• Z. Zhao
  

• A. Novokhatski
  

We describe the method to measure total HOM losses and synchrotron losses in a storage ring based on a straightforward model of beam-cavity interaction and precise knowledge of RF power distribution. This method works well at higher currents. The comparison of the measured HOM losses and estimation for cavity and resistive wall losses is given for both LER and HER rings of the PEP-II B-factory.

• A. Zholents
  

Subpicosecond x-ray pulses are now routinely obtained at the ALS, BESSY and SLS light sources using laser e-beam slicing technique. Other x-ray pulse shortening techniques were also proposed and are now under consideration for ALS, APS, DIAMOND and PETRA light sources. In this talk I review current results and discuss R&D plans and activity.

• T. Shintake
  

• J. Rossbach
  

• H. L. Andrews
  
• C. H. Boulware, C. A. Brau, J. D. Jarvis
  Vanderbilt University, Nashville, Tennessee

• M. Roehrs
  
• C. Gerth, H. Schlarb
  DESY, Hamburg

• R. Kersevan
  
• L. Goirand
  ESRF, Grenoble

• J. Kreutzkamp
  
• L. Hagge
  DESY, Hamburg

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

• R. Rossmanith
  
• T. Baumbach, A. Bernhard, A.-S. Muller, D. Wollmann
  University of Karlsruhe, Karlsruhe
• H.-H. Braun, M. Korostelev, Y. Papaphilippou, F. Zimmermann
  CERN, Geneva
• S. Casalbuoni, A. W. Grau, M. Hagelstein, B. K. Kostka
  FZK, Karlsruhe
• E. Mashkina, E. Steffens
  University of Erlangen-Nurnberg, Physikalisches Institut II, Erlangen

• E. Al-Dmour
  
• D. Einfeld, M. Q. Quispe
  ALBA, Bellaterra (Cerdanyola del Valles)

• K. Kershaw
  
• F. Chapron, A. Y. Coin, F. Delsaux, T. Feniet, J. L. Grenard, R. V. Valbuena
  CERN, Geneva

• C.-Y. Liu
  
• K.-B. Liu, H. M. Shih
  NSRRC, Hsinchu

• J. Ruan
  
• H. Edwards, R. P. Fliller, J. K. Santucci
  Fermilab, Batavia, Illinois

The current Fermilab A0 Photoinjector laser system includes a seed laser, a flashlamp pumped multipass amplifier cavity, a flashlamp pumped 2-pass amplifier system followed by an IR to UV conversion stage. However the current system can only deliver up to 800 pulses due to the low efficiency of Nd:Glass used inside multi-pass cavity. In this paper we will report the effort to develop a new multi pass cavity based on Nd:YLF crystal end-pumped by diode laser. We will also discuss the foreseen design of the laser system for the NML accelerator test facility at Fermilab.

• N. V. Mokhov
  
• P. Ferracin, G. L. Sabbi
  LBNL, Berkeley, California
• V. Kashikhin, M. Monville
  Fermilab, Batavia, Illinois

At the LHC upgrade luminosity of 10³⁵ cm^-2 s^-1, collision product power in excess of a kW is deposited in the inner triplet quadrupoles. The quadrupole field sweeps secondary particles from pp-collisions into the superconducting coils, concentrating the power deposition at the magnetic mid-planes. The local peak power density can substantially exceed the conductor quench limits and reduce component lifetime. Under these conditions, block-coil geometries may result in overall improved performance by removing the superconductor from the magnetic mid-planes and/or allowing increased shielding at such locations. First realistic energy deposition simulations are performed for an interaction region based on block-coil quadrupoles with parameters suitable for the LHC upgrade. Results are presented on 3-D distributions of power density and accumulated dose in the inner triplet components as well as on dynamic heat loads on the cryogenic system. Optimization studies are performed on configuration and parameters of the beam pipe, cold bore and cooling channels. The feasibility of the proposed design is discussed.

• J. W. Staples
  
• J. M. Byrd, R. B. Wilcox
  LBNL, Berkeley, California

Long-term phase drifts of less than a femtosecond per hour have been demonstrated in a 2 km length of single-mode optical fiber, stabilized interferometrically at 1530 nm. Recent improvements include a wide-band phase detector that reduces the possibility of fringe jumping due to fast external perturbations of the fiber and locking of the master CW laser wavelength to a molecular absorption line. Mode-locked lasers may be synchronized using two wavelengths of the comb, multiplexed over one fiber, each wavelength individually interferometrically stabilized.

• S. P. Virostek
  
• M. A. Green, D. Li, M. S. Zisman
  LBNL, Berkeley, California

The Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling in a short section of a realistic cooling channel using a muon beam at Rutherford Appleton Laboratory (RAL) in the UK. A five-coil, superconducting spectrometer solenoid magnet at each end of the cooling channel will provide a 4 T uniform field region for the scintillating fiber tracker within the magnet bore tubes. The tracker modules are used to measure the muon beam emittance as it enters and exits the cooling channel. The cold mass for the 400 mm warm bore magnet consists of two sections: a three-coil spectrometer magnet and a two-coil matching section that matches the uniform field of the solenoid into the MICE cooling channel. The detailed design and analysis of the two spectrometer solenoids has been completed, and the fabrication of the magnets is in its final stages. The primary features of the spectrometer solenoid magnetic and mechanical designs are presented along with a summary of key fabrication issues and photos of the fabrication process.

• 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.

• M. J. Borden
  
• C. A. Chapman, C. T. Kelsey, J. F. O'Hara, J. Sturrock
  LANL, Los Alamos, New Mexico

Dose rate modeling and post irradiation measurements of the Isotope Production Facility beamline, at the Los Alamos Neutron Science Center (LANSCE) accelerator, have determined that a radiation shielding shutter is required to protect personnel from shine from irradiated targets for routine beam tunnel entries. This paper will describe radiation dose modeling, shielding calculations and the failsafe mechanical shutter design.

• J. E. Spencer
  

We consider optimization of the generalized luminosity per unit cost of a linear collider in this ES&H era. Examples running over the length of the LC, starting at the source and ending at the dump, suggest that both costs (capital and operating) and environmental issues can be improved in a compatible way. Thus, a RoHS by any other name (WEES or OSHA) need not present thorny problems requiring unexpected R&D but a push to leverage many recent advances that might otherwise be overlooked or avoided. The physics is interesting and the true amortized cost may be seriously underestimated by ignoring such issues. For example, the entire, interior surface of a laser driven RF gun involves interesting materials science where the space requires continuous UHV to sustain stable, acceptable quantum efficiency as well as avoid RF breakdown damage in an environment that is also subject to radiation damage. All of these can seriously reduce a gun's output and LCs luminosity. Intelligent design of rad-hard systems can approach the ideal of bug-proof software that needn't produce overly slow or ponderous systems while providing opportunities to innovate that justify the costs.

• J. E. Spencer
  
• S. D. Anderson, Z. R. Wolf
  SLAC, Menlo Park, California
• M. Boussoufi
  UCD/MNRC, McClellan, California
• G. Gallagher, D. E. Pellet
  UCD, Davis, California
• J. T. Volk
  Fermilab, Batavia, Illinois

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) to improve reliability and longevity since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas. Examples include NdFeB magnets, considered for the damping rings, injection and extraction lines and final focus, electronic and electro-optic devices to be utilized in detector readout, accelerator controls and the CCDs required for the vertex detector, as well as high and low temperature superconducting materials (LTSMs) because some magnets will be superconducting. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented for NdFeB materials at EPAC04 where the damage appeared proportional to the distances between the effective operating point and Hc. We have extended those doses, included other manufacturer's samples and measured induced radioactivities. We have also added L and HTSMs as well as a variety of relevant semiconductor and electro-optic materials including PBG fiber that we studied previously only with gamma rays.

• V. P. Yakovlev
  
• J. L. Hirshfield
  Omega-P, Inc., New Haven, Connecticut
• A. Kanareykin
  Euclid TechLabs, LLC, Solon, Ohio
• S. Kazakov
  KEK, Ibaraki
• E. Nenasheva
  Ceramics Ltd., St. Petersburg
• S. V. Shchelkunov
  Columbia University, New York

Fast, electrically-controlled ferroelectric RF vector modulators are under development for different accelerator applications in the frequency range 0.4 - 1.3 GHz. The exact design of a vector modulator depends on the electrical parameters of particular ferroelectric material to be used, namely its dielectric constant, loss tangent and tunability. The exact values of these parameters were unknown in this frequency domain for low loss BST material that is planned to be used. A special two-disc test cavity has been designed and built that allows direct measurements of these parameters for large (100 mm in diameter) ferroelectric rings that are to be used in vector modulators. The results of measurements are presented.

• D. Stout
  
• S. Assadi, I. E. Campisi, F. Casagrande, M. T. Crofford, W. R. DeVan, X. Geng, T. W. Hardek, S. Henderson, M. P. Howell, Y. W. Kang, W. C. Stone, W. H. Strong, D. C. Williams, P. A. Wright
  ORNL, Oak Ridge, Tennessee

The SNS project was completed with only limited SRF facilities installed as part of the project, namely a 5 MW, 805 MHz RF test stand, a fundamental power coupler processing system, a concrete test cave shell, and temporary cleaning/assembly facilities. A concerted effort has been initiated to install the infrastructure and equipment necessary to maintain and repair the superconducting Linac, and to support power upgrade R&D. Installation of a Class10/100/10,000 cleanroom and outfitting of the test cave with RF, vacuum, controls, personnel protection and cryogenics systems is underway. A horizontal cryostat, which can house a helium vessel/cavity and fundamental power coupler for full power, pulsed testing, is being procured. Equipment for cryomodule assembly/disassembly and cavity processing also is being designed. This effort, while derived from the experience of the SRF community, will provide a unique high power test capability as well as long term maintenance capabilities. This paper presents the current status and the future plans for the SNS SRF facilities.

• D. C. Williams
  
• X. Geng, P. Ladd
  ORNL, Oak Ridge, Tennessee

The superconducting linac of the Spallation Neutron Source (SNS) has 23 cryomodules each of which incorporate either 3 or 4 niobium cavities. These cavities are submerged in a bath of liquid helium and maintained at an operating temperature of ~ 2K. This bath is surrounded by heat shields and a multilayer blanket within the cryomodule shell. The pressure in this area needs to be maintained at <5·10^-5 torr to limit heat leak due to gas convection. Some cryomodules have developed helium leaks into this vacuum cavity and now need to be actively pumped. This paper provides an overview of the Insulating Vacuum System (IVS) that has been installed for this purpose.

• C. J. Liaw
  
• R. Schroeder, R. Sikora
  BNL, Upton, Long Island, New York

• P. I. Pavlishin
  
• M. Babzien, I. Pogorelsky, D. Stolyarov, V. Yakimenko
  BNL, Upton, Long Island, New York
• M. S. Zolotorev
  LBNL, Berkeley, California

Optical stochastic cooling for the Relativistic Heavy Ion Collider (RHIC) based on optical parametric amplification was proposed by M. Babzien et al., Phys. Rev. ST Accel. Beams v.7, 012801, (2004). According to this proposal a CdGeAs2 nonlinear crystal is used as an active medium for the optical parametric amplifier because of extremely large nonlinear coefficient, wide transparency range, and possibility to be phase matched over the required spectral range. We discuss experimental results of the parametric amplifier gain and coherency for the conditions applicable to optical stochastic cooling for RHIC.

