IPAC2012 - List of Keywords (coupling)

Paper	Title	Other Keywords	Page
MOEPPB002	The MICE Experiment	emittance, target, solenoid, electron	76
	A.P. Blondel DPNC, Genève, Switzerland
	Ionization Cooling is the only practical solution to preparing high brilliance muon beams for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) is under development at the Rutherford Appleton Laboratory (UK) by an international collaboration. The muon beam line has been commissioned and first measurements of emittance with particle physics detectors have been performed. The remaining apparatus is currently under construction. First results with a liquid-hydrogen absorber will be produced in 2013; a couple of years later a full cell of a representative ionization cooling channel, including RF re-acceleration, will be in operation. The design offers opportunities for tests with various absorbers and several optics configurations. Results will be compared with detailed simulations of cooling channel performance to ensure full understanding of the cooling process. on behalf of the MICE collaboration

MOEPPB010	Measurement of Satellite Bunches at the LHC	photon, emittance, synchrotron, ion	97
	A. Jeff, M. Andersen, A. Boccardi, S. Bozyigit, E. Bravin, T. Lefèvre, A. Rabiller, F. Roncarolo CERN, Geneva, Switzerland A.S. Fisher SLAC, Menlo Park, California, USA C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Adam Jeff is a DITANET fellow, supported by the EU's Marie Curie actions contract PITN-GA-2008-215080. The RF gymnastics involved in the delivery of proton and lead ion bunches to the LHC can result in satellite bunches of varying intensity occupying the nominally empty RF buckets. Quantification of these satellites is crucial for bunch-by-bunch luminosity normalization as well as for machine protection. We present an overview of the longitudinal density monitor (LDM) which is the principal instrument for the measurement of satellite bunches in the LHC. The LDM uses single photon counting of synchrotron light. The very high energies reached in the LHC, combined with a dedicated undulator for diagnostics, allow synchrotron light measurements to be made with both protons and heavy ions. The arrival times of photons are collected over a few million turns, with the resulting histogram corrected for the effects of the detector’s deadtime and afterpulsing in order to reconstruct the longitudinal profile of the entire LHC ring. The LDM has achieved a dynamic range in excess of 10⁵ and a time resolution of 90 ps. Example results are presented and the measurements are benchmarked against satellite distributions based on collision data from the LHC experiments.

MOEPPB011	The Two Methods for Beam Profile Measurement of BEPCⅡ Storage Ring	synchrotron, monitoring, synchrotron-radiation, emittance	100
	L. Wang, J. Cao IHEP, Beijing, People's Republic of China
	The two method as spatial interferometor and visible light imaging for real time beam profile measurment for BEPCⅡ Storage Ring will be introduced in detail, including optical Magnification measurment, point spread function measurement, image reversion and spatial coherence measurment. the transverse emittance and copouling coefficient was gotten from the result of the beam profile monitor.

MOPPC008	LHC Optics Determination with Proton Tracks Measured in the Roman Pots Detectors of the TOTEM Experiment	proton, optics, scattering, lattice	136
	H. Niewiadomski, H. Burkhardt CERN, Geneva, Switzerland F.J. Nemes KFKI, Budapest, Hungary
	The TOTEM experiment at the LHC is equipped with near beam movable devices – called Roman Pots (RP) – which detect protons scattered at the interaction point (IP) arrived to the detectors through the magnet lattice of the LHC. Proton kinematics at IP is reconstructed from positions and angles measured by the RP detectors, on the basis of the optical functions between IP and the RP locations. The precision of optics determination is therefore of the key importance for the experiment. TOTEM developed a novel method of machine optics determination making use of angle-position distributions of elastically scattered protons observed in the RP detectors. The method has been successfully applied to the data samples registered in 2010 and 2011. The studies have shown that the transport matrix could be estimated with a precision better than 1%.

MOPPC024	Modelling of the AGS Using Zgoubi - Status	simulation, optics, closed-orbit, multipole	181
	F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, V. Schoefer, N. Tsoupas BNL, Upton, Long Island, New York, USA
	A computer model, based on the ray-tracing code Zgoubi, is being developed in view of on-line simulation of the RHIC injector AGS, and of beam and spin dynamics simulations and studies in the presence of the cold and warm helical partial snakes. A status of this work is given here.

MOPPC027	Synchro-Betatron Effects in the Presence of Large Piwinski Angle and Crab Cavities at the HL-LHC	betatron, luminosity, simulation, damping	190
	S.M. White BNL, Upton, Long Island, New York, USA R. Calaga CERN, Geneva, Switzerland R. Miyamoto ESS, Lund, Sweden
	Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP). The reduction of beta-star at the collision points for the high luminosity LHC (HL-LHC) requires an increment in the crossing angle to maintain the normalized beam separation to suppress the effects of long-range beam-beam interactions. However, increase in crossing angle may give rise to synchro-betatron resonances which may negatively affect the beam emittance and lifetime. 6D weak-strong and strong-strong simulations are performed to study the effect of synchro-betatron resonances in the context of the HL-LHC layout and its suppression via crab crossing.

MOPPC028	Coherent Beam-Beam Effects Observation and Mitigation at the RHIC Collider	emittance, simulation, damping, dipole	193
	S.M. White, M. Bai, W. Fischer, Y. Luo, A. Marusic, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work partially supported by Brookhaven Science Associates, LARP, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

MOPPC070	Field Emission Simulation for KEK-ERL 9-Cell Superconducting Cavity	cavity, electron, simulation, linac	295
	E. Cenni Sokendai, Ibaraki, Japan T. Furuya, H. Sakai, M. Satoh, K. Shinoe, K. Umemori KEK, Ibaraki, Japan M. Sawamura JAEA/ERL, Ibaraki, Japan
	In order to develop the Energy Recovery Linac at KEK, we are studying the performance of L-band superconducting cavities by means of vertical tests. One of the limiting factor for the cavities performance is power losses due to field emitted electrons. With regard to this phenomena, a particle tracking code is used to study electron trajectories and deposited energy on the inner surface of the cavity. Different emitters location were tested within a range of accelerating field and phases in order to reproduce different scenario. The final goal of this study is to locate the sources of the electrons inside the cavity through a deeper understanding of the phenomena. To validate the results from the simulation the outcome data are compared with other particle tracking codes.

MOPPD008	RF and Stochastic Cooling System of the HESR	pick-up, accumulation, controls, kicker	385
	R. Stassen, F.J. Etzkorn, G. Schug, H. Stockhorst FZJ, Jülich, Germany T. Katayama GSI, Darmstadt, Germany L. Thorndahl CERN, Geneva, Switzerland
	The High Energy Storage Ring HESR (1.5-15 GeV/c) for antiprotons at the FAIR complex (Facility for Antiprotons and Ion Research) in Darmstadt (GSI) will have a dedicated stochastic cooling system not only during the experiments to fulfill the beam requirements, but also during the accumulation due to the postponed RESR. Here the cooperation of stochastic cooling with different Barrier-Bucket configurations is necessary for an high accumulation efficiency. The latest hardware configurations and recent tests results of both the RF-system with air-cooled cavities and the stochastic cooling based on slot-ring couplers will be presented.

MOPPD011	Analysis of Frequency Spectrum of Bunched Beam Related to Transverse Laser Cooling*	synchrotron, laser, betatron, ion	391
	K. Jimbo Kyoto University, Institute for Advanced Energy, Kyoto, Japan Z.Q. He TUB, Beijing, People's Republic of China M. Nakao, A. Noda, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan
	Using synchro-betatron coupling, transverse laser cooling is pursued at an ion storage/cooler ring, S-LSR, Kyoto University. A bunched 40 keV 24Mg+ beam was cooled by a co-propagating laser of 280 nm wavelength. Synchrotron oscillation in the longitudinal direction and betatron oscillation in the horizontal direction were intentionally coupled by an RF drift tube located at the finite dispersive section (D =1.1 m) where longitudinal cooling force was transmitted to the horizontal direction.* Analyzing bunched Schottky signals, which represents longitudinal physical quantities of the beam, we try to obtain an evidence of synchro-betatron coupling and accordingly laser cooling of the beam in the transverse direction. * H. Okamoto, Phys. Rev. E 50, 4982 (1994)

MOPPD013	Observation of 2-Component Bunched Beam Signal with Laser Cooling	laser, betatron, ion, injection	397
	H. Souda, M. Nakao, A. Noda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan M. Grieser MPI-K, Heidelberg, Germany Z.Q. He TUB, Beijing, People's Republic of China K. Ito, H. Okamoto HU/AdSM, Higashi-Hiroshima, Japan K. Jimbo Kyoto University, Institute for Advanced Energy, Kyoto, Japan Y. Yuri JAEA/TARRI, Gunma-ken, Japan
	Funding: Work supported by Advanced Compact Accelerator Development Project of MEXT, Global COE program "The Next Generation of Physics, Spun from Universality and Emergence" and Grant-in-Aid for JSPS Fellows. Longitudinal beam temperature during a laser cooling was measured through bunch length measurement at S-LSR. 40keV 24Mg+ beams were bunched by an RF voltage with a harmonic number of 5 and were cooled by a co-propagating laser with a wavelength of 280nm. Bunch length was measured by time-domain signal from a pair of parallel-plate electrostatic pickups with a length of 140mm. Injected non-cooled beams gave a bunch length of 2.5m (2-σ) and cooled beam has a 2-component of broad and sharp distribution. Broad distribution had a longitudinal length of 2.2m, which is close to that of initial beam. The length of the sharp distribution shrunk to 0.25m and is considered as a cooled part. Capture efficiency of cooling, which represents the ratio of the particle numbers of cooled part and the total particle number, varies by the change of the detuning of the laser (fixed frequency or scanning). With scanning range of 2GHz, capture efficiency was improved from 66% to 92%, whereas the bunch became longer by 10% with scanning. Approach to improve the number of cooled particle and cut uncooled part* will be applied to attain a strong signal with a low-current beam with a low temperature. * J. S. Hangst et al., Phys. Rev. Lett. 74, 4432 (1995). ** A. Noda et al., these proceedings.

MOPPP047	Characterization of the First SRF Electron Beam Source at the Naval Postgraduate School	cavity, cathode, electron, SRF	667
	A.D. Holmes, A.B. Baxter, C.W. Bennett, J.R. Harris, J.W. Lewellen, R. Swent NPS, Monterey, California, USA J.M. Didoszak, J.M. Utschig ONR, Arlington, Virginia, USA
	In June 2011, the Naval Postgraduate school (NPS) received the 500 MHz Mark I quarter-wave superconducting RF (SRF) electron beam source and, among other firsts, completed the first cool down and characterization of an SRF beam source at a US Naval facility. The Mark I has a photocathode with adjustable position and uses a unique cascaded RF coupler design. As part of an on-going advanced electron source development project, the NPS Beam Physics Laboratory (BPL) team continues characterization of the Mark I cavity at various cathode stalk, coupler, and probe positions. Methods and experimentation used to measure the cavity Q and β, as well as characteristic results, with respect to coupler, cathode stalk, and probe positions are presented.

MOPPR023	Stripline BPM with Integral In-Vacuo Termination	impedance, pick-up, vacuum, quadrupole	828
	A. Stella, A. Ghigo, V.L. Lollo, F. Marcellini, M. Serio INFN/LNF, Frascati (Roma), Italy
	We report the design and realization of a stripline type beam position monitor to be used in the SPARC LAB transfer lines. While the directional properties provided by matched termination at the downstream end are not strictly required in a transfer line, yet matched loads at the end of the stripline electrodes are preferable to reduce the loss factor and to avoid unwanted reflection to the detection electronic. The Integration of a matched resistive load inside the vacuum chamber allows to halve the number of UHV feedthroughs.

MOPPR039	Development of Beam Position Monitor for PEFP Linac and Beam line	linac, proton, DTL, quadrupole	864
	J.Y. Ryu, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, K.T. Seol KAERI, Daejon, Republic of Korea
	Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government. The development of the Beam Position Monitor (BPM) is in progress for the linac and beam lines of the Proton Engineering Frontier Project (PEFP). We choose a strip line BPM for the PEFP 20-MeV and 100-MeV beam lines in order to increase the sensitivity of the relatively long bunches in the beam lines. We also selected the same type BPM for the proton linac in the energy range between 20-MeV and 100-MeV. The prototype BPM was designed, fabricated and tested at KAERI site, where the 20-MeV linac was operated. To check the performance of the BPM, we performed the field mapping. The characteristics and test results of the BPM on the test bench as well as with 20-MeV proton beam will be presented in this paper.

MOPPR044	Optics and Emittance Studies using the ATF2 Multi-OTR System	emittance, quadrupole, target, controls	879
	J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López IFIC, Valencia, Spain J. Cruz, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515. A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction.

MOPPR057	Development of a Cavity Beam Position Monitor for CLIC	cavity, dipole, linac, factory	915
	F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin JAI, Egham, Surrey, United Kingdom E. Calvo, N. Chritin, F. Guillot-Vignot, T. Lefèvre, L. Søby CERN, Geneva, Switzerland A. Lunin, M. Wendt, V.P. Yakovlev Fermilab, Batavia, USA S.R. Smith SLAC, Menlo Park, California, USA
	The Compact Linear Collider (CLIC) project presents many challenges to its subsystems and the beam diagnostics in particular must perform beyond current limitations. The requirements for the CLIC main beam position monitors foresee a spacial resolution of 50 nm while delivering a 10 ns temporal resolution within the bunch train. We discuss the design of the microwave cavity pick-up and associated electronics, bench top tests with the first prototype cavity, as well as some of the machine-specific integration and operational issues.

