate various plasma wakefield accelerator schemes that rely on multiple electron bunches to drive a large amplitude plasma wave, which are followed by a witness bunch at a phase where it will sample the high acceleration gradient and gain energy. Experimental verifications of various two bunch schemes are available in the literature; here we provide analytical calculations and numerical simulations of the wakefield dependency and the transformer ratio when M drive bunches and one witness bunch are fed into a high density plasma, where M is between 2 and 10. This is a favorable setup since the bunches can be adjusted such that the transformer ratio and the efficiency of the accelerator are enhanced compared to single bunch schemes. The possibility of a five bunch ILC afterburner to accelerate a witness bunch from 100 GeV to 500 GeV is also examined.

THPMS032	Plasma Wakefield Acceleration Experiments using Two Subpicosecond Electron Bunches	plasma, electron, target, inverse-free-electron-laser	3073
	P. Muggli E. K. Kallos, T. C. Katsouleas USC, Los Angeles, California W. D. Kimura STI, Washington K. Kusche, P. I. Pavlishin, D. Stolyarov, V. Yakimenko BNL, Upton, Long Island, New York
	Funding: This work is supported by US DoE under contracts DE-FG02-92-ER40745 and DE-FG02-04ER41294. Two ~100 fs electron bunches, separated in energy by approximately 1.8 MeV and in time by 0.5-1 ps, were sent through a capillary discharge plasma. The plasma density was varied from ~1·10¹⁴/cc to ~1·10¹⁷/cc. A 2-D PWFA model indicates the net wakefield produced by the bunches will depend on their relative charge, temporal separation, and the plasma density. This will affect the amount of energy gain or loss of the second bunch. During measurements of the energy spectrum of the second bunch, we observed a difference in the amount of gain or loss depending on the plasma density, which is consistent with the model prediction.

THPMS033	Scaling of Energy Gain with Plasma Parameters in a Plasma Wakefield Accelerator	plasma, ion, emittance, focusing	3076
	P. Muggli I. Blumenfeld, F.-J. Decker, M. J. Hogan, R. Ischebeck, R. H. Iverson, N. A. Kirby, R. Siemann, D. R. Walz SLAC, Menlo Park, California C. E. Clayton, C. Huang, C. Joshi, W. Lu, K. A. Marsh, W. B. Mori, M. Zhou UCLA, Los Angeles, California T. C. Katsouleas, E. Oz USC, Los Angeles, California
	Funding: This work was supported by the Department of Energy contracts DE-AC02-76SF00515, DE-FG02-92ER40727, DE-FG02-92-ER40745. DE-FG02-03ER54721, DE-FC02-01ER41179 and NSF grant Phy-0321345. Systematic measurements of energy gain as a function of plasma parameters in the SLAC electron beam-driven plasma wakefield acceleration (PWFA) experiments lead to very important understanding of the beam-plasma interaction. In particular, measurements as a function of the plasma length Lp show that the energy gain increases linearly with Lp in the 10 to 30 cm range. Based on this scaling, the plasma was subsequently lengthened to Lp=90cm, resulting in the first demonstration of the doubling of the energy of a fraction of the incoming 42GeV electrons. The peak accelerating gradient is larger than 40GV/m and is sustained over meter-scale plasma lengths. These measurements also reveal that the optimum plasma density for acceleration is about 2.7·10¹⁷/cc, larger than the value predicted by the linear theory for the approximately 20 microns bunch length, confirming that the experiment is conducted in the non-linear regime of the PWFA. Detailed experimental results will be presented. "Energy doubling of 42 GeV electrons in a meter scale plasma wakefield accelerator", I. Blumenfeld et. al., Nature, 2006, accepted

THPMS050	Designing Photonic Bandgap Fibers for Particle Acceleration	lattice, vacuum, emittance, impedance	3103
	R. J. Noble E. R. Colby, B. M. Cowan, C. M.S. Sears, R. Siemann, J. E. Spencer SLAC, Menlo Park, California
	Funding: Supported by U. S. Dept. of Energy contract DE-AC02-76SF00515 Photonic bandgap (PBG) fibers with hollow core defects have been suggested for use as laser driven accelerator structures. The modes of a periodic PBG fiber lie in a set of allowed bands. A fiber with a central vacuum defect can support so-called defect modes with frequencies in the bandgap and electromagnetic fields confined spatially near the central defect. A defect mode suitable for relativistic particle acceleration must have a longitudinal electric field in the central defect and a phase velocity near the speed of light (SOL). We explore the design of the defect geometry to support well-confined accelerating modes in such PBG fibers. The details of the surface boundary separating the defect from the surrounding matrix are found to be the critical ingredients for optimizing the accelerating mode properties. We give examples of improved accelerating modes in fiber geometries with modified defect surfaces.