• H. G. Kirk
  

• K.-J. Kim
  

• G. Tosin
  
• R. Basilio, J. F. Citadini, M. Potye
  LNLS, Campinas

• 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.

• G. Wuestefeld
  
• R. Follath, A. Meseck
  BESSY GmbH, Berlin

The cascaded High Gain Harmonic Generation (HGHG) scheme proposed for the BESSY-FEL contains an inherent potential for providing jitter free radiation pulses for pump and probe experiments. In an HGHG stage an energy modulation is imprinted to the electron beam by a seeding radiation. A dispersive section converts this energy modulation to a spatial modulation which is optimized for a particular harmonic. The subsequent radiator is optimized for this harmonics and generates radiation with high power which is used as seeding radiation for the next stage. After passage through the modulator, the seeding radiation become redundant and can be separated from the prebunched electrons using a deflecting dispersive chicane. This radiation and the final FEL output will have a fixed temporal separation as the first one is the driving seeding radiation for the second one. Using the planned test facility for HGHG scheme at BESSY as an example, we present simulation studies for a sequences of two jitter free pump and probe pulses including the deflecting chicane and a suitable beam line.

• S. Khan
  
• G. Angelova, V. G. Ziemann
  UU/ISV, Uppsala
• J. Boedewadt, A. Winter
  Uni HH, Hamburg
• M. Hamberg, N. X. Javahiraly, M. Larsson, P. Salen, P. van der Meulen
  FYSIKUM, AlbaNova, Stockholm University, Stockholm
• A. Meseck
  BESSY GmbH, Berlin
• E. Saldin, H. Schlarb, B. Schmidt, E. Schneidmiller, M. V. Yurkov
  DESY, Hamburg

* E. Saldin, E. Schneidmiller, M. Yurkov, NIM A 539 (2005), 499

• S. Casalbuoni
  
• T. Baumbach, A. Bernhard, D. Wollmann
  University of Karlsruhe, Karlsruhe
• A. W. Grau, M. Hagelstein, B. K. Kostka, R. Rossmanith
  FZK, Karlsruhe
• E. Mashkina, E. Steffens
  University of Erlangen-Nurnberg, Physikalisches Institut II, Erlangen
• F. Zimmermann
  CERN, Geneva

• M. Boscolo
  
• I. Boscolo, S. Cialdi, V. Petrillo
  INFN-Milano, Milano
• F. Castelli
  Universita degli Studi di Milano, Milano
• M. Ferrario, C. Vaccarezza
  INFN/LNF, Frascati (Roma)

• G. Gatti
  
• A. M. Cook, J. B. Rosenzweig, R. Tikhoplav
  UCLA, Los Angeles, California

• C. Vaccarezza
  
• D. Alesini, M. Bellaveglia, S. Bertolucci, R. Boni, M. Boscolo, M. Castellano, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, C. Ligi, M. Migliorati, A. Mostacci, E. Pace, L. Palumbo, L. Pellegrino, M. A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stella, F. Tazzioli, M. Vescovi, C. Vicario
  INFN/LNF, Frascati (Roma)
• F. Alessandria, A. Bacci, R. Bonifacio, I. Boscolo, F. Broggi, F. Castelli, S. Cialdi, C. De Martinis, A. F. Flacco, D. Giove, C. Maroli, V. Petrillo, A. R. Rossi, L. Serafini
  INFN-Milano, Milano
• M. Bougeard, P. Breger, B. Carre, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Monchicourt, P. Salieres, O. Tcherbakoff
  CEA, Gif-sur-Yvette
• L. Catani, E. Chiadroni, A. Cianchi, E. Gabrielli, C. Schaerf
  INFN-Roma II, Roma
• F. Ciocci, G. Dattoli, A. Dipace, A. Doria, F. Flora, G. P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, P. L. Ottaviani, S. Pagnutti, G. Parisi, L. Picardi, M. Quattromini, A. Renieri, G. Ronci, C. Ronsivalle, M. Rosetti, E. Sabia, M. Sassi, A. Torre, A. Zucchini
  ENEA C. R. Frascati, Frascati (Roma)
• M.-E. Couprie
  SOLEIL, Gif-sur-Yvette
• P. Emma
  SLAC, Menlo Park, California
• M. Mattioli, D. Pelliccia
  Universita di Roma I La Sapienza, Roma
• P. Musumeci, M. Petrarca
  INFN-Roma, Roma
• C. Pellegrini, S. Reiche, J. B. Rosenzweig
  UCLA, Los Angeles, California
• A. Perrone
  INFN-Lecce, Lecce

• V. Petrillo
  
• A. Bacci, C. Maroli, A. R. Rossi, L. Serafini, P. Tomassini
  INFN-Milano, Milano
• A. Colzato
  Universita degli Studi di Milano, Milano

• K. Togawa
  
• A. Higashiya, T. Shintake
  RIKEN Spring-8 Harima, Hyogo

• T. Kasuga
  
• T. A. Agoh, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Harada, S. Hiramatsu, T. Honda, K. Hosoyama, M. Izawa, E. Kako, H. Kawata, M. Kikuchi, Y. Kobayashi, M. Kuriki, T. Mitsuhashi, T. Miyajima, S. Nagahashi, T. Naito, T. Nogami, S. Noguchi, T. Obina, S. Ohsawa, M. Ono, T. Ozaki, S. Sakanaka, H. Sasaki, S. Sasaki, K. Satoh, M. Satoh, T. Shioya, T. Shishido, T. Suwada, M. Tadano, T. Takahashi, Y. Tanimoto, M. Tawada, M. Tobiyama, K. Tsuchiya, T. Uchiyama, K. Umemori, S. Yamamoto
  KEK, Ibaraki
• R. Hajima, H. Iijima, N. Kikuzawa, E. J. Minehara, R. Nagai, N. Nishimori, M. Sawamura
  JAEA/ERL, Ibaraki
• H. Hanaki, H. T. Tomizawa
  JASRI/SPring-8, Hyogo-ken
• A. Ishii, I. Ito, H. Kudoh, N. Nakamura, H. Sakai, S. Shibuya, K. Shinoe, H. Takaki
  ISSP/SRL, Chiba
• M. Katoh, A. Mochihashi, M. Shimada
  UVSOR, Okazaki

• M. Katoh
  
• K. Hayashi, M. Hosaka, A. Mochihashi, M. Shimada, J. Yamazaki
  UVSOR, Okazaki
• Y. Takashima
  Nagoya University, Nagoya

• Q. K. Jia
  

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

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

• S. Sasaki
  
• I. McNulty
  ANL, Argonne, Illinois
• T. Shimada
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

Photons that carry orbital angular momentum are of great interest to the optics and laser communities*. This exotic property of photon beams was recently demonstrated in the x-ray regime** and may be useful to probe angular momentum in matter***. However, by comparison to the visible light regime, it is difficult to fabricate efficient achromatic optics to generate these optical modes in x-rays. In spite of these inconveniences, there has been no investigation of the possibility of using a synchrotron light source to directly generate an x-ray beam with transverse optical modes. In this paper, we investigate use of an APPLE-type undulator for generating Laguerre-Gaussian (LG) and Hermite-Gaussian (HG) mode beams. We find that the second harmonic radiation in the circular mode corresponds to an LG beam with l=1, and the second harmonic in the linear mode corresponds to an HG beam with l=1. The combination of an APPLE undulator and conventional monochromator optics may provide an opportunity for a new type of experimental research in the synchrotron radiation community. Detailed discussion will be presented in the conference. We thank C. Quitmann for insightful comments.

* M. Padgett, J. Courtial, L. Allen, Physics Today, p. 35, May, 2004.** A. G. Peele et al., Optics Letters, 27, 1752 (2002).*** M. VanVeenendaal and I. McNulty, Phys. Rev. Lett., submitted.

• 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.

• Y. Hao
  
• L.-H. Yu
  BNL, Upton, Long Island, New York

Quiet start scheme is broadly utilized in Self Amplified Spontaneous Radiation (SASE) FEL simulations, which is proven to be correct and efficient. Nevertheless, due to the existing of energy modulation effect and the dispersion section, the High Gain Harmonic Generation (HGHG) FEL simulation will not be improved by the traditional quiet start method. A new approach is presented to largely decrease the macro-particles per slice that can be implemented in both time-independent and time-dependent simulation, accordingly expedites the HGHG FEL simulation especially high order harmonic cascade case and makes the multi-parameter scanning be possible.

• A. Temnykh
  

The design of insertion device depends on the properties of the permanent magnet material used. While magnetic material properties such as coercive force, residual induction and magnetization variation with temperature are provided by manufacturer, demagnetization caused by radiation can be only roughly estimated based on very few published data. To obtain data which can be reliably used in ERL insertion device design, we irradiated two materials of very different coercive forces and measured their demagnetization as function of radiation dose. For irradiation we used 5GeV electron beam from Cornell 12GeV Synchrotron. Radiation dose was measured using the calorimetric technique. One of the materials was similar to what we plan to use in construction of ERL undulators. Detailed information on experimental setup, radiation dose measurement techniques, results and analysis will be presented.

• G. Andonian
  
• R. B. Agustsson, A. M. Cook, M. P. Dunning, E. Hemsing, A. Y. Murokh, S. Reiche, J. B. Rosenzweig
  UCLA, Los Angeles, California
• M. Babzien, K. Kusche, R. Malone, V. Yakimenko
  BNL, Upton, Long Island, New York

• M. P. Dunning
  
• G. Andonian, E. Hemsing, S. Reiche, J. B. Rosenzweig
  UCLA, Los Angeles, California
• M. Babzien, V. Yakimenko
  BNL, Upton, Long Island, New York

• E. Hemsing
  
• G. Andonian, J. B. Rosenzweig
  UCLA, Los Angeles, California
• M. Babzien, V. Yakimenko
  BNL, Upton, Long Island, New York
• A. Gover
  University of Tel-Aviv, Faculty of Engineering, Tel-Aviv

• J. T. Frederico
  
• G. Gatti
  INFN/LNF, Frascati (Roma)
• S. Reiche, R. Tikhoplav
  UCLA, Los Angeles, California

• S. Reiche
  
• K. Goldammer
  BESSY GmbH, Berlin
• P. Musumeci
  Rome University La Sapienza, Roma

• S. Reiche
  

• 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)

• Y. T. Ding
  
• P. Emma, Z. Huang
  SLAC, Menlo Park, California

* E. Saldin et al, Nucl. Instr. and Meth. A 539, 499 (2005).** A. Zholents, Phys. Rev. ST Accel. Beams 8, 040701 (2005); A. Zholents et al., in Proceedings of FEL2004, 582 (2004).