MOPPR073	Analysis of Resonant TE Wave Modulation Signals for Electron Cloud Measurements	electron, resonance, factory, cavity	957
	S. De Santis LBNL, Berkeley, California, USA D. Alesini INFN/LNF, Frascati (Roma), Italy J.P. Sikora CLASSE, Ithaca, New York, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy under Contracts DE-FC02-08ER41538, DE-AC02-05CH11231. Recent TE wave measurements of the electron cloud density in the beampipe at CesrTA and DAΦNE have shown that, especially near cutoff, the microwave excitation takes place by coupling to a standing wave, rather than to a propagating TE mode. With the beampipe acting as a resonant cavity, the effect of the periodic electron cloud density is a modulation of the cavity's resonant frequency. As a result, the measured sidebands are a combination of amplitude, phase, and frequency modulation, as the periodic cloud density modulates this resonant frequency. The quality factor Q of the resonance will determine its response to transients in the electron cloud density, and the resulting effect on modulation sidebands. In order to estimate the peak electron cloud density and its spacial distribution, knowledge of the Q and the standing wave pattern need to be determined, either by experimental measurements or simulation codes. In this paper we analyze the dependence of the modulation sidebands on the electron cloud density in two different regimes, when the cloud rise/decay time is much longer, or much shorter than the filling time of the resonance.

MOPPR088	Cavity BPM for 1300 MHz Cryomodules	cavity, dipole, wakefield, cryomodule	993
	N. Barov, D.J. Newsham, D. Wu Far-Tech, Inc., San Diego, California, USA
	Funding: Work supported by DOE grant DE-SC00004498 A cavity BPM for 1300 MHz cryomodules is under development by FAR-TECH, Inc. The BPM is capacitively loaded to fit in a small area, and uses a novel coupling scheme which further cuts down space requirements. We discuss status of the fabrication, and eventual plan to test the diagnostic at the ANL Wakefield Accelerator facility.

TUYA03	Performance and Prospects of BEPCII	luminosity, optics, feedback, injection	1030
	Q. Qin IHEP, Beijing, People's Republic of China
	BEPCII, the upgrade project of Beijing Electron Positron Collider (BEPC), has been put into operation for both high energy physics experiments as well as synchrotron radiation application since its completion in 2009. The peak luminosity reaches 6.5*10³² cm^-2 s^-1 at 1.89 GeV with e⁺e⁻ collisions of each beam current 700 mA. The collider operates for dedicated synchrotron radiation mode with 250 mA electron beams at 2.5 GeV. The performance of BEPCII should be reported and the measures to upgrade its luminosity described.
	Slides TUYA03 [5.529 MB]

TUYB02	Manufacture and Testing of Optical-scale Accelerator Structures from Silicon and Silica	laser, electron, acceleration, vacuum	1050
	R.J. England, E.R. Colby, R. Laouar, C. McGuinness, B. Montazeri, R.J. Noble, K. Soong, J.E. Spencer, D.R. Walz, Z. Wu SLAC, Menlo Park, California, USA R.L. Byer, C.M. Chang, K.J. Leedle, E.A. Peralta Stanford University, Stanford, California, USA B.M. Cowan Tech-X, Boulder, Colorado, USA M. Qi Purdue University, West Lafayette, Indiana, USA
	We report on recent progress in the design, manufacture and testing of optical-scale accelerator structures made from silicon and silica. The potential of these structures for the development of extremely compact, efficient, and low cost accelerators producing attosecond electron pulses will be discussed, together with various possible applications.
	Slides TUYB02 [17.226 MB]

TUOAA03	Tests of Low Emittance Tuning Techniques at SLS and DAΦNE	quadrupole, emittance, alignment, collider	1065
	S.M. Liuzzo, M.E. Biagini, P. Raimondi INFN/LNF, Frascati (Roma), Italy M. Aiba Paul Scherrer Institut, Villigen, Switzerland M. Böge PSI, Villigen, Switzerland
	The SuperB collider design is based on extremely low emittances, comparable to those of synchrotron light sources. A Low Emittance Tuning (LET) algorithm was developed for SuperB and has been tested last year at DIAMOND. This paper will report on the results of the application of LET to SLS (PSI) and DAΦNE (LNF) in order to compare and confirm the previous results. In this tests, the correction of orbit, dispersion and coupling is applied simultaneously to the detection of Beam Position Monitors tilts. The effect of beam based alignment at DAΦNE is also presented, together with an evaluation of the effects of other possible sources of emittance growth.
	Slides TUOAA03 [4.313 MB]

TUOBC02	Small-Beta Collimation at SuperKEKB to Stop Beam-Gas Scattered Particles and to Avoid Transverse Mode Coupling Instability	interaction-region, impedance, scattering, simulation	1104
	H. Nakayama, Y. Funakoshi, K. Kanazawa, K. Ohmi, Y. Ohnishi, Y. Suetsugu KEK, Tsukuba, Japan H. Nakano Tohoku University, Graduate School of Science, Sendai, Japan
	At SuperKEKB, beam particles which are Coulomb-scattered by the residual gas molecular change direction and will be eventually lost by hitting beam pipe inner wall. Due to large vertical beta function and small beam pipe radius just before IP, most of Coulomb-scattered particles are lost there and are very dangerous for the Belle-II detector. To stop such particles before the IP, vertical collimators are installed in the ring. However, such vertical collimators should be placed very close (few mm) to the beam and therefore induce transverse mode coupling instability. To avoid beam instability and achieve collimation at the same time, we need to install vertical collimators where vertical beta function is SMALL, since maximum collimator width determined by aperture condition is proportional to β^1/2, and minimum collimator width determined by instability is proportional to β^2/3. We present our strategy to stop beam-gas scattered particles and simulated loss rate in the interaction region. We will also show dedicated vertical collimator design to achieve less instability.
	Slides TUOBC02 [2.196 MB]

TUPPC003	Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors	quadrupole, emittance, sextupole, betatron	1152
	A. Chancé, J. Payet CEA/DSM/IRFU, France B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC016	Progress of Emittance Coupling Correction at the SPring-8 Storage Ring	resonance, betatron, storage-ring, survey	1191
	M. Takao, M. Masaki, Y. Shimosaki, K. Soutome, S. Takano, C. Zhang JASRI/SPring-8, Hyogo-ken, Japan
	The vertical beam spread, or the emittance coupling, is one of the most important parameters for the high brilliance light source storage ring. By the precise alignment of the magnets and the proper COD correction, at the commissioning phase of the SPring-8 storage ring we succeeded in achieving the very small coupling ~0.2 % without correction. However, the coupling had grown large with the years, so recently we have corrected it and recovered the initial performance. The scheme of the coupling correction at the SPring-8 storage ring is the global one, which is based on the perturbation theory with single resonance approximation. In the beginning of the correction the coupling was corrected by means of minimizing the vertical beam size. Then the performance of the coupling correction has been further improved by changing the scheme to minimizing the betatron coupling mode in the vertical oscillation of the horizontally kicked beam. This result implies that the higher order coupling contributes to the emittance coupling, which can be corrected by the higher skew multi-pole magnet. The present status of the coupling correction at the SPring-8 storage ring will be reported.

TUPPC018	Estimation of Orbit and Optics Distortion of SuperKEKB by Tunnel Deformation	emittance, quadrupole, optics, luminosity	1197
	A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto KEK, Ibaraki, Japan
	The tunnel which was used for the KEKB B-factory is reused for the accelerator tunnel of the SuperKEKB. The total vertical displacement of the tunnel subsidence reached almost 30mm during 10 years KEKB operation. In order to operate the SuperKEKB which might be more delicate machine than the previous KEKB B-factory, we are evaluating the optics distortion by the tunnel deformation and studying the machine performance after the orbit and optics correction. We report the estimation of the machine performance degradation by the tunnel subsidence and the requirement of the correction.

TUPPC020	A Scheme for Horizontal-vertical Coupling Correction at SuperKEKB	simulation, optics, lattice, target	1203
	H. Sugimoto, H. Koiso, A. Morita, Y. Ohnishi, K. Oide KEK, Ibaraki, Japan
	SuperKEKB is an 7 GeV electron and 4 GeV positron double ring collider project based on the nano beam scheme and is aimed to break the world's luminosity record. A horizontal flat beam is essential to realize the nano beam collisions. One of critical effect that induces unexpected coupling is machine error, such as magnet misalignment and field imperfection. Coupling correction, therefore, plays key role in the actual beam operation. In this study, we numerically explore a possible scheme for coupling correction in the SuperKEKB lattice. Some coupling measurement and correction methods are applied to the model lattice considering magnet misalignments and finite BPM resolution. Based on the results, the attainable smallest coupling in the actual SuperKEKB is discussed.

TUPPC023	Waist Corrections at the Interaction Point of ATF2 in the Presence of IPBSM Fringe Rotations and Input Beam Sigma13, Sigma24	sextupole, simulation, quadrupole, alignment	1212
	S. Bai, J. Gao IHEP, Beijing, People's Republic of China P. Bambade LAL, Orsay, France
	The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam (or equivalently a σ13 correlation), as well as a σ24 correlation, can break the orthogonality in the main σ34 and σ32 waist corrections during the minimization and result in larger vertical beam sizes at IP. Both effects are studied, analytically and in simulation, and a practical procedure is suggested for diagnosing the presence of a residual fringe tilt, by measuring the influence of the horizontal waist correction on the minimum vertical beam size.

TUPPC026	Design of Compact C-Band Standing-Wave Accelerating Structure Enhancing RF Phase Focusing	bunching, cavity, focusing, simulation	1221
	H.R. Yang, M.-H. Cho, J. Jang, S.H. Kim, W. Namkung, S.J. Park POSTECH, Pohang, Kyungbuk, Republic of Korea J.-S. Oh NFRI, Daejon, Republic of Korea
	Funding: Work supported by POSTECH Physics BK21 Program. We design a C-band standing-wave accelerating structure for an X-ray source of the imaging and medical applications. It is capable of producing 6-MeV, 100-mA pulsed electron beams which is focused by less than 1.5 mm without external magnets. As an RF source, we use peak 1.5-MW magnetron with duty factor of 0.08%. The accelerating structure is a bi-periodic and on-axis-coupled structure with a built-in bunching section, which consists 3 bunching cells, 13 normal cells and a coupler cell. It operated with π/2-mode standing-waves. The bunching section is designed to enhance the RF phase focusing in order to achieve 1.2-mm beam spot size. Each cavity is designed with the MWS code to maximize the effective shunt impedance within 3.5% inter-cell coupling. In this paper, we present design details of RF cavities and the beam dynamics simulation by the PARMELA code.

TUPPC040	Model Calibration and Optics Correction Using Orbit Response Matrix in the Fermilab Booster	booster, optics, dipole, acceleration	1251
	M.J. McAteer, S.E. Kopp The University of Texas at Austin, Austin, Texas, USA V.A. Lebedev, E. Prebys Fermilab, Batavia, USA A.V. Petrenko BINP SB RAS, Novosibirsk, Russia
	A beam-based method of optical model calibration using the measured orbit response matrix, known as the LOCO method, was successfully applied to Fermilab's rapid-cycling Booster synchrotron. Orbit responses were measured by individually changing the strength of each dipole corrector throughout the acceleration cycle, and dispersion was measured by changing the beam's radial offset. The model calibration procedure revealed large calibration errors for all elements in the Booster's recently-installed multipole corrector packages and beam position monitors. The resulting model was used to correct coupling and beta beating.

TUPPC045	Modeling Investigation on a Deflecting-Accelerating Composite RF-cavity System for Phase Space Beam Control	cavity, simulation, klystron, electron	1266
	Y.-M. Shin, M.D. Church, P. Piot Fermilab, Batavia, USA
	Phase space manipulations between the longitudinal and transverse degree of freedoms hold great promise toward the precise control of electron beams. Such transverse-to-longitudinal phase space exchange have been shown to be capable of exchanging the transverse and horizontal emittance or controlling the charge distribution of an electron bunch, for beam-driven advanced accelerator methods. The main limitation impinging on the performance of this exchange mechanism stems from the external coupling nature of a realistic deflecting cavity, compared to a thin-lens model. As an extended idea from , this paper presents the design of a composite 3.9-GHz RF-system consisting of a deflecting- and accelerating-mode cavities. The system design analysis is discussed with particle-in-cell (PIC) simulations of the device performance. A. Zholents, PAC'11.

TUPPC046	Further Analysis of Real Beam Line Optics from a Synthetic Beam	optics, linac, closed-orbit, electron	1269
	R.M. Bodenstein UVa, Charlottesville, Virginia, USA Y. Roblin, M.G. Tiefenback JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript for U.S. Government purposes. Standard closed-orbit techniques for Twiss parameter measurement are not applicable to the open-ended Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. The evolution of selected sets of real orbits in the accelerator models the behavior of a “synthetic” beam. This process will be validated against beam profile-based Twiss parameter measurements and should provide the distributed optical information needed to optimize beamline tuning for an open-ended system. This work will discuss the current and future states of this technique, as well as an example of its use in the CEBAF machine.

TUPPC082	Non-linear Beam Dynamics Tests at the CERN PS in the Framework of the Multi-turn Extraction	pick-up, synchrotron, extraction, betatron	1365
	M. Giovannozzi, G. Arduini, J.M. Belleman, S.S. Gilardoni, C. Hernalsteens, A. Lachaize, G. Métral, Y. Papaphilippou CERN, Geneva, Switzerland
	In the framework of the CERN PS Multi-Turn Extraction several campaigns of measurements probing the non-linear beam dynamics have been carried out. These measurements range from the measurement of non-linear chromaticity to phase space portraits, de-coherence and re-coherence measurements, secondary island tune etc. In this paper these measurements will be reviewed and the results presented and discussed in details.

TUPPD065	An Electron Gun Test Stand to Prepare for the MAX IV Project	gun, cathode, injection, linac	1551
	S. Werin, E. Elafifi, M. Eriksson, D. Kumbaro, F. Lindau, S. Thorin MAX-lab, Lund, Sweden E. Mansten Lund University, Division of Atomic Physics, Lund, Sweden
	The MAX IV facility, currently under construction, will include a 3 GeV linac injector with two RF guns providing beams for the two operations modes: ring injection and the Short Pulse Facility. The ring injection will be done by a thermionic 3 GHz RF gun developing from the current MAX-lab RF gun. The SPF gun will be a laser driven photo cathode 3 GHz RF gun based on the 1.6 cell BNL/SLAC type. The guns will be operated with short (0.7 us) RF pulses from a SLED system. A test stand to fine tune the operation of the two different systems has been assembled at the MAX IV laboratory (former MAX-lab). The experience in RF commissioning and initial measurements of energy, charge and quantum efficiency will be reported and the extension of the test stand for full emittance characterization will be outlined.