THPMS059	Correlating Pulses from Two Spitfire, 800nm Lasers	laser, photon, electron, background	3121
	W. D. Zacherl E. R. Colby, C. Mcguinness SLAC, Menlo Park, California T. Plettner Stanford University, Stanford, Califormia
	Funding: Department of Energy contracts DE-AC02-76SF00515, DE-FG03-97ER41043-III The E163 laser acceleration experiments conducted at SLAC have stringent requirements on the temporal properties of two regeneratively amplified, 800nm, Spitfire laser systems. To determine the magnitude and cause of timing instabilities between the two Ti:Sapphire amplifiers, we pass the two beams through a cross-correlator and focus the combined beam onto a Hamamatsu G1117 photodiode. The photodiode has a bandgap such that single photon processes are suppressed and only the second order, two-photon process produces an observable response. The response is proportional to the square of the intensity. The diode is also useful as a diagnostic to determine the optimal configuration of the compression cavity. Yoshihiro Takagi et al, 'Multiple- and Single-shot autocorrelator based on two-photon conductivity in semiconductors.' Optics Letters, Vol. 17, No. 9, May 1, 1992.

THPMS073	Progress towards a Gap Free Dielectric-Loaded Accelerator	coupling, vacuum, impedance, simulation	3151
	C.-J. Jing S. H. Gold NRL, Washington, DC A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio S. Kazakov KEK, Ibaraki R. Konecny, J. G. Power ANL, Argonne, Illinois
	One of the major concerns in the development of Dielectric-Loaded Accelerating (DLA) structures is the destructive breakdown at dielectric joints caused by a local electric field enhancement induced by the discontinuity of the dielectric constant on the surface of the joint gap. Our previous X-band traveling wave DLA structure design, for example, incorporated two separate impedance matching sections with at least two dielectric joints. In this paper, we present a new design to avoid this problem. This scheme is based on a coaxial type coupler which is able to implement mode conversion and impedance matching at the same time and therefore to eliminate joint gap induced breakdown. The new structure is under construction; bench test results will be presented C. Jing, W. Gai, J. Power, R. Konecny, S. Gold, W. Liu and A. Kinkead, IEEE, Trans. PS, vol.33 No.4, Aug. 2005, pp.1155-1160.

THPMS077	Progress towards Development of a Diamond-Based Cylindrical Dielectric Accelerating Structure	plasma, impedance, vacuum, controls	3163
	A. Kanareykin M. E. Conde, W. Gai ANL, Argonne, Illinois R. Gat Coating Technology Solution, Inc., Somerville C.-J. Jing, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio
	Funding: This research is supported by the US Department of Energy In this talk, we present our recent developments on a high gradient diamond-based cylindrical dielectric loaded accelerator (DLA). The final goal of this research is to achieve a record accelerating gradient (~ 600 MV/m) in a demonstration of the structure at high power and with accelerated beam. We discuss here a new technology for the development of cylindrical diamond-based waveguides and the design, fabrication and high power testing of a cylindrical diamond-based DLA accelerating structure. The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators: high RF breakdown level, extremely low dielectric losses and the highest thermoconductive coefficient available. Multipacting of the CVD diamond can be suppressed by diamond surface dehydrogenation. A plasma supported Chemical Vapor Deposition (CVD) technology to produce low loss high quality cylindrical diamond layers is presented. Special attention is devoted to the numerical optimization of the coupling section, where the surface magnetic and electric fields are minimized relative to the accelerating gradient and within known metal surface breakdown limits.

THPMS078	Status of the Microwave PASER Experiment	dipole, electron, permanent-magnet, resonance	3166
	P. Schoessow S. P. Antipov, M. E. Conde, W. Gai, J. G. Power ANL, Argonne, Illinois E. Bagryanskaya International Tomography Center, SB RAS, Novosibirsk V. Gorelik, A. Kovshik, A. V. Tyukhtin, N. Yevlampieva Saint-Petersburg State University, Saint-Petersburg A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio L. Schachter Technion, Haifa
	Funding: Work supported by US Department of Energy The PASER is a new method for particle acceleration, in which energy from an active medium is transferred to a charged particle beam. The effect is similar to the action of a maser or laser with the stimulated emission of radiation being produced by the virtual photons in the electromagnetic field of the beam. We are developing a demonstration PASER device operating at X-band, based on the availability of a new class of active materials that exhibit photoinduced electron spin polarization. We will report on the status of active material development and measurements, numerical simulations, and preparations for microwave PASER experiments at the Argonne Wakefield Accelerator facility.