• J. E. Spencer
  
• Y. A. Hussein
  SLAC, Menlo Park, California

This paper presents an efficient, RF-coupled, 95-GHz undulatory (snake-like) antenna that can be fabricated using IC technology. While there are many uses for directed power at this frequency our interest is in understanding the propagation of the input power through the circuit and its radiative characteristics for comparison to earlier work in the THz range (see PAC05). 95 GHz was chosen because test equipment was available (WR-10 waveguide and HP network analyzer). Different materials, heights and widths of the circuit were considered on a low-loss, 0.10-mm thick quartz substrate e.g. 0.75 microns of elevated gold corresponding to three skin depths. The design is compared to more conventional RF technology using a low energy, high power electron beam and to higher energy, lower power Smith Purcell gratings and free-electron-lasers (FELs). The FDTD results show narrow-band, 80% radiation efficiency with a dipole-like radiation pattern that is enhanced by adding periods. The radiated power was calculated using two different techniques that agreed quite well i.e. by integrating the far-field Poynting vector as well as subtracting the output power from input power.

• P. Evtushenko
  
• S. V. Benson, D. Douglas, G. Neil
  Jefferson Lab, Newport News, Virginia

• M. G. Fedurin
  
• P. Mortazavi, J. B. Murphy, G. Rakowsky
  BNL, Upton, Long Island, New York

• W. Guo
  
• G. L. Carr, S. Krinsky, J. Rose
  BNL, Upton, Long Island, New York

A notable feature of the proposed National Synchrotron Light Source II is that the vertical emittance is close to the diffraction limit of 1 Angstrom. With such a small emittance, the brightness is strongly affected by the longitudinal parameters, such as the momentum spread. Various effects are discussed and tolerances on the longitudinal parameters will be given. The lower level RF feedback system will be designed based on these tolerances.

• B. Podobedov
  
• L. Yang
  IUCF, Bloomington, Indiana

• T. Watanabe
  
• D. A. Harder, R. K. Li, J. B. Murphy, G. Rakowsky, Y. Shen, X. J. Wang
  BNL, Upton, Long Island, New York

We report the experimental characterization of the FEL efficiency enhancement using a tapered undulator in a single-pass seeded FEL amplifier at the NSLS SDL. The last 3 m of the 10 m NISUS undulator was linearly tapered so that the magnetic field strength at the end of the undulator was reduced by 5 %. The FEL energy gain along the undulator was measured for both the tapered and un-tapered undulator. The FEL energy with the taper was measured to be about 3.2 times higher than that without the taper. We also experimentally characterized the spectrum and the transverse distribution of the FEL light for both the tapered and un-tapered undulator. The experimental results are compared with the numerical simulation code, GENESIS 1.3.

• V. Kain
  
• E. Carlier, E. H.R. Gaxiola, B. Goddard, M. Gourber-Pace, E. Gschwendtner, M. Meddahi, H. Vincke, H. Vincke, J. Wenninger
  CERN, Geneva

• B. C. Brown
  
• P. Adamson, D. Capista, D. E. Johnson, I. Kourbanis, D. K. Morris, M.-J. Yang
  Fermilab, Batavia, Illinois

High intensity operation of the Fermilab Main Injector has resulted in increased activation of machine components. Efforts to permit operation at high power include creation of collimation systems to localize losses away from locations which require maintenance. As a first step, a collimation system to remove halo from the incoming beam was installed in the Spring 2006 Facility Shutdown*. We report on commissioning studies and operational experience including observations of Booster beam properties, effects on Main Injector loss and activation, and operational results.

* B. C. Brown, et al., "Collimation System for the Fermilab Booster to Main Injector Transfer Line", this conference.

• B. C. Brown
  
• D. Capista, I. Kourbanis, N. V. Mokhov, V. Sidorov
  Fermilab, Batavia, Illinois

A collimation system has been created for removing proton beam halo in the 8 GeV transfer line from the Fermilab Booster to Main Injector. A pair of 1.14 meter collimators with 5.08 cm rectangular apertures are installed in a 5 meter straight section. Horizontal and vertical motion systems allow them to be positioned such that halo can be scraped from four sides. An additional pair of collimators, placed one cell (90 degrees) downstream scrape halo which is of opposite phase. Each collimator pair can scrape about 600 Watts of beam power, limited by long term activation of materials outside of the beam line tunnel. Personnel exposure is reduced by surrounding the iron absorber with a layer of marble. Design features,radiation calculations and instrumentation considerations will be described.

• T. Sen
  
• V. E. Scarpine, R. Thurman-Keup
  Fermilab, Batavia, Illinois

• I. Baek
  
• R. Remec
  ORNL, Oak Ridge, Tennessee
• R. M. Ronningen, X. Wu, A. Zeller
  NSCL, East Lansing, Michigan

In supporting pre-conceptual research and development of the Rare-Isotope Accelerator facility or similar next-generation exotic beam facilities, one critical focus area is to estimate the level of activation and radiation in the linear accelerator second stripping region and to determine if remote handling is necessary in this area. A basic geometric layout of the second stripping region having beamline magnets, beam pipes and boxes, a stripper foil, beam slits, and surrounding concrete shielding was constructed for Monte Carlo simulations. Beam characteristics were provided within the stripping region based on this layout. Radiation fields, radioactive inventories, levels of activation, heat loads on surrounding components, and prompt and delayed radiation dose rates were simulated using Monte-Carlo radiation transport code PHITS. Preliminary results from simulations using a simplified geometry show that remote handling of foils and slits will be necessary. Simulations using a realistic geometry are underway and the results will be presented.

• I. Baek
  
• G. Bollen, M. Hausmann, D. Lawton, R. M. Ronningen, A. Zeller
  NSCL, East Lansing, Michigan

To support pre-conceptual research and development for rare isotope beam production via projectile fragmentation at the Rare-Isotope Accelerator facility or similar next-generation exotic beam facilities, the interactions between primary beams and beryllium and liquid-lithium production targets in the fragment pre-separator area were simulated using the Monte-Carlo radiation transport code PHITS. The purpose of this simulation is to determine the magnitude of the radiation fields in the pre-separator area so that levels of hadron flux and energy deposition can be obtained. It was of particular interest to estimate the maximum radiation doses to magnet coils and other components such as the electromagnetic pump for a liquid-lithium loop, and to estimate component lifetimes. We will show a detailed geometry of the pre-separator area developed for these simulations. We will provide verification that trajectories of beams and fragments when transported in the PHITS simulations agree with results from standard ion-optics calculations. We will present estimates of radiation doses to pre-separator components and give estimates for component lifetimes.

• M. A. Kostin
  
• L. Ahle, S. Reyes, K. L. Whittaker
  LLNL, Livermore, California
• I. Baek, V. Blideanu, G. Bollen, D. Lawton, R. M. Ronningen
  NSCL, East Lansing, Michigan
• T. Burgess, D. L. Conner, T. A. Gabriel, R. Remec
  ORNL, Oak Ridge, Tennessee
• D. J. Vieira
  LANL, Los Alamos, New Mexico

• Y.-J. Chen
  
• A. Paul
  LLNL, Livermore, California

An investigation is being made into the feasibility of making a compact proton accelerator for medical radiation treatment. The accelerator is based on high gradient insulation (HGI) technology. The beam energy should be tunable between 70 and 250 MeV to allow the Bragg peak to address tumors at different depths in the patient. The desired radiation dose is consistent with a beam charge of 40 pico-coulombs. The particle source is a small 2 mm plasma device from which a several nano-second pulse can be extracted. The beam current is selectable by the potential of the extraction electrode and is adjustable in the range of 10-100 milli-Amperes. This beam is then accelerated and focused by the next three electrodes forming a Accel-Deaccel-Accel (ADA) structure leading to the DWA accelerator block. The spot size is adjustable over 2 to 10 mm. A transparent grid terminates the injector section and prevents the very high gradient of the HGI structure from influencing the overall focusing of the system. The beam energy is determined by the length of the DWA structure that is charged. This give independent selection of beam dose, size and energy.

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

We present a preliminary design of an interaction region for a Super-B Factory with luminosity of 1x10³⁶ cm²/s. The collision has a ± 17 mrad crossing angle and the first magnetic element starts 30 cm from the collision point. We show that synchrotron radiation backgrounds are controlled and are at least as good as the backgrounds calculated for the PEP-II accelerator. How the beams get into and out of a shared beam pipe is illustrated along with the control of relatively high synchrotron radiation power from the outgoing beams. The high luminosity makes radiative bhabha backgrounds significantly higher than that of the present B-Factories and this must be addresed in the initial design.

• A. V. Aleksandrov
  
• S. Assadi, W. Blokland, P. Chu, S. M. Cousineau, V. V. Danilov, C. Deibele, J. Galambos, S. Henderson, D.-O. Jeon, M. A. Plum, A. P. Shishlo, M. P. Stockli, Y. Zhang
  ORNL, Oak Ridge, Tennessee

The Spallation Neutron Source accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H^- injector, capable of producing one-ms-long pulses at 60 Hz repetition rate with 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The 2.5 MeV beam from the Front End is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in the Superconducting Linac. With the completion of beam commissioning, the accelerator complex began operation in June 2006 and beam power is being gradually ramped up toward the design goal. Operational experience with the injector and linac will be presented including chopper performance, transverse emittance evolution along the linac, and the results of a beam loss study.

• S. Banna
  
• V. Berezovsky, L. Schachter
  Technion, Haifa

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

• W. A. Franklin
  

*M. Zolotorev and A. Zholents, Phys Rev. E 50 (1994) 3087.

• M. T.F. Pivi
  
• R. E. Kirby, T. W. Markiewicz, T. O. Raubenheimer, J. Seeman, L. Wang
  SLAC, Menlo Park, California
• F. Le Pimpec
  PSI, Villigen

Possible remedies for the electron cloud in the Damping Ring of the International Linear collider includes conditioning of the surface and chamber with grooves. We installed chambers in PEP-II to test the secondary electron yield (SEY) of coated TiN and TiZrV NEG samples and study the effect of electron and photon conditioning in situ. We have also installed vacuum chambers with rectangular groove profile in straight sections to test this possible mitigation technique. In this paper, we will describe the PEP-II test layout, results and impact on impedance.

• E. Kako
  
• H. Hayano, S. Noguchi, T. Shishido, K. Watanabe, Y. Yamamoto
  KEK, Ibaraki

• T. Semba
  
• Y. Itou, S. Kajiura, T. Masumoto, T. Tagawa
  Hitachi Ltd., Ibaraki-ken
• S. Noguchi, N. Ohuchi, K. Saito, A. Terashima, K. Tsuchiya
  KEK, Ibaraki

• D. Horan
  
• D. J. Bromberek, D. A. Meyer, G. J. Waldschmidt
  ANL, Argonne, Illinois

High-power tests were conducted on a 350MHz, single-cell copper accelerating cavity driven simultaneously by two H-loop input couplers for the purpose of determining the reliability, performance, and power-handling capability of the cavity and related components, which have routinely operated at 100kW power levels. The test was carried out utilizing the APS 350MHz RF Test Stand, which was modified to split the input rf power into two 1/2-power feeds, each supplying power to a separate H-loop coupler on the cavity. Electromagnetic simulations of the two-coupler feed system were used to determine coupler match, peak cavity fields, and the effect of phasing errors between the coupler feedlines. The test was conducted up to a maximum total rf input power to the cavity of 200kW CW. Test apparatus details and performance data will be presented.

• J. Norem
  
• D. Huang
  IIT, Chicago, Illinois
• P. Stoltz, S. A. Veitzer
  Tech-X, Boulder, Colorado

Recent experimental work done to develop high gradient, low frequency cavities for muon cooling, has led to a model of rf breakdown and high gradient limits in warm structures. We have recently been extending this model to try to explain some superconducing rf quench mechanisms, as well as DC and dielectric breakdown. The model assumes that the dominant mechanisms in warm metal systems are fractures caused by the the electric tensile stress, and surface micro-topography that is strongly determined by the the cavity design and history*. We describe how these processes can determine all measurable parameters in warm systems. With superconducting systems, these mechanisms also apply, however field emission, impurities and temperature produce a somewhat different picture of quenching and pulsed power processing. We describe the model and some recent extensions and improvements in some detail and a variety of results accelerators and other applications.

* Hassanein et. al. Phys. Rev. STAB, 9, 062001

• J. Norem
  
• A. Bross, A. Moretti, Z. Qian
  Fermilab, Batavia, Illinois
• D. Huang, Y. Torun
  IIT, Chicago, Illinois
• D. Li, M. S. Zisman
  LBNL, Berkeley, California
• R. A. Rimmer
  Jefferson Lab, Newport News, Virginia

The MuCool Experiment has been continuing to take data with 805 and 201 MHz cavities in the MuCool Test Area. The system uses rf power sources from the Fermilab Linac. Although the experimental program is primarily aimed at the Muon Ionization Cooling Experiment (MICE), we have been studying the dependence of rf limits on frequency, cavity material, high magnetic fields, gas pressure, coatings, etc. with the general aim of understanding the basic mechanisms involved. The 201 MHz cavity, essentially a prototype for the MICE experiment, was made using cleaning techniques similar to those employed for superconducting cavities and operates at its design field with very little conditioning.

• J. P. Ozelis
  
• R. H. Carcagno, C. M. Ginsburg, Y. Huang, B. Norris, T. Peterson, V. Poloubotko, R. Rabehl, I. Rakhno, C. Reid, D. A. Sergatskov, C. Sylvester, M. Wong, C. Worel
  Fermilab, Batavia, Illinois

As part of a program to improve cavity performance reproducibility for the ILC, Fermilab is developing a facility for vertical testing of SRF cavities. It operates at a nominal temperature of 2K, using an existing cryoplant that can supply LHe in excess of 20g/sec and provides steady-state bath pumping capacity of 125W at 2K. The below-grade cryostat consists of a 4.9m long vacuum vessel and 4.5m long LHe vessel. The cryostat is equipped with external and internal magnetic shielding to reduce the ambient magnetic field to <10mG. Internal fixed and external movable radiation shielding ensures that radiation levels from heavily field-emitting cavities remain low. In the event that radiation levels exceed allowable limits, an integrated personnel safety system consisting of RF switches, interlocks, and area radiation monitors disables RF power to the cavity. In anticipation of increased throughput requirements that may be met with additional test stand installations, sub-systems have been designed to be easily upgradeable or to already meet these anticipated needs. Detailed facility designs, performance during system commissioning, and results from initial cavity tests are presented.

• J. P. Ozelis
  
• C. Grenoble, T. Powers
  Jefferson Lab, Newport News, Virginia
• R. Nehring
  Fermilab, Batavia, Illinois

Fermilab is developing a facility for vertical testing of SRF cavities as part of a program to improve cavity performance reproducibility for the ILC. The RF system for this facility, using the classic combination of oscillator, phase detector/mixer, and loop amplifier to detect the resonant cavity frequency and lock onto the cavity, is based on the proven production cavity test systems used at Jefferson Lab for CEBAF and SNS cavity testing. The design approach is modular in nature, using commercial-off-the-shelf (COTS) components. This yields a system that can be easily debugged and modified, and with ready availability of spares. Data acquisition and control is provided by a PXI-based hardware platform in conjunction with software developed in the LabView programming environment. This software provides for amplitude and phase adjustment of incident RF power, and measures all relevant cavity power levels, cavity thermal environment parameters, as well as field emission-produced radiation. It also calculates the various cavity performance parameters and their associated errors. Performance during system commissioning and initial cavity tests will be presented.

• V. A. Dolgashev
  
• Y. Higashi, T. Higo
  KEK, Ibaraki
• C. D. Nantista, S. G. Tantawi
  SLAC, Menlo Park, California

We report results of the first high power tests of single-cell traveling-wave and standing-wave accelerating structures. These tests are part of an experimental and theoretical study of RF breakdown in normal conducting structures at 11.4 GHz*. The goal of this study is to determine the gradient potential of normal conducting, RF powered particle beam accelerators. The test setup consists of reusable mode converters and short test structures powered by SLAC?s XL-4 klystron. This setup was created for economic testing of different cell geometries, cell materials and preparation techniques with short turn-around time. The mode launchers and structures were manufactured at SLAC and KEK and tested in the klystron test laboratory at SLAC.

* V. A. Dolgashev et al., "RF Breakdown In Normal Conducting Single-Cell Structures," SLAC-PUB-11707, Particle Accelerator Conference (PAC 05), Knoxville, Tennessee, 16-20 May 2005, pp. 595- 599.

• M. A. Drury
  
• E. Daly, G. K. Davis, J. F. Fischer, C. Grenoble, W. R. Hicks, J. Hogan, K. King, R. Nichols, T. E. Plawski, J. P. Preble, T. M. Rothgeb, H. Wang
  Jefferson Lab, Newport News, Virginia

The Thomas Jefferson National Accelerator Facility has begun a cryomodule refurbishment project. The goal of this project is robust 6 GeV, 5 pass operation of the Continuous Electron Beam Accelerator Facility (CEBAF). The scope of the project includes removing, refurbishing and replacing 10 CEBAF cryomodules at a rate of three per year. Refurbishment includes reprocessing of SRF cavities to eliminate field emission and increase the nominal gradient from the original 5 MV/m to 12.5 MV/m. New "dogleg" couplers between the cavity and helium vessel flanges will intercept secondary electrons that produce arcing on the 2 K ceramic window in the Fundamental Power Coupler (FPC). Modification of the Qext of the FPC will allow higher gradient operations. Other changes include new ceramic RF windows for the air to vacuum interface of the FPC and improvements to the mechanical tuners. Any damaged or worn components will be replaced as well. Currently, the first of the refurbished cryomodules has been installed and tested both in the Cryomodule Test Facility and in place in the North Linac of CEBAF. This paper will summarize the results of these tests.

• I. E. Campisi
  
• S. Assadi, F. Casagrande, M. S. Champion, M. T. Crofford, G. W. Dodson, J. Galambos, M. Giannella, S. Henderson, M. P. Howell, Y. W. Kang, K.-U. Kasemir, S.-H. Kim, Z. Kursun, P. Ladd, H. Ma, D. Stout, W. H. Strong, Y. Zhang
  ORNL, Oak Ridge, Tennessee

The Superconducting Linac at SNS has been operating with beam for almost two years. As the first operational pulsed superconducting linac, many of the aspect of its performance were unknown and unpredictable. A lot of experience has been gathered during the commissioning of its components, during the beam turn on and during operation at increasingly higher beam power. Some cryomodules have been cold for well over two years and have been extensively tested. The operation has been consistently conducted at 4.4 K and 10 and 15 pulses per second, with some cryomodules tested at 30 and 60 pps and some tests performed at 2 K. Careful balance between safe operational limits and the study of conditions, parameters and components that create physical limits has been achieved. This paper presents the experience and the performance of the superconducting cavities and of the associated systems with and without beam.

• S.-H. Kim
  
• I. E. Campisi, F. Casagrande, M. T. Crofford, Y. W. Kang, Z. Kursun, D. Stout, A. V. Vassioutchenko
  ORNL, Oak Ridge, Tennessee

The cryomodule tests are on going to have better understandings of physics as a whole and eventually to provide safe and reliable operation for neutron production. Some features are revealed to be interesting issues and need more attentions than expected, such as operating condition, collective effects between cavities, HOM coupler issues, end-group stability, cavity-coupler interactions, and vacuum/gas physics, waiting for more investigations. Up to now SNS cryomodules were mainly tested at 4.4 K, 10 pulse per second (pps) and 30 pps/60 pps tests are under progress. This paper presents the experiences and the observations during tests of cryomodules.

• A. Burrill
  
• I. Ben-Zvi, R. Calaga, H. Hahn, V. Litvinenko, G. T. McIntyre
  BNL, Upton, Long Island, New York
• P. Kneisel, J. Mammosser, J. P. Preble, C. E. Reece, R. A. Rimmer, J. Saunders
  Jefferson Lab, Newport News, Virginia

One of the key components for the Energy Recovery Linac being built by the Electron cooling group in the Collider Accelerator Department is the 5 cell accelerating cavity which is designed to accelerate 2 MeV electrons from the gun up to 15-20 MeV, allow them to make one pass through the ring and then decelerate them back down to 2 MeV prior to sending them to the dump. This cavity was designed by BNL and fabricated by AES in Medford, NY. Following fabrication it was sent to Thomas Jefferson Lab in VA for chemical processing, testing and assembly into a string assembly suitable for shipment back to BNL and integration into the ERL. The steps involved in this processing sequence will be reviewed and the deviations from processing of similar SRF cavities will be discussed. The lessons learned from this process are documented to help future projects where the scope is different from that normally encountered.

• Y. Suetsugu
  
• K. Shibata
  KEK, Ibaraki

• P. Krejcik
  

• V. E. Scarpine
  
• A. H. Lumpkin
  ANL, Argonne, Illinois
• G. R. Tassotto
  Fermilab, Batavia, Illinois

An Optical Transition Radiation (OTR) detector has been installed in the Fermilab NuMI proton beamline, which operates at beam powers of up to ~300 kW, to obtain real-time, spill-by-spill beam profiles for neutrino production. A series of Optical Transition Radiation (OTR) detectors were design, constructed and installed in various beamlines at Fermilab and previous near-field OTR images of lower-intensity 120 GeV and 150 GeV protons with larger transverse beam size have been presented at BIW06 and IEEE NSS06. NuMI OTR images of 120 GeV protons for beam intensities up to 2.8·10¹³ at a spill rate of 0.5 Hz and small transverse beam size of ~1 mm (σ) are presented here. The NuMI OTR detector uses a 6 micron Kapton foil with 0.12 micron of aluminum which reduces beam scatter by 70% compared to an adjacent Secondary Emission Monitor (SEM). Beam profiles are extracted from the OTR images and compared to the adjacent SEM. The OTR detector provides two-dimensional beam shape such as ellipticity and tilt, as well as complementary beam centroid and beam intensity information. In addition, response of the OTR detector over different intensities and transverse positions is presented.