TUPPP004	Low-alpha Operation for the SOLEIL Storage Ring	optics, injection, radiation, photon	1608
	M.-A. Tordeux, J. Barros, A. Bence, P. Brunelle, N. Hubert, M. Labat, P. Lebasque, A. Nadji, L.S. Nadolski, J.-P. Pollina SOLEIL, Gif-sur-Yvette, France C. Evain PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
	The low momentum compaction factor (alpha) operation has been recently established on the SOLEIL Storage Ring. Both time resolved X-ray and THz radiation user communities are taking benefit from a hybrid filling pattern with a 4.7 ps RMS bunch length. At a value of 1.7 10^-5 (nominal alpha /25) and a current per bunch of 65 μA, stable THz radiation is produced in the range of 8 - 20 cm^-1 (measurements and comparison with Coherent Synchrotron Radiation (CSR) modeling are reported elsewhere, ). Several low-alpha optics have been investigated and the optics presented at IPAC’11 has been selected for the operation. This paper presents the comprehensive experimental characterization of this optics. Specificities of the low-alpha operation, driven by the very demanding user experiments, are reviewed: closed orbit stability issues, extremely tight injected current step when refilling which implies a specific Linac tuning, low current diagnostics optimization, short bunch measurements, insertion devices effect on the CSR characteristics and radiation safety aspects justified by beam losses at injection. C. Evain, A. Loulergue et al., this conference. ** E. Roussel et al., this conference.

TUPPP015	Status and Recent Progress of SPring-8	emittance, lattice, storage-ring, optics	1638
	H. Ohkuma JASRI/SPring-8, Hyogo-ken, Japan
	The SPring-8 is an 8 GeV synchrotron radiation facility that has been in operation since 1997. The SPring-8 has been operated well and total user time has reached more than 53,700 hours, 75% of the total operation time. The average user time per year is about 4,000 hours. The average availability is about 98% in the past 15 years. The operational status and recent progress overview of SPring-8 is presented: the local lattice modification of 30-m long straight section for installing small gap (min. gap is 5.2 mm) in-vacuum undulators, the emittance coupling correction for the vertical beam size reduction, the test operation of low energy operation for the energy saving, and the study of lower emittance optics for the present SPring-8 storage ring. An outline of a future upgrade with a full-scale major lattice modification is also presented. We also present a little about recent progress of SPring-8 injecting accelerators.

TUPPP039	Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS	lattice, quadrupole, emittance, radiation	1698
	C. Sun, C. Steier, W. Wan LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP086	A Synchronized FIR/VUV Light Source at Jefferson Lab	FEL, laser, wiggler, electron	1789
	S.V. Benson, D. Douglas, G. Neil, M.D. Shinn, G.P. Williams JLAB, Newport News, Virginia, USA
	Funding: This work was supported by U.S. DOE Contract No. DE-AC05-84-ER40150, the Air Force Office of Scientific Research, DOE Basic Energy Sciences. We describe a dual FEL configuration on the UV Demo FEL at Jefferson Lab that would allow simultaneous lasing at THz and UV wavelengths. The THz source would be an FEL oscillator with a short wiggler providing diffraction-limited pulses with pulse energy exceeding 50 microJoules. The THz source would use the exhaust beam from a UVFEL. The coherent harmonics in the VUV from the UVFEL are outcoupled through a hole. The THz source uses a shorter resonator with either hole or edge coupling to provide very high power THz pulses. Simulations indicate excellent spectral brightness in the THz region with over 100 W/cm^-1 output.

TUPPR018	Beam Impedance Study of the Stripline Kicker for the CLIC Damping Ring	impedance, kicker, damping, simulation	1849
	C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain M.J. Barnes CERN, Geneva, Switzerland I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: FPA2010-21456-C02-01 CLIC Pre-Damping (PDR) and Damping Rings (DR) are required for reducing the emittance of the electron and positron beams before being accelerated in the main linac. Several stripline kicker systems are used to inject and extract the beam from the PDR and DR. Wakefields produced by the charged particles when passing through the aperture of the stripline kickers may become an important source of emittance growth; for this reason, simulations of longitudinal and transverse beam impedance in the frequency domain, and their equivalent in the time domain are needed. First analytical approaches, future simulations and tests planned are presented in this paper.

TUPPR025	Higher-Order Modes and Beam Loading Compensation in CLIC Main Linac	impedance, beam-loading, HOM, higher-order-mode	1867
	O. Kononenko, A. Grudiev CERN, Geneva, Switzerland
	Compensation of transient beam loading is one of the major performance issues of the future compact linear collider (CLIC). Recent calculations, which consider only the most important fundamental mode, have shown that the 0.03% limit on the rms relative bunch-to-bunch energy spread in the main beam can be reached by optimizing the RF power pulse shape for the TD26, the CLIC baseline accelerating structure. Here, using HFSS and massively parallel ACE3P codes developed at SLAC, we perform an additional dedicated study of the influence of higher-order modes on the energy spread compensation scheme. It is shown that taking these modes into account in the accelerating structure does not increase the rms energy spread in the main beam above the CLIC specification level. Results of the HFSS and ACE3P simulations are also in a good agreement.

TUPPR026	Conceptual Design of the CLIC Damping Ring RF System	cavity, damping, beam-loading, linac	1870
	A. Grudiev CERN, Geneva, Switzerland
	In order to achieve high luminosity in CLIC, ultra-low emittance bunches have to be generated in both electron and positron damping rings. To achieve this goal, big energy loss per turn in the wigglers has to be compensated by the RF system. This results in very strong beam loading transients affecting the longitudinal bunch position and bunch length. In this paper, conceptual design of the RF system for the CLIC damping ring is presented. Baseline and several alternatives are discussed and the corresponding requirements for the cavities and the RF power sources are presented in order to meet stringent tolerances on the bunch-to-bunch phase and bunch length variations.

TUPPR027	Study of Multipolar RF Kicks from the Main Deflecting Mode in Compact Crab Cavities for LHC	cavity, multipole, dipole, simulation	1873
	A. Grudiev, J. Barranco, R. Calaga, R. De Maria, M. Giovannozzi, R. Tomás CERN, Geneva, Switzerland
	A crab cavity system is under design in the frame work of the High Luminosity LHC project. Due to transverse space constraints on one hand and the RF frequency requirements on the other hand, the design of the crab cavities has to be compact. This results in the crab cavity shape being far from axially symmetric and, as a consequence, higher order multipolar components of the main deflecting mode are non-zero. In this paper, multipolar RF kicks from the main deflecting mode have been calculated in the compact crab cavities for LHC. They are compared to the multipolar error in magnetic elements of LHC. The influence of the RF kicks on the beam dynamics has been investigated and possible acceptable tolerances are presented.

TUPPR047	Vibration Model Validation for Linear Collider Detector Platforms	simulation, luminosity, damping, ground-motion	1921
	K.J. Bertsche, J.W. Amann, T.W. Markiewicz, M. Oriunno, A.W. Weidemann, G.R. White SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. The ILC and CLIC reference designs incorporate reinforced-concrete platforms underneath the detectors so that the two detectors can each be moved onto and off of the beamline in a Push-Pull configuration. These platforms could potentially amplify ground vibrations which would reduce luminosity. In this paper we compare vibration models to experimental data on reinforced concrete structures, estimate the impact on luminosity, and summarize implications for the design of a reinforced concrete platform for the ILC or CLIC detectors.

TUPPR049	An X-band Standing Wave Dielectric Loaded Accelerating Structure	multipactoring, cavity, simulation, resonance	1927
	C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA S.H. Gold NRL, Washington, DC, USA S. Kazakov Fermilab, Batavia, USA R. Konecny ANL, Argonne, USA
	Funding: DOE SBIR Phase I grant #DE-SC0006303 An 11.4 GHz standing wave dielectric loaded accelerating structure was recently developed. We expect to achieve a 120 MV/m gradient powered by a 10 MW 200 ns rf pulse from the X-band Magnicon at the Naval Research Laboratory. The structure uses on-axis rf coupling, which helps to localize the maximum EM fields within the dielectric region. Bench testing shows excellent agreement with the simulation results. The high power rf test is scheduled for January 2012.

TUPPR050	Design and simulation of Prebuncher for S-band Traveling Linear Accelerator	cavity, simulation, electron, linac	1930
	S. Zarei, F. AbbasiDavani, S. Ahmadiannamini, F. Ghasemi sbu, Tehran, Iran H. Shaker IPM, Tehran, Iran
	An S-band Traveling wave linear accelerator with an RF input peak power level up to 2.5 MW, for accelerating 1 mA beam of electron up to 15 MeV, is under construction in Iran. This article presents design procedure of a prebuncher for this accelerator. One standing-cavity type prebuncher is required for bunching electron beam for this accelerator. The intended prebuncher is driven by a coaxial line at 2 kW and operated at the same frequency of the other parts of the accelerator. The magnetic coupling applied has been applied for power coupling to the prebuncher cavity. The optimum dimensions of the prebuncher were obtained by using 2D and 3D electromagnetic codes in the frequency domain. Prebuncher cavity consists of a copper body and coupling loop feed.

TUPPR055	Upgrading the CEBAF Injector with a New Booster, Higher Voltage Gun, and Higher Final Energy	booster, gun, cryomodule, cavity	1945
	R. Kazimi, A. Freyberger, F.E. Hannon, A.S. Hofler, A. Hutton JLAB, Newport News, Virginia, USA
	Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177. The U.S. Govt. retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this for U.S. Govt. purposes. The CEBAF accelerator at Jefferson Lab will be upgraded from 6 GeV to 12 GeV in the next few years. To meet the requirement of the new machine and also to take the opportunity to improve the beam quality, the CEBAF injector will be upgraded with a higher voltage gun, a new booster, and a new accelerating RF module. The CEBAF injector creates and accelerates three beams at different currents simultaneously. The beams are interleaved, each at one third of RF frequency, traveling through the same beam line. The higher voltage gun will lower the space charge effects making it easier to operate at different current with the same setup. The new booster with optimized beam dynamics will complete the bunching process and provides initial acceleration matched to the new gun voltage. Using our latest SRF design, the new booster has significantly lower XY coupling effects that should improve our beam setup and operation for the highly sensitive parity experiments scheduled for the CEBAF’s future. Finally, the new accelerating RF module will roughly double the injector final energy to match the rest of the 12 GeV accelerator. In this paper we will provide more detail about this upgrade.

TUPPR070	High-Gradient Photonic Band-gap (PBG) Structure Breakdown Testing at Ku-Band	diagnostics, lattice, HOM, damping	1984
	B.J. Munroe, A.M. Cook, M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA
	Photonic Band-gap (PBG) structures continue to be a promising area of research forfuture accelerator structures. Previous experiments at X-Band have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. Two single-cell standing-wave structures have been constructed at MIT to investigate breakdown performance of PBG structures. A metallic structure with small rods will be used to test performance with very high surface temperature rise, while an over-moded structure with dielectric rods will investigate alternative solutions to the issue of surface temperature rise. Both structures are expected to reach gradients of at least 100 MV/m and will utilize novel diagnostics, including fast camera imaging and optical spectroscopy of breakdowns.

TUPPR090	Analysis of Ferrite Heating of the LHC Injection Kickers and Proposals for Future Reduction of Temperature	kicker, injection, vacuum, impedance	2038
	M.J. Barnes, L. Ducimetière, N. Garrel, B. Goddard, V. Mertens, W.J.M. Weterings CERN, Geneva, Switzerland
	The two LHC injection kicker magnet (MKI) systems produce a kick of 1.3 T-m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen, consisting of a ceramic tube with conductors on the inner wall, is placed in the aperture of the magnets. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against wake fields. The conductors initially used gave adequately low beam coupling impedance however inter-conductor discharges occurred during pulsing of the magnet; hence an alternative design was implemented to meet the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time and good high voltage behaviour. During 2011 the LHC has been operated with high intensity beam, coasting for many hours at a time, resulting in heating of both the ferrite yoke and beam impedance reduction ferrites, of the MKIs. This paper presents an analysis of thermal measurement data and an extrapolation of the heating for future operation; in addition means are discussed for reducing ferrite heating and improving cooling.

WEPPC022	Elliptical SRF Cavity Design for PEFP Extension	cavity, linac, SRF, proton	2251
	H.S. Kim, Y.-S. Cho, J.-H. Jang, H.-J. Kwon KAERI, Daejon, Republic of Korea
	Funding: * This work is supported by the Ministry of Education, Science and Technology of the Korean Government. To increase the beam energy up to 1 GeV by extending a PEFP 100-MeV proton linac, a study on the superconducting RF linac is underway. SRF technology is chosen due to its operational flexibility and lower beam loss, as well as its high accelerating performance and low operating cost. Preliminary study on the beam dynamics shows that two types of cavity with geometrical beta of 0.50 and 0.74 can cover the entire energy range from 100 MeV to 1 GeV. Assuming the achievable peak surface electric field to be 30 MV/m and 35 MV/m for medium and high beta cavity, respectively, we designed the six-cell elliptical cavities by optimizing the cavity parameters such as peak field ratio, inter-cell coupling and r/Q through the geometrical parameter sweep. The details of the SRF cavity design for PEFP extension will be presented.

WEPPC028	Slim Elliptical Cavity at 800 MHz for Local Crab Crossing	cavity, damping, impedance, HOM	2263
	L. Ficcadenti, J. Tückmantel CERN, Geneva, Switzerland
	A slim highly eccentric elliptical Crab cavity with vertical deflection at 800 MHz, compatible to beam line distances everywhere in the LHC ring, was designed. It is a good fall-back solution in case of problems with new compact 400 MHz designs. Simulated RF characteristics of the delfecting mode, HOM spectra and damping, tuning and multipacting effects are presented. First the most simple HOM coupling system was investigated. The rejection of the working mode was not sufficient and a notch filter was added. Results of both cases will be presented.