THPMS079	Nonlinear Permittivity Effects in Dielectric Accelerating Structures	controls, diagnostics, linac, simulation	3169
	P. Schoessow A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio V. P. Yakovlev Omega-P, Inc., New Haven, Connecticut
	Funding: Work supported by the US Department of Energy New low loss ferroelectric ceramic materials* possessing large variations in the permittivity as a function of the electric field present interesting and potentially useful applications for dielectric loaded accelerating structures, both wakefield-based and driven by an external rf source. We will consider X-band cylindrical dielectric structures and report numerical results on frequency multiplication, wave steepening and shock formation, and the effect of nonlinearities on the mode structure of these devices. We will examine applications of nonlinear dielectric devices to high gradient acceleration, rf sources, and beam diagnostics. * ''Fast Switching Ferroelectric Materials for Accelerator Applications'', A. Kanareykin et al., Proceedings of Advanced Accelerator Concepts 2006 (in press)

THPMS080	Inverse-Transition Radiation Laser Acceleration Experiments at SLAC	laser, electron, radiation, vacuum	3172
	T. Plettner R. L. Byer Stanford University, Stanford, Califormia E. R. Colby, R. Ischebeck, C. Mcguinness, R. J. Noble, C. M.S. Sears, R. Siemann, J. E. Spencer, D. R. Walz SLAC, Menlo Park, California
	We present a series of laser-driven particle acceleration experiments that are aimed at studying laser-particle acceleration as an inverse-radiation process. To this end we employ a semi-open vacuum setup with a thin planar boundary that interacts with the laser and the electromagnetic field of the electron beam. Particle acceleration from different types of boundaries will be studied and compared to the theoretical expectations from the Inverse-radiation picture and the field path integral method. We plan to measure the particle acceleration effect from transparent, reflective, black, and rough surface boundaries. While the agreement between the two acceleration pictures is straightforward to prove analytically for the transparent and reflective boundaries the equivalence is not clear-cut for the absorbing and rough-surface boundaries. Therefore, experimental observation may be the most reliable method for establishing the appropriate model for the interaction of the laser field with the particle beam in the presence of a loaded vacuum structure.

THPMS082	Muon Acceleration to 750 GeV in the Tevatron Tunnel for a 1.5 TeV mu+ mu- Collider	dipole, lattice, quadrupole, emittance	3178
	D. J. Summers L. M. Cremaldi, R. Godang, B. R. Kipapa, H. E. Rice UMiss, University, Mississippi R. B. Palmer BNL, Upton, Long Island, New York
	Funding: Work supported by DE-FG02-91ER40622 and DE-AC02-98CH10886. Muon acceleration from 30 to 750 GeV in 72 orbits using two rings in the 1000m radius Tevatron tunnel is explored. The first ring ramps at 400 Hz and accelerates muons from 30 to 400 GeV in 28 orbits using 14 GV of 1.3 GHz superconducting RF. The ring duplicates the Fermilab 400 GeV main ring FODO lattice, which had a 61m cell length. Muon survival is 80%. The second ring accelerates muons from 400 to 750 GeV in 44 orbits using 8 GV of 1.3 GHz superconducting RF. The 30 T/m main ring quadrupoles are lengthened 87% to 3.3m. The four main ring dipoles in each half cell are replaced by three dipoles which ramp at 550 Hz from -1.8T to +1.8T interleaved with two 8T fixed superconducting dipoles. The ramping and superconducting dipoles oppose each other at 400 GeV and act in unison at 750 GeV. Muon survival is 92%. Two mm copper wire, 0.28mm grain oriented silicon steel laminations, and a low duty cycle mitigate eddy current losses. Low emittance muon bunches allow small aperatures and permit magnets to ramp with a few thousand volts. Little civil construction is required. The tunnel exists.

THPMS083	The EMMA Lattice Design	lattice, resonance, quadrupole, longitudinal-dynamics	3181
	J. S. Berg S. R. Koscielniak TRIUMF, Vancouver S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon A. G. Ruggiero BNL, Upton, Long Island, New York
	Funding: Work Supported by the United States Department of Energy, Contract No. DE-AC02-98CH10886. EMMA is a 10 to 20 MeV electron ring designed to test our understanding of beam dynamics in a relativistic linear non-scaling fixed field alternating gradient accelerator (FFAG). This paper describes the design of the EMMA lattice. We begin with a description of the experimental goals that impact the lattice design. We then describe what motivated the choice for the basic lattice parameters, such as the type of cells, the number of cells, and the RF frequency. We next list the different configurations that we wish to operate the machine in so as to accomplish our experimental goals. Finally, we enumerate the detailed lattice parameters, showing how these parameters result from the various lattice configurations.

THPMS093	Muon Acceleration with the Racetrack FFAG	extraction, injection, lattice, betatron	3202
	D. Trbojevic
	Funding: Supported by the U. S. Department of Energy under Contract No. DE-AC02-98CH10886. Muon acceleration for muon collider or neutrino factory is still in the stage where further improvements are likely as a result of further study. This report presents a design of the racetrack non-scaling Fixed Field Alternating Gradient (NS-FFAG) accelerator to allow fast muon acceleration in small number of turns. The racetrack design is made of four arcs: two arcs at opposite sides have a smaller radius and are made of closely packed combined function magnets, while two additional arcs with a very large radius are used for muon extraction, injection, and RF accelerating cavities. The ends of the large radii arcs are geometrically matched at the connections to the arcs with smaller radii. The dispersion and both horizontal and vertical amplitude functions are matched at the central energy.

THPMS094	Acceleration of Electrons with the Racetrack Non-Scaling FFAG for e-RHIC	linac, betatron, electron, lattice	3205
	D. Trbojevic I. Ben-Zvi, J. S. Berg, M. Blaskiewicz, V. Litvinenko, W. W. MacKay, V. Ptitsyn, T. Roser, A. G. Ruggiero BNL, Upton, Long Island, New York
	Funding: Supported by the U. S. Department of Energy under Contract No. DE-AC02-98CH10886 Acceleration of electrons up to 10 GeV for a future electron-ion collider eRHIC (Relativistic Heavy Ion Collider) could be performed with the energy recovery linac with multiple passes. An energy recovery scheme is required if a superconducting linac is used for acceleration. We report on an attempt to make a combination of a multi-pass linac with non-scaling Fixed Field Alternating Gradient (NS-FFAG) arcs. Two NS-FFAG arcs would allow electrons to pass through the same structure with different energies. The beam will be accelerated by the superconducting linac at the top of the sine function, and returned to the front of the linac by the non-scaling FFAG. This process is repeated until the total energy of 10 GeV is reached. After collisions the beam is brought back by the NS-FFAG and decelerated before being dumped.

THPMS097	Laser Plasma Acceleration Experiment at the Naval Research Laboratory	electron, laser, plasma, injection	3214
	D. Kaganovich D. F. Gordon, A. Ting NRL, Washington, DC
	The traditional long term strategy for producing high quality electron beams in a single stage LWFA involves three elements: operation in the resonant or standard regime, the use of optical guiding to extend the acceleration region, and external injection of a precisely-phased, high quality injection electron bunch. The standard regime and optical guiding has been studied by many research groups and promise good results for the acceleration. The creation of the electron beam for external injection is still a very problematic issue. Recently, quasi-monoenergetic acceleration of particles from the background plasma has been observed in simulations and experiments operating in a shorter pulse regime. Such quasi-monoenergetic electrons could be a candidate for injection into a following stage of standard LWFA. We are in the initial stage of experiments to generate injection electrons using the HD-LIPA schemes with a 10 TW 50 fs laser system. The second stage accelerator is a capillary discharge plasma channel for extended acceleration distance. Preliminary results, including statistics on the stability of quasi-monoenergetic acceleration, will be presented.

THPAN022	Conceptual Studies of the EUROTRANS Front-End	rfq, linac, emittance, beam-losses	3274
	C. Zhang M. Busch, H. Klein, H. Podlech, U. Ratzinger IAP, Frankfurt am Main
	Funding: Work supported by European Commission (contract number: FI6W-CT-2004-516520) EUROTRANS (EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in an Accelerator Driven System) is calling for an efficient high-current CW front-end accelerator system. A combination of RFQ, normal conducting CH^- (Crossbar H-mode) and super-conducting CH-DTL which aims to work at 352MHz and accelerate a 30mA proton beam to 17MeV has been studied as a promising candidate. The preliminary conceptual study results are reported with respect to beam dynamics design.