• M. A. Holloway
  
• S. V. Benson, W. Brock, J. L. Coleman, D. Douglas, R. Evans, P. Evtushenko, K. Jordan, D. W. Sexton
  Jefferson Lab, Newport News, Virginia
• R. B. Fiorito, P. G. O'Shea, A. G. Shkvarunets
  UMD, College Park, Maryland

Optical Transition Radiation Interferometry (OTRI) has proven to be effective tool for measuring rms beam divergence. We present rms emittance measurement results of the 115 MeV energy recovery linac at the Thomas Jefferson National Laboratories Free electron Laser using OTRI. OTRI data from both near field beam images and far field angular distribution images give evidence of two spatial and angular distributions within the beam. Using the unique features of OTRI we segregate the two distributions of the beam and estimate separate rms emittance values for each component.

• O. Grimm
  

• F. Sannibale
  
• D. Filippetto
  INFN/LNF, Frascati (Roma)
• G. V. Stupakov
  SLAC, Menlo Park, California
• M. S. Zolotorev
  LBNL, Berkeley, California

By analysing the pulse to pulse intensity fluctuations of the radiation emitted by a charge particle in the incoherent part of the spectrum, it is possible to extract information about the spatial distribution of the beam. At the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory, we have developed and tested a simple scheme based on this principle that allows for the absolute measurement of the bunch length. A description of the method and the experimental results are presented.

• A. Bonatto
  
• R. Pakter, F. B. Rizzato
  IF-UFRGS, Porto Alegre

In the present analysis we study the self consistent propagation of nonlinear electromagnetic pulses in a one dimensional relativistic electron-ion plasma, from the perspective of nonlinear dynamics. We show how a series of Hamiltonian bifurcations give rise to the electric fields which are of relevance in the subject of particle acceleration. Nonlinear coupling of plasma waves and electromagnetic pulses triggers strong chaotic dynamics which may detrap the plasma wave from the electromagnetic pulse, leading to wave breaking. Connections with results of earlier analysis are discussed.

• M. Uesaka
  
• F. Sakamoto, A. Sakumi
  The University of Tokyo, Nuclear Professional School, Ibaraki-ken

• S. Kashiwagi
  
• R. Kato, J. Yang
  ISIR, Osaka
• R. Kuroda
  AIST, Tsukuba, Ibaraki
• K. Sakaue, M. Washio
  RISE, Tokyo
• J. Urakawa
  KEK, Ibaraki

*M. Goldstein et al., Proc. of the 27th Int. FEL conference, Stanford, California, USA (2005) pp.422-425**A. Endo, Sematic EUV source workshop, Barcelona, Spain (2006)

• T. Kondoh
  
• H. Kashima, J. Yang, Y. Yoshida
  ISIR, Osaka

• A. V. Tyukhtin
  
• S. N. Galyamin
  Saint-Petersburg State University, Saint-Petersburg

The possibility of using an active medium to amplify the generated wakefield of an electron beam and employing the amplified wakefield to accelerate a second beam has been recognized recently*. This acceleration scheme is one of several related methods referred to as the Particle Acceleration by Stimulated Emission of Radiation (PASER). However, only the case of an active medium with a single resonant frequency has been analyzed until now. In this paper we present the results of analytical and numerical studies of Cherenkov radiation (CR) in an active medium with two resonant frequencies. We show that this medium can amplify CR even in the case of a purely real refractive index. In contrast to a medium with a single resonant frequency the amplification effect takes place in the absence of metal boundaries but only for sufficiently strong restrictions on the parameters of the medium. The amplification can be effective even for a medium with a relatively small inversion. Examples of CR amplification are given for several active materials. The effect may be useful both for wakefield accelerators and Cherenkov detectors.

*L. Schachter, Phys. Rev., E, 62, 1252 (2000); N. V.Ivanov, A. V.Tyukhtin, Tech. Phys. Lett., 32, 449 (2006).

• G. Ellwood
  
• R. J.S. Greenhalgh
  STFC/RAL, Chilton, Didcot, Oxon

Spoilers in the ILC Beam Delivery System are required to survive without failure a minimum of 1-2 direct impacts from each energetic electron or positron bunch of charged particles, in addition to maintaining low geometric and resistive wall wake fields. The transient shock wave resulting from rapid localised beam heating and its implications for spoiler design are studied using ANSYS. Shockwave propagation is modelled in 2 dimensions showing the effect of dilatational shockwaves striking free surfaces, producing reflected dilatational and distortional waves. The implication of these relflected waves on the damage of the collimators is also discussed.

• Y. Ivanyushenkov
  
• I. R. Bailey, J. A. Clarke, J. B. Dainton, O. B. Malyshev, L. I. Malysheva, G. A. Moortgat-Pick, D. J. Scott
  Cockcroft Institute, Warrington, Cheshire
• D. P. Barber
  DESY, Hamburg
• E. Baynham, T. W. Bradshaw, A. J. Brummitt, F. S. Carr, A. J. Lintern, J. Rochford
  STFC/RAL, Chilton, Didcot, Oxon
• P. Cooke
  Liverpool University, Science Faculty, Liverpool
• B. J.A. Shepherd
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

An undulator based positron source is a baseline for the International Linear Collider (ILC). The HeliCal collaboration in the UK is working on the development of a full scale 4-m long undulator module. Several prototypes have been built and tested in the R&D phase of the programme that culminated in the development of manufacturing techniques suitable for construction of the first full scale undulator sections. This paper details the design and the construction status of 4-m long undulator module.

• J.-L. Fernandez-Hernando
  
• G. A. Blair, S. T. Boogert
  Royal Holloway, University of London, Surrey
• G. Ellwood, R. J.S. Greenhalgh
  STFC/RAL, Chilton, Didcot, Oxon
• L. Keller
  SLAC, Menlo Park, California
• N. K. Watson
  Birmingham University, Birmingham

• R. J. Barlow
  
• N. Bliss
  STFC/DL, Daresbury, Warrington, Cheshire
• T. R. Edgecock
  STFC/RAL, Chilton, Didcot, Oxon
• N. Marks, H. L. Owen, M. W. Poole
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• K. J. Peach
  JAI, Oxford
• J. K. Pozimski
  Imperial College of Science and Technology, Department of Physics, London

• S. P. Antipov
  
• M. E. Conde, W. Gai, R. Konecny, W. Liu, J. G. Power, Z. M. Yusof
  ANL, Argonne, Illinois
• L. K. Spentzouris
  Illinois Institute of Technology, Chicago, Illinois

Metamaterials (MTM) are artificial periodic structures made of small elements and designed to obtain specific electromagnetic properties. As long as the periodicity and the size of the elements are much smaller than the wavelength of interest, an artificial structure can be described by a permittivity and permeability, just like natural materials. Metamaterials can be customized to have the permittivity and permeability desired for a particular application. Waveguides loaded with metamaterials are of interest because the metamaterials can change the dispersion relation of the waveguide significantly. Slow backward waves, for example, can be produced in a LHM-loaded waveguide without corrugations. In this paper we present theoretical studies and computer modeling of waveguides loaded with 2D anisotropic metamaterials, including the dispersion relation for a MTM-loaded waveguide. The dispersion relation of a MTM-loaded waveguide has several interesting frequency bands which are described. It is shown theoretically that dipole mode suppression may be possible. Therefore, metamaterials can be used to suppress wakefields in accelerating structures.

• J. Long
  
• S. Chemerisov, W. Gai, C. D. Jonah, W. Liu, H. Wang
  ANL, Argonne, Illinois

• 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)

• R. A. Marsh
  
• M. A. Shapiro, R. J. Temkin
  MIT/PSFC, Cambridge, Massachusetts
• E. I. Smirnova
  LANL, Los Alamos, New Mexico

Results are reported on experimental wakefield measurements made on a 6 cell, 17 GHz metallic PBG accelerator structure. Wakefields were observed using a variety of detectors and methods. The PBG structure is open, containing no outer wall, and radiation has been observed through a window in the surrounding vacuum vessel. The input and output ports have also been used with windows to observe radiation coupling out of the ports. Estimations of radiation are made using HFSS and an EFIE code. Measurements have been made using video diode detectors, wavemeters, heterodyne receivers, and a bolometer. Plans are discussed for future experiments with injected power and longer structures.

• M. C. Thompson, H. Badakov, J. B. Rosenzweig, M. C. Thompson, G. Travish
  UCLA, Los Angeles, California
• M. J. Hogan, R. Ischebeck, N. A. Kirby, R. Siemann, D. R. Walz
  SLAC, Menlo Park, California
• P. Muggli
  USC, Los Angeles, California
• A. Scott
  UCSB, Santa Barbara, California
• R. B. Yoder
  Manhattan College, Riverdale, New York

The breakdown threshold of a dielectric subjected to the GV/m-scale electric-fields of an intense electron-beam has been measured. In this experiment at the Final Focus Test Beam (FFTB) facility, the 30 GeV SLAC electron beam was focused down and propagated through short fused-silica capillary-tubes with internal diameters of as little as 100 microns. The electric field at the inner surface of the tubes was varied from about 1 GV/m to 22 GV/m by adjusting the longitudinal compression of the electron bunch. The onset of breakdown, as indicated by a bright discharge, was found to correlate to a surface field of about 4 GV/m. An analysis of the damage sustained to the beam-exposed fibers, and its correlation to field amplitude, is also reported.

• A. M. Cook
  
• H. Badakov, R. J. England, J. B. Rosenzweig, R. Tikhoplav, G. Travish, O. Williams
  UCLA, Los Angeles, California
• A. Kanareykin
  Euclid TechLabs, LLC, Solon, Ohio
• M. C. Thompson
  LLNL, Livermore, California

Experimental work is planned to study the performance of a beam-driven cylindrical dielectric wakefield accelerating structure as a source of THz coherent Cerenkov radiation. For an appropriate choice of dielectric tube geometry and driving electron bunch parameters, the device operates in a single-mode regime, producing narrow-band radiation in the THz range. This source can potentially produce high power levels relative to currently available sources, with ~50 μJ radiated energy per pulse achievable using the electron beam currently in operation at the Neptune Advanced Accelerator Research Laboratory at UCLA (~13 MeV beam energy, ~200 μm RMS bunch length, ~500 pC bunch charge). Preparations underway for installation of the experiment are discussed.

• G. Travish
  
• H. Badakov, A. M. Cook, J. B. Rosenzweig, R. Tikhoplav
  UCLA, Los Angeles, California
• M. K. Berry, I. Blumenfeld, F.-J. Decker, M. J. Hogan, R. Ischebeck, R. H. Iverson, N. A. Kirby, R. Siemann, D. R. Walz
  SLAC, Menlo Park, California
• A. Kanareykin
  Euclid TechLabs, LLC, Solon, Ohio
• P. Muggli
  USC, Los Angeles, California
• M. C. Thompson
  LLNL, Livermore, California

Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC FFTB, are foreseen to be produced soon at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of >10 GV/m. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 μm and 200 μm ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in excess of 4 GV/m (2 GV/m accelerating field) in fused silica. With the construction and commissioning of the SABER facility at SLAC, new experiments are made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. The E169 collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures.

• P. Muggli
  
• M. Babzien, K. Kusche, V. Yakimenko
  BNL, Upton, Long Island, New York
• E. K. Kallos
  USC, Los Angeles, California
• W. D. Kimura
  STI, Washington

The presentation will cover experimental results on generation and measurement of the beams with theμbunches length from 1 to 50 microns at Brookhaven Accelerator Test Facility. Arbitrary number of microbunches is sliced out of 5 ps long beam using wire mesh and slits. The details of beam structure are characterized using CSR interferometer and 6 mm long plasma wakefield channel with the controllable plasma density.

• I. Blumenfeld
  
• M. K. Berry, F.-J. Decker, M. J. Hogan, R. Ischebeck, R. H. Iverson, N. A. Kirby, R. Siemann, D. R. Walz
  SLAC, Menlo Park, California
• C. E. Clayton, C. Huang, C. Joshi, W. Lu, K. A. Marsh, W. B. Mori, M. Zhou
  UCLA, Los Angeles, California
• T. C. Katsouleas, P. Muggli, E. Oz
  USC, Los Angeles, California

Recent experiments at SLAC have shown that high gradient acceleration of electrons is achievable in meter scale plasmas. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch length and beam waist location were varied systematically at constant charge. Here we investigate the correlation of peak beam current to the decelerating gradient. Limits on the transformer ratio will also be discussed. The results are compared to simulation.

• G. R. Bower
  
• R. Arnold, M. Woods
  SLAC, Menlo Park, California
• N. Sinev
  University of Oregon, Eugene, Oregon
• Y. Sugimoto
  KEK, Ibaraki

• T. Plettner
  
• R. L. Byer
  Stanford University, Stanford, Califormia
• E. R. Colby, R. Ischebeck, C. Mcguinness, R. J. Noble, C. M.S. Sears, R. Siemann, J. E. Spencer, D. R. Walz
  SLAC, Menlo Park, California

• A. R. Rossi
  
• A. Bacci, C. Maroli, L. Serafini
  INFN-Milano, Milano
• V. Petrillo
  Universita' degli Studi di Milano, Milano

• S. A. Kostromin
  

• F. Zimmermann
  
• E. Benedetto, G. Rumolo, D. Schulte, R. Tomas
  CERN, Geneva
• W. Fischer
  BNL, Upton, Long Island, New York
• G. Franchetti
  GSI, Darmstadt
• K. Ohmi
  KEK, Ibaraki
• M. T.F. Pivi, T. O. Raubenheimer
  SLAC, Menlo Park, California
• K. G. Sonnad, J.-L. Vay
  LBNL, Berkeley, California

• R. Holtzapple
  
• G. W. Codner, M. A. Palmer, E. Tanke
  CESR-LEPP, Ithaca, New York
• J. S. Kern
  Alfred University, Alfred, New York

Presently, CESR is operated at two different beam energies, low energy (E=2GeV) for high energy physics (CESR-c), and high energy (E=5.3GeV) for synchrotron radiation production (CHESS). The electron and positron bunches vertical dynamics at these two energies are vastly different, in part due to the change in the pretzel orbit, the presence of wiggler magnets at low energy, and synchrotron radiation power at two vastly different energies. Using the 32 channel photomultiplier array*, we measured the vertical beam dynamics on a turn-by-turn basis during CHESS and CESR-c operation as well as dedicated machine studies time. For these studies we quantify the electron cloud effects such as vertical tune shift and vertical beam size blow-up along the electron and positron trains at these two vastly different beam energies. In addition, the turn-by-turn capability of the PMT array allows us to study the vertical bunch dynamics over 10k turns.

* Design and Implementation of an Electron and Positron Multibunch Turn-by-Turn Vertical Beam Profile Monitor in CESR-PAC2007 proceedings

• M. Borland
  
• L. Emery, V. Sajaev
  ANL, Argonne, Illinois

The Advanced Photon Source (APS) has decided to implement a system using pulsed* crab cavities to produce short x-ray pulses using Zholents'** scheme. This paper describes beam dynamics issues related to implementation of this scheme in a single APS straight section. Modeling of the cavity is used to demonstrate that the deflection will be independent of transverse position in the cavity. Parameters and performance for a standard and lengthened APS straight section are shown. Finally, tolerances are discussed and obtained from tracking simulations.

* M. Borland et al., these proceedings.** A. Zholents et al., NIM A 425, 385 (1999).

• C. P. Neuman
  
• P. G. O'Shea
  UMD, College Park, Maryland

(*) Simulation of Longitudinally Modulated Electron Beams. C. P. Neuman and P. G. O'Shea. In 2006 Advanced Accelerator Concepts Workshop, AIP Conference Proceedings, 877, 621-627. Melville, AIP (2006).

• C. P. Neuman
  
• P. G. O'Shea
  UMD, College Park, Maryland

(*) Simulation of Longitudinally Modulated Electron Beams. C. P. Neuman and P. G. O'Shea. In 2006 Advanced Accelerator Concepts Workshop, AIP Conference Proceedings 877, edited by M. Conde and C. Eyberger, 621-627. Melville, NY, AIP (2006).

• J. Shi
  
• G. Hoffstaetter
  CLASSE, Ithaca

A self-consistant simulation method is developed for the study of coherent synchrotron radiation effects by using a perturbation expansion of retarded radiation field and the particle-in-cell method. The perturbation expansion of the radiation field is based on the fact that the time dependance of a bunch particle distribution has typically two significantly different time scales, a fast time scale related to the linear dynamics and a slow time scale of the beam-size growth due to nonlinear perturbations. Since the scale of the retardation of the radiation field is usually much shorter than the slow time scale of the particle distribution, the retardation on the slow time scale of the particle distribution is treated perturbatively while the retardation on the fast time scale is removed by transformations associated the linear lattice. With this method, the particle-radiation interaction can be calculated in configuration space without memorizing the history of the particle distribution.

• D. Schiller
  
• S. Reiche, M. Ruelas
  UCLA, Los Angeles, California

• M. Blaskiewicz
  

A multipurpose coherent instability simulation code has been written, documented, and released for use. TRANFT (tran-eff-tee) uses fast Fourier transforms to model transverse wakefields, transverse detuning wakes and longitudinal wakefields in a computationally efficient way. Dual harmonic RF allows for the study of enhanced synchrotron frequency spread. When coupled with chromaticity, the theoretically challenging but highly practical post head-tail regime is open to study. Detuning wakes allow for transverse space charge forces in low energy hadron beams, and a switch allowing for radiation damping makes the code useful for electrons.

• R. P. Fliller
  
• D. A. Edwards, H. Edwards
  Fermilab, Batavia, Illinois
• K. C. Harkay, K.-J. Kim
  ANL, Argonne, Illinois
• T. W. Koeth
  Rutgers University, The State University of New Jersey, Piscataway, New Jersey

The A0 photoinjector is being reconfigured to test the principal of transverse to longitudinal emittance exchange as proposed by Emma et. al., Kim and Sessler, and others. The ability to perform such an exchange could have major advantages to FELs by reducing the transverse emittance. Several schemes to carry out the exchange are possible and will be reported separately. At the Fermilab A0 Photoinjector we are constructing a beamline to demonstrate this transverse to longitudinal emittance exchange. This beamline will consist of a dogleg, and a TM110 5 cell copper cavity followed by another dogleg. The beamline is designed to reuse the bunch compressor dipoles of the photoinjector, along with some existing diagnostics. Beamline layout and optics discussed along with inital data. Future possibilites of performing a similar experiment at the proposed NML facility at Fermilab are also discussed.

• S. Prestemon
  
• S. Marks, D. Schlueter
  LBNL, Berkeley, California

• W. R. Flavell
  

* e.g. J Andruszkow et al., Phys. Rev. Lett., 85, 3825, (2000).**e.g. G. R. Neil et al., Phys. Rev. Lett. 84, 662, (2000).*** e.g. H Wabnitz et al., Nature, 420, 467, (2002), T Laarmann et al., Phys. Rev. Lett., 95, 063402 (2005)

• A. Paech
  
• W. Ackermann, T. Weiland
  TEMF, Darmstadt
• O. Grimm
  DESY, Hamburg

One method to measure the bunch shape at the FLASH facility at DESY, Hamburg is based on the observation of synchrotron radiation generated at the first bunch compressor. For the correct interpretation of the results it is mandatory to know how various parameters of the real setup, in contrast to theoretical assumptions, influence the observed spectrum. The aim of this work therefore is to calculate the generation of synchrotron radiation of a moving point charge inside the bunch compressor with the emphasis of including the effects of the vertical and horizontal vacuum chamber walls in the vicinity of the last dipole magnet. Because of the small wavelength in comparison with the chamber geometries this is a demanding task. One idea to cope with the difficulties is to use optical methods such as the uniform theory of diffraction (UTD). In this paper the applicability and limitations of the proposed method are discussed. Furthermore a comparison of simulated and new measured fields is shown.

• E. Chiadroni
  
• M. Castellano
  INFN/LNF, Frascati (Roma)
• A. Cianchi
  INFN-Roma II, Roma
• K. Honkavaara
  Uni HH, Hamburg
• G. Kube
  DESY, Hamburg
• V. M. Merlo, F. Stella
  Universita di Roma II Tor Vergata, Roma

The characterization of the transverse phase space for high charge density and high energy electron beams is a fundamental requirement in many particle accelerator facilities, since knowledge of the characteristics of the accelerated beams is of great importance for the successful development of the next generation light sources and linear colliders. The development of suitable beam diagnostics, non-invasive and non-intercepting, is therefore necessary to measure the properties of such beams. Optical Diffraction Radiation (ODR) is considered the most promise candidate, as testified by the interest of many laboratories all around the world. An experiment based on the detection of ODR has been set up at DESY FLASH Facility to measure the electron beam transverse parameters. The radiation is emitted by a 700 MeV-energy electron beam passing through a slit of 0.5 mm or 1 mm aperture depending on the beam size. The slit is opened by chemical etching on a screen made of aluminum deposited on a silicon substrate. Radiation is then detected by a air-cooled high sensitivity CCD camera. The status of the experiment and preliminary results are reported.

• R. Tsujii
  
• T. Hosokai
  RLNR, Tokyo
• K. Kinoshita, Y. Kondo, A. Maekawa, Y. Shibata, M. Uesaka, A. Yamazaki
  UTNL, Ibaraki
• T. Takahashi
  KURRI, Osaka
• A. G. Zhidkov
  Central Research Institute of Electric Power Industry, Komae

• K. Satou
  
• N. Hayashi, H. Hotchi, Y. Irie, M. Kinsho, M. Kuramochi, P. K. Saha, Y. Yamazaki
  JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
• S. Lee
  KEK, Ibaraki

• D. Xiang
  
• W.-H. Huang
  TUB, Beijing

* Dao Xiang and Wen-Hui Huang, Nucl. Instr. and Meth. in Phys. Res. B, 254 (2007) 165.** Dao Xiang and Wen-Hui Huang, Nucl. Instr. and Meth. in Phys. Res. A, 570 (2007) 357.*** Dao Xiang and Wen-Hui Huang, Phys. Rev. ST-AB, 10 (2007) 012801.