WEPPC057	Design of SSR1 Single Spoke Resonators for PXIE	cavity, SRF, niobium, cryomodule	2342
	L. Ristori, M.H. Awida, I.V. Gonin, M. Merio, D. Passarelli, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. The Project X Injector Experiment (PXIE) at Fermilab contains one cryomodule of Single Spoke Resonators operating at 325 MHz with a geometrical beta of 0.2. Two prototypes have been tested successfully at high gradients in the Fermilab Vertical Test Stand (VTS). We have welded a Stainless Steel helium vessel on the first prototype and tested it in the spoke-dedicated Test Cryostat. With excellent results in hand, an order for ten bare resonators was placed with US industry. A new design for the helium vessel was developed for these resonators with the main goal of reducing the sensitivity of the resonator to variations of the helium pressure to meet the requirements of PXIE. A new tuner was developed despite the good results of the first prototype. The new design was inevitable due to the different behavior of the resonator in the new helium vessel. Other aspects were improved such as the maintainability of the tuner motor and piezoelectric actuators allowing their replacement from access ports on the cryomodule's vacuum vessel.

WEPPC058	Development at ANL of a Copper-brazed Joint for the Coupling of the Niobium Cavity End Wall to the Stainless Steel Helium Vessel in the Fermilab SSR1 Resonator	niobium, cavity, vacuum, SRF	2345
	L. Ristori Fermilab, Batavia, USA W.F. Toter ANL, Argonne, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. In order to reduce the sensitivity of the Fermilab SSR1 resonator to helium pressure variations, it was concluded that the cavity and helium vessel end-walls needed to be structurally coupled by means of a transition ring. With the materials to be connected being Niobium and Stainless Steel, it was decided to utilize the same technology already developed for the cavity flanges which consists of a furnace-brazed joint utilizing oxygen-free electrolytic copper. Small-scale and full-scale annular samples have been constructed at Argonne National Laboratory and subject to tensile tests, thermal cycling and visual inspections to qualify the joint. The transition ring is electron-beam welded to the cavity and TIG welded to the helium vessel, the process is explained in detail.

WEPPC082	First Results on Cornell TE-type Sample Host Cavities	cavity, niobium, vacuum, pick-up	2402
	Y. Xie, M. Liepe CLASSE, Ithaca, New York, USA
	Funding: Work supported by NSF and Alfred P. Sloan Foundation. In order to measure surface resistance of new materials other than niobium such as Nb3Sn and MgB2, two sample host niobium cavities operating at TE modes have been developed at Cornell University. The first one is a 6GHz pillbox TE011 cavity modified from an older vision enabling testing 2.75'' diameter flat sample plates. The second one is an optimized mushroom-shape niobium cavity operating at both 5GHz TE012 and 6GHz TE013 modes for 3.75'' diameter flat sample plates . First results from the commissioning of the two TE cavities will be reported.

WEPPC105	Study of Etching Rate Uniformity in SRF Cavities	cavity, plasma, electron, SRF	2462
	J. Upadhyay, S. Popović, L. Vušković ODU, Norfolk, Virginia, USA H.L. Phillips, A-M. Valente-Feliciano JLAB, Newport News, Virginia, USA
	Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The crucial aspect of the technology development is dependence of the etching rate and surface roughness on the frequency of the power supply, pressure, power level, driven electrode shape and chlorine concentration in gas mixture during plasma processing. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders are used as diagnostic ports for the measurement of the plasma parameters and as holders for the samples to be etched. The plasma properties are highly correlated with the shape of the driven electrode and the percentage of chlorine concentration in Argon/chlorine gas mixtures. The effect of the plasma parameters and chlorine gas concentration are investigated at RF (100 MHz) and microwave (2.45 GHz) frequencies.

WEPPD043	The Studies of Power System Harmonics at TLS	power-supply, cryogenics, dipole, controls	2609
	T.-S. Ueng, J.-C. Chang, Y.F. Chiu, K.C. Kuo, Y.-C. Lin NSRRC, Hsinchu, Taiwan
	The power system harmonic distortion in the utility system of NSRRC is investigated for improving the power system performance. The monitored power quality data at the point of common coupling is examined and compared with industrial standards. In addition, the harmonic characteristics of electric power for the accelerator magnets and adjustable speed drives which contribute the most harmonics are analyzed. Furthermore, the approach to mitigate the harmonic effects for improving the power quality is studied.

WEPPD063	Construction of Disk-loaded Buncher for S-Band Low Energy TW Electron Linear Accelerator	electron, linac, impedance, cavity	2666
	F. Ghasemi, F. AbbasiDavani, S. Ahmadiannamini, M.Sh. Shafiee sbu, Tehran, Iran M.L. Lamehi Rashti, H. Shaker IPM, Tehran, Iran
	The project of design and construction of Traveling linear electron accelerator is being performed by the Institute for Research in Fundamental Sciences (IPM) and Shahid Beheshti University in Iran. By using the results of the calculations and by dynamic simulation of electron beam in the designed buncher, the dimensions of the designed sample have been obtained. This paper discuss construction of this buncher.

WEPPD072	Frequency Fine-tuning of a Spin-flip Cavity for Antihydrogen Atoms	cavity, resonance, antiproton, vacuum	2690
	S. Federmann, F. Caspers, E. Mahner CERN, Geneva, Switzerland B. Juhasz, E. Widmann SMI, Vienna, Austria
	As part of the ASACUSA collaboration physics program a spin-flip cavity for measurements of the ground-state hyperfine transition frequency of anti-hydrogen atoms is needed. The purpose of the cavity is to excite anti-hydrogen atoms depending on their polarisation by a microwave field operating at 1.42 GHz. The delicacy of designing such a cavity lies in achieving and maintaining the required properties of this field over a large aperture of 10cm and for a long period of time (required amplitude stability is 1% within 12h). The present paper presents the frequency fine tuning techniques to obtain the desired centre frequency of 1.42 GHz with a Q value below 500 as well as the tuning circuit used for the frequency sweep over the desired bandwidth of 6 MHz.

WEPPD075	A Novel Planar Balun Structure for Continuous Wave 1 kW, 500 MHz Solid-state Amplifier Design	simulation, synchrotron, impedance, HOM	2699
	T.-C. Yu, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, C.H. Lo, M.H. Tsai, Ch. Wang, T.-T. Yang, M.-S. Yeh NSRRC, Hsinchu, Taiwan
	In general, the coaxial type balun plays key role in push-pull amplifier design in the increasing high power solid-state technique transmitter design for accelerator application. However, the coaxial baluns not only increase the complexity in manufacturing procedure but also introduce additional tolerance variation between modules. The variation between parallel power modules would decreases combining efficiency and thus increase the operation cost. Here, a novel planar balun has been proposed and successfully implemented on 1kW solid-state amplifier design for continuous operation with newly designed water cooling plates. The long-term CW test has demonstrated the feasibility of the newly designed planar is quite suitable for CW operation with its excellent low loss, balance property and also low tolerance between modules in mass production.

WEPPD078	Progress with PXIE MEBT Chopper	kicker, simulation, vacuum, radio-frequency	2708
	V.A. Lebedev, A.Z. Chen, R.J. Pasquinelli, D.W. Peterson, G.W. Saewert, A.V. Shemyakin, D. Sun, M. Wendt Fermilab, Batavia, USA T. Tang SLAC, Menlo Park, California, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy A capability to provide a large variety of bunch patterns is crucial for the concept of the Project X serving MW-range beam to several experiments simultaneously. This capability will be realized by the Medium Energy Beam Transport’s (MEBT) chopping system that will divert 80% of all bunches of the initially 5mA, 2.1 MeV CW 162.5 MHz beam to an absorber according to a pre-programmed bunch-by-bunch selection. Being considered one of the most challenging components, the chopping system will be tested at the Project X Injector Experiment (PXIE) facility that will be built at Fermilab as a prototype of the Project X front end. The bunch deflection will be made by two identical sets of travelling-wave kickers working in sync. Presently, two versions of the kickers are being investigated: a helical 200 Ω structure with a switching-type 500 V driver and a planar 50 Ω structure with a linear ±250 V amplifier. This paper will describe the chopping system scheme and functional specifications for the kickers, present results of electromagnetic measurements of the models, discuss possible driver schemes, and show a conceptual mechanical design.

WEPPP006	Using Simulations to Understand Particle Dynamics and Resonance in the Micro-accelerator Platform	laser, resonance, electron, acceleration	2732
	J.C. McNeur, G. Travish UCLA, Los Angeles, USA H. Hairong UESTC, Chengdu, Sichuan, People's Republic of China R.B. Yoder Manhattanville College, Purchase, New York, USA
	Funding: Work funded in part by grant HDTRA1-09-1-0043 from the US Defense Threat Reduction Agency and under a grant from NNSA/NA-221 Office of Nonproliferation and Verification Research and Development. The Micro-Accelerator Platform (MAP) is a slab-symmetric micron-scale electron accelerator. Electrons gain energy via a standing wave electromagnetic resonance powered by a side coupled Ti:Sapphire laser. In this paper, we will discuss simulations of resonance and particle dynamics in this structure. Three-dimensional simulations showing evidence of stable 1 GeV/m acceleration are detailed along with simulations studying defocusing and wakefield effects in the MAP. Additionally, optimization of the structure and the coupling of laser power into the cavity will be explored.

WEPPR038	Independent Component Analysis (ICA) Applied to Long Bunch Beams in the Los Alamos Proton Storage Ring	betatron, linac, injection, extraction	3018
	J.S. Kolski, R.J. Macek, R.C. McCrady, X. Pang LANL, Los Alamos, New Mexico, USA
	Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis (PCA), which is the BSS foundation of the well known model independent analysis (MIA), ICA is more robust to noise, coupling, and nonlinearity. ICA of turn-by-turn beam position data has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch and discuss the source signals identified as betatron motion and longitudinal beam structure.

WEPPR062	The Mode Matching Method Applied to Beam Coupling Impedance Calculations of Finite Length Devices	impedance, simulation, cavity, resonance	3069
	N. Biancacci, E. Métral, B. Salvant CERN, Geneva, Switzerland M. Migliorati, L. Palumbo URLS, Rome, Italy V.G. Vaccaro Naples University Federico II and INFN, Napoli, Italy
	The infinite length approximation is often used to simplify the calculation of the beam coupling impedance of accelerator elements. This is expected to be a reasonable assumption for devices whose length is greater than the transverse dimension but may be less accurate approximation for segmented devices. This contribution presents the study of the beam coupling impedance in the case of a finite length device: a cylindrical cavity loaded with a toroidal slab of material. In order to take into account the finite length we will decompose the field in the cavity and in the beam pipe into a set of orthonormal modes and apply the mode matching method to obtain the impedance. To validate our method, we will present comparisons between analytical formulas and 3D electromagnetic CST simulations as well as applications to the impedance of short beam pipe inserts, where the longitudinal and transverse dimensions are difficult to model in numerical simulations.

WEPPR070	Beam Coupling Impedance Simulations of the LHC TCTP Collimators	impedance, simulation, cavity, vacuum	3090
	H.A. Day, R.M. Jones UMAN, Manchester, United Kingdom F. Caspers, A. Dallocchio, L. Gentini, A. Grudiev, E. Métral, B. Salvant CERN, Geneva, Switzerland
	As part of an upgrade to the LHC collimation system, 8 TCTP and 1 TCSG collimators are proposed to replace existing collimators in the collimation system. In an effort to review all equipment placed in the accelerator complex for potential side effects due to collective effects and beam-equipment interactions, beam coupling impedance simulations are carried out in both the time-domain and frequency-domain of the full TCTP design. Particular attention is paid to trapped modes that may induce beam instabilities and beam-induced heating due to cavity modes of the device.

WEPPR071	Evaluation of the Beam Coupling Impedance of New Beam Screen Designs for the LHC Injection Kicker Magnets	impedance, kicker, simulation, injection	3093
	H.A. Day, R.M. Jones UMAN, Manchester, United Kingdom M.J. Barnes, F. Caspers, H.A. Day, E. Métral, B. Salvant CERN, Geneva, Switzerland
	During the 2011 run of the LHC there was a measured temperature increase in the LHC Injection Kicker Magnets (LHC-MKI) during operation with 50ns bunch spacing. This was suspected to be due to increased beam-induced heating of the magnet due to beam impedance. Due to concerns about future heating with the increased total intensity to nominal and ultimate luminosities a review of the impedance reduction techniques within the magnet was required. A number of new beam screen designs are proposed and their impedance evaluated. Heating estimates are also given with a particular attention paid to future intensity upgrades to ultimate and HL-LHC parameters.

WEPPR072	Increasing Instability Thresholds in the SPS by Lowering Transition Energy	optics, emittance, injection, extraction	3096
	H. Bartosik, G. Arduini, T. Argyropoulos, T. Bohl, S. Cettour-Cave, K. Cornelis, J. Esteban Muller, W. Höfle, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova CERN, Geneva, Switzerland
	A new optics for the SPS with lower transition energy was tested experimentally during 2010-2011, showing a significant increase of the single bunch instability thresholds at injection, due to the 3-fold increase of the slip factor. This paper summarizes the series of performed machine studies for different LHC bunch structures and intensities. In particular, the search of the TMCI threshold in the new optics is presented. Observations on the longitudinal multi-bunch stability are compared between the nominal and the low-transition optics. Finally, optics variants with higher vertical tunes are discussed, which can allow to further increase the TMCI and vertical instability thresholds by reducing the vertical beta function.

WEPPR074	Effect of the TEM Mode on the Kicker Impedance	impedance, kicker, simulation, vacuum	3102
	C. Zannini, G. Rumolo, V.G. Vaccaro CERN, Geneva, Switzerland C. Zannini EPFL, Lausanne, Switzerland
	The kickers are major contributors to the CERN SPS beam coupling impedance. As such, they may represent a limitation to increasing the SPS bunch current in the frame of a luminosity upgrade of the LHC. The C-Magnet supports a transverse electromagnetic (TEM) mode due to the presence of two conductors. Due to the finite length of the structure this TEM mode affects the impedance below a certain frequency (when the penetration depth in the ferrite becomes comparable to the magnetic circuit length). A theoretical model was developed to take into account also the impedance contribution due to the TEM mode. The model is found to be in good agreement with CST 3D electromagnetic (EM) simulations. It allows for generic terminations in the longitudinal direction. An example of kicker is analyzed taking into account also the external cables.

WEPPR085	Observation of Instabilities of Coherent Transverse Ocillations in the Fermilab Booster	booster, damping, injection, space-charge	3129
	Y. Alexahin, N. Eddy, E. Gianfelice-Wendt, V.A. Lebedev, W.L. Marsh, W. Pellico, A.K. Triplett Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. The Fermilab Booster - built more than 40 years ago - operates well above the design proton beam intensity of 4.e12 ppp. Still, the Fermilab neutrino experiments call for even higher intensity of 5.5·10¹² ppp. A multitude of intensity related effects must be overcome in order to meet this goal including suppression of coherent dipole instabilities of transverse oscillations which manifest themselves as a sudden drop in the beam current. In this report we present the results of observation of these instabilities at different tune, coupling and chromaticity settings and discuss possible cures.

WEPPR094	Large Volume Resonant Microwave Discharge for Plasma Cleaning of a CEBAF 5-Cell Srf Cavity	cavity, plasma, electron, SRF	3156
	S. Ahmed, K. Macha, J.D. Mammosser JLAB, Newport News, Virginia, USA M. Nikolić, S. Popović, J. Upadhyay, L. Vušković ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. We report preliminary results on plasma generation in a 5-cell CEBAF SRF cavity for the application of cavity interior surface cleaning. CEBAF currently has ~300 of these five cell cavities installed in the JLab accelerator which are mostly limited by cavity surface contamination. The development of an in-situ cavity surface cleaning method utilizing a resonant microwave discharge could lead to significant performance improvement. This microwave discharge is currently being used for set of plasma cleaning procedures targeted to the removal of various organic, metal and metal oxide impurities. These contaminants are responsible for the increase of surface resistance and the reduction of RF performance in installed cavities. CEBAF five cell cavity volume is ~ 0.5 m2, which places the discharge in the category of large-volume plasmas. Our preliminary study includes microwave breakdown and optical spectroscopy, which was used to define the operating pressure range and the rate of removal of organic impurities.

WEPPR097	Comparing New Models of Transverse Instability with Simulations	space-charge, simulation, synchrotron, wakefield	3165
	M. Blaskiewicz BNL, Upton, Long Island, New York, USA
	Recently, Balbekov* has produced an ordinary integro-differential equation that approximates the Vlasov equation for beams with wakefields and large space charge tune shift. The present work compares this model with simulations. In particular, the claim that certain types of transverse wakes cannot lead to mode coupling instabilities, which contradicts earlier work*, is explored V. Balbekov, PRSTAB, 14, 094401 (2011). ** M. Blaskiewicz, PRSTAB 1, 044201 (1998).

THEPPB005	Study on the Injection Optimization and Transverse Coupling for CSNS/RCS	injection, emittance, beam-losses, collimation	3240
	M.Y. Huang, J. Qiu, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	The injection system of the China Spallation Neutron Source uses H⁻ stripping and phase space painting method to fill large ring acceptance with the linac beam of small emittance. The emittance evolution, beam losses, and collimation efficiency during the injection procedures for different injection parameters, such as the injection emittances, starting injection time, twiss parameters and momentum spread, were studied, and then the optimized injection parameters was obtained. In addition, the phase space painting scheme which also affect the emittance evolution and beam losses were simulated and the optimization range of phase space painting were obtained. There will be wobble in the power supply of the injection bumps, and the wobble effects were presented. In order to study the transverse coupling, the injection procedures for different betatron tunes and momentum spreads were studied.

THPPC003	Development of a Broad-band Magnetic Alloy Cavity at GSI	cavity, impedance, storage-ring, ion	3275
	T.S. Mohite, U. Ratzinger IAP, Frankfurt am Main, Germany R. Balß, P. Hülsmann GSI, Darmstadt, Germany
	FINEMET, a Magnetic Alloy material, is often used to build a broad-band cavity for an accelerator or a storage ring. A research on the broad-band FINEMET cavity is of prime importance not only for the present accelerator facility but also for the future storage rings and synchrotron in upcoming FAIR facility alongside the GSI, Darmstadt. In several measurements, high intensity rare-isotope beams, with lower life time, are demanded at injection energy in Experimental Storage Ring (ESR) at GSI. A longitudinal beam stacking of such beams by means of using a special barrier-bucket RF cavity is found appropriate to serve this purpose. Additionally, this cavity is supposed to provide the compressed bunches at lower energies for HITRAP, an ion-trap facility for experiments with highly charged ions, in FAIR. Several measurements are being performed, along with the theoretical analysis, to achieve the designed parameters for the planned barrier-bucket cavity. 60 FINEMET ring cores have been tested to confirm their designed electrical properties. Some of these ring cores are then loaded, in steps, in a test cavity, which will further be used as the barrier-bucket cavity for the ESR. C. Dimopoulou et al., JACoW Proceedings of COOL 2007, Bad Kreuznach, Germany

THPPC007	Coupling Cavity Design of RF Input Coupler Tests for the IFMIF/EVEDA Prototype RFQ Linac	cavity, rfq, linac, beam-transport	3284
	S. Maebara JAEA, Ibaraki-ken, Japan M. Ichikawa Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
	In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a 175MHz RFQ, which has a longitudinal length of 9.78m, was proposed to accelerate deuteron beam up to 5MeV. The operation frequency of 175MHz was selected to accelerate a large current of 125mA in cw mode. The overall driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. For the transmitted RF power tests of RF couplers, a coupling cavity to connect with two RF couplers is needed. For this purpose, two types of coupling cavities for the 175MHz have been designed. One is a capacitive coupling cavity with a co-axial waveguide and double loop coupling structures, and the other one is a ridge cavity type with a rectangular waveguide. In this article, these RF designs and engineering designs will be presented in detail.

THPPC008	Coupling Factor Evaluation of the RF Input Coupler for the IFMIF/EVEDA RFQ Linac	rfq, beam-loading, linac, cavity	3287
	S. Maebara JAEA, Ibaraki-ken, Japan M. Ichikawa Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan A. Palmieri INFN/LNL, Legnaro (PD), Italy
	In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a 175 MHz RFQ, which has a longitudinal length of 9.78m, was proposed to accelerate deuteron beam up to 5MeV. The operation frequency of 175MHz was selected to accelerate a large current of 125mA in CW mode. The overall driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. As a part of the validation of the coupler design, the beta factor (coupling coefficient) was measured on Aluminum RFQ at INFN Legnaro with on-purpose, real-scale dummy aluminum couplers for the installed depths of L=27, 40, 45, 48 and 73 mm. In this article, measurement and calculation results performed with the 3D code HFSS for coupling factor evaluation will be presented in details.

THPPC021	A Microwave Paraphoton and Axion Detection Experiment with 300 dB Electromagnetic Shielding at 3 GHz	cavity, photon, shielding, pick-up	3320
	M. Betz, F. Caspers CERN, Geneva, Switzerland
	Funding: Work supported by the Wolfgang-Gentner-Programme of the Bundesministerium für Bildung und Forschung (BMBF). For the microwave equivalent of "light shining through the wall" (LSW) experiments, a sensitive microwave detector and very high electromagnetic shielding is required. The screening attenuation between the axion-generating cavity and the nearby detection-cavity should be greater than 300 dB, in order to push beyond the presently existing exclusion limits. To achieve these goals in practice, a "box in a box" concept was utilized for shielding the detection-cavity, while a vector signal analyzer was used as a microwave receiver with a very narrow resolution bandwidth in the order of a few micro-Hz. This contribution will present the experimental layout and show the results to date.

THPPC022	Enhanced Coupling Design of a Detuned Damped Structure for CLIC	wakefield, damping, simulation, dipole	3323
	A. D'Elia, A. Grudiev, V.F. Khan, W. Wuensch CERN, Geneva, Switzerland T. Higo KEK, Ibaraki, Japan R.M. Jones UMAN, Manchester, United Kingdom
	The key feature of the improved coupling design in the Damped Detuned Structure (DDS) is focused on the four manifolds. Rectangular geometry slots and rectangular manifolds are used. This results in a significantly stronger coupling to the manifolds compared to the previous design. We describe the new design together with its wakefield damping properties.

THPPC023	RF Loads for Energy Recovery	cavity, synchrotron, vacuum, proton	3326
	S. Federmann, M. Betz, F. Caspers CERN, Geneva, Switzerland
	Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ̊C) are discussed. Another design deals with a very high temperature (up to 800 ̊C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the actual microwave absorber and is not brazed to the metallic enclosure.

THPPC026	A Transverse Deflecting Cavity for the Measurement of Short Low Energy Bunches at EBTF	cavity, electron, simulation, impedance	3335
	G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom S.R. Buckley, P. Goudket, C. Hill, P.A. McIntosh, J.W. McKenzie, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The Electron Beam Test Facility (EBTF) at Daresbury Laboratory will deliver low energy (5/6 MeV) short bunches (~40 fs) to a number of industrial experimental stations and for scientific research. In order to measure the longitudinal profile of the bunch an S-band transverse deflecting cavity will be inserted into the beamline. A transverse kick of around 5 MV is required hence a 9 cell design has been chosen. The design of the transverse deflecting cavity has been influence by the competing demands of high RF efficiency and minimising the unwanted transverse kick at the entrance and exit of the cavity which cause the electrons to be displaced while traversing the cavity. This has led to a shortened end cell structure design to minimise the kick applied at the entrance and exit to the cavity. In order to minimise the impact of the input coupler a dummy waveguide has been placed on the opposing side of the cavity to minimise the monopole component of the RF fields in the coupling cell. The coupler is located at the central cell of the cavity to avoid exciting the nearby modes. Tracking of the beam is performed in GPT including space charge, due to the low energy of the electrons.

THPPC033	Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D	cavity, electron, vacuum, simulation	3356
	D.L. Bowring, A.J. DeMello, A.R. Lambert, D. Li, S.P. Virostek, M.S. Zisman LBNL, Berkeley, California, USA D.M. Kaplan Illinois Institute of Technology, Chicago, Illinois, USA R.B. Palmer BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Muon Accelerator Program (MAP) collaboration is working to develop an ionization cooling channel for future muon colliders. The ionization cooling channel requires the operation of high-gradient, normal-conducting RF cavities in solenoidal magnetic fields up to 5 T. However, experiments conducted at Fermilab's MuCool Test Area (MTA) show that increasing the solenoidal field strength reduces the maximum achievable cavity gradient. This gradient limit is characterized by an RF breakdown process that has caused significant damage to copper cavity interiors. The damage is likely caused by field-emitted electrons, focused by the solenoidal magnetic field onto small areas of the inner cavity surface. Local heating may then induce material fatigue and surface damage. Fabricating a cavity with beryllium walls would mitigate this damage due to beryllium's low density, low thermal expansion, and high electrical and thermal conductivity. This poster addresses the design and fabrication of a pillbox RF cavity with beryllium walls, in order to evaluate the performance of high-gradient cavities in strong magnetic fields.

THPPC040	Improved RF Design for an 805 MHz Pillbox Cavity for the US MuCool Program	cavity, simulation, ion, multipactoring	3371
	Z. Li, C. Adolphsen, L. Ge SLAC, Menlo Park, California, USA D.L. Bowring, D. Li LBNL, Berkeley, California, USA
	Funding: Work supported by US DOE under contract number DE-AC02-05CH11231, and DE-AC02-76SF00515. Normal conducting RF cavities are required to operate at high gradient in the presence of strong magnetic field in muon ionization cooling channels for a Muon Collider. Experimental studies using an 805 MHz pillbox cavity at MTA of Fermilab has shown significant degradation in gradient performance and damage in the regions that are correlated with high RF fields in magnetic field up to 4 Tesla. These effects are believed to be related to the dark current and/or multipacting activities in the presence of external magnetic field. To improve the performance of the cavity, a new RF cavity with significantly lower surface field enhancement was designed, and will be built and tested in the near future. Numerical analyses of multipacting and dark current were performed using the 3D parallel code Track3P for both the original and new improved cavity profiles in order to gain more insight in understanding of the gradient issues under strong external magnetic field. In this paper, we will present the improved RF design and the dark current and multipacting analyses for the 805 MHz cavity.

THPPC041	704 MHz Fast High-power Ferroelectric Phase Shifter for Energy Recovery Linac Applications	cavity, controls, linac, pulsed-power	3374
	S.V. Shchelkunov Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA J.L. Hirshfield Omega-P, Inc., New Haven, USA A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA S. Kazakov, V.P. Yakovlev Fermilab, Batavia, USA A.B. Kozyrev LETI, Saint-Petersburg, Russia E. Nenasheva Ceramics Ltd., St. Petersburg, Russia
	Funding: Research supported by the U.S. Department of Energy, Office of High Energy Physics Development, tests, and evaluation of a fast electrically-controlled 704 MHz tuner for Energy Recovery Linacs that employs an electrically -controlled ferroelectric component are presented. The tuner is a refinement of an already tested prototype described elsewhere. In the new concept, a collection of ferroelectric assemblies behave as cavities configured as transmission components within a coaxial waveguide. Each assembly is based on a ring-like ferroelectric ceramic with its height, inner and outer diameters, and the shape of edges adjusted to insure a clean operating mode, and relatively low field strength. Several assemblies serve to widen the passband and increase tunability. The tuner is to deliver fast (~100-200 ns) phase adjustment from 0-to-100 degrees when biased by voltages from 0-to-15kV; the design promises to handle 50 kW CW and 900 kW of pulsed power. A scaled version is also considered to operate at 1300 MHz while handling 500 kW of pulsed power. Our latest findings, related issues, and plans for experiments are discussed.

THPPC044	Development of the Dual Slot Resonance Linac	linac, cavity, resonance, impedance	3383
	N. Barov, X. Chang, R.H. Miller, D.J. Newsham Far-Tech, Inc., San Diego, California, USA
	Funding: Work supported by DOE Grant DE-FG02-08ER85034 We report the status of the Dual Slot Resonance (DSR) linac under development by FAR-TECH. In this linac type, cell-to-cell coupling is provided by a pair of close-coupled resonant slots, resulting in very strong coupling vs. a typical side-coupled linac design, as well as a much more compact radial space requirement. We discuss the status of the structure fabrication, the RF distribution system, and installation and testing at the UCLA Pegasus facility.

THPPC047	Fabrication and Initial Tests of an Ultra-High Gradient Compact S-Band (HGS) Accelerating Structure	klystron, linac, vacuum, accelerating-gradient	3392
	L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh RadiaBeam, Santa Monica, USA V.A. Dolgashev SLAC, Menlo Park, California, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	Funding: Work supported by US DOE grant # DE-SC000866. RadiaBeam Technologies reports on the RF design and fabrication of a ultra-high gradient (50 MV/m) S-Band accelerating structure (HGS) operating in the pi-mode at 2.856 GHz. The compact HGS structure offers a drop-in replacement for conventional S-Band linacs in research and industrial applications such as drivers for compact light sources, medical and security systems. The electromagnetic design (optimization of the cell shape in order to maximize RF efficiency and minimize surface fields at very high accelerating gradients) has been carried out with the codes HFSS and SuperFish while the thermal analysis has been performed by using the code ANSYS. The initial cold tests are presented together with the plans for high-power tests currently ongoing at Lawrence Livermore National Laboratory (LLNL).

THPPC049	Progress on the MICE 201 MHz RF Cavity at LBNL	cavity, simulation, resonance, electron	3398
	T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA A.J. DeMello, D. Li, S.P. Virostek, M.S. Zisman LBNL, Berkeley, California, USA
	The international Muon Ionization Cooling Experiment (MICE) aims at demonstrating transverse cooling of muon beams by ionization. The ionization cooling channel of MICE requires eight 201-MHz normal conducting RF cavities to compensate for the longitudinal beam energy loss in the cooling channel. In this paper, we present recent progresses on MICE RF cavity at LBNL, which includes electro-polishing, intended to improve the cavity performance in the presence of strong external magnetic field; low power RF measurements on resonant frequency and Q value of each cavity with a pair of curved- beryllium windows to terminate the cavity irises. Multipacting simulations are conducted using SLAC’s ACE-3P code to study the effects in the cavity and coupler regions with the influence by external magnetic field.

THPPC057	S-band High Power RF System for 10 GeV PAL-XFEL	cavity, simulation, klystron, linac	3419
	W.H. Hwang, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Kim, H.-S. Lee, Y.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 120 Hz. In high power operation, it is important to decrease the rf electric field to protect rf break-down in high power rf components. To obtain the maximum beam, we must reduce the phase difference between waveguide branches including accelerating structure and minimize the environment influences. This paper describes the waveguide system and high power rf components for the PxFEL.

THPPC059	Design of SLED System with Dual Side-wall Coupling Irises and Biplanar Power Splitter for PAL XFEL	simulation, klystron, cavity, factory	3425
	Y.D. Joo, I. Hwang, C. Kim, B.-J. Lee PAL, Pohang, Kyungbuk, Republic of Korea
	The SLED system of the PAL XFEL is required to be operated with the RF input power of 80 MW and the pulse width of 4 us. The high RF dose from the RF breakdown at the coupling holes and power splitter prohibits that the original design of the SLED serve this operation condition. To reduce the gradient at the cavity coupling structure, the concept of dual side-wall coupling irises is introduced. In addition, the 3dB splitter is modified with the concept of biplanar coupler structure.

THPPC066	Adjustable High Power Coax RF Coupler without Moving Parts	cavity, extraction, solenoid	3443
	M.L. Neubauer, A. Dudas, R. Sah Muons, Inc, Batavia, USA A. Nassiri ANL, Argonne, USA
	A high power fundamental RF power coupler (FPC) with an adjustable in situ coupling factor would be highly desirable for a number of applications; for example, the 352 MHz light source at APS and Project X. A Phase I project has been completed with a prototype constructed and modeled. The prototype includes a coaxial TEE with two windows a quarter wavelength apart, and a ferrite tuner. Two materials were tested and their characteristics measured in terms of loss and magnetic field requirements to produce the desired change in coupling. A VSWR of better than 1.05:1 and a bandwidth of at least 8% at 1.15:1 was measured. The tradeoffs of a final design are proposed based upon these results.

THPPD039	Magnetic Analysis of a Single-Aperture 11T Nb3Sn Demonstrator Dipole for LHC Upgrades	dipole, injection, simulation, sextupole	3596
	B. Auchmann, M. Karppinen CERN, Geneva, Switzerland V. Kashikhin, A.V. Zlobin Fermilab, Batavia, USA
	Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy The planned upgrade of the LHC collimation system foresees additional collimators to be installed in the dispersion suppressor areas around points 2, 3, and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33-T 15-m-long NbTi LHC main dipoles with shorter 11-T Nb3Sn dipoles compatible with the LHC lattice and main systems. To demonstrate this possibility, in 2011 Fermilab and CERN started a joint R&D program with the goal of building a 5.5-m-long twin-aperture dipole prototype suitable for installation in the LHC by 2014. The first step of this program is the development of a 2-m-long single-aperture demonstration dipole with the nominal field of 11 T at the LHC nominal current of ~11.85 kA and 60-mm bore with ~20% margin. This paper presents the results of magnetic analysis of the single-aperture Nb3Sn demonstrator dipole for the LHC collimation system upgrade.

THPPD058	Reduction of Conductive EMI Noise Resulted from the Commercial Power Supply	power-supply, high-voltage, vacuum, impedance	3644
	C.S. Chen, C.K. Chan, J.-C. Chang, Y.L. Chu, K.H. Hsu, C.Y. Kuo, Y.-H. Liu, C.S. Yang NSRRC, Hsinchu, Taiwan
	Almost every electronic equipment must be connected to power system. Because of the complexity of power lines, the reduction of conductive electro-magnetic interference (C-EMI) plays an important role in precise measurements. In this paper, a line impedance stabilization network (LISN) was built up to get the spectrum from power lines. After several measurements by some commercial power supplies, it is found that some of these power supplies induce effectively C-EMI into power lines, even if a passive filter is bound in power line. These noises may influence numerous equipments in a local area near the sources. Therefore, how to choose a suitable filter is a decisive factor to reduce the magnitude of C-EMI.

THPPD072	Performance Optimization of the Stacked-Blumlein	simulation, impedance, high-voltage, induction	3680
	L.W. Zhang, J. Li, W.D. Wang CAEP/IFP, Mainyang, Sichuan, People's Republic of China Y. Li CAEP, Mainyang, Sichuan, People's Republic of China
	Funding: This work was supported by the National Natural Science Foundation of China (11035004) For the applications of the Dielectric Wall Accelerator (DWA), the stacked Blumlein pulse generator comprised of parallel-plate transmission lines is being developed. The peak output voltage of the stacked Blumlein will be much lower than expected due to the parasitic coupling among the individual pulse forming lines of the Blumlein stack. The finite difference time domain method is used to model the stacked Blumlein structure and determine the outputs. We present the optimization of a 20-Blumleins-stack in this paper. The results for different structures are discussed.

THPPP003	Coupling Impedance Study of the New Injection Kicker Magnets of the JPARC Main Ring	impedance, kicker, simulation, vacuum	3725
	K. Fan, S. Fukuoka, H. Matsumoto, T. Sugimoto, T. Toyama KEK, Ibaraki, Japan
	New lumped inductance kicker magnets have been developed for the J-PARC main ring injection system. For high intensity beam operation, the beam coupling impedance of the new kickers is a critical issue, which not only generates significant heating inside the ferrite impairing the performance of the kickers, but also drives beam instability. Numerical simulations based on CST studio have been studied during the design stage to optimize the kicker structure. Impedance measurements based on wire method have been carried out. The measured results agree well with the simulation results.

THPPP004	Design and Test of Injection Kicker Magnets for the JPARC Main Ring	kicker, impedance, injection, proton	3728
	K. Fan, S. Fukuoka, K. Ishii, H. Matsumoto, H. Someya, T. Sugimoto, T. Toyama KEK, Ibaraki, Japan
	The present injection kicker magnets of the JPARC main ring consists of three transmission type kickers. To overcome the operational problems, four lumped inductance kicker magnets have been developed for the simplicity and the high reliability. The tight requirements on the rise and fall time create difficulties for the new design. Magnetic field measurements, coupling impedance measurements and have been carried out. The measurement results show that the new kicker magnets can satisfy the requirements of beam injection.

THPPP005	Space Charge Effect in the Presence of x-y Coupling in J-PARC MR	lattice, space-charge, emittance, simulation	3731
	K. Ohmi KEK, Ibaraki, Japan S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	It is crucial issue to suppress beam loss due to space charge force in J-PARC MR. We focus x-y coupling as a source of the beam loss. x-y coupling is measured by turn-by-turn beam position monitors in J-PARC MR. A space charge simulation under the measured x-y coupling evaluates the beam loss. Tolerance of x-y coupling and how to improve the beam loss are discussed.

THPPP019	Tune Determination of Strongly Coupled Betatron Oscillations in a Fast Ramping Synchrotron	booster, damping, betatron, quadrupole	3770
	Y. Alexahin, E. Gianfelice-Wendt, W.L. Marsh, A.K. Triplett Fermilab, Batavia, USA
	Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Tune identification - i.e. attribution of the spectral peak to a particular normal mode of oscillations - can present a significant difficulty in the presence of strong transverse coupling when the normal mode with a lower damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The introduced earlier phased sum algorithm* helped to recover the weaker normal mode signal from the noise, but by itself proved to be insufficient for automatic peak identification in the case of close phase advance distribution in both planes. To resolve this difficulty we modified the algorithm by taking and analyzing Turn-by-Turn data for two different ramps with the beam oscillation excited in each plane in turn. Comparison of the relative amplitudes of Fourier components allows for automatic correct tune identiﬁcation. The proposed algorithm was implemented in the Fermilab Booster B38 console application and successfully used in tune, coupling and chromaticity measurements. * Y. Alexahin, E. Gianfelice-Wendt, W. Marsh, Proc. IPAC10, Kyoto, May 2010, p. 1179.

THPPP021	6 Batch Injection and Slipped Beam Tune Measurements in Fermilab’s Main Injector	injection, booster, proton, target	3776
	D.J. Scott, D. Capista, I. Kourbanis, K. Seiya, M.-J. Yang Fermilab, Batavia, USA
	During Nova operations it is planned to run the Fermilab Recycler in a 12 batch slip stacking mode. In preparation for this, measurements of the tune during a six batch injection and then as the beam is slipped by changing the RF frequency, but without a 7th injection, have been carried out in the Main Injector. The coherent tune shifts due to the changing beam intensity were measured and compared well with the theoretically expected tune shift. The tune shifts due to changing RF frequency, required for slip stacking, also compare well with the linear theory, although some nonlinear affects are apparent at large frequency changes. These results give us confidence that the expected tunes shifts during 12 batch slip stacking Recycler operations can be accommodated.

THPPP029	Simultaneous Global Coupling and Vertical Dispersion Correction in RHIC	quadrupole, proton, polarization, heavy-ion	3794
	C. Liu, Y. Luo, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Residual vertical dispersion on the order of ±0.2 m (peak to peak) has been measured at store energies for both polarized proton and heavy ion beams. The hypothesis is that this may have impact on the polarization transmission efficiency during the energy ramp, the beam lifetimes, and, especially for heavy ions, the dynamics aperture. An algorithm to correct global coupling and dispersion simultaneously using skew quads was developed for RHIC. Simulation results together with the measured coupling and dispersion functions before and after correction will be shown for both injection and store together with an assessment of overall collider performance improvement.

THPPP031	RF Design of ESS RFQ	rfq, simulation, cavity, linac	3800
	O. Piquet, M. Desmons, A. France CEA/DSM/IRFU, France O. Delferrière CEA/IRFU, Gif-sur-Yvette, France
	The low energy front end of ESS is based on a 352 MHz, 5-m long Radiofrequency Quadrupole (RFQ) cavity. It will accelerate and bunch proton beams from 75 keV to 3 MeV. The beam current is 50 mA (75 mA as an upgrade scenario) for 4% duty cycle. A complete RF analysis of the ESS RFQ has been performed using 3D RF simulating codes and a RFQ 4-wire transmission line model. Proposed RFQ is a 4 vane-type structure where 2D cross-section is optimized for lower power dissipation, while featuring simple geometrical shape suitable for easy machining. RF calculations are performed for the whole RFQ, and mainly for the following parts: end cells, vacuum port, tuners and RF coupling ports. Power losses are particularly calculated in order to achieve Thermo-mechanical calculations.

THPPP036	First Measurements of an Coupled CH Power Cavity for the FAIR Proton Injector	cavity, linac, proton, DTL	3812
	R. M. Brodhage, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany G. Clemente, L. Groening GSI, Darmstadt, Germany
	For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. For this second tank technical and mechanical investigations have been performed to develop a complete technical concept for manufacturing. In Spring 2011, the construction of the first power prototype has started. The main components of this cavity were ready for measurements in fall 2011. At that time, the cavity was tested with a preliminary aluminum drift tube structure, which will allow precise frequency and field tuning. This paper will report on the recent technical developments and achievements. It will outline the main tuning and commissioning steps towards that novel type of proton DTL and it will show very promising results of the latest measurements.

THPPP049	Tuning Procedure for the LINAC4 PI Mode Structure (PIMS)	simulation, cavity, linac, electron	3850
	P. Ugena Tirado, F. Gerigk, R. Wegner CERN, Geneva, Switzerland
	PI-Mode-Structure (PIMS) cavities will be used in the high energy section of LINAC4 (10²-160 MeV). Each cavity is made of 7 coupled cells, operated in the π-mode at a resonant frequency of 352.2 MHz. The cell length remains constant for each of the 12 cavities but changes from cavity to cavity to synchronise with the increased beam energy. This paper reports on the tuning process required to get a constant voltage in each cell at the resonant frequency and consisting in re-machining to the required level the tuning rings located on each cell-wall. An algorithm based on single cell detuning, equivalent circuit simulations and precise 3D simulations for the 3 different cell types of each cavity has been developed and successfully applied to the tuning of the first PIMS cavity. In order to reduce the simulation effort for the remaining 11 cavities, an interpolation algorithm based on 3 cavities has been developed and validated. In a second tuning step, after the electron beam welding of all cells, the final adjustment of single-cell frequencies and field flatness is achieved by cutting the length of one plunger tuner per cell.

THPPP066	Beam Tuning Strategy of the FRIB Linac Driver	linac, cavity, solenoid, ion	3889
	Y. Zhang FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The FRIB linac driver will deliver heavy ion beams up to uranium, with an energy of 200 MeV/u and total power on target of 400 kW. To reach the design power for heaviest ions, multi-charge-state beams will be accelerated simultaneously in this SRF linac. Beam tuning of the linac driver is among the most challenging tasks. In this paper, we discuss the beam tuning strategy, which includes the cavity synchronous phase and acceleration gradient setup, beam trajectory correction, and transverse matching with horizontal-vertical coupled beams as superconducting solenoids are used for transverse focusing in the linac segments.

THPPP068	Investigation of a Multi-cell Cavity Structure Proposed for Improved Hydroforming	cavity, focusing, HOM, SRF	3895
	K.R. Shin ORNL RAD, Oak Ridge, Tennessee, USA A.E. Fathy University of Tennessee, Knoxville, Tennessee, USA J.A. Holmes, Y.W. Kang ORNL, Oak Ridge, Tennessee, USA
	A multi-cell cavity structure with rectangular coupling aperture between cavity cells is proposed. This investigation is to study the RF properties of such structure that may provide high yield in hydroforming. In mechanical point of view, the rectangular aperture iris may provide much improved structure quality in hydroforming since it can help to reduce the stress incurring within the sheet metal with improved structural malleability. The necking procedure can be easier because of greater perimeter in the iris geometry. Peak electric and magnetic fields per accelerating gradient may increase however, compared to traditional TESLA type elliptical cavity structure. The rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing may be achieved. 3D simulations with CST MWS have been carried out to analyze EM field properties and the cavity parameters.

THPPP093	Progress on MICE RFCC Module	cavity, vacuum, solenoid, controls	3954
	D. Li, D.L. Bowring, A.J. DeMello, S.A. Gourlay, M.A. Green, N. Li, T.O. Niinikoski, H. Pan, S. Prestemon, S.P. Virostek, M.S. Zisman LBNL, Berkeley, California, USA A.D. Bross, R.H. Carcagno, V. Kashikhin, C. Sylvester Fermilab, Batavia, USA Y. Cao, S. Sun, L. Wang, L. Yin SINAP, Shanghai, People's Republic of China A.B. Chen, B. Guo, L. Li, F.Y. Xu ICST, Harbin, People's Republic of China D.M. Kaplan Illinois Institute of Technology, Chicago, Illinois, USA T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA
	Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231, US Muon Accelerator Program and NSF MRI award: 0959000. Recent progress on the design and fabrication of the RFCC (RF and Coupling Coil) module for the international MICE (Muon Ionization Cooling Experiment) will be reported. The MICE ionization cooling channel has two RFCC modules; each having four 201-MHz normal conducting RF cavities surrounded by one superconducting coupling coil (solenoid) magnet. The magnet is designed to be cooled by 3 cryocoolers. Fabrication of the RF cavities is complete; preparation for the cavity electro-polishing, low power RF measurements and tuning are in progress at LBNL. Fabrication of the cold mass of the first coupling coil magnet has been completed in China and the cold mass arrived at LBNL in late 2011. Preparations for testing the cold mass are currently under way at Fermilab. Plans for the RFCC module assembly and integration are being developed and will be described.

THPPR030	High Power Test of RF Separator For 12 GeV Upgrade of CEBAF at Jefferson Lab	cavity, vacuum, ion, extraction	4032
	S. Ahmed, C. Hovater, G.A. Krafft, J.D. Mammosser, M. Spata, M.J. Wissmann JLAB, Newport News, Virginia, USA J.R. Delayen ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate enough to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, several options including the extension of existing normal conducting (NC) and a potential 499 MHz TEM-type superconducting (SC) cavity design have been investigated using computer simulations. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test to 4 kW is required to confirm the cavity’s operate-ability at these elevated gradient and power levels. We have assembled a 2-cell cavity, pumped down to 2.0·10^-9 torr using ion pump and confirmed the low level RF performance. A high power test is in progress and will be completed soon. The detailed numerical and experimental results will be discussed in the paper.

THPPR043	Applications of X-band 950 keV and 3.95 MeV Linac X-ray Source for On-site Inspection	linac, radiation, focusing, shielding	4071
	M. Uesaka, K. Demachi, K. Dobashi, T. Fujiwara, H.F. Jin, M. Jin, H. Zhu The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan Y. Hattori Hitachi Engineering & Services Co.,Ltd., Japan J. Kusano, N. Nakamura, M. Yamamoto Accuthera Inc., Kawasaki, Kanagawa, Japan I. Miura Mitsubishi Chemical Corporation, Japan E. Tanabe AET, Kawasaki-City, Japan
	Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of a 250 kW magnetron and a cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. We have also developed a portable X-band (9.3GHz) 3.95MeV linac for on-site bridge inspection. The system consists of a 62kg X-ray source part without 80kg target collimator, a 62kg RF power source and other utility box of 116kg. Designed X-ray dose rate is 2 Sv/min@1m with 200pps repetition rate and we have achieved 0.5 Sv/min@1m with 50pps repetition rate. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding by 950keV linac and degradation of reinforced concrete sample by 3.95MeV is under way. Updated measurement results will be presented.

THPPR050	Fabrication and High Power RF Test of A C-band 6MeV Standing-wave Linear Accelerating Structure	simulation, gun, electron, target	4089
	J.H. Shao, H. Chen, H. Zha TUB, Beijing, People's Republic of China
	We have designed a C-band standing-wave bi-periodic on-axis coupled linear accelerating structure for industrial and medical applications [1]. The output electron energy is 6MeV and the pulse current intensity is 100mA. The structure has been fabricated and measured in cold test. The cold test results show a good agreement between the simulation and actual measurement. At present, it’s under high power RF test. In this paper, we illustrate the fabrication, the results of cold test and newly high power RF test.

THPPR069	Compact, Inexpensive X-Band Linacs as Radioactive Isotope Source Replacements	linac, simulation, radiation, electron	4136
	S. Boucher, R.B. Agustsson, X.D. Ding, L. Faillace, P. Frigola, A.Y. Murokh, M. Ruelas, S. Storms RadiaBeam, Santa Monica, USA
	Funding: Work supported by DNDO Phase II SBIR HSHQDC-10-C-00148 and DOE Phase II SBIR DE-SC0000865. Radioisotope sources are still commonly used in a variety of industrial and medical applications. The US National Research Council has identified as a priority the replacement of high-activity sources with alternative technologies, due to the risk of accidents and diversion by terrorists for use in radiological dispersal devices (“dirty bombs”). RadiaBeam Technologies is developing novel, compact, inexpensive linear accelerators for use in a variety of such applications as cost-effective replacements. The technology is based on the MicroLinac (originally developed at SLAC), an X-band linear accelerator powered by an inexpensive and commonly available magnetron. Prototypes are currently under construction. This paper will describe the design, engineering, fabrication and future testing of these linacs at RadiaBeam. Future development plans will also be discussed.

Paper

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MOEPPB002

The MICE Experiment

emittance, target, solenoid, electron

76

A.P. Blondel
DPNC, Genève, Switzerland

Ionization Cooling is the only practical solution to preparing high brilliance muon beams for a neutrino factory or muon collider. The muon ionization cooling experiment (MICE) is under development at the Rutherford Appleton Laboratory (UK) by an international collaboration. The muon beam line has been commissioned and first measurements of emittance with particle physics detectors have been performed. The remaining apparatus is currently under construction. First results with a liquid-hydrogen absorber will be produced in 2013; a couple of years later a full cell of a representative ionization cooling channel, including RF re-acceleration, will be in operation. The design offers opportunities for tests with various absorbers and several optics configurations. Results will be compared with detailed simulations of cooling channel performance to ensure full understanding of the cooling process.
on behalf of the MICE collaboration

MOEPPB010

Measurement of Satellite Bunches at the LHC

photon, emittance, synchrotron, ion

97

A. Jeff, M. Andersen, A. Boccardi, S. Bozyigit, E. Bravin, T. Lefèvre, A. Rabiller, F. Roncarolo
CERN, Geneva, Switzerland
A.S. Fisher
SLAC, Menlo Park, California, USA
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Adam Jeff is a DITANET fellow, supported by the EU's Marie Curie actions contract PITN-GA-2008-215080.
The RF gymnastics involved in the delivery of proton and lead ion bunches to the LHC can result in satellite bunches of varying intensity occupying the nominally empty RF buckets. Quantification of these satellites is crucial for bunch-by-bunch luminosity normalization as well as for machine protection. We present an overview of the longitudinal density monitor (LDM) which is the principal instrument for the measurement of satellite bunches in the LHC. The LDM uses single photon counting of synchrotron light. The very high energies reached in the LHC, combined with a dedicated undulator for diagnostics, allow synchrotron light measurements to be made with both protons and heavy ions. The arrival times of photons are collected over a few million turns, with the resulting histogram corrected for the effects of the detector’s deadtime and afterpulsing in order to reconstruct the longitudinal profile of the entire LHC ring. The LDM has achieved a dynamic range in excess of 10⁵ and a time resolution of 90 ps. Example results are presented and the measurements are benchmarked against satellite distributions based on collision data from the LHC experiments.

MOEPPB011

The Two Methods for Beam Profile Measurement of BEPCⅡ Storage Ring

synchrotron, monitoring, synchrotron-radiation, emittance

100

L. Wang, J. Cao
IHEP, Beijing, People's Republic of China

The two method as spatial interferometor and visible light imaging for real time beam profile measurment for BEPCⅡ Storage Ring will be introduced in detail, including optical Magnification measurment, point spread function measurement, image reversion and spatial coherence measurment. the transverse emittance and copouling coefficient was gotten from the result of the beam profile monitor.

MOPPC008

LHC Optics Determination with Proton Tracks Measured in the Roman Pots Detectors of the TOTEM Experiment

proton, optics, scattering, lattice

136

H. Niewiadomski, H. Burkhardt
CERN, Geneva, Switzerland
F.J. Nemes
KFKI, Budapest, Hungary

The TOTEM experiment at the LHC is equipped with near beam movable devices – called Roman Pots (RP) – which detect protons scattered at the interaction point (IP) arrived to the detectors through the magnet lattice of the LHC. Proton kinematics at IP is reconstructed from positions and angles measured by the RP detectors, on the basis of the optical functions between IP and the RP locations. The precision of optics determination is therefore of the key importance for the experiment. TOTEM developed a novel method of machine optics determination making use of angle-position distributions of elastically scattered protons observed in the RP detectors. The method has been successfully applied to the data samples registered in 2010 and 2011. The studies have shown that the transport matrix could be estimated with a precision better than 1%.

MOPPC024

Modelling of the AGS Using Zgoubi - Status

simulation, optics, closed-orbit, multipole

181

F. Méot, L. A. Ahrens, Y. Dutheil, J.W. Glenn, H. Huang, T. Roser, V. Schoefer, N. Tsoupas
BNL, Upton, Long Island, New York, USA

A computer model, based on the ray-tracing code Zgoubi, is being developed in view of on-line simulation of the RHIC injector AGS, and of beam and spin dynamics simulations and studies in the presence of the cold and warm helical partial snakes. A status of this work is given here.

MOPPC027

Synchro-Betatron Effects in the Presence of Large Piwinski Angle and Crab Cavities at the HL-LHC

betatron, luminosity, simulation, damping

190

S.M. White
BNL, Upton, Long Island, New York, USA
R. Calaga
CERN, Geneva, Switzerland
R. Miyamoto
ESS, Lund, Sweden

Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
The reduction of beta-star at the collision points for the high luminosity LHC (HL-LHC) requires an increment in the crossing angle to maintain the normalized beam separation to suppress the effects of long-range beam-beam interactions. However, increase in crossing angle may give rise to synchro-betatron resonances which may negatively affect the beam emittance and lifetime. 6D weak-strong and strong-strong simulations are performed to study the effect of synchro-betatron resonances in the context of the HL-LHC layout and its suppression via crab crossing.

MOPPC028

Coherent Beam-Beam Effects Observation and Mitigation at the RHIC Collider

emittance, simulation, damping, dipole

193

S.M. White, M. Bai, W. Fischer, Y. Luo, A. Marusic, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work partially supported by Brookhaven Science Associates, LARP, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In polarized proton operation in RHIC coherent beam-beam modes are routinely observed with beam transfer function measurements in the vertical plane. With the existence of coherent modes a larger space is required in the tune diagram than without them and stable conditions can be compromised for operation with high intensity beams as foreseen for future luminosity upgrades. We report on experiments and simulations carried out to understand the existence of coherent modes in the vertical plane and their absence in the horizontal plane, and investigate possible mitigation strategies.

MOPPC070

Field Emission Simulation for KEK-ERL 9-Cell Superconducting Cavity

cavity, electron, simulation, linac

295

E. Cenni
Sokendai, Ibaraki, Japan
T. Furuya, H. Sakai, M. Satoh, K. Shinoe, K. Umemori
KEK, Ibaraki, Japan
M. Sawamura
JAEA/ERL, Ibaraki, Japan

In order to develop the Energy Recovery Linac at KEK, we are studying the performance of L-band superconducting cavities by means of vertical tests. One of the limiting factor for the cavities performance is power losses due to field emitted electrons. With regard to this phenomena, a particle tracking code is used to study electron trajectories and deposited energy on the inner surface of the cavity. Different emitters location were tested within a range of accelerating field and phases in order to reproduce different scenario. The final goal of this study is to locate the sources of the electrons inside the cavity through a deeper understanding of the phenomena. To validate the results from the simulation the outcome data are compared with other particle tracking codes.

MOPPD008

RF and Stochastic Cooling System of the HESR

pick-up, accumulation, controls, kicker

385

R. Stassen, F.J. Etzkorn, G. Schug, H. Stockhorst
FZJ, Jülich, Germany
T. Katayama
GSI, Darmstadt, Germany
L. Thorndahl
CERN, Geneva, Switzerland

The High Energy Storage Ring HESR (1.5-15 GeV/c) for antiprotons at the FAIR complex (Facility for Antiprotons and Ion Research) in Darmstadt (GSI) will have a dedicated stochastic cooling system not only during the experiments to fulfill the beam requirements, but also during the accumulation due to the postponed RESR. Here the cooperation of stochastic cooling with different Barrier-Bucket configurations is necessary for an high accumulation efficiency. The latest hardware configurations and recent tests results of both the RF-system with air-cooled cavities and the stochastic cooling based on slot-ring couplers will be presented.

MOPPD011

Analysis of Frequency Spectrum of Bunched Beam Related to Transverse Laser Cooling*

synchrotron, laser, betatron, ion

391

K. Jimbo
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
Z.Q. He
TUB, Beijing, People's Republic of China
M. Nakao, A. Noda, H. Souda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan

Using synchro-betatron coupling, transverse laser cooling is pursued at an ion storage/cooler ring, S-LSR, Kyoto University. A bunched 40 keV 24Mg+ beam was cooled by a co-propagating laser of 280 nm wavelength. Synchrotron oscillation in the longitudinal direction and betatron oscillation in the horizontal direction were intentionally coupled by an RF drift tube located at the finite dispersive section (D =1.1 m) where longitudinal cooling force was transmitted to the horizontal direction.* Analyzing bunched Schottky signals, which represents longitudinal physical quantities of the beam, we try to obtain an evidence of synchro-betatron coupling and accordingly laser cooling of the beam in the transverse direction.
* H. Okamoto, Phys. Rev. E 50, 4982 (1994)

MOPPD013

Observation of 2-Component Bunched Beam Signal with Laser Cooling

laser, betatron, ion, injection

397

H. Souda, M. Nakao, A. Noda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
M. Grieser
MPI-K, Heidelberg, Germany
Z.Q. He
TUB, Beijing, People's Republic of China
K. Ito, H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan
K. Jimbo
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
Y. Yuri
JAEA/TARRI, Gunma-ken, Japan

Funding: Work supported by Advanced Compact Accelerator Development Project of MEXT, Global COE program "The Next Generation of Physics, Spun from Universality and Emergence" and Grant-in-Aid for JSPS Fellows.
Longitudinal beam temperature during a laser cooling was measured through bunch length measurement at S-LSR. 40keV 24Mg+ beams were bunched by an RF voltage with a harmonic number of 5 and were cooled by a co-propagating laser with a wavelength of 280nm*. Bunch length was measured by time-domain signal from a pair of parallel-plate electrostatic pickups with a length of 140mm. Injected non-cooled beams gave a bunch length of 2.5m (2-σ) and cooled beam has a 2-component of broad and sharp distribution. Broad distribution had a longitudinal length of 2.2m, which is close to that of initial beam. The length of the sharp distribution shrunk to 0.25m and is considered as a cooled part. Capture efficiency of cooling, which represents the ratio of the particle numbers of cooled part and the total particle number, varies by the change of the detuning of the laser (fixed frequency or scanning). With scanning range of 2GHz, capture efficiency was improved from 66% to 92%, whereas the bunch became longer by 10% with scanning. Approach to improve the number of cooled particle and cut uncooled part** will be applied to attain a strong signal with a low-current beam with a low temperature.
* J. S. Hangst et al., Phys. Rev. Lett. 74, 4432 (1995).
** A. Noda et al., these proceedings.

MOPPP047

Characterization of the First SRF Electron Beam Source at the Naval Postgraduate School

cavity, cathode, electron, SRF

667

A.D. Holmes, A.B. Baxter, C.W. Bennett, J.R. Harris, J.W. Lewellen, R. Swent
NPS, Monterey, California, USA
J.M. Didoszak, J.M. Utschig
ONR, Arlington, Virginia, USA

In June 2011, the Naval Postgraduate school (NPS) received the 500 MHz Mark I quarter-wave superconducting RF (SRF) electron beam source and, among other firsts, completed the first cool down and characterization of an SRF beam source at a US Naval facility. The Mark I has a photocathode with adjustable position and uses a unique cascaded RF coupler design. As part of an on-going advanced electron source development project, the NPS Beam Physics Laboratory (BPL) team continues characterization of the Mark I cavity at various cathode stalk, coupler, and probe positions. Methods and experimentation used to measure the cavity Q and β, as well as characteristic results, with respect to coupler, cathode stalk, and probe positions are presented.

MOPPR023

Stripline BPM with Integral In-Vacuo Termination

impedance, pick-up, vacuum, quadrupole

828

A. Stella, A. Ghigo, V.L. Lollo, F. Marcellini, M. Serio
INFN/LNF, Frascati (Roma), Italy

We report the design and realization of a stripline type beam position monitor to be used in the SPARC LAB transfer lines. While the directional properties provided by matched termination at the downstream end are not strictly required in a transfer line, yet matched loads at the end of the stripline electrodes are preferable to reduce the loss factor and to avoid unwanted reflection to the detection electronic. The Integration of a matched resistive load inside the vacuum chamber allows to halve the number of UHV feedthroughs.

MOPPR039

Development of Beam Position Monitor for PEFP Linac and Beam line

linac, proton, DTL, quadrupole

864

J.Y. Ryu, Y.-S. Cho, J.-H. Jang, H.S. Kim, H.-J. Kwon, K.T. Seol
KAERI, Daejon, Republic of Korea

Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
The development of the Beam Position Monitor (BPM) is in progress for the linac and beam lines of the Proton Engineering Frontier Project (PEFP). We choose a strip line BPM for the PEFP 20-MeV and 100-MeV beam lines in order to increase the sensitivity of the relatively long bunches in the beam lines. We also selected the same type BPM for the proton linac in the energy range between 20-MeV and 100-MeV. The prototype BPM was designed, fabricated and tested at KAERI site, where the 20-MeV linac was operated. To check the performance of the BPM, we performed the field mapping. The characteristics and test results of the BPM on the test bench as well as with 20-MeV proton beam will be presented in this paper.

MOPPR044

Optics and Emittance Studies using the ATF2 Multi-OTR System

emittance, quadrupole, target, controls

879

J. Alabau-Gonzalvo, C. Blanch Gutierrez, A. Faus-Golfe, J.J. García-Garrigós, J. Resta-López
IFIC, Valencia, Spain
J. Cruz, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Funding Agency: FPA2010-21456-C02-01. Work supported in part by Department of Energy Contract DE-AC02-76SF00515.
A multi-OTR system (4 beam ellipse diagnostic devices based on optical transition radiation) was installed in the extraction line of ATF2 and has been fully operational since September 2011. The OTRs have been upgraded with a motorized zoom-control lens system to improve beam finding and accommodate different beam sizes. The system is being used routinely for beam size and emittance measurements as well as coupling correction. In this paper we present measurements performed during the winter run of 2011 and the early 2012 runs. We show the reconstruction of twiss parameters and emittance, discuss the reliability of the OTR system and show comparisons with simulations. We also present new work to calculate all 4 coupling terms and form the “4-D” intrinsic emittance of the beam utilizing all the information available from the 2-D beam profile images. We also show details and experimental results for performing a 1-shot automated coupling correction.

MOPPR057

Development of a Cavity Beam Position Monitor for CLIC

cavity, dipole, linac, factory

915

F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin
JAI, Egham, Surrey, United Kingdom
E. Calvo, N. Chritin, F. Guillot-Vignot, T. Lefèvre, L. Søby
CERN, Geneva, Switzerland
A. Lunin, M. Wendt, V.P. Yakovlev
Fermilab, Batavia, USA
S.R. Smith
SLAC, Menlo Park, California, USA

The Compact Linear Collider (CLIC) project presents many challenges to its subsystems and the beam diagnostics in particular must perform beyond current limitations. The requirements for the CLIC main beam position monitors foresee a spacial resolution of 50 nm while delivering a 10 ns temporal resolution within the bunch train. We discuss the design of the microwave cavity pick-up and associated electronics, bench top tests with the first prototype cavity, as well as some of the machine-specific integration and operational issues.

MOPPR073

Analysis of Resonant TE Wave Modulation Signals for Electron Cloud Measurements

electron, resonance, factory, cavity

957

S. De Santis
LBNL, Berkeley, California, USA
D. Alesini
INFN/LNF, Frascati (Roma), Italy
J.P. Sikora
CLASSE, Ithaca, New York, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy under Contracts DE-FC02-08ER41538, DE-AC02-05CH11231.
Recent TE wave measurements of the electron cloud density in the beampipe at CesrTA and DAΦNE have shown that, especially near cutoff, the microwave excitation takes place by coupling to a standing wave, rather than to a propagating TE mode. With the beampipe acting as a resonant cavity, the effect of the periodic electron cloud density is a modulation of the cavity's resonant frequency. As a result, the measured sidebands are a combination of amplitude, phase, and frequency modulation, as the periodic cloud density modulates this resonant frequency. The quality factor Q of the resonance will determine its response to transients in the electron cloud density, and the resulting effect on modulation sidebands. In order to estimate the peak electron cloud density and its spacial distribution, knowledge of the Q and the standing wave pattern need to be determined, either by experimental measurements or simulation codes. In this paper we analyze the dependence of the modulation sidebands on the electron cloud density in two different regimes, when the cloud rise/decay time is much longer, or much shorter than the filling time of the resonance.

MOPPR088

Cavity BPM for 1300 MHz Cryomodules

cavity, dipole, wakefield, cryomodule

993

N. Barov, D.J. Newsham, D. Wu
Far-Tech, Inc., San Diego, California, USA

Funding: Work supported by DOE grant DE-SC00004498
A cavity BPM for 1300 MHz cryomodules is under development by FAR-TECH, Inc. The BPM is capacitively loaded to fit in a small area, and uses a novel coupling scheme which further cuts down space requirements. We discuss status of the fabrication, and eventual plan to test the diagnostic at the ANL Wakefield Accelerator facility.

TUYA03

Performance and Prospects of BEPCII

luminosity, optics, feedback, injection

1030

Q. Qin
IHEP, Beijing, People's Republic of China

BEPCII, the upgrade project of Beijing Electron Positron Collider (BEPC), has been put into operation for both high energy physics experiments as well as synchrotron radiation application since its completion in 2009. The peak luminosity reaches 6.5*10³² cm^-2 s^-1 at 1.89 GeV with e⁺e⁻ collisions of each beam current 700 mA. The collider operates for dedicated synchrotron radiation mode with 250 mA electron beams at 2.5 GeV. The performance of BEPCII should be reported and the measures to upgrade its luminosity described.

Slides TUYA03 [5.529 MB]

TUYB02

Manufacture and Testing of Optical-scale Accelerator Structures from Silicon and Silica

laser, electron, acceleration, vacuum

1050

R.J. England, E.R. Colby, R. Laouar, C. McGuinness, B. Montazeri, R.J. Noble, K. Soong, J.E. Spencer, D.R. Walz, Z. Wu
SLAC, Menlo Park, California, USA
R.L. Byer, C.M. Chang, K.J. Leedle, E.A. Peralta
Stanford University, Stanford, California, USA
B.M. Cowan
Tech-X, Boulder, Colorado, USA
M. Qi
Purdue University, West Lafayette, Indiana, USA

We report on recent progress in the design, manufacture and testing of optical-scale accelerator structures made from silicon and silica. The potential of these structures for the development of extremely compact, efficient, and low cost accelerators producing attosecond electron pulses will be discussed, together with various possible applications.

Slides TUYB02 [17.226 MB]

TUOAA03

Tests of Low Emittance Tuning Techniques at SLS and DAΦNE

quadrupole, emittance, alignment, collider

1065

S.M. Liuzzo, M.E. Biagini, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
M. Aiba
Paul Scherrer Institut, Villigen, Switzerland
M. Böge
PSI, Villigen, Switzerland

The SuperB collider design is based on extremely low emittances, comparable to those of synchrotron light sources. A Low Emittance Tuning (LET) algorithm was developed for SuperB and has been tested last year at DIAMOND. This paper will report on the results of the application of LET to SLS (PSI) and DAΦNE (LNF) in order to compare and confirm the previous results. In this tests, the correction of orbit, dispersion and coupling is applied simultaneously to the detection of Beam Position Monitors tilts. The effect of beam based alignment at DAΦNE is also presented, together with an evaluation of the effects of other possible sources of emittance growth.

Slides TUOAA03 [4.313 MB]

TUOBC02

Small-Beta Collimation at SuperKEKB to Stop Beam-Gas Scattered Particles and to Avoid Transverse Mode Coupling Instability

interaction-region, impedance, scattering, simulation

1104

H. Nakayama, Y. Funakoshi, K. Kanazawa, K. Ohmi, Y. Ohnishi, Y. Suetsugu
KEK, Tsukuba, