• L. R. Evans
  

• S. Henderson
  

The Spallation Neutron Source (SNS) will be the world's leading pulsed neutron source, with design beam power capability of 1.4 MW. The SNS Construction Project was completed in June 2006. The accelerator complex was successfully commissioned during the construction phase of the project in seven discrete commissioning runs. The facility is now in the first of a three year performance ramp-up phase, in which the beam power, reliability and operating time will be increased to the baseline design values of 1.4 MW, 90% and 5000 hours respectively. Meanwhile, neutron scattering instruments are being constructed and commissioned in preparation for full user operations in 2009. The progress toward bringing the SNS to its full capabilities will be presented.

• Z. Zhao
  

• P. Raimondi
  

• J. Q. Wang
  
• L. Ma, C. Zhang
  IHEP Beijing, Beijing

• M. E. Biagini
  
• D. Alesini, D. Babusci, R. Boni, M. Boscolo, F. Bossi, B. Buonomo, A. Clozza, G. O. Delle Monache, T. Demma, G. Di Pirro, A. Drago, A. Gallo, S. Guiducci, C. Ligi, F. Marcellini, G. Mazzitelli, C. Milardi, F. Murtas, L. Pellegrino, M. A. Preger, L. Quintieri, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, G. Sensolini, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Zobov
  INFN/LNF, Frascati (Roma)
• S. Bettoni
  CERN, Geneva
• I. Koop, E. Levichev, P. A. Piminov, D. N. Shatilov, V. V. Smaluk
  BINP SB RAS, Novosibirsk
• K. Ohmi
  KEK, Ibaraki

*DAPHNE Upgrade Team, "DAPHNE Upgrade for Siddharta run", DAPHNE Tech. Note G-68, LNF-INFN, Dec. 2006

• M. Eriksson
  
• M. Berglund, M. Brandin, D. Kumbaro, P. Lilja, L.-J. Lindgren, L. Malmgren, M. Sjostrom, S. Thorin, E. J. Wallen, S. Werin
  MAX-lab, Lund
• H. Tarawneh
  SESAME, Amman

• P. F. Tavares
  
• F. Arroyo, R. H.A. Farias, L. C. Jahnel, C. Pardine, C. Rodrigues
  LNLS, Campinas

• U. B. Blell
  
• A. V. Batrakov, S. A. Onischenko, G. E. Ozur
  Institute of High Current Electronics, Tomsk
• J. Florenkowski, U. Kopf, C. Muehle, M. Petryk, I. J. Petzenhauser, P. J. Spiller
  GSI, Darmstadt

• F. Ludwig
  
• B. Lorbeer, H. Schlarb, A. Winter
  DESY, Hamburg

The next generation of FEL's (Free Electron Lasers) require a long and short term stable synchronisation of RF reference signals with an accuracy of 10 fs. For that an optical synchronisation system is developed for FLASH at DESY, that is based on optical pulse train which carry the timing information encoded in its precise repetition rate. The optical pulse train has to be converted into an RF signal to provide a local reference for calibration and operation of RF based devices. The drift and jitter performance of the optical to RF converter influences directly the phase stability of the accelerator. Three different methods for optical to RF converters, namely the direct photodiode detection, injection locking and a sagnac loop interferometer are currently under investigation. In this paper we concentrate on the jitter and drift performance of the direct photodiode conversion and show its limitations from measurement results.

• I. Birkel
  
• E. Huttel, A.-S. Muller, P. Wesolowski
  FZK, Karlsruhe

• 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

• W. X. Cheng
  
• T. Obina
  KEK, Ibaraki

• K. Fan
  
• H. Kobayashi, H. Matsumoto, Y. Sakamoto
  KEK, Ibaraki

• K. Fan
  
• Y. Arakaki, I. Sakai
  KEK, Ibaraki

• Y. Kobayashi
  
• K. Harada, T. Honda, T. Miyajima, S. Nagahashi
  KEK, Ibaraki
• N. Nakamura, H. Takaki
  ISSP/SRL, Chiba

• I. Sugai
  
• T. Hattori, K. K. Kawasaki
  Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo
• Y. Irie
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• H. Kawakami, M. Oyaizu, A. Takagi, Y. Takeda
  KEK, Ibaraki

• S. Varnasseri
  
• M. M. Shehab, G. Vignola
  SESAME, Amman

• Y. L. Yang
  
• Y. B. Chen, L. J. Huang, W. Li, L. Liu, B. Sun, J. H. Wang, K. Zheng, Z. R. Zhou
  USTC/NSRL, Hefei, Anhui

• K. Zheng
  
• Y. B. Chen, L. J. Huang, W. Li, L. Liu, B. Sun, J. H. Wang, L. Wang, Y. L. Yang, Z. R. Zhou
  USTC/NSRL, Hefei, Anhui

In this paper, HLS (Hefei light Source) bunch-by-bunch measurement and feedback system will be introduced. This system is integrated with longitudinal oscillation measurement system, fast vector control, fiber notch filter and bunch current detection system. The detail of the two fronts will be shown. Some experimental results by this system are also present in this paper, as phase-space tracing, mode dumping rate, and feedback experiments.

• S. Redaelli
  
• R. W. Assmann, P. Gander, M. Jonker, M. Lamont, R. Losito, A. Masi, M. Sobczak
  CERN, Geneva

• C.-K. Chang
  
• H. C. Chen, M. J. Horng, J. A. Li, T. F. Lin, Y. K. Lin, Y.-C. Liu
  NSRRC, Hsinchu

• K. T. Hsu
  
• J. Chen, P. C. Chiu, S. Y. Hsu, K. H. Hu, C. H. Kuo, D. Lee
  NSRRC, Hsinchu

• N. Marks
  
• B. J.A. Shepherd
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

• G. Feng
  
• B. Deriy, J. Wang
  ANL, Argonne, Illinois

Due to the circuit topology of ramping power supplies used in the APS Booster ring, they are unable to follow the linear current ramp to the desired accuracy of 0.1%. In addition, those supplies are also sensitive to AC line perturbation. To improve the performance, a linear regulator using paralleled MOSFET devices in series with the power supply is proposed. The control algorithm uses a real-time current feedback loop to force the MOSFETs to work in the linear operation mode. By using this linear MOSFET regulator, the MOSFETs' drain to source voltage, and hence the voltage imposed on magnets can be regulated very quickly. As a result, the regulation of the magnet current can be improved significantly. So far the simulation results show that with the linear regulator the current regulation can be improved to better than 0.1%. Because of the high bandwidth of the linear regulator, it can reduce the harmonic content in the output current as well as the noises due to the AC line disturbance. A sextupole power supply has been set up to verify the proposed topology. This paper discusses the circuit topology, the regulation algorithm, and the experiment results.

• D. J. Harding
  
• C. L. Bartelson, B. C. Brown, J. A. Carson, W. Chou, J. DiMarco, H. D. Glass, D. E. Johnson, V. S. Kashikhin, I. Kourbanis, W. F. Robotham, M. Tartaglia
  Fermilab, Batavia, Illinois

During the design of the Fermilab Main Injector synchrotron it was recognized that the aperture was limited at the beam transfer and extraction points by the combination of the Lambertson magnets and the reused Main Ring quadrupoles located between the Lambertsons. Increased intensity demands on the Main Injector from antiproton production for the collider program, slow spill to the meson fixed target program, and high intensity beam to the high energy neutrino program have led us to replace the aperture-limiting quadrupoles with newly built magnets that have the same physical length but a larger aperture. The magnets run on the main quadrupole bus, and must therefore have the same excitation profile as the magnets they replaced. We present here the design of the magnets, their magnetic performance, and the accelerator performance.

• M. Hu
  
• D. R. Broemmelsiek, B. Chase, J. L. Crisp, N. E. Eddy, P. W. Joireman, K. Y. Ng
  Fermilab, Batavia, Illinois

• P. M. McIntyre
  
• A. D. McInturff, A. Sattarov
  Texas A&M University, College Station, Texas

The block coil geometry utilized in recent high-field dipole development has significant benefit for applications requiring rapid cycling, since it intrinsically suppresses coupling currents between strands. A conceptual design for a 6 Tesla dipole has been studied for such applications, in which the intra-strand losses are minimized by using bronze-process Nb3Sn superconducting wire developed for ITER. That conductor provides isolated fine filaments and optimum matrix resistance between filaments. The block-coil geometry further accommodates placement of He cooling channels inside the coil, so that heat from radiation and from AC losses can be removed with minimum temperature rise in the coil. The design could be operated with supercritical helium cooling, and should make it possible to operate with a continuous ramp rate of 5-10 T/s.

• S. M. Hartman
  
• S. F. Mikhailov, V. Popov, Y. K. Wu
  FEL/Duke University, Durham, North Carolina

At Duke University, a booster synchrotron was recently commissioned as part of the HIGS upgrade. For the ramping magnet power supply controls, a scheme was developed to present the high level operator interface in terms of the physics quantities of the accelerator, i.e. the effective focusing strength of the magnets. This scheme allows for the nonlinearities of the magnets – a result of the extremely compact footprint of this booster – to be incorporated into the low level software. This facilitates machine studies and simplifies use of physics modeling. In addition, it simplifies operation, allowing the booster to ramp to any energy from the 0.27 GeV of the injector linac to the 1.2 GeV maximum of the Duke Storage Ring. The high level of flexibility of this system if further advanced by incorporating the level of tunability typically found in a storage ring control system. Tuning changes made during steady-state operation are automatically propagated to the waveforms which make up the booster ramp. This approach provides a good match to the wide operation modes of the Duke Storage Ring and its associated free electron laser, and may useful for other compact booster synchrotrons.

• M. J. Borden
  
• J. F. O'Hara, E. M. Perez, B. J. Roller, V. P. Vigil, L. S. Walker
  LANL, Los Alamos, New Mexico

Large maintenance dose burdens have necessitated the development of radiation resistant water manifolds for use on DC magnets in the Proton Storage Ring, at the Los Alamos Neutron Science Center (LANSCE) accelerator. This paper will describe dose measurements and the mechanical design of radiation resistant water manifolds used in PSR.

• D. Teytelman
  
• W. X. Cheng, J. W. Flanagan, T. Naito, M. Tobiyama
  KEK, Ibaraki
• A. Drago
  INFN/LNF, Frascati (Roma)
• J. D. Fox
  SLAC, Menlo Park, California

Damping ring at the Accelerator Test Facility (ATF) is a storage ring with 714 MHz RF frequency and harmonic number of 330. The ring is used in both single and multibunch regimes. In both cases significant longitudinal dipole motion has been observed in the ring. A prototype longitudinal feedback channel using a Gproto baseband processing channel and a set of horizontal striplines has been constructed for the machine. The prototype allowed both suppression of the longitudinal motion and studies of the motion sources. In this paper we present the results of these studies including measurements of steady-state oscillation amplitudes, eigenmodal patterns, and growth and damping rates. Using measured growth rates we estimate the driving impedances. We also present the effect of the longitudinal stabilization on the energy spread of the extracted beam as documented by a screen monitor.

• R. W. Shaw
  
• M. J. Borden, T. Spickermann
  LANL, Los Alamos, New Mexico
• C. S. Feigerle
  University of Tennessee, Knoxville, Tennessee
• Y. Irie
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• M. A. Plum, L. L. Wilson
  ORNL, Oak Ridge, Tennessee
• I. Sugai, A. Takagi
  KEK, Ibaraki

Diamond stripping foils are under development for the SNS. Free-standing, flat 350 microgram/cm² foils as large as 17 x 25 mm have been prepared. These nano-textured polycrystalline foils are grown by microwave plasma-assisted chemical vapor deposition in a corrugated format to maintain their flatness. They are mechanically supported on a single edge by a residual portion of their silicon growth substrate; typical fine foil supporting wires are not required for diamond foils. Six foils were mounted on the SNS foil changer in early 2006 and have performed well in commissioning experiments at reduced operating power. A diamond foil was used during a recent experiment where 12 microCoulombs of protons, approximately 40% of the design value, were stored in the ring. A few diamond foils have been tested at LANSCE/PSR, where one foil was in service for a period of five months (820 Coulombs of integrated injected charge) before it was replaced. Diamond foils have also been tested in Japan at KEK (650 keV H-) where their lifetimes slightly surpassed those of evaporated carbon foils, but fell short of those for Sugai's new hybrid boron carbon (HBC) foils.

• N. Tsoupas
  
• R. Heese, R. Meir, I. Pinayev, J. Rose, T. V. Shaftan, C. Stelmach
  BNL, Upton, Long Island, New York

The proposed NSLS II light source* to be built at Brookhaven National Laboratory utilizes a LINAC and a Booster with a Storage-ring which share the same tunnel, but at different horizontal planes. The Booster which accepts beam from the LINAC, accelerates the electron beam to an energy of 3.0 GeV and the beam is extracted to the Booster_to_Storage_Ring(BtS) transport line. The BtS line transports the beam and injects it into the Storage ring . In order to facilitate the design of the BtS transfer line, the line has been partitioned in three sections which can be considered as independent. The function of each the three sections will be discussed in details and the procedure for the design of the BtS line and other details about the optics and the magnetic elements of the line will be presented in the paper. The LINAC to Booster beam transfer line will also be discussed.

*NSLS II CDR BNL

• K. A. Drees
  
• L. Ahrens, J. G. Alessi, M. Bai, D. S. Barton, J. Beebe-Wang, M. Blaskiewicz, J. M. Brennan, K. A. Brown, D. Bruno, J. J. Butler, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, W. Fischer, W. Fu, G. Ganetis, J. Glenn, M. Harvey, T. Hayes, H.-C. Hseuh, H. Huang, J. Kewisch, R. C. Lee, V. Litvinenko, Y. Luo, W. W. MacKay, G. J. Marr, A. Marusic, R. J. Michnoff, C. Montag, J. Morris, B. Oerter, F. C. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, F. Severino, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, A. Zaltsman, S. Y. Zhang
  BNL, Upton, Long Island, New York

After the last successful RHIC Au-Au run in 2004 (Run-4), RHIC experiments now require significantly enhanced luminosity to study very rare events in heavy ion collisions. RHIC has demonstrated its capability to operate routinely above its design average luminosity per store of 2x10²⁶ cm^-2 s^-1. In Run-4 we already achieved 2.5 times the design luminosity in RHIC. This luminosity was achieved with only 40% of bunches filled, and with β* = 1 m. However, the goal is to reach 4 times the design luminosity, 8x10²⁶ cm^-2 s^-1, by reducing the beta* value and increasing the number of bunches to the accelerator maximum of 111. In addition, the average time in store should be increased by a factor of 1.1 to about 60% of calendar time. We present an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency of RHIC Au-Au operations during Run-7.

• I. Kourbanis
  

• T. Koseki
  

• M. Benedikt
  
• W. Bartmann, C. Carli, B. Goddard, S. Hancock, J. M. Jowett, Y. Papaphilippou
  CERN, Geneva

• K. Seiya
  
• T. Berenc, B. Chase, J. E. Dey, P. W. Joireman, I. Kourbanis, J. Reid
  Fermilab, Batavia, Illinois

• H. Huang
  
• L. Ahrens, M. Bai, K. A. Brown, C. J. Gardner, J. Glenn, F. Lin, A. U. Luccio, W. W. MacKay, T. Roser, S. Tepikian, N. Tsoupas, K. Yip, K. Zeno
  BNL, Upton, Long Island, New York

Dual partial snake scheme has provided polarized proton beams with 1.5*10¹¹ intensity and 65% polarization for RHIC spin program. To overcome the residual polarization loss due to horizontal resonances in the AGS, a new string of quadrupoles have been added. The horizontal tune can now be set in the spin tune gap generated by the two partial snakes, such that horizontal resonances are avoided. This paper presents the accelerator setup and preliminary results.

• W. Fischer
  
• M. Blaskiewicz, J. M. Brennan, H.-C. Hseuh, H. Huang, V. Ptitsyn, T. Roser, P. Thieberger, D. Trbojevic, J. Wei, S. Y. Zhang
  BNL, Upton, Long Island, New York
• U. Iriso
  ALBA, Bellaterra (Cerdanyola del Valles)

Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. These include dynamic pressure rises – including pressure instabilities, a reduction of the stability threshold for bunches crossing the transition energy, and possibly slow emittance growth. We report on the main observations in operation and dedicated experiments, as well as the effect of various countermeasures including baking, NEG coated warm pipes, pre-pumped cold pipes, bunch patterns, scrubbing, and anti-grazing rings.

• X. Huang
  
• S.-Y. Lee
  IUCF, Bloomington, Indiana
• K. Y. Ng
  Fermilab, Batavia, Illinois

We systematically measured the emittance evolution of a fast cycling proton accelerator on a turn-by-turn basis under various beam intensities via an ionization profile monitor (IPM). The vertical emittance growth rate was derived and phenomenologically analyzed. The transverse and longitudinal components in the horizontal beam size were separated by making use of their different evolution behaviors. The quadrupole mode beam size oscillation after transition crossing is also studied and explained. We found a considerable space-charge-induced emittance growth rate component in the vertical plane but not as much for the horizontal plane. We carried out multiparticle simulations to understand the mechanism of space-charge-induced emittance growth. The major sources of emittance growth were found to be the random skew-quadrupole and dipole field errors in the presence of large space-charge tune spread.

PRSTAB 9, 014202 (2006)

• R. A. Kishek
  
• G. Bai, B. L. Beaudoin, S. Bernal, D. W. Feldman, R. Feldman, R. B. Fiorito, T. F. Godlove, I. Haber, T. Langford, P. G. O'Shea, C. Papadopoulos, B. Quinn, M. Reiser, D. Stratakis, D. F. Sutter, J. C.T. Thangaraj, K. Tian, M. Walter, C. Wu
  UMD, College Park, Maryland

Circular accelerators and storage rings have traditionally been designed with limited intensity in order to avoid resonances and instabilities. The possibility of operating a ring beyond the Laslett tune shift limit has been suggested but little tested, apart from a pioneering experiment by Maschke at the BNL AGS in the early 1980s. We have recently circulated the highest-space-charge beam in a ring to date in the University of Maryland Electron Ring (UMER), achieving a breakthrough both in the number of turns and in the amount of current propagated. At undepressed tunes of up to 7.6, the space charge in UMER is sufficient to depress the tune by nearly a factor of 2, resulting in tune shifts up to 3.6. This makes the UMER beam the most intense beam that has been propagated to date in a circular lattice. This is an exciting and promising result for future circular accelerators, and the UMER beam can now be used as a platform to study intense space charge dynamics in rings.

• K. Furukawa
  

• R. Schmidt
  
• R. W. Assmann, E. Carlier, B. Dehning, R. Denz, B. Goddard, E. B. Holzer, V. Kain, B. Puccio, B. Todd, J. A. Uythoven, J. Wenninger, M. Zerlauth
  CERN, Geneva

• P. Cameron
  
• J. Cupolo, W. C. Dawson, C. Degen, A. Della Penna, L. T. Hoff, Y. Luo, A. Marusic, R. Schroeder, C. Schultheiss, S. Tepikian
  BNL, Upton, Long Island, New York
• M. Gasior
  CERN, Geneva

Tune feedback was first implemented in RHIC in 2002 as a specialist activity. The transition to full operational status was impeded by dynamic range problems, as well as by overall loop instabilities driven by large coupling. The dynamic range problem was solved by the CERN development of the Direct Diode Detection Analog Front End. Continuous measurement of all projections of the betatron Eigenmodes made possible the world's first implementation of coupling feedback during beam acceleration, resolving the problem of overall loop instabilites. Simultaneous tune and coupling feedbacks were utilized as specialist activities for ramp development during the 2006 RHIC run. At the beginning of the 2007 RHIC run there remained two obstacles to making these feedbacks fully operational in RHIC - chromaticity measurement and control, and the presence of strong harmonics of the power line frequency in the betatron spectrum. We report here on progress in tune, coupling, and chromaticity measurement and feedback, and discuss the relevance of our results to the LHC commissioning effort. The results of investigations of power line harmonics in RHIC are presented elsewhere in these proceedings.

• A. Jackson
  

• S. V. Weber
  
• F. Bødker, H. Bach, N. Hauge, J. Kristensen, L. K. Kruse, S. P. Møller, S. M. Madsen
  Danfysik A/S, Jyllinge
• M. J. Boland, R. T. Dowd, G. LeBlanc, M. J. Spencer, Y. E. Tan
  ASP, Clayton, Victoria
• N. H. Hertel, J. S. Nielsen
  ISA, Aarhus

• A. Nadji
  
• J. C. Besson, F. Bouvet, P. Brunelle, A. Buteau, L. Cassinari, M.-E. Couprie, J.-C. Denard, J.-M. Filhol, C. Herbeaux, J.-F. Lamarre, V. Le Roux, P. Lebasque, M.-P. Level, A. Loulergue, P. Marchand, L. S. Nadolski, R. Nagaoka, B. Pottin, M.-A. Tordeux
  SOLEIL, Gif-sur-Yvette

• J. Feikes
  
• M. Abo-Bakr, T. Birke, J. Borninkhof, P. Budz, K. B. Buerkmann-Gehrlein, R. Daum, O. Dressler, V. Duerr, F. Falkenstern, H. G. Glass, H. G. Hoberg, J. Kolbe, J. Kuszynski, R. Lange, I. Mueller, R. Muller, J. Rahn, G. Schindhelm, T. Schneegans, Th. Schroeter, D. Schueler, E. Weihreter, G. Wuestefeld
  BESSY GmbH, Berlin
• G. Brandt, R. Fliegauf, A. Hoehl, R. Klein, R. Muller, R. Thornagel, G. Ulm
  PTB, Berlin

The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, has built an electron storage ring in close cooperation with BESSY for energies between 200 MeV and 600 MeV. This storage ring, named Metrology Light Source (MLS), will mainly be used for radiometry and can be operated as a primary source standard. The spectral range of the MLS is optimized for UV, EUV and also for Terahertz radiation. Commissioning is planed for May 2007. First MLS commissioning results will be reported.

• Y. Kobayashi
  
• S. Asaoka, W. X. Cheng, K. Haga, K. Harada, T. Honda, T. Ieiri, S. Isagawa, M. Izawa, T. Kageyama, T. Kasuga, M. Kikuchi, K. Kudo, H. Maezawa, A. Mishina, T. Mitsuhashi, T. Miyajima, H. Miyauchi, S. Nagahashi, T. T. Nakamura, H. Nakanishi, T. Nogami, T. Obina, K. Oide, M. Ono, T. Ozaki, C. O. Pak, H. Sakai, Y. Sakamoto, S. Sakanaka, H. Sasaki, Y. Sato, T. Shioya, M. Tadano, T. Takahashi, S. Takasaki, Y. Tanimoto, M. Tejima, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, S. Yamamoto, Ma. Yoshida, S. I. Yoshimoto
  KEK, Ibaraki

• L. Wang
  
• G. Feng, W. Li, L. Liu, H. Xu
  USTC/NSRL, Hefei, Anhui
• S. C. Zhang
  USTC, Hefei, Anhui

• J. H. Park
  
• J. Y. Huang, C. Kim, I. S. Ko, Y. W. Parc, S. J. Park
  PAL, Pohang, Kyungbuk
• D. Xiang
  TUB, Beijing

A high-brightness electron beam is emitted from a photo-cathode (PC) RF gun for use in the FIR (Far Infrared) facility being built at the Pohang Accelerator Laboratory (PAL). The beam dynamics study for the PAL XFEL injector is essencial to generate low emittance electron beam from the PC RF gun. The XFEL injector requires 1 nC beam with short bunch length and low emittance. This conditions are simulated with PARMELA code and then are realized on experimental conditions. The experimental conditions for the XFEL injector are measured with beam diagnostic devices such as ICT and Faraday cup for charge measurement, a spectrometer for beam energy measurement. In this article, we present the experimental approaches of the beam dynamics study for the XFEL injector.

wpjho@postech.ac.kr (Jangho Park)

• D. Einfeld
  

• Y.-C. Liu
  
• H.-P. Chang, J. Chen, P. J. Chou, K. T. Hsu, K. H. Hu, C. H. Kuo, C.-C. Kuo, K.-K. Lin, G.-H. Luo, M.-H. Wang
  NSRRC, Hsinchu

• R. Bartolini
  

• C. Christou
  
• V. C. Kempson
  Diamond, Oxfordshire

• B. Singh
  
• R. Bartolini, R. T. Fielder, E. C. Longhi, I. P.S. Martin
  Diamond, Oxfordshire

• V. Sajaev
  
• M. Borland, A. Xiao
  ANL, Argonne, Illinois

APS has recently held a round of discussions on upgrade options for the APS storage ring. Several options were discussed that included both storage ring and energy-recovery linac options. Here we present a storage ring lattice that fits into the APS tunnel and has a number of significant improvements over the existing storage ring. The present APS lattice has 40-fold symmetry with each sector having one 5-m-long straight section for insertion device (ID) placement. Each sector also provides one beamline for radiation from the bending magnet. The upgrade lattice preserves locations of the existing insertion devices but provides for increased ID straight section length to accommodate 8-m-long insertion devices. This lattice also decreases emittance by a factor of two down to 1.6 nm rad. And last but not least, it provides two additional 2.1-m-long ID straight sections per sector with one of these straight sections being parallel to the existing bending magnet beamline. We also present dynamic aperture optimization, lifetime calculations, and other nonlinear-dynamics-related simulations.

• N. Sereno
  
• M. Borland, H. W. Friedsam
  ANL, Argonne, Illinois

In the recent past, the Advanced Photon Source (APS) was asked by the U. S. Department of Energy to explore a revolutionary upgrade based on emerging energy recovery linac (ERL) technology. In an ERL, the energy of the 7-GeV, 100-mA beam is recovered after the beam passes through user beamlines by decelerating the beam back through the same superconducting linac cavities that accelerated it. The main constraint on this upgrade is that the existing APS beamlines not be disturbed. This requires that the APS storage ring be used as a single-pass transport line in the overall ERL beamline layout. A natural place to locate the ERL is inside the existing APS storage ring ‘‘infield'' area, which has unoccupied space south of the existing APS injector complex. Other important constraints include minimal disturbance of existing building structures and injector beamlines. The existing injector complex would be preserved so that existing operation can be continued through and even possibly beyond ERL commissioning. In this paper, we describe a layout that satisfies these constraints. We also estimate the amount of emittance increase the beam will experience before ring injection.

• V. P. Suller
  
• M. G. Fedurin
  BNL, Upton, Long Island, New York
• P. Jines, D. J. Launey, T. A. Miller, Y. Wang
  LSU/CAMD, Baton Rouge, Louisiana

• H. Nishimura
  
• R. J. Donahue, R. M. Duarte, D. Robin, F. Sannibale, C. Steier, W. Wan
  LBNL, Berkeley, California

We plan to commission top-off injection at the Advanced Light Source in the near future. In order to guarantee radiation safety, we have been simulating the injection process to exclude the possibility of injected electrons traveling down the user's photon beam lines. As the final stage of our simulation study, we use photon beam line CAD drawings to define the beam line's aperture in the phase space which electrons must not enter. Then we virtually inject electrons from within these phase spaces backwards into the storage ring to prove that such electrons can never get back to the real injection point under any possible scenario. This paper summarizes such inverse tracking studies.

• C. Steier
  
• B. J. Bailey, K. M. Baptiste, W. Barry, A. Biocca, W. E. Byrne, M. J. Chin, R. J. Donahue, R. M. Duarte, M. P. Fahmie, J. Gath, S. R. Jacobson, J. Julian, J.-Y. Jung, S. Kwiatkowski, S. Marks, R. S. Mueller, H. Nishimura, J. W. ONeill, S. Prestemon, D. Robin, S. L. Rossi, F. Sannibale, T. Scarvie, D. Schlueter, D. Shuman, G. D. Stover, CA. Timossi, T. Warwick, J. M. Weber, E. C. Williams
  LBNL, Berkeley, California

The Advanced Light Source is currently being upgraded for top-off operation. This major facility upgrade will provide an improvement in brightness from soft x-ray undulators of about one order of magnitude and keep the ALS competitive with the newest intermediate energy light sources. Major components of the upgrade include making the booster synchrotron capable of full energy operation, radiation safety studies, improvements to interlocks and collimation systems, diagnostics upgrades as well as emittance improvements in the main storage ring. The project status will be discussed as well as results of major parts of the commissioning.

• L. Yang
  
• S. L. Kramer, B. Podobedov
  BNL, Upton, Long Island, New York
• S.-Y. Lee
  IUCF, Bloomington, Indiana

• S. F. Mikhailov
  
• O. Anchugov, N. Gavrilov, G. Y. Kurkin, Yu. Matveev, D. Shvedov, N. Vinokurov
  BINP SB RAS, Novosibirsk
• M. D. Busch, M. Emamian, S. M. Hartman, Y. Kim, J. Li, V. Popov, G. Swift, P. W. Wallace, P. Wang, Y. K. Wu
  FEL/Duke University, Durham, North Carolina
• C. R. Howell
  TUNL, Durham, North Carolina

A booster synchrotron has been built and recently commissioned at Duke University Free Electron Laser Laboratory (DFELL) as part of the High Intensity Gamma-ray Source (HIGS) facility upgrade. HIGS is developed collaboratively by the DFELL and Triangular Universities Nuclear Laboratory (TUNL). The booster will provide top-off injection into the Duke FEL storage ring in the energy range of 0.27 - 1.2 GeV. When operating the Duke storage ring to produce high energy Compton gamma ray beams above 20 MeV, continuous electron beam loss occurs. The lost electrons will be replenished by the booster injector operating in the top-off mode. The compactness of the booster posed a challenge for its development and commissioning. The booster has been successfully commissioned in 2006. This paper reports experience of commissioning and initial operation of the booster.

• S. F. Mikhailov
  
• S. M. Hartman, J. Li, V. Popov, Y. K. Wu
  FEL/Duke University, Durham, North Carolina

A booster synchrotron has been recently commissioned at Duke University FEL Laboratory as a part of the High Intensity Gamma-ray Source (HIGS) facility. The booster will provide top-off injection into the storage ring in the energy range of 0.27 - 1.2 GeV. In order to minimize the cost of the project, the booster is designed with a very compact footprint. As a result, unconventionally high field bending magnets at 1.76 T are required. A main ramping power supply drives all dipoles and quadrupoles. Quadrupole trims are used to compensate for tune changes caused by the change of relative focusing strength during ramping. Sextupoles compensate for chromatic effects caused by dipole magnet pole saturation. All these compensations have to be performed as a function of beam energy. Above 1.1 GeV, where the magnets are heavily saturated, the reduction of dynamic aperture is compensated by redistribution of strength among the sextupole families. With these compensations, effects of the magnet saturation do not cause any considerable beam loss during energy ramping.

• S. Tochitsky
  
• C. Joshi, C. Sung
  UCLA, Los Angeles, California

Seeded FEL/IFEL techniques can be used for modulation of a relativistic electron beam longitudinally on the radiation wavelength. However, in the 1-10 THz range, which is of particular importance for matched injection of prebunched electrons into a laser-driven plasma accelerating structure, a suitable radiation source is not available. At the UCLA Neptune Laboratory we have built and fully characterized a radiation source tunable in the range of 1-3 THz. The THz pulse is produced by mixing two CO2 laser lines in a noncollinear phase-matched GaAs crystal at room temperature. The crystal is pumped by 200 ns pulses of a dual beam TEA CO2 laser running at 1 Hz. A grating placed in each lasing section allowed to cover the spectral range for the difference frequency from 0.5-4.5 THz with a step of 30-40 GHz. The achieved narrow bandwidth of ~10^-5 and the output power of 2kW are sufficient for seeding a single-pass, waveguide FEL amplifier-prebuncher*. These pulses were used to measure the coupling efficiency and the attenuation for different types of THz waveguides and the results will be reported.

* C. Sung et al. "Seeded FEL/IFEL techniques for radiation amplification and electron microbunching in the terahertz range" Phys. Rev. STAB, 2006 (to be published)

• X. Huang
  
• W. J. Corbett, Y. Nosochkov, J. A. Safranek, J. J. Sebek, A. Terebilo
  SLAC, Menlo Park, California

• J. A. Safranek
  
• W. J. Corbett, S. M. Gierman, R. O. Hettel, X. Huang, J. J. Sebek, A. Terebilo
  SLAC, Menlo Park, California

• K. Jordan
  
• S. V. Benson, D. Douglas, P. Evtushenko, C. Hernandez-Garcia, G. Neil
  Jefferson Lab, Newport News, Virginia

Notional designs for ERL-driven high average power free electron lasers often invoke amplifier-based architectures. To date, however, amplifier FELs have been limited in average power output to values several orders of magnitude lower than those demonstrated in optical-resonator based systems; this is due at least in part to the limited electron beam powers available from their driver accelerators. In order to directly contrast the performance available from amplifiers to that provided by high-power cavity-based resonators, we have developed a scheme to test an amplifier FEL in the JLab SRF ERL driver. We describe an accelerator system design that can seamlessly and non-invasively integrate a 10 m wiggler into the existing system and which provides, at least in principle, performance that would support high-efficiency lasing in an amplifier configuration. Details of the design and an accelerator performance analysis will be presented.

• I. Pinayev
  
• J. Rose, T. V. Shaftan, L.-H. Yu
  BNL, Upton, Long Island, New York

• J. Rose
  
• I. Pinayev, T. V. Shaftan
  BNL, Upton, Long Island, New York

• T. V. Shaftan
  
• J. Beebe-Wang, J. Bengtsson, G. Ganetis, W. Guo, R. Heese, H.-C. Hseuh, E. D. Johnson, V. Litvinenko, A. U. Luccio, W. Meng, S. Ozaki, I. Pinayev, S. Pjerov, D. Raparia, J. Rose, S. Sharma, J. Skaritka, C. Stelmach, N. Tsoupas, D. Wang, L.-H. Yu
  BNL, Upton, Long Island, New York

We present conceptual design of the NSLS-II injection system. The injection system consists of low-energy linac, booster and transport lines. We review the requirements on the injection system imposed by the storage ring design and means of meeting these requirements. We discuss main parameters and layout of the injection system components.

• J. Pasternak
  
• B. Autin
  CERN, Geneva
• J. Fourrier, E. Froidefond
  LPSC, Grenoble
• F. Meot
  CEA, Gif-sur-Yvette
• D. Neuveglise, T. Planche
  Sigmaphi, Vannes

• M. Steck
  
• C. Dimopoulou, A. Dolinskii, F. Nolden
  GSI, Darmstadt

• V. Variale
  
• P. A. Bak, G. I. Kuznetsov, B. A. Skarbo, M. A. Tiunov
  BINP SB RAS, Novosibirsk
• A. Boggia
  Universita e Politecnico di Bari, Bari
• T. Clauser, V. Valentino
  INFN-Bari, Bari
• A. C. Raino
  Bari University, Science Faculty, Bari

The Radioactive Ion Beam (RIB) production with ISOL technique should require a charge breeder device to increase the ion acceleration efficiency and reduce greatly the production cost. The "charge breeder" is a device designed to accept RIB with charge state +1 and in order to increase their charge state up to +n. Recently, at the INFN section of Bari first and at LNL (Italy) then, a new charge breeder device, based on an EBIS ion source called BRIC, has been developed. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) - Quadrupole aiming to filtering the unwanted masses and then making a selective more efficient containment of the wanted ions. The RF test measurements for Ar gas confirm, as foreseen by simulation results* that the selective containment can be obtained. More measurements on the selective containment of heavier element ions (more close to the radioactive ion produced with ISOL technique) like Xe are needed to study with more details that effect. In this contribution new measurements on the rf selective containement in BRIC for Xe gas will be presented and discussed.

* V. Variale and M. Claudione, "BRICTEST: a code for charge breeding simulations in RF quadrupolar field", NIM in Phys. res. A 543 (2005) 403-414.

• C. Milardi
  
• D. Alesini, M. E. Biagini, C. Biscari, R. Boni, M. Boscolo, B. Buonomo, A. Clozza, G. O. Delle Monache, T. Demma, E. Di Pasquale, G. Di Pirro, A. Drago, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, P. Iorio, C. Ligi, F. Marcellini, C. Marchetti, G. Mazzitelli, L. Pellegrino, M. A. Preger, L. Quintieri, P. Raimondi, R. Ricci, U. Rotundo, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, S. Tomassini, C. Vaccarezza, M. Zobov
  INFN/LNF, Frascati (Roma)
• J. D. Fox, D. Teytelman
  SLAC, Menlo Park, California
• E. Levichev, S. A. Nikitin, P. A. Piminov, D. N. Shatilov
  BINP SB RAS, Novosibirsk

• J. Seeman
  
• M. E. Biagini, P. Raimondi
  INFN/LNF, Frascati (Roma)
• Y. Cai, M. K. Sullivan, U. Wienands
  SLAC, Menlo Park, California

Submitted for the High Luminosity Study Group for an Asymmetric Super-B-Factory: Parameters are being studied for a high luminosity e⁺e^- collider operating at the Upsilon 4S that would deliver a luminosity of over 10³⁶/cm²/s. This collider would use a novel combination of linear collider and storage ring techniques. In this scheme an electron beam and a positron beam at 4 GeV x 7 GeV are stored in low-emittance damping rings similar to those designed for a Linear Collider (LC). A LC style interaction region is included in the ring to produce sub-millimeter vertical beta functions at the collision point. A large crossing angle (±30 mrad) is used at the collision point to allow beam separation and reduce the hourglass effect. Beam currents of about 3 A x 2 A in 1700 bunches can produce a luminosity of 10³⁶/cm²/s. Design parameters and beam dynamics effects are discussed.

• M. Ikegami
  
• H. Asano, T. Kobayashi
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• K. Hasegawa, T. Ito, T. Morishita, S. Sato, A. Ueno
  JAEA/LINAC, Ibaraki-ken
• Z. Igarashi, H. Tanaka
  KEK, Ibaraki
• H. Sako
  JAEA, Ibaraki-ken

• 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

* 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

• 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

* K. Takayama, et al., "Experimental Demonstration of the Induction Synchrotron", PAC07.** K. Takayama, et al., PCT/JP2006/308502 (2006).*** T. Dixit, et al., PAC07.

• M. Tomizawa
  
• A. Y. Molodozhentsev, M. J. Shirakata
  KEK, Ibaraki

• M. Tomizawa
  
• A. Y. Molodozhentsev, E. Nakamura, I. Sakai, M. Uota
  KEK, Ibaraki

• P. K. Saha
  
• H. Hotchi, Y. Irie, F. Noda
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon

• N. Yu. Kazarinov
  
• V. Aleksandrov, V. Shevtsov, A. Tuzikov
  JINR, Dubna, Moscow Region
• Y. Jongen
  IBA, Louvain-la-Neuve

• N. Yu. Kazarinov
  
• V. Aleksandrov, V. Shevtsov
  JINR, Dubna, Moscow Region
• Y. Jongen
  IBA, Louvain-la-Neuve

• M. J. Barnes
  
• F. Caspers, L. Ducimetiere, N. Garrel, T. Kroyer
  CERN, Geneva

• C. B. Bracco, C. B. Bracco
  EPFL, Lausanne
• R. W. Assmann, S. Redaelli, G. Robert-Demolaize
  CERN, Geneva

• H. Burkhardt
  
• G. Arduini, S. Bart Pedersen, C. Fischer, JJ. G. Gras, A. Koschik, D. K. Kramer, S. Redaelli
  CERN, Geneva

• M. DiCastro
  
• L. Bottura, L. Deniau, N. J. Sammut, S. Sanfilippo, D. Sernelius, W. Venturini Delsolaro
  CERN, Geneva

• F. Gerigk
  
• M. Aiba, C. Carli, M. Martini
  CERN, Geneva
• S. M. Cousineau
  ORNL, Oak Ridge, Tennessee

• B. Goddard
  
• W. Bartmann, M. Benedikt, A. Koschik, T. Kramer
  CERN, Geneva

• G. Robert-Demolaize
  
• R. W. Assmann, C. B. Bracco, S. Redaelli, Th. Weiler
  CERN, Geneva

• A. Gomez Alonso
  
• R. Schmidt
  CERN, Geneva

• W. J.M. Weterings
  
• G. Bellodi, J. Borburgh, T. Fowler, F. Gerigk, B. Goddard, K. Hanke, M. Martini, L. Sermeus
  CERN, Geneva

• B. Jones
  
• D. J. Adams, C. M. Warsop
  STFC/RAL/ISIS, Chilton, Didcot, Oxon

• S. Wang
  
• F. R. Brumwell, J. C. Dooling, R. Kustom, G. E. McMichael, M. E. Middendorf
  ANL, Argonne, Illinois

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.

• W. Chou
  
• M. A. Kostin
  NSCL, East Lansing, Michigan
• J. R. Lackey, Z. Tang
  Fermilab, Batavia, Illinois
• R. J. Macek
  LANL, Los Alamos, New Mexico
• P. S. Yoon
  Rochester University, Rochester, New York

Carbon foils are widely used in charge-exchange injection in high intensity hadron accelerators. There are a variety of physics issues associated with the use of carbon foils, including stripping efficiency, energy deposition, foil lifetime (temperature rise, mechanical stress and buckling), multiple Coulomb scattering, large angle single Coulomb scattering, energy straggling and radiation activation. This paper will give a brief discussion of these issues based on the study of the Proton Driver and experience of the Fermilab Booster. Details can be found in Ref*.

* W. Chou et al., "Transport and Injection of 8 GeV H^- Ions," Fermilab-TM-2285 (2007).

• W. Chou
  
• D. Capista, E. Griffin, K. Y. Ng, D. Wildman
  Fermilab, Batavia, Illinois

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).

• W. Chou
  
• C. L. Bartelson, B. C. Brown, D. Capista, J. L. Crisp, J. DiMarco, J. Fitzgerald, H. D. Glass, D. J. Harding, B. Hendricks, D. E. Johnson, V. S. Kashikhin, I. Kourbanis, W. F. Robotham, T. Sager, M. Tartaglia, L. Valerio, R. C. Webber, M. Wendt, D. Wolff, M.-J. Yang
  Fermilab, Batavia, Illinois

A two-year Large Aperture Quadrupole (WQB) Project was completed in the summer of 2006 at Fermilab.* Nine WQBs were designed, fabricated and bench-tested by the Technical Division. Seven of them were installed in the Main Injector and the other two for spares. They perform well. The aperture increase meets the design goal and the perturbation to the lattice is minimal. The machine acceptance in the injection and extraction regions is increased from 40π to 60π mm-mrad. This paper gives a brief report of the operation and performance of these magnets. Details can be found in Ref**.

* D. Harding et al, "A Wide Aperture Quadrupole for the Fermilab Main Injector," this conference.
** W. Chou, Fermilab Beams-doc-#2479, http://beamdocs.fnal.gov/AD-public/DocDB/DocumentDatabase

• A. I. Drozhdin
  
• B. C. Brown, D. E. Johnson, I. Kourbanis, N. V. Mokhov, I. Rakhno, V. Sidorov
  Fermilab, Batavia, Illinois
• K. Koba
  KEK, Ibaraki

• D. E. Johnson
  
• A. Z. Chen, I. Rakhno
  Fermilab, Batavia, Illinois

A 8 GeV H^- superconducting linac has been proposed as an alternative injector for the Main Injector to support a 2 MW Neutrino program. An injection absorber is required to accept protons generated after the secondary stripping foil which will intercept the un-stripped H^- and H0 particles after the MI primary foil injection point. The motivations underlying the choice of a compact internal absorber over an external absorber will be discussed. We show that using a high-Z material (tungsten) for the inner shielding allows the construction a compact absorber that can take a very intense beam and fits within the existing enclosure. The absorber requirements and a shielding design and the results of energy deposition calculations are presented.

• D. E. Johnson
  
• J. Beebe-Wang, C. J. Liaw, D. Raparia
  BNL, Upton, Long Island, New York

The technique for H^- charge exchange for multi-turn injection utilizing stripping foils in the energy range of a few hundred MeV has been used at many labs for decades and most recently up to 1 GeV at the SNS. Utilization the beam from the proposed Proton Driver* would permit the extension of this technique up to 8 GeV. The injection layout and required accelerator modifications are discussed. Results from transverse and longitudinal simulations are presented.

* W. G. Foster and J. A. MacLachlan, "A Multi-mission 8 GeV Injector Linac as a Fermilab Booster Replacement", Proc. Of LINAC-2002, Gyeongju, Korea, p.86.

• J. R. Lackey
  
• F. G. Garcia, M. Popovic, E. Prebys
  Fermilab, Batavia, Illinois

The operation and performance of the new, 15 Hz, H^- charge exchange injection system for the FNAL Booster is described. The new system installed in 2006 was necessary to allow injection into the Booster at up to 15 Hz. It was built using radiation hardened materials which will allow the Booster to reliably meet the high intensity and repetition rate requirements of the Fermilab's HEP program. The new design uses three orbit bump magnets (Orbmps) rather than the usual four and permits injection into the Booster without a septum magnet. Injection beam line modification and compensation for the quadrupole gradients of the Orbmp magnets is discussed.

• L. R. Prost
  
• A. V. Shemyakin
  Fermilab, Batavia, Illinois

A 0.1 A, 4.3 MeV DC electron beam is routinely used to cool 8 GeV antiprotons in Fermilab's Recycler storage ring. While the primary function of the electron cooler is to increase the longitudinal phase-space density of the antiprotons, significant transverse cooling rates have been observed as well. Numerical characterization of electron cooling is done by two types of measurements: friction force measurements by the voltage jump method and diffusion/cooling rates measurements. The paper will present the recent measurement results and will compare them to a non-magnetized model.

• D. E. Johnson
  
• M. Xiao
  Fermilab, Batavia, Illinois

Upon the termination of the Fermilab Collider program, the current Recycler anti-proton storage ring will be converted to a proton pre-injector for the Main Injector synchrotron. This is scheduled to increase the beam power for the 120 GeV Neutrino program to upwards of 700KW. A transport line that can provide direct injection from the Booster to the Recycler while preserving direct injection from the Booster into the Main Injector and the 8 GeV Booster Neutrino program will be discussed,and its concept design will be presented.

• A. I. Drozhdin
  
• W. Pellico, X. Yang
  Fermilab, Batavia, Illinois

• A. I. Drozhdin
  
• W. Pellico, X. Yang
  Fermilab, Batavia, Illinois

• T. J. Loew
  
• S. R. Abbott, M. L. Galloway, D. Leitner, C. M. Lyneis
  LBNL, Berkeley, California

• M. Walter
  
• G. Bai, B. L. Beaudoin, S. Bernal, D. W. Feldman, T. F. Godlove, I. Haber, R. A. Kishek, P. G. O'Shea, C. Papadopoulos, M. Reiser, D. Stratakis, D. F. Sutter, J. C.T. Thangaraj, C. Wu
  UMD, College Park, Maryland

The University of Maryland Electron Ring (UMER) is a low energy, high current recirculator for beam physics research. The electron beam current is adjustable from 0.7 mA, an emittance dominated beam, to 100 mA, a strongly space charge dominated beam. UMER is addressing issues in beam physics relevant to many applications that require intense beams of high quality such as advanced concept accelerators, free electron lasers, spallation neutron sources, and future heavy-ion drivers for inertial fusion. The primary focus of this presentation is experimental results and improvements in multi-turn operation of the electron ring. Transport of a low current beam over 100 turns (3600 full lattice periods) has been achieved. Results of high current, space charge dominated multi-turn transport will also be presented.

• M. Walter
  
• G. Bai, B. L. Beaudoin, S. Bernal, D. W. Feldman, T. F. Godlove, I. Haber, R. A. Kishek, P. G. O'Shea, C. Papadopoulos, M. Reiser, D. Stratakis, D. F. Sutter, J. C.T. Thangaraj, C. Wu
  UMD, College Park, Maryland

The University of Maryland Electron Ring (UMER) is a low energy, high current recirculator for beam physics research. The electron storage ring has been closed and recent operations have been focused on achieving multi-turn transport. An entire suite of terminal diagnostics is available for time-resolved phase space measurements of the beam. These diagnostics have been mounted and tested at several points on the ring before it was closed. UMER utilizes a unique injection scheme which uses the fringe fields of an offset quadrupole to assist a pulsed dipole in bending the beam into the ring. Similar concepts, along with more traditional electrostatic methods, are being considered for beam extraction. This presentation will focus on the recent efforts to design and deploy these major subsystems required for beam extraction.

• B. R. Poole
  
• D. T. Blackfield, S. D. Nelson
  LLNL, Livermore, California

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.

• J. G. Alessi
  
• E. N. Beebe, J. Brodowski, A. Kponou, M. Okamura, A. I. Pikin, D. Raparia, J. Ritter, L. Snydstrup, V. Zajic
  BNL, Upton, Long Island, New York

A part of a new EBIS-based heavy ion preinjector, the low energy beam transport (LEBT) section between the high current EBIS and the RFQ is a challenging design, because it must serve many functions. In addition to the requirement to provide an efficient matching between the EBIS and the RFQ, this line must serve as a fast switchyard, allowing singly charged ions from external sources to be transported into the EBIS trap region, and extracted, highly charged ions to be deflected to off-axis diagnostics (time-of-flight, or emittance). The space charge of the 5-10 mA extracted heavy ion beam is a major consideration in the design, and the space charge force varies for different ion beams having Q/m from 1-0.16. The line includes electrostatic lenses, spherical and parallel-plate deflectors, magnetic solenoid, and diagnostics for measuring current, charge state distributions, emittance, and profile. A prototype of this beamline has been built, and results of tests will be presented.

• C. J. Gardner
  
• L. Ahrens, J. G. Alessi, J. Benjamin, M. Blaskiewicz, J. M. Brennan, K. A. Brown, C. Carlson, W. Fischer, J. Glenn, M. Harvey, T. Hayes, H. Huang, G. J. Marr, J. Morris, F. C. Pilat, T. Roser, F. Severino, K. Smith, D. Steski, P. Thieberger, N. Tsoupas, A. Zaltsman, K. Zeno
  BNL, Upton, Long Island, New York

Gold ions for the 2007 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators will be reviewed with a focus on improvements in the quality of beam delivered to RHIC. In particular, more uniform stripping foils between Booster and AGS, and a new bunch merging scheme in AGS promise to provide beam bunches with reduced longitudinal emittance for RHIC.

• Y. Luo
  
• P. Cameron, A. Della Penna, T. Satogata, D. Trbojevic
  BNL, Upton, Long Island, New York

A beam-based method was proposed and applied to check the polarities of the arc sextupoles in the Relativistic Heavy Ion Collider (RHIC) with repetitive local horizontal bumps. Wrong sextupole polarities can be easily identified from mismatched signs and amplitudes of the horizontal and vertical tune shifts from bump to bump and/or from arc to arc. This check takes less than 2 hours for both RHIC Blue and Yellow rings. Tune shifts in both planes during this study were tracked with a high-resolution baseband tunemeter (BBQ) system. This method was successfully used to the sextupole polarity check in the RHIC run06.

• T. Satogata
  
• L. Ahrens, M. Bai, J. M. Brennan, D. Bruno, J. J. Butler, K. A. Drees, A. V. Fedotov, W. Fischer, M. Harvey, T. Hayes, W. Jappe, R. C. Lee, W. W. MacKay, G. J. Marr, R. J. Michnoff, B. Oerter, E. Pozdeyev, T. Roser, F. Severino, K. Smith, S. Tepikian, N. Tsoupas
  BNL, Upton, Long Island, New York

There is significant interest in RHIC heavy ion collisions at c.m. energies of 5-50 GeV/u, motivated by a search for the QCD phase transition critical point. The low end of this energy range is well below the nominal RHIC injection c.m. energy of 19.6 GeV/u. There are several challenges that face RHIC operations in this regime, including longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the status of work to address these challenges and include results from beam tests of low-energy RHIC operations with protons and gold.

• A. G. Ruggiero
  
• J. G. Alessi, E. N. Beebe, A. I. Pikin, T. Roser, D. Trbojevic
  BNL, Upton, Long Island, New York

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.

• S. Y. Zhang
  
• V. Ptitsyn
  BNL, Upton, Long Island, New York

The beam emittance growth in RHIC polarized proton runs has a dependence on the dynamic pressure rise, which is caused by the electron cloud and peaked at the end of the beam injection and the early energy acceleration. This emittance growth is usually presented without beam instability, and it is slower than the ones above the instability threshold. The effect on the machine luminosity, nevertheless, is significant, and it is currently a limiting factor in machine performance. The electron cloud is substantially reduced at the store, the emittance growth there has no dependence on the bunch spacing and instead it has a clear dependence on the beam-beam parameter. The results of the machine operation and beam studies will be reported.

• A. J. Gonsalves
  
• D. L. Bruhwiler, J. R. Cary
  Tech-X, Boulder, Colorado
• E. Cormier-Michel
  University of Nevada, Reno, Reno, Nevada
• E. Esarey, C. G.R. Geddes, W. Leemans, K. Nakamura, C. B. Schroeder, C. Toth
  LBNL, Berkeley, California
• S. M. Hooker
  OXFORDphysics, Oxford, Oxon

• C. G.R. Geddes
  
• J. R. Cary
  Tech-X, Boulder, Colorado
• E. Cormier-Michel
  University of Nevada, Reno, Reno, Nevada
• E. Esarey, W. Leemans, K. Nakamura, D. Panasenko, G. R.D. Plateau, C. B. Schroeder, C. Toth
  LBNL, Berkeley, California

Laser wakefield accelerators produce accelerating gradients up to hundreds of GeV/m and narrow energy spread, and have recently demonstrated energies up to GeV and improved stability [*,**] using electrons self trapped from the plasma. Controlled injection and staging can further improve beam quality by circumventing tradeoffs between energy, stability, and energy spread/emittance. We present experiments demonstrating production of a stable electron beam near 1 MeV with 100 keV level energy spread and central energy stability by using the plasma density profile to control self injection, and supporting simulations. A 10 TW laser pulse was focused near the downstream edge of a mm-long hydrogen gas jet. The plasma density near focus is decreasing in the laser propagation direction, which changes the wake phase velocity and reduces the trapping threshold. This allows stable self trapping and low absolute energy spread. Simulations indicate that such beams can be post accelerated to form high energy, high quality, stable beams, and experiments are under investigation.

* Geddes et al, Nature v431 no7008, 538 (2004).** Leemans et al, Nature Physics v2 no10, p696 (2006)

• C. M. Bhat
  
• B. Chase, C. Gattuso, P. W. Joireman
  Fermilab, Batavia, Illinois

The Recycler is the primary antiproton repository for the Tevatron collider at Fermilab. Stored antiproton beam intensity has been steadily increased to about 450·10¹⁰ over the last three years. We have used the technique of longitudinal momentum mining* in the Recycler to extract constant intensity and constant longitudinal emittance antiproton bunches for collider operation since early 2005. Since then, the Recycler has played a critical role in the luminosity performance of the Tevatron; the peak proton-antiproton luminosity has been raised by a factor of about three and a world record luminosity of 2.31·10³²cm^-2s^-1 has been achieved. Recently, many improvements have been implemented in the antiproton mining and stacking schemes used in the Recycler to handle higher intensity beam. In this paper we discuss morphing during antiproton stacking, reducing longitudinal emittance dilution, and use of soft mining buckets to maintain low peak density and control the beam instability during mining. In addition we present past and current performance of mining and beam stacking RF manipulations.

* C. M. Bhat, Phys. Letts. A Vol. 330 (2004), p 481

• R. Corsini
  

• E. Metral
  
• G. Arduini, R. W. Assmann, A. Boccardi, T. Bohl, C. B. Bracco, F. Caspers, M. Gasior, O. R. Jones, K. K. Kasinski, T. Kroyer, S. Redaelli, G. Robert-Demolaize, G. Rumolo, R. J. Steinhagen, Th. Weiler, F. Zimmermann
  CERN, Geneva
• F. Roncarolo
  UMAN, Manchester
• B. Salvant
  EPFL, Lausanne

• P. Marchand
  
• P. Bosland, P. Bredy
  CEA, Gif-sur-Yvette
• H. D. Dias, M. D. Diop, M. E. El Ajjouri, J. L. Labelle, R. L. Lopes, M. Louvet, C. M. Monnot, F. Ribeiro, T. Ruan, R. Sreedharan, K. Tavakoli, C. G. Thomas-Madec
  SOLEIL, Gif-sur-Yvette

• F. Tamura
  
• S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Toda, M. Yoshii
  KEK, Ibaraki
• K. Hasegawa, M. Nomura, A. Schnase, M. Yamamoto
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

• L. Shen
  
• Y. L. Chi, C. Huang
  IHEP Beijing, Beijing

• M. J. Barnes
  
• G. D. Wait
  TRIUMF, Vancouver

The present AGS injection kickers at A5 location were designed for 1.5 GeV proton injection. Recent high intensity runs have pushed the transfer kinetic energy to 1.94 GeV, but with an imperfect matching in transverse phase space. Space charge forces result in both fast and slow beam size growth and beam loss as the size exceeds the AGS aperture. An increase in the AGS injection energy to 2 GeV with adequate kick strength would greatly reduce the beam losses making it possible to increase the intensity from 70 TP (70 * 10¹² protons/s) to 100 TP. R&D studies* have been undertaken by TRIUMF, in collaboration with BNL, to design two new kicker magnets for the AGS A10 location to provide an additional kick of 1.5 mrad to 2 GeV protons. TRIUMF has designed and built a prototype 12.5 Ω transmission line kicker magnet with rise and fall times of 100 ns, 3% to 97% and field uniformity of (±)1% over 85% of the aperture, powered by matched 12.5 Ω pulse-forming lines. This paper describes the results of detailed capacitance and inductance measurements, on the prototype magnet, and compares these with predictions from 2D and 3D electromagnetic simulations.

*L. Ahrens, R. B. Armenta, M. J. Barnes, E. W Blackmore, C. J. Gardner, O. Hadary, G. D. Wait, W. Zhang, "Design Concept for AGS Injection Kicker Upgrade to 2 GeV", PAC 2005, Knoxville Tennessee.

• 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

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.

• J. Li
  
• N. Solyak
  Fermilab, Batavia, Illinois
• T. Wong
  Illinois Institute of Technology, Chicago, Illinois

Fermilab has developed a third harmonic superconducting cavity operating at the frequency of 3.9 GHz to improve the beam performance for the FLASH user facility at DESY. It is interesting to investigate the coupling interaction between the SRF cavity and the power coupler with or without beam loading. The coupling of the power coupler to the cavity needs to be determined to minimize the power consumption and guarantee the best performance for a given beam current. In this paper, we build and analyze an equivalent circuit model containing a series of lumped elements to represent the resonant system. An analytic solution of the required power from the generator as a function of the system parameters has also been given based on a vector diagram.

• J. T.M. Lyles
  
• S. Archuletta, D. Baca, J. Davis, D. Rees, P. A. Torrez
  LANL, Los Alamos, New Mexico

A new 200 MHz RF system is being developed for the LANSCE proton drift tube linac (DTL). A planned upgrade will replace parts of the DTL RF system with new generation components. When installed for the LANSCE-R project, the new system will reduce the total number of electron power tubes from twenty-four to seven in the DTL plant. The 3.4 MW final power amplifier will use a Thales TH628 Diacrode. This state-of-the-art device eliminates the large anode modulator of the present triode system, and will be driven by a new tetrode intermediate power amplifier. In this mode of operation, this intermediate stage will provide 150 kW of peak power. The first DTL tank requires up to 400 kW of RF power, which will be provided by the same tetrode driver amplifier. A prototype system is being constructed to test components, using some of the infrastructure from previous RF projects. High voltage DC power became available through innovative re-engineering of an installed system. A summary of the design and construction of the intermediate power amplifier will be presented and test results will be summarized.

• J. Rose
  
• A. Blednykh, W. Guo, P. Mortazavi, N. A. Towne
  BNL, Upton, Long Island, New York

• M. A. Plum
  

The Spallation Neutron Source accelerator complex consists of a 2.5 MeV H^- front-end injector system, a 186 MeV normal-conducting linear accelerator, a 1 GeV superconducting linear accelerator, an accumulator ring, and associated beam transport lines. The linac was commissioned in five discrete runs, starting in 2002 and completed in 2005. The accumulator ring and associated beam transport lines were commissioned in two runs in February and April 2006. With the completed commissioning of the SNS accelerator, the facility has begun initial low-power operations. In the course of beam commissioning, most beam performance parameters and beam intensity goals have been achieved at low duty factor. A number of beam dynamics measurements have been performed, including emittance evolution, transverse coupling in the ring, beam instability thresholds, and beam distributions on the target. The commissioning results, achieved beam performance and initial operating experience of the SNS will be presented.

• T. R. Edgecock
  

• S. P. Møller
  
• T. Andersen, F. Bødker, A. Baurichter, P. A. Elkiaer, C. E. Hansen, N. Hauge, T. Holst, I. Jensen, L. K. Kruse, S. M. Madsen, M. Sager, S. V. Weber
  Danfysik A/S, Jyllinge
• K. Blasche
  BTE Heidelberg, Ingeniurburo, Schriesheim
• B. Franczak
  GSI, Darmstadt

• J. Brossard
  
• M. Alabau
  IFIC, Valencia
• D. A.-K. Angal-Kalinin
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• P. Bambade, T. Derrien
  LAL, Orsay
• O. Napoly, J. Payet
  CEA, Gif-sur-Yvette

• J. Yang
  
• K. Kan, T. Kondoh, Y. Yoshida
  ISIR, Osaka

• B. Chung
  
• Y.-S. Cho
  KAERI, Daejon
• Y. Y. Lee
  BNL, Upton, Long Island, New York

The Proton Engineering Frontier Project (PEFP) is a research project to develop a 100 MeV, 20 mA pulsed proton linear accelerator to be used in basic/applied scientific R&D programs and industrial applications. The PEFP proposes the 1.0 GeV synchrotron accelerator as an extension of the PEFP linac, which is a 30 Hz rapid-cycling synchrotron (RCS) with the injection energy of 100 MeV. The target beam power is 87 kW at 1.0GeV in the first stage. The high intensity RCS is one of the important challenges for the spallation neutron source. The conceptual lattice design of the RCS as well as the simulations of an injection system is described in this paper.

• F. Tecker
  
• C. Biscari, A. Ghigo
  INFN/LNF, Frascati (Roma)
• E. Bressi
  CNAO Foundation, Milan
• R. Corsini, S. Doebert, P. K. Skowronski, P. Urschutz
  CERN, Geneva
• A. Ferrari
  UU/ISV, Uppsala

• T. Yokoi
  
• S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon

• P. Lebrun
  
• L. Michelotti, J.-F. Ostiguy
  Fermilab, Batavia, Illinois

• C. Toth
  
• D. L. Bruhwiler, J. R. Cary
  Tech-X, Boulder, Colorado
• E. Esarey, C. G.R. Geddes, W. Leemans, K. Nakamura, D. Panasenko, C. B. Schroeder
  LBNL, Berkeley, California

Colliding laser pulses* have been proposed as a method for controlling injection of electrons into a laser wakefield accelerator (LWFA) and hence producing high quality relativistic electron beams with energy spread below 1% and normalized emittances below 1 micron. The original proposal relied on three coaxial pulsesI. One pulse excites a plasma wake, and a collinear pulse following behind it collides with a counterpropagating pulse forming a beat pattern that boosts background electrons into accelerating phase. A variation of this method uses only two laser pulses** which may be non-collinear. The first pulse drives the wake, and beating of the trailing edge of this pulse with the colliding pulse injects electrons. Non-collinear injection avoids optical elements on the electron beam path (avoiding emittance growth). We report on progress of non-collinear experiments at LBNL, using the Ti:Sapphire laser at the LOASIS facility of LBNL. Preliminary results indicate that electron beam properties are affected by the second beam. Details of the experiment will be presented.

* E. Esarey, et al, Phys. Rev. Lett 79, 2682 (1997).** G. Fubiani, Phys. Rev. E 70, 016402 (2004).

• W. Leemans
  
• E. Esarey, C. G.R. Geddes, N. H. Matlis, G. R.D. Plateau, C. B. Schroeder, C. Toth, J. Van Tilborg
  LBNL, Berkeley, California

At LBNL, laser wakefield accelerators (LWFA) now produce ultra-short electron bunches with energies up to 1 GeV[1]. As femtosecond electron bunches exit the plasma they radiate a strong burst in the terahertz range[2,3], via coherent transition radiation (CTR). Measuring the CTR properties allows non-invasive bunch-length diagnostics[4], a key to continuing rapid advance in LWFA technology. In addition, this method of CTR generation provides very high peak power that can lead novel THz-based applications. Experimental bunch length characterizations through electro-optic sampling as well as bolometric analysis are presented. Measurements demonstrate both the shot-by-shot stability of bunch parameters, and femtosecond synchronization between bunch, THz pulse, and laser beam.

[1] W. P. Leemans et al., Nature Physics 2, 696(2006)[2] W. P. Leemans et al., PRL 91, 074802(2003)[3] C. B. Schroeder et al., PRE 69, 016501(2004)[4] J. van Tilborg et al., PRL 96, 014801(2006)

• I. Reichel
  

The current design for the injection and extraction lines into and out of the ILC Damping Rings is presented as well as the design for the abort line. Due to changes of the geometric boundary conditions by other subsystems of the ILC a modular approach has been used to be able to respond to recurring layout changes while reusing previously designed parts. Available beam dynamics studies for those lines are discussed.

• 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

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.

• 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

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.

• K. L.F. Bane
  
• A. Seryi
  SLAC, Menlo Park, California

The main linac of the International Linear Collider (ILC) accelerates short, high peak current bunches into the Beam Deliver System (BDS) on the way to the interaction point. In the BDS wakefields are excited by the resistance of the beam pipe walls and by beam pipe transitions that will tend to degrade the emittance of the beam bunches. In this report we calculate the effect on emittance of incoming jitter or drift, and of misalignments of the beam pipes with respect to the beam axis, both analytically and through multi-particle tracking. Finally, we discuss ways of ameliorating the wake effects in the BDS.

• D. Trbojevic
  

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.

• D. Kaganovich
  
• D. F. Gordon, A. Ting
  NRL, Washington, DC

• R. P. Nunes
  
• R. Pakter, F. B. Rizzato
  IF-UFRGS, Porto Alegre

The goal of this work is to analyze the envelope dynamics of magnetically focused and high-intensity charged particle beams. As known, beams with mismatched envelopes decay into its equilibrium state with a simultaneous increasing of emittance. This emittance growth implies that, in the stationary regime, the transverse phase-space of the beam is characterized by a tenuous population of hot particles around a dense population of cold particles. To describe this emittance growth, it was used the test-particle approach for the development of a simplified self-consistent macroscopic model, whose self-consistency is a result of the inclusion of the emittance growth into the envelope equation. The model is then compared with full N-particle beam simulations and the agreement is shown to be quite reasonable. The model revealed to be useful to understand the physical aspects of the problem and is computationally faster when compared with full simulations.

• S. Liu
  
• S. Araki, M. K. Fukuda, M. Takano, N. Terunuma, J. Urakawa
  KEK, Ibaraki
• K. Hirano
  NIRS, Chiba-shi

• A. Y. Molodozhentsev
  
• T. Koseki, M. Tomizawa
  KEK, Ibaraki

• Yu. A. Kubyshin
  
• A. V. Poseryaev, V. I. Shvedunov
  MSU, Moscow
• J. P. Rigla
  UPC, Barcelona

• N. Sereno
  
• M. Borland
  ANL, Argonne, Illinois

In recent years, we have explored various upgrade options for the Advanced Photon Source (APS) storage ring that would provide the user community higher brightness. Increased brightness would be accomplished by reducing the emittance of the storage ring as well as increasing the stored beam current from 100 mA to 200 mA. Two upgrade lattices were developed that reduce the effective beam emittance to 1 nm from the present 2.7 nm. These lattices have reduced dynamic aperture compared to the present ring lattice, which may require a reduced emittance booster to minimize injection losses. This paper describes injection tracking simulations that explore how high the booster emittance can be and still have no losses at injection for the 1-nm ring upgrade lattices. An alternative booster lattice is presented with reduced emittance compared to the present booster lattice (65 nm). The proposed low-emittance booster lattice would add pole-face windings to the existing booster dipoles and hence would not require replacement of the existing booster magnets.

• A. Xiao
  
• L. Emery
  ANL, Argonne, Illinois

We present a lattice design based on the theoretical-minimum-emittance (TME) cell for the International Linear Collider (ILC0 6.6-km 5-GeV damping ring. Several areas are discussed: momentum compaction, lattice layout, injection and extraction, circumference adjusters, phase adjuster, and dynamic aperture calculation with multipole errors.

• Y. Alexahin
  
• E. Gianfelice-Wendt
  Fermilab, Batavia, Illinois
• V. V. Kapin
  MEPhI, Moscow
• F. Schmidt
  CERN, Geneva

Turn-by-turn BPM data provide immediate information on the coupledoptics functions at BPM locations. In the case of small deviations from the known (design) uncoupled optics some cognizance of the sources of perturbation, BPM calibration errors and tilts can also be inferred without detailed lattice modelling. In practical situations, however, fitting the lattice model with the help of some optics code would lead to more reliable results. We present an algorithm for coupled optics reconstruction from TBT data on the basis of MAD-X and give examples of its application for the Fermilab Tevatron and Booster accelerators.

• E. Gianfelice-Wendt
  
• Y. Alexahin
  Fermilab, Batavia, Illinois

The Main Injector (MI) is a rapid cycling multipurpose accelerator. After completion of the Tevatron Run II, its primary application will be the acceleration of high intensity proton beams for neutrino experiments. To achieve the intensity goal a detailed knowledge of the optics and transverse impedances is necessary which can be obtained from Turn-By-Turn (TBT) beam position measurements. The recent MI Beam Position Monitor system upgrade made it possible to apply the TBT data analysis methods which were successfully used by the authors for the Tevatron. We present the results of MI optics measurements and the impedance estimates obtained from the betatron phase advance dependence on beam current.

• T. Sen
  
• H. J. Kim
  Fermilab, Batavia, Illinois

• M.-J. Yang
  

• X. Zhang
  
• A. Z. Chen, W. Chou, B. M. Hanna, K. Y. Ng, J.-F. Ostiguy, L. Valerio, R. M. Zwaska
  Fermilab, Batavia, Illinois

Estimates indicate that the electron cloud effect could be a limiting factor for Main Injector intensity upgrades, with or without a the presence of a new 8 GeV superconducting 8GeV Linac injector. The effect may turn out to be an issue of operational relevance for other parts of the Fermilab accelerator complex as well. To improve our understanding of the situation, two sections of specially made vacuum test pipe outfitted for electron cloud detection with ANL provided Retarding Field Analyzers (RFAs), were installed in the Tevatron and the Main Injector. In this report we present some measurements, compare them with simulations and discuss future plans for studies.

• S. Bernal
  
• B. L. Beaudoin, R. A. Kishek, P. G. O'Shea, M. Reiser, D. F. Sutter
  UMD, College Park, Maryland

The University of Maryland Electron Ring (UMER) is designed for the transport of low energy (10 keV), high current (100 mA) electrons in a 72-magnetic-quadrupole lattice over an 11.5 m circumference. With these parameters, and a typical single-particle phase advance per period of 76 deg., space charge is extreme. However, high current is not necessary for establishing space charge dominated transport in UMER. In fact, low current (0.6 mA) beam transport in combination with longer full-lattice periods can yield strong space charge conditions. All 72 quadrupoles are needed, though, to yield beams with relatively small cross sections, as required for emittance-dominated transport. We present results of calculations and experiments that demonstrate the low-current, high space charge regime in UMER. We also discuss the use of Collins-type insertions for matching into the ring lattice.

• J. Li
  
• S. Huang, S. F. Mikhailov, V. Popov, Y. K. Wu
  FEL/Duke University, Durham, North Carolina

As part of the High Intensity Gamma-Ray Source (HIGS) upgrade, the booster synchrotron has been recently commissioned. The booster ramps the electron beam between 0.27 and 1.2 GeV for top-off injection into the Duke storage ring. It has symmetrical injection/extraction schemes with a bumped orbit. The injection/extraction kickers and corresponding septa are located in the opposite straight sections of the booster ring separated by about 1/4 of the vertical betatron wave. Due to the nonideal properties of the magnetic material, the magnetic field leaks out into the stored beam chamber, which directly results in orbit distortion, tune and chromaticity shifts and change of coupling. These effects caused by the extraction septum have been measured as a function of extraction energy. Based upon the measurements, we have developed a scheme to compensate the dynamics effects mentioned above.

• A. Fukasawa
  
• D. Alesini, M. Ferrario, B. Spataro
  INFN/LNF, Frascati (Roma)
• A. Boni, B. D. O'Shea, J. B. Rosenzweig
  UCLA, Los Angeles, California
• L. Ficcadenti, A. Mostacci, L. Palumbo
  Rome University La Sapienza, Roma

• R. M. Bodenstein
  
• M. G. Tiefenback
  Jefferson Lab, Newport News, Virginia

The CEBAF recirculating accelerator consists of two CW superconducting RF linacs, through which an electron beam is accelerated for up to 5 passes. Focusing and steering elements affect each pass differently, requiring a multipass steering protocol to correct the orbits. Perturbations include lens misalignments (including long-term ground motion), BPM offsets, and focusing and steering from RF fields inside the cavities. A previous treatment of this problem assumed all perturbations were localized at the quadrupoles and the absence of x-y coupling. Having analyzed the problem and characterized the solutions, we developed an empirical iterative protocol to compare against previous results in the presence of skew fields and cross-plane coupling. We plan to characterize static and acceleration-dependent components of the beam line perturbations to allow systematic and rapid configuration of the accelerator at different linac energy gains.

• J. A. Holmes
  
• M. R. Perkett
  Denison University, Granville, Ohio
• M. A. Plum, J.-G. Wang, Y. Zhang
  ORNL, Oak Ridge, Tennessee

Simulations of the transport of H⁰ and H^- beams to the SNS ring injection dump are carried out using the ORBIT code. During commissioning and early operations, beam losses in this region have been the highest in the accelerator and presented the most obvious hurdle to cross in achieving high intensity operation. Two tracking models are employed:

1. a piecewise continuous symplectic representation of the lattice elements in the injection chicane and dump line, and
2. particle tracking in full 3D magnetic fields, as obtained from OPERA code evaluations.

• J.-G. Wang
  

The SNS ring injection dump beam line has been suffering high beam losses since its commissioning. In order to understand the mechanisms of the beam losses, we have built a 3D simulation model consisting of three injection chicane dipoles and one injection dump septum. The magnetic field distributions and the 3D particle trajectories in the model are obtained. The study has clearly shown two design problems causing beam losses in the injection dump beam line. This paper reports our simulation model, particle trajectory calculations, beam losses due to small vertical aperture of the injection dump septum and inadequate focusing down stream. The remedy of the beam losses is also discussed.

• C. Montag
  

Polarized protons are injected into the Relativistic Heavy Ion Collider (RHIC) just above transition energy. When installation of a cold partial Siberian snake in the AGS required lowering the injection energy by Delta gamma=0.56, the transition energy in RHIC had to be lowered accordingly to ensure proper longitudinal matching. This paper presents lattice modifications implemented to lower the transition energy by ∆ γ_t=0.8.

• J. G. Alessi
  
• E. N. Beebe, O. Gould, A. Kponou, R. Lockey, A. I. Pikin, D. Raparia, J. Ritter, L. Snydstrup
  BNL, Upton, Long Island, New York

An Electron Beam Ion Source (EBIS), capable of producing high charge states and high beam currents of any heavy ion species in short pulses, is ideally suited for injection into a synchrotron. An EBIS-based, high current, heavy ion preinjector is now being built at Brookhaven to provide increased capabilities for the Relativistic Heavy Ion Collider (RHIC), and the NASA Space Radiation Laboratory (NSRL). Benefits of the new preinjector include the ability to produce ions of any species, fast switching between species to serve the simultaneous needs of multiple programs, and lower operating and maintenance costs. A state-of-the-art EBIS, operating with an electron beam current of up to 10 A, and producing multi-milliamperes of high charge state heavy ions, has been developed at Brookhaven, and has been operating very successfully on a test bench for several years. The present performance of this high-current EBIS will be presented, along with details of the design of the scaled-up EBIS for RHIC, and the status of its construction. Other aspects of the project, including design and construction of the heavy ion RFQ, Linac, and matching beamlines, will also be mentioned.

• T. W. Hardek
  
• M. S. Champion, M. T. Crofford, H. Ma, M. F. Piller
  ORNL, Oak Ridge, Tennessee
• K. Smith, A. Zaltsman
  BNL, Upton, Long Island, New York

The Spallation Neutron Source (SNS) accumulator ring is a fixed-frequency proton storage ring located at the output of the SNS Linear Accelerator (Linac). Its purpose is to convert 1 millisecond H^- beam pulses from the SNS Linac into high-intensity 695 nanosecond pulses of protons for delivery to the neutron target. The RF bunching system controls longitudinal beam distribution during the accumulation process and maintains a 250+ nanosecond gap required for beam extraction. The RF system consists of three stations which operate at a beam revolution frequency of 1.05 MHz while a fourth station provides a second harmonic component at 2.1 MHz. The beam pulse at extraction consists of 1.6·10¹⁴ protons representing a peak beam current of 52 amperes. The system utilizes four 600kW tetrodes to provide the RF current necessary to produce the 40kV peak-bunching voltage and to control phase and amplitude at this high beam current. In this paper we review the design concepts incorporated into this heavily beam-loaded RF system and discuss its commissioning status.

• C. Joshi
  

• M. J. Boland
  
• D. J. Peake
  ASP, Clayton, Victoria
• R. P. Rassool
  Melbourne

• Y. E. Tan
  
• M. J. Boland, R. T. Dowd, G. LeBlanc, M. J. Spencer
  ASP, Clayton, Victoria

• E. Huttel
  
• I. Birkel, A.-S. Muller, P. Wesolowski
  FZK, Karlsruhe

• T. Fujita
  
• S. Sasaki, M. Shoji, T. Takashima
  JASRI/SPring-8, Hyogo-ken

• A. Y. Molodozhentsev
  
• T. Koseki, M. Tomizawa
  KEK, Ibaraki
• S. Machida
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon

• G. Arduini
  
• T. Bohl, H. Burkhardt, E. Metral, G. Rumolo
  CERN, Geneva
• B. Salvant
  EPFL, Lausanne

• H. Damerau
  
• M. Morvillo, E. N. Shaposhnikova, J. Tuckmantel, J.-L. Vallet
  CERN, Geneva

• R. Tomas
  
• G. Arduini, G. Rumolo, F. Zimmermann
  CERN, Geneva
• R. Calaga
  BNL, Upton, Long Island, New York
• A. Faus-Golfe
  IFIC, Valencia

In recent years several measurements of the SPS non-linear chromaticity have been performed in order to determine the non-linear optics model of the SPS machine at injection energy for different cycles. In 2006 additional measurements have been performed at injection and during the ramp for the cycle used to accelerate the LHC beam. New and more robust matching algorithms have been developed in 2006 to fit the model to the measurements up to arbitrary chromatic order. In this paper we describe the algorithms used in the analysis of the data and we summarize and compare the results from all experiments.

• J. Chen
  
• P. C. Chiu, K. T. Hsu, S. Y. Hsu, K. H. Hu, C. H. Kuo, D. Lee, C.-J. Wang, C. Y. Wu
  NSRRC, Hsinchu

• J. C. Dooling
  
• F. R. Brumwell, L. Donley, K. C. Harkay, R. Kustom, M. K. Lien, G. E. McMichael, M. E. Middendorf, A. Nassiri, S. Wang
  ANL, Argonne, Illinois

In the IPNS RCS, a single proton bunch (h=1) is accelerated from 50 MeV to 450 MeV in 14.2 ms. The bunch experiences an instability shortly after injection (<1 ms). During the first 1 ms, the beam is bunched but little acceleration takes place; thus, this period of operation is similar to that of a storage ring. Natural vertical oscillations (assumed to be tune lines) show the vertical tune to be rising toward the bare tune value, suggesting neutralization of space charge and a reduction of its detuning effects. Neutralization time near injection ranges from 0.25 ms - 0.5 ms, depending on the background gas pressure. Oscillations move from the LSB to the USB before disappearing. Measurements made with a recently installed pinger system show the horizontal chromaticity to be positive early but approaching zero later in the cycle. The vertical chromaticity is negative throughout the cycle. During pinger studies, two lines are observed, suggesting the formation of islands. Neutralization of the beam space charge implies the generation of plasma in the beam volume early in the cycle which may then dissipate as the time-varying electric fields of the beam become stronger.

• K. C. Harkay
  
• Y.-C. Chae, L. Emery, L. H. Morrison, A. Nassiri, G. J. Waldschmidt
  ANL, Argonne, Illinois

The Advanced Photon Source storage ring is normally operated with 100 mA of beam current. A number of high-current studies were carried out to determine the multibunch instability limits. The longitudinal multibunch instability is dominated by the rf cavity higher-order modes (HOMs), and the coupled-bunch instability (CBI) threshold is bunch-pattern dependent. We can stably store 200 mA with 324 bunches, and the CBI threshold is 245 mA. With 24 bunches, several components are approaching temperature limits above 160 mA, including the HOM dampers. We do not see any CBI at this current. The transverse multibunch instabilities are most likely driven by the resistive wall impedance; there is little evidence that the dipole HOMs contribute. Presently, we rely on the chromaticity to stabilize the transverse multibunch instabilities. When we stored beam up to 245 mA, we used high chromaticity, and the beam was transversely stable. The stabilizing chromaticity was studied as a function of current. We can use these experimental results to predict multibunch instability thresholds for various upgrade options, such as smaller-gap or longer ID chambers and the associated increased impedance.

• W. E. Norum
  
• B. X. Yang
  ANL, Argonne, Illinois

Bunch purity is an important source quality factor for the magnetic resonance experiments at the Advanced Photon Source. Conventional bunch-purity monitors utilizing time-to-amplitude converters are subject to dead time. We present a novel design based on a single field-programmable gate array (FPGA) that continuously processes pulses at the full speed of the detector and front-end electronics. The FPGA provides 7778 single-channel analyzers (six per RF bucket). The starting time and width of each single-channel analyzer window can be set to a resolution of 178 ps. A detector pulse arriving inside the window of a single-channel analyzer is recorded in an associated 32-bit counter. The analyzer makes no contribution to the system dead time. Two channels for each RF bucket count pulses originating from the electrons in the bucket. The other four channels on the early and late side of the bucket provide estimates of the background. A single-chip microcontroller attached to the FPGA acts as an EPICS IOC to make the information in the FPGA available to the EPICS clients.

• Y. Alexahin
  

To avoid multiple head-on collisions the proton and antiproton beams in the Tevatron move along separate helical orbits created by 7 horizontal and 8 vertical electrostatic separators. Still the residual long-range beam-beam interactions can adversely affect particle motion at all stages from injection to collision. With increased intensity of the beams it became necessary to modify the orbits in order to mitigate the beam-beam effect on both antiprotons and protons. This report summarizes the work done on optimization of the Tevatron helical orbits, outlines the applied criteria and presents the achieved results.

• A. Jansson
  
• K. Bowie, T. Fitzpatrick, R. Kwarciany, C. Lundberg, D. Slimmer, L. Valerio, J. R. Zagel
  Fermilab, Batavia, Illinois

Two Ionization Profile Monitors (IPMs) were installed in the Tevatron in 2006. The detectors are capable of resolving single bunches turn-by-turn, using a combination of gas injection to boost the ionization signal and very fast and sensitive electronics to detect it. This paper presents recent improvements to the system hardware and its use for beam monitoring. In particular, the correction of beam size oscillations observed at injection is discussed.

• A. Valishev
  
• G. Annala, V. A. Lebedev, R. S. Moore
  Fermilab, Batavia, Illinois

• M.-J. Yang
  
• J. L. Crisp, P. S. Prieto
  Fermilab, Batavia, Illinois

• M.-J. Yang
  

• K. G. Sonnad
  
• C. M. Celata, M. A. Furman, D. P. Grote, J.-L. Vay, M. Venturini
  LBNL, Berkeley, California

The Fermilab main injector (MI) is being considered for an upgrade as part of the high intensity neutrino source (HINS) effort. This upgrade will involve a significant increasing of the bunch intensity relative to its present value. Such an increase will place the MI in a regime in which electron-cloud effects are expected to become important. We have used the electrostatic particle-in-cell code WARP, recently augmented with new modeling capabilities and simulation techniques, to study the dynamics of beam-electron cloud interaction. This study involves a systematic assesment of beam instabilities due to the presence of electron clouds.

• A. Kanareykin
  
• W. Gai, J. G. Power
  ANL, Argonne, Illinois
• C.-J. Jing, A. L. Kustov, P. Schoessow
  Euclid TechLabs, LLC, Solon, Ohio

We report on the experimental and numerical investigation of beam breakup (BBU) effects in dielectric structures resulting from parasitic wakefields. The experimental program focuses on measurements of BBU in a number of wakefield devices: (a) a 26 GHz power extraction structure; (b) a high gradient dielectric wakefield accelerator; (c) a wakefield structure driven by a high current ramped bunch train for multibunch BBU studies. New beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable at the AWA facility. The numerical part of this research is based on a particle-Green's function based beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the accurate numerical results obtained from the new BBU code with the results of the detailed experimental measurements. An external focusing system for the control of the beam in the presence of strong transverse wakefields is considered.

• E. Pozdeyev
  
• I. Ben-Zvi, P. Cameron, K. A. Drees, D. M. Gassner, D. Kayran, V. Litvinenko, G. J. Mahler, T. Rao
  BNL, Upton, Long Island, New York

The ERL Prototype project is currently under development at the Brookhaven National Laboratory. The ERL is expected to demonstrate energy recovery of high-intensity beams with a current of up to a few hundred milliamps, while preserving the emittance of bunches with a charge of a few nanocoulombs produced by a high-current SRF gun. To successfully accomplish this task the machine will include beam diagnostics that will be used for accurate characterization of the three dimensional beam phase space at the injection and recirculation energies, transverse and longitudinal beam matching, orbit alignment, beam current measurement, and machine protection. This paper outlines requirements on the ERL diagnostics and describes its setup and modes of operation.