THPAN032	Study of the Beam Dynamics in a Linac with the Code RETAR	electron, radiation, emittance, diagnostics	3298
	A. R. Rossi A. Bacci, C. Maroli, L. Serafini INFN-Milano, Milano V. Petrillo Universita' degli Studi di Milano, Milano
	The three-dimensional fully relativistic and self-consistent code RETAR has been applied to model the dynamics of high-brightness electron beams and in particular to assess the importance of the retarded radiative part of the emitted electromagnetic fields in all conditions where the electrons experience strong accelerations. In this analysis we evaluate the radiative energy losses in the electron emission process from the photocathode of an injector, during the successive acceleration of the electron beam in the RF cavity and the focalization due to the magnetic field of the solenoid, taking also into account the e.m. field of the laser illuminating the cathode and the inhomogeneities on the cathode surface. The analysis is specifically carried out with parameters of importance in the framework of the SPARC and PLASMONX projects.

THPAN039	Space Charge Effects for JPARC Main Ring	injection, resonance, sextupole, space-charge	3315
	A. Y. Molodozhentsev T. Koseki, M. Tomizawa KEK, Ibaraki
	The JPARC Main Ring should provide the beam power up to 0.8MW at the maximum energy of 50GeV. According to the basic operation scenario during the injection period 8 bunches with the maximum bunch power up to 100kW should be created around the ring. In frame of this report we present the space charge effects in combination with the nonlinear resonances, caused by the machine imperfection, for different beam intensities and different machine operation scenario, including the Main Ring RF system, the collimator system of the RCS-MR beam line and the MR collimation system. The measured field data for main magnets of the ring has been taken into account for this study.

THPAN040	Study of Halo Formation in JPARC-MR	emittance, simulation, beam-losses, space-charge	3318
	K. Ohmi S. Igarashi, H. Koiso, T. Koseki, K. Oide KEK, Ibaraki
	JPARC is a high intensity proton facility which is constructing as a joint project JAERI-KEK in Japan. JPARC equips two proton ring accelerators, Rapid Cycle Synchrotron (RCS) and Main Ring (MR). We discuss the space charge effect of MR in this paper. The proton beam with the population of 4.15·10¹³ x 8 bunches is accelerated from 3 GeV to 50 GeV and extracted with 0.5 Hz in MR. Beam loss during the acceleration is caused by an incoherent emittance growth due to the space charge force. We discuss the emittance growth and halo formation using a computer simulation based on the particle in cell method.

THPAN082	Implementation of Spread Mass Model of Ion Hose Instability in Lamda	ion, simulation, induction, 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.

THPAS011	Investigation of Residual Vertical Intrinsic Resonances with Dual Partial Siberian Snakes in the AGS	resonance, polarization, betatron, emittance	3534
	F. Lin L. Ahrens, M. Bai, K. A. Brown, E. D. Courant, J. Glenn, H. Huang, A. U. Luccio, W. W. MacKay, T. Roser, N. Tsoupas BNL, Upton, Long Island, New York S.-Y. Lee IUCF, Bloomington, Indiana
	Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, No. DE-FG02-92ER40747, NSF PHY-0552389, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA) Two partial helical dipole snakes were found to be able to overcome all imperfection and intrinsic spin resonances provided that the vertical betatron tunes were maintained in the spin tune gap near the integer 9. Recent vertical betatron tune scan showed that the two weak resonances at the beginning of the acceleration cycle may be the cause of polarization loss. This result has been confirmed by the vertical polarization profile measurement, and spin tracking simulations. Possible cure of the remaining beam polarization is discussed.