• B. Y. Wang
  
• P. Lu, B. Sun, J. Wang, J. H. Wang, H. Xu
  USTC/NSRL, Hefei, Anhui

A simple measurement method of beam bunch length in time domain for HLS (Hefei Light Source) has been proposed. The Bunch length measurement system is composed of an optical system, a high speed photo-receiver and a wide bandwidth oscilloscope. The photo-receiver which is made by FEMTO has high sensitivity and high bandwidth, which converts the synchrotron radiation light into electronic signal. The oscilloscope which is made by Tektronix is TDS7704B, which has a high bandwidth up to 7GHz and show the bunch length in time domain. The measurement results of the bunch length and its analysis are given. We compare the results with that determined by the conventional method using a streak camera.

• K. R. Kim
  
• Y.-S. Cho, I.-S. Hong, H. S. Kim, B.-S. Park, S. P. Yun
  KAERI, Daejon
• H. J. Kim, J. H. So
  Kyungpook National University, Daegu

The test beam line was installed at the MC-50 cyclotron of KIRAMS (Korea Institute of Radiological And Medical Sciences). It has been supporting many pilot and feasibility studies on the development of beam utilization technologies of PEFP (Proton Engineering Frontier Project). The energy measurement with high accuracy is very important for the some experiments such as radiation hardness test of semiconductor devices, nuclear physics, detector test, etc. SSB and Si(Li) detector was used as del-E and E detector and the thickness of detectors are 2mm and 5mm each. The available energy range is 10MeV~39MeV and the flux was controlled not to be exceed 1·10⁺⁰⁵/cm²-sec using a 0.5mm diameter collimator.

• A. P. Zhukov
  
• S. Assadi
  ORNL, Oak Ridge, Tennessee

We are developing a sophisticated system of beam loss pattern evaluation and residual radiation estimation. We have installed a number of Neutron Detectors and Ionization Chambers along LINAC. In this paper we present our implementation and simulation of the losses by inserting Faraday Cups, using Beam Stops and running Wire Scanners at different energies. The measured losses are simulated by 3-D transport codes (GEANT4, SHIELD, MCNPX). We compare two different sets of Beam Loss Monitors: Ionization Chambers (detecting X-ray and gamma radiation) and Photo-Multiplier Tubes with a neutron converter (detecting neutrons) and outline that such a combination is a better way to measure beam losses than relying on detectors of one type. We interpret the loss signal in terms of beam current lost in the SNS LINAC with accurate longitudinal loss distribution and plan to automate beam steering according to loss monitors readings by using vast Loss Pattern Database developed by simulating different loss scenarios with the transport codes.

• G. M. Kazakevich
  
• H. Edwards, R. P. Fliller, V. A. Lebedev, S. Nagaitsev, R. Thurman-Keup
  Fermilab, Batavia, Illinois

OTR interferometry (OTRI) is an attractive diagnostic for investigation of relativistic electron beam parameters. The diagnostic is currently under development at the A0 Photoinjector. This diagnostic is applicable for NML accelerator test facility that will be built at Fermilab. The experimental setups of the OTR interferometers for the Photoinjector prototype are described in the report. Results of simulations and measurements are presented and discussed.

• A. V. Tyukhtin
  
• S. P. Antipov
  ANL, Argonne, Illinois
• A. Kanareykin, P. Schoessow
  Euclid TechLabs, LLC, Solon, Ohio

Cherenkov radiation (CR) is extensively used for detection of charged particles. The prompt nature of the radiation is one major advantage for diagnostics that measure temporal properties of the beam. However, low signal levels and small angles of radiation with respect to the particle trajectory present limitations on the use of traditional detector media. Using modern artificial metamaterials as Cherenkov radiators can provide essential advantages. As a rule metamaterials are characterized by strong dispersion and anisotropy that can be engineered to the requirements of the detector. We present theoretical and numerical analyses of CR in bulk anisotropic and dispersive media and in waveguides. The properties exhibited by these materials (large angles of radiation, two maxima in the angular distributions, etc.) allow the design of detectors with unusual characteristics, like a detector that registers almost all moving particles, and simultaneously only particles with velocity exceeding a predetermined threshold. We consider the case of a material that is approximately equivalent to an isotropic left-handed medium that also presents advantages as a Cherenkov medium.

• E. Bravin
  
• A. Brambilla, M. Jolliot, S. Renet
  CEA, Grenoble
• S. Burger, C. Dutriat, T. Lefevre, V. Talanov
  CERN, Geneva
• J. M. Byrd, K. Chow, H. S. Matis, M. T. Monroy, A. Ratti, W. C. Turner
  LBNL, Berkeley, California

• B. Dehning
  
• E. Effinger, J. E. Emery, G. Ferioli, G. Guaglio, E. B. Holzer, D. K. Kramer, L. Ponce, V. Prieto, M. Stockner, C. Zamantzas
  CERN, Geneva

• B. Dehning
  
• E. Effinger, J. E. Emery, G. Ferioli, E. B. Holzer, D. K. Kramer, L. Ponce, M. Stockner, C. Zamantzas
  CERN, Geneva

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

• A. H. Lumpkin
  
• W. Berg, N. Sereno, B. X. Yang, C. Yao
  ANL, Argonne, Illinois
• D. W. Rule
  NSWC, West Bethesda, Maryland

We have investigated the angular distribution patterns (far-field focus) of optical transition radiation (OTR) and optical diffraction radiation (ODR) generated by 7-GeV electron beams passing through and near an Al metal plane, respectively. The 70-μrad opening angles of the OTR patterns provide calibration factors for the system. Effects of the upstream quadrupole focusing strength on the patterns as well as polarization effects were observed. The OTR data are compared to an existing OTR single-foil model, while ODR profile results are compared to expressions for single-edge diffraction. ODR was studied with impact parameters of about 1.25 mm, close to the gamma λ?bar value of 1.4 mm for 628-nm radiation. We expect angle-pointing information along the x axis parallel to the mirror edge is available from the single-lobe ODR data as well as divergence information at the sub-100-μrad level. Experimental and model results will be presented.

• A. H. Lumpkin
  
• V. E. Scarpine, G. R. Tassotto
  Fermilab, Batavia, Illinois

We have successfully imaged for the first time the angular distribution patterns of optical transition radiation (OTR) generated by 120-GeV proton beams passing through an Al metal plane. These experiments were performed at FNAL with the same chamber, foil, and camera design as with the near-field experiments previously reported. In this case the lens-to-CID-chip separation was remotely adjusted to provide the focus-at-infinity, or far-field optical imaging. The ~8-mrad opening angle of OTR patterns confirm/provide the calibration factors for the system. We also used linear polarizers to select the orthogonal polarization components of the radially polarized OTR. The OTR angular distribution results are compared to an existing analytical model. We show angle pointing information is available from the single-foil OTR data at the sub-mrad level and divergence information at about the 1-mrad level. Data have been obtained in transport lines both before the antiproton production target and before the NuMI target with particle intensities of about 5 to 22 x ·10¹². A two-foil interferometer calculation was also performed. Single-foil experimental and modeling results will be presented.

• A. H. Lumpkin
  
• P. Evtushenko, A. Freyberger
  Jefferson Lab, Newport News, Virginia
• C. Liu
  PKU/IHIP, Beijing

We have evaluated the feasibility of using the optical diffraction radiation (ODR) generated as a 1- to 6-GeV CW electron beam passes nearby the edge of a single metal conducting plane as a nonintercepting (NI) relative beam size monitor for CEBAF. Previous experiments were successfully done using near-field imaging on the lower-current, 7-GeV beam at APS, and an analytical model was developed for near-field imaging. Calculations from this model indicate sufficient beam-size sensitivity in the ODR profiles for beam sizes in the 30-50 micron regime as found in the transport lines of CEBAF before the experimental targets. With anticipated beam currents of 100 microamps, the ODR signal from the charge integrated over the video field time should be ~500 times larger than in the APS case. These signal strengths will allow a series of experiments to be done on beam energy dependencies, impact parameters, polarization effects, and wavelength effects that should further elucidate the working regime of this technique and test the model. Plans for the diagnostics station that will also provide reference optical transition radiation (OTR) images will also be described.

• W. Berg
  
• L. Erwin, S. E. Shoaf, B. X. Yang
  ANL, Argonne, Illinois

ANL has developed a high-resolution optical transition radiation (OTR) imaging monitor system for the LCLS injection linac at SLAC. The imaging station, OTR-S1, will be located at the S1 spectrometer with a beam energy of 135 MeV. The system will be used to acquire 2-D transverse beam distributions of the accelerated photocathode-gun-generated electron beam. We anticipate an average beam current of 0.2-1 nC and nominal beam spot size of σ-x 130 microns, σ-y 100 microns. The imaging system was designed for a field of view h/v: 10x7.5 mm. The spatial resolution of ~12 microns was verified over the central 5x4 mm region in the visible. A 12-bit digital camera acquires the image and a Mac-based digital frame capturing system was employed for the initial lab-based performance testing of the device. We are reporting on system development, image capture system, testing methodology, and test data analysis. Commissioning results will be reported as they become available.

• C. Yao
  
• A. H. Lumpkin
  ANL, Argonne, Illinois
• D. W. Rule
  NSWC, West Bethesda, Maryland

Interest in nonintercepting (NI) beam size monitoring for top-up operations at the Advanced Photon Source (APS) motivated our investigations of optical diffraction radiation (ODR) techniques. We have reported our experiment results earlier. In particular, we wanted to monitor the beam size in the booster-to-storage ring (BTS) transport line using near-field ODR. An analytical model was numerically evaluated for the APS BTS beam size cases. In addition, the simulations show that near-field ODR profiles have sensitivity to beam size in the 20- to 50-μm region, which are relevant to X-ray FELs and the international linear collider (ILC). The simulation indicates that the orthogonal polarization component is close to a Gaussian distribution and more sensitive to beam size variations, and therefore is more suitable for beam size measurement. Under some circumstances the parallel polarization component shows a non-Gaussian distribution that is also beam size dependent. This report describes the simulation method, the results, and the comparison with experiment results.

• R. B. Fiorito
  
• B. L. Beaudoin, S. J. Casey, D. W. Feldman, P. G. O'Shea, B. Quinn, A. G. Shkvarunets
  UMD, College Park, Maryland

We present strong evidence of the observation of optical transition radiation (OTR) from aluminized silicon targets intercepting the UMER 10 keV, 100 ns pulsed electron beam, using fast (300ps and 1ns rise time) photomultiplier tubes. An intensified gated (3ns-1ms) CCD camera is used to image the beam using OTR and to study its time evolution throughout the beam pulse. A comparison of wave forms and time resolved OTR images is presented along with time integrated images obtained with phosphor screens for different initial conditions, i.e. beam currents and gun bias voltages.

correspondance email: rfiorito@umd.edu

• A. G. Shkvarunets
  
• M. E. Conde, W. Gai, J. G. Power
  ANL, Argonne, Illinois
• R. B. Fiorito, P. G. O'Shea
  UMD, College Park, Maryland

We have developed a new optical diffraction radiation (ODR) - dielectric foil radiation interferometer to measure the divergence of the low energy (8 - 14 MeV) ANL - Advanced Wakefield Accelerator electron beam. The interferometer employs an electro-formed micromesh first foil, which overcomes the inherent scattering limitation in the solid first foil of a conventional OTR interferometer, and an optically transparent second foil. The interference of forward directed ODR from the mesh and optical radiation from the dielectric foil is observed in transmission. This geometry allows a small gap between the foils (1 - 2 mm), which is required to observe fringes from two foils at low beam energies. Our measurements indicate that a single Gaussian distribution is sufficient to fit the data.

correspondance email: shkvar@umd.edu

• T. J. Maxwell
  
• C. L. Bohn, D. Mihalcea, P. Piot
  Northern Illinois University, DeKalb, Illinois

Electrons impinging on a thin metallic foil are seen to deliver small bursts of transition radiation (TR) as they cross the boundary from one medium to the next. A popular diagnostic application is found for compact electron bunches. In this case they will emit radiation more or less coherently with an N-squared enhancement of the intensity on wavelengths comparable to the bunch size, generating coherent transition radiation (CTR). Several detailed analytical descriptions have been proposed for describing the resulting spectral distribution, often making different simplifying assumptions. Given that bunches tenths of millimeters long can generate measurable spectra into the millimeter range, concern may arise as to weak diffraction effects produced by optical interference devices containing elements with dimensions in the centimeter range. The work presented here is a report on an upcoming graduate thesis exploring these effects as they apply to the Fermilab/NICADD photoinjector laboratory using a minimal C++ code that implements the methods of virtual quanta and vector diffraction theory.

• S. Huang, S. Huang
  PKU/IHIP, Beijing
• J. Li, Y. K. Wu
  FEL/Duke University, Durham, North Carolina

One of critical beam parameters for the storage ring based light sources is the energy spread of the electron beam. An accurate measurement of the energy spread remains a challenge. It is well known that the electrons with different energies can degrade the spontaneous emission spectrum of a two-wiggler system in an optical-klystron configuration. The reduced modulation in the spectrum can be used to determine the energy spread of the beam. This paper describes our newly developed energy spread measurement system employing a scanning spectrometer and a fast CCD. A fast CCD with a burst mode of operation is used so that dynamical changes of the energy spread from tens of microseconds to tens of milliseconds can be measured. This system will be used in the beam instability research and free-electron laser research. Together with compact wigglers, such a system can be developed as a dedicated beam diagnostic for storage rings and linacs.

• A. E. Dabrowski
  
• H.-H. Braun, R. Corsini, S. Doebert, T. Lefevre, F. Tecker, P. Urschutz
  CERN, Geneva
• M. Velasco
  NU, Evanston

A non-destructive bunch length detector has been installed in the CLIC Test Facility (CTF3). Using a series of down-converting mixing stages and filters, the detector analyzes the power spectrum of the electromagnetic field picked-up by a single waveguide. This detector evolved from an earlier system which was regularly used for bunch length measurements in CTF2. Major improvements are increase of frequency reach from 90 GHz to 170 GHz, allowing for sub-pico second sensitivity, and single shot measurement capability using FFT analysis from large bandwidth waveform digitisers. The results of the commissioning of the detector in 2006 are presented.

• M. A. Palmer
  
• B. Cerio, R. Holtzapple, J. S. Kern
  Alfred University, Alfred, New York
• J. Dobbins, D. L. Hartill, C. R. Strohman
  CLASSE, Ithaca
• E. Tanke
  CESR-LEPP, Ithaca, New York
• M. E. Watkins
  CMU, Pittsburgh, Pennsylvania

A fast vertical beam profile monitor has been implemented at the Cornell Electron Storage Ring (CESR). Readout is based on the Hamamatsu H7260K multianode photomultiplier. This device has a 32 channel linear anode array with 1 mm channel pitch and sub-nanosecond rise time. It provides the ability to probe individual electron and position bunches which are separated by 14 ns within the trains in CESR. A custom 72 MHz digitizer unit allows synchronous multibunch and turn-by-turn data acquisition. An on-board digital signal processor provides local data processing capability. This system provides the capability to probe a range of single bunch and multibunch beam dynamics issues as well as machine stability issues. In this paper we describe the profile monitor hardware, data acquisition system, calibration of the profile monitor, and data analysis software.

• V. Tang
  
• C. G. Brown, T. L. Houck
  LLNL, Livermore, California

Traditionally, thin metal foils are employed for optical transition radiation (OTR) beam diagnostics but the possibility of plating or shorting accelerator insulating surfaces precludes their routine use on high-demand machines. The successful utilization of dielectric foils in place of metal ones would alleviate this issue but necessitates more modeling and understanding of the OTR data for inferring desired beam parameters because of the dielectric's finite permittivity. Additionally, the temperature dependence of the relevant foil parameters must be accounted for due to instantaneous beam heating. Here, we analyze quartz and kapton foil OTR data from the Flash X-Ray (FXR) induction linear accelerator using a model that includes these effects and discuss the resultant FXR beam profiles.

• X. P. Ding
  
• M. Babzien, K. Kusche, V. Yakimenko
  BNL, Upton, Long Island, New York
• D. B. Cline
  UCLA, Los Angeles, California
• W. D. Kimura
  STI, Washington
• F. Zhou
  SLAC, Menlo Park, California

Two compressed electron beam bunches from a single 60-MeV bunch have been generated in a reproducible manner during compression in the magnetic chicane - "dog leg" arrangement at ATF. Measurements indicate they have comparable bunch lengths (~100-200 fs) and are separated in energy by ~1.8 MeV with the higher-energy bunch preceding the lower-energy bunch by 0.5-1 ps. Some simulation results for analyzing the double-bunch formation process are also presented.

• W. D. Zacherl
  
• I. Blumenfeld, M. J. Hogan, R. Ischebeck
  SLAC, Menlo Park, California
• C. E. Clayton, P. Muggli, M. Zhou
  UCLA, Los Angeles, California

A typical diagnostic used to determine the bunch length of ultra-short electron bunches is the autocorrelation of coherent transition radiation. This technique can produce artificially short bunch length results due to the attenuation of low frequency radiation if corrections for the material properties of the Michelson interferometer and detector response are not made. Measurements were taken using FTIR spectroscopy to determine the absorption spectrum of various materials and the response of a Molectron P1-45 pyroelectric detector. The material absorption data will be presented and limitations on the detector calibration discussed.

• W. J. Corbett
  
• A. S. Fisher, X. Huang, J. A. Safranek, J. J. Sebek
  SLAC, Menlo Park, California
• A. H. Lumpkin
  ANL, Argonne, Illinois
• W. Y. Mok
  Life Imaging Technology, Palo Alto, California

In the nominal SPEAR3 storage ring optics, the natural radiation pulse length is 40ps fwhm per bunch. Due to the double-bend achromat lattice configuration, it is relatively straightforward to reduce the momentum compaction factor (α) and hence reduce the bunch length by modest values. In this paper we present streak camera measurements of the bunch length in the nominal optics, and with ~α/20 and α/50 optics as a function of single-bunch current. The results demonstrate <10ps fwhm radiation pulses with up 5x10⁸ particles/bunch (~100μ amp). Radiation pulse power, bunch length scaling and broadband impedance estimates are discussed.

• R. Ischebeck
  
• M. K. Berry, I. Blumenfeld, F.-J. Decker, M. J. Hogan, R. H. Iverson, N. A. Kirby, R. Siemann, D. R. Walz
  SLAC, Menlo Park, California
• C. E. Clayton, C. Huang, C. Joshi, W. Lu, K. A. Marsh, W. B. Mori, M. Zhou
  UCLA, Los Angeles, California
• T. C. Katsouleas, P. Muggli, E. Oz
  USC, Los Angeles, California

Particles are leaving the meter-long plasma wakefield accelerator with a large energy spread. To determine the spectrum of these particles, four diagnostics have been set up. These were used to determine energies of the particles that gain energy in the plasma, those that lose energy by driving the wake and the self-injected particles that are accelerated from rest.

• H. Loos
  
• T. Borden, P. Emma, J. C. Frisch, J. Wu
  SLAC, Menlo Park, California

The ultra-short bunches of the electron beam for LCLS are generated in two 4-dipole bunch compressors located at energies of 250 MeV and 4.3 GeV. Although an absolute measurement of the bunch length can be done by using a transverse deflecting cavity in an interceptive mode, a non-interceptive single shot method is needed as a relative measurement of the bunch length used in the continuous feedback for beam energy and peak current. We report on the design and implementation of two monitors measuring the integrated power of coherent edge radiation from the last dipole in each chicane. The first monitor is installed in early 2007 and we compare its performance with the transverse cavity measurement and other techniques.

• C. Mcguinness
  
• R. L. Byer, T. Plettner
  Stanford University, Stanford, Califormia
• E. R. Colby, R. Ischebeck, R. J. Noble, C. M.S. Sears, R. Siemann, J. E. Spencer, D. R. Walz
  SLAC, Menlo Park, California

The laser acceleration experiments conducted for the E163 project at the NLC Test Accelerator facility at SLAC have stringent requirements on the temporal properties of the electron and laser beams. A system has been implemented to measure the relative phase stability between the RF sent to the gun, the RF sent to the accelerator, and the laser used to generate the electrons. This system shows rms timing stability better than 1 psec. Temporal synchronicity between the 0.5 psec electron bunch, and the 0.5 psec laser pulse is also of great importance. Cherenkov radiation is used to measure the arrival time of the electron bunch with respect to the laser pulse, and the path length of the laser transport is adjusted to optimize temporal overlap. A linear stage mounted onto a voice coil is used to make shot-by-shot fine timing adjustments to the laser path. The final verification of the desired time stability and control is demonstrated by observing the peak of the laser-electron interaction signal over the course of several minutes.

• A. Novokhatski
  
• J. Seeman, M. K. Sullivan
  SLAC, Menlo Park, California

The PEP-II B-factory at SLAC has recently experienced unexpected aborts due to anomalously high radiation levels at the BaBar detector. Before the problem was finally traced we performed the wake field analysis of the Q-2 bellows, which is situated at a distance of 2.2 m from the interaction point. Analysis showed that electric field in a small gap between a ceramic tile and metal flange can be high enough to produce sparks or even breakdowns. Later the traces of sparks were found in this bellows.

• A. Novokhatski
  
• S. DeBarger, S. Ecklund, N. Kurita, J. Seeman, M. K. Sullivan, S. P. Weathersby, U. Wienands
  SLAC, Menlo Park, California

A new Q2-bellows absorber will damp only transverse wake fields and will not produce additional beam losses due to Cherenkov radiation. The design is based on the results of the HOM analysis. Geometry of the slots and absorbing tiles was optimized to get maximum absorbing effect.

• R. L. Warnock
  

Realistic modeling of coherent synchrotron radiation (CSR) and the space charge force in single-pass systems and rings usually requires at least a two-dimensional (2-D) description of the charge/current density of the bunch. Since that leads to costly computations, one often resorts to a 1-D model of the bunch for first explorations. This paper provides several improvements to previous 1-D theories, eliminating unnecessary approximations and physical restrictions.