THPAS020	3D Simulations of Secondary Electron Generation and Transport in a Diamond Amplifier for Photocathodes	electron, scattering, simulation, lattice	3555
	D. A. Dimitrov I. Ben-Zvi, X. Chang, T. Rao, J. Smedley, Q. Wu BNL, Upton, Long Island, New York D. L. Bruhwiler, R. Busby, J. R. Cary Tech-X, Boulder, Colorado
	The Relativistic Heavy Ion Collider (RHIC) contributes fundamental advances to nuclear physics by colliding a wide range of ions. A novel electron cooling section, which is a key component of the proposed luminosity upgrade for RHIC, requires the acceleration of high-charge electron bunches with low emittance and energy spread. A promising candidate for the electron source is the recently developed concept of a high quantum efficiency photoinjector with a diamond amplifier. We have started to implement algorithms, within the VORPAL particle-in-cell framework, for modeling of secondary electron and hole generation, and for charge transport in diamond. The algorithms include elastic and various inelastic scattering processes over a wide range of charge carrier energies. Initial results from the implemented capabilities will be presented and discussed. The work at Tech-X Corp. is supported by the U. S. Department of Energy under a Phase I SBIR grant.

THPAS054	QUINDI - A Code to Simulate Coherent Emission from Bending Systems	radiation, electron, lattice, diagnostics	3612
	D. Schiller S. Reiche, M. Ruelas UCLA, Los Angeles, California
	With this, we present a newly developed code, QUINDI, to address the numerical challenge of calculating the radiation spectra from electron bunches in bending magnet systems. This provides a better tool for designing diagnostic systems such as bunch length monitors in magnetic chicanes. The program calculates emission on a first principle basis, combining the dominant emission processes in a bending magnet system - edge and synchrotron radiation. The core algorithm is based on the Lienard-Wiechert potential and utilizes parallel computer architecture to cover complete electron beam distributions with a high resolution spatial grid. The program is aimed towards long frequency components to model the coherence level of the emitted radiation from the electron bunch.

THPAS055	Long Time Electron Cloud Instability Simulation Using QuickPIC With Pipelining Algorithm	simulation, electron, plasma, betatron	3615
	B. Feng V. K. Decyk, C. Huang, W. B. Mori UCLA, Los Angeles, California T. C. Katsouleas, P. Muggli USC, Los Angeles, California
	Funding: This work was supported by the Department of Energy contract DE-FG02-92-ER40745 We proposed a novel algorithm, which uses pipelining to reduce the simulation time for beam-electron cloud interaction. In the pipelining algorithm the processors are divided into subgroups, and during the simulation different groups will be on consecutive time steps. The pipelining algorithm is applied to the fully parallelized Particle-In-Cell (PIC) code QuickPIC to overcome the limit of the number of processors that can be used at each time step. With the new algorithm, the accuracy of the simulation is preserved; and the speed of the simulation is improved by a factor proportional to the number of processors available. The long term beam evolution results for the CERN-LHC and the FNAL main injector are presented using the QuickPIC with pipelining algorithm.

THPAS064	e^-/e⁺ Accelerating Structure with Cyclical Variation of Azimuth Asymmetry	focusing, gun, emittance, space-charge	3633
	A. Krasnykh
	Funding: Work supported by the U. S. Department of Energy under contract number DE-AC03-76SF00515 A classical electron/positron accelerating structure is a disk loaded cylindrical waveguide. The accelerator structure here has azimuth symmetry. The proposed structure contains a disk-loaded cylindrical waveguide where there is a periodical change of rf-field vs. azimuth. The modulation deforms the rf-field in such a manner that the accelerated particles undergo transverse focusing forces. The new class of accelerator structures covers the initial part of e⁺/e^- linacs where a bunch is not rigid and additional transverse focusing fields are necessary. We discuss a bunch formation with a high transverse aspect ratio in the proposed structure and particularly in the photoinjector part of a linac.

THPAS086	Beam Emittance Simulations for a High Gradient Pulsed DC/RF Gun	gun, emittance, simulation, electron	3684
	P. Chen R. Yi, D. Yu DULY Research Inc., Rancho Palos Verdes, California
	Funding: Work supported by DOE SBIR Grant No. DE-FG02-03ER83878. One of the most important targets for building modern particle accelerators is to increase the beam brightness. The purposes of building a dc/rf gun are to seek high bunch charge and low beam transverse emittance, two key parameters for enhancing brightness of accelerators. We present simulation results of the beam emittance changes in a dc/rf gun under different gun voltages. SUPERFISH and PARMELA were used to simulate the beam dynamics in the gun. These simulations indicate that a small beam transverse emittance (< 0.5 mm.mrad) can be obtained when the voltage on the dc gap is lower than 200 kV and the bunch charge is 200 pc, and increments of dc gap voltages will greatly improve the emittances.

THPAS103	Design of a Thin Quadrupole to be Used in the AGS Synchrotron	quadrupole, multipole, sextupole, simulation	3723
	N. Tsoupas L. Ahrens, R. Alforque, M. Bai, K. A. Brown, E. D. Courant, J. Glenn, H. Huang, A. K. Jain, W. W. MacKay, M. Okamura, T. Roser, S. Tepikian BNL, Upton, Long Island, New York
	Funding: Work supported by the US Department of Energy The AGS synchrotron employs two partial helical snakes* to preserve the polarization of the proton beam during acceleration in the AGS. The effect of the helical snakes on the beam optics is significant at injection energy, with the effect greatly diminishing early in the acceleration cycle. In order to compensate for the effect of the snakes on the beam optics, we have introduced eight compensation quadrupoles in straight sections of the AGS at the proximity of the partial snakes. At injection the strength of these eight quads is set at a high value but ramped down to zero when the effect of the snakes diminishes. Four of the compensation quadrupoles had to be placed in very short straight sections therefore had to be 'thin' with a length of ~30 cm. The 'thin' quadrupoles were laminated and designed to minimize the strength of the dodecoupole harmonic. The thickness of the lamination was also calculated** to keep the ohmic losses generated by the eddy currents in the laminations below an acceptable limit. Comparison of the measured and calculated harmonics will be presented and the ohmic losses due to the eddy currents, as a function of time during rumping will be discussed. * H. Huang, et al., Proc. EPAC06, (2006), p. 273.** OPERA computer code. Vector Fields Inc.

FROBC01	30 GHz High-Gradient Accelerating Structure Test Results	linac, electron	3818
	J. A. Rodriguez H. Aksakal, Z. Nergiz Ankara University, Faculty of Sciences, Tandogan/Ankara G. Arnau-Izquierdo, R. Corsini, S. Doebert, R. Fandos, A. Grudiev, I. Syratchev, M. Taborelli, F. Tecker, P. Urschutz, W. Wuensch CERN, Geneva M. A. Johnson UU/ISV, Uppsala O. M. Mete Ankara University, Faculty of Engineering, Tandogan, Ankara
	The CLIC study is high power testing accelerating structures in a number of different materials and accelerating structure designs to understand the physics of breakdown, determine the appropriate scaling of performance and in particular to find ways to increase achievable accelerating gradient. The most recent 30 GHz structures which have been tested include damped structures in copper, molybdenum, titanium and aluminum. The results from these new structures are presented and compared to previous ones to determine dependencies of quantities such as achievable accelerating gradient, pulse length, power flow, conditioning rate and breakdown rate.
	Slides

FRZKI04	Plasma Accelerators - Progress and the Future	plasma, electron, laser, injection	3845
	C. Joshi
	In recent months plasma accelerators have set new records: The first laser wakefield accelerator to demonstarte near GeV beam with large charge and good beam quality in a table-top device at LBNL, and the energy-doubling of the SLAC beam in a short plasma channel by the plasma wakefield acceleration technique. These two events, happening at two different laboratories signifies a coming of age of advanced accelerator R&D.
	Slides

FRPMN010	Emittance Measurements at the 100 keV Beam Stage of the Injector Linac of the IFUSP Microtron	emittance, linac, microtron, cathode	3898
	T. F. Silva A. A. Malafronte, M. N. Martins USP/LAL, Sao Paulo
	Funding: Work supported by FAPESP and CNPq In this work we describe the determination of the beam emittance for the 100-keV injector of the IFUSP racetrack microtron. We measured the beam spot diameter at a fluorescent screen located 40 cm after a 3-mm diameter collimator (placed at the entrance to the first chopper cavity). A solenoid lens located upstream to the collimator was used to produce a beam waist at the fluorescent screen position. We used the collimator and the beam waist sizes to calculate the emittance for 80 and 90 keV beams. Results showed no dependence with energy, indicating that the collimator is limiting the beam emittance at 2.32(5) ??mm?mrad.

FRPMN033	Adiabatic Damping During Acceleration in the Induction Synchrotron	synchrotron, damping, induction, 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.

FRPMN070	Controlled Longitudinal Emittance Blow-up in the CERN PS	emittance, injection, simulation, quadrupole	4186
	H. Damerau M. Morvillo, E. N. Shaposhnikova, J. Tuckmantel, J.-L. Vallet CERN, Geneva
	The longitudinal emittance of the bunches in the CERN PS must be increased before transition crossing to avoid beam loss due to a fast vertical instability. This controlled blow-up is essential for all high-intensity beams in the PS, including those for transfer to the LHC. The higher harmonic 200 MHz RF system (six cavities) used for this blow-up has to generate a total RF voltage which, for the most demanding blow-up, is comparable to the voltage of the main RF cavities. The system is presently subject to a major upgrade and a possible reduction in the number of higher harmonic RF cavities installed is under consideration. To determine the minimum required, detailed simulations and machine development studies to optimize the longitudinal blow-up have been performed. Further options to produce the required longitudinal emittance using other RF systems are also analyzed. The results obtained for the different scenarios for the longitudinal blow-up are presented and compared in this paper.

FRPMS022	Progress on Modeling of Ultrafast X-Ray Streak Cameras	electron, simulation, cathode, space-charge	3961
	G. Huang J. M. Byrd, J. Feng, J. Qiang, W. Wan LBNL, Berkeley, California
	Streak cameras continue to be useful tools for studying ultra phenomena on the sub-picosecond time scale and beyond. We have employed accelerator modeling tools to understand the key parts of the streak camera in order to improve the time resolution. This effort has resulted in an start-to-end model of the camera including a dedicated 3D modeling of time-dependent fields. This model has contributed to the recent achievement of 230 fsec (FWHM) resolution measured using 266 nm laserat the Advanced Light Source Streak Camera Laboratory. We will report on our model and its comparison with experiments. We also extrapolate the performance of this camera including several possible improvements.

FRPMS025	Streak Camera Temporal Resolution Improvement Using a Time-Dependent Field	electron, cathode, space-charge, laser	3973
	J. Qiang J. M. Byrd, J. Feng, G. Huang LBNL, Berkeley, California
	Funding: This work was supported by the U. S. Department of Energy under Contract no. DE-AC02-05CH11231. Streak camera is an important diagnostic device in the studies of laser plasma interaction, the detailed structure of photo reaction from material science to biochemistry, and in the measurement of the longitudinal distribution of a beam in accelerators. In this paper, we report on a new method which can potentially improve the temporal resolution of a streak camera down to femtoseconds. This method uses a time-dependent acceleration field to defocus the photo electrons longitudinally. This not only reduces the time dispersion distortion caused by initial energy spread but also mitigates the effects from the space-charge forces. An illustration of the method shows significant improvement of the modulation transfer function (MFT) compared with the conventional design.

FRPMS067	Energy Measurement in a Plasma Wakefield Accelerator	plasma, electron, radiation, linac	4168
	R. Ischebeck M. K. Berry, I. Blumenfeld, F.-J. Decker, M. J. Hogan, R. H. Iverson, N. A. Kirby, R. Siemann, D. R. Walz SLAC, Menlo Park, California C. E. Clayton, C. Huang, C. Joshi, W. Lu, K. A. Marsh, W. B. Mori, M. Zhou UCLA, Los Angeles, California T. C. Katsouleas, P. Muggli, E. Oz USC, Los Angeles, California
	Funding: DOE DE-AC02-76SF00515 (SLAC), DE-FG02-92-ER40745, DE-FG03-92ER40745, DE-FC02-01ER41179, DE-FG03-92ER40727, DE-FG02-03ER54721, DE-F52-03NA00065:A004, DE-AC-0376SF0098, NSF ECS-9632735, NSF-Phy-0321345 Particles are leaving the meter-long plasma wakefield accelerator with a large energy spread. To determine the spectrum of these particles, four diagnostics have been set up. These were used to determine energies of the particles that gain energy in the plasma, those that lose energy by driving the wake and the self-injected particles that are accelerated from rest.

FRPMS082	Precise Calculation of Traveling-Wave Periodic Structure	emittance, dipole, synchrotron, higher-order-mode	4249
	L. Wang Z. Li, A. Seryi SLAC, Menlo Park, California
	Funding: Work supported by the U. S. Department of Energy under contract DE-AC02-76SF00515 The effects of the round edge beam hole on the frequency and wake field are studied using variational method, which allows for rounded iris disk hole without any approximation in shape treatment. The frequency and wake field of accelerating mode and dipole mode are studied for different edge radius cases, including the flat edge shape that is often used to approximately represent the actual structure geometry. The edge hole shape has weak effect on the frequency, but much effect on the wake field. Our study shows that the amounts of wake fields are not precise enough with the assumption of the flat edge beam hole instead of round edge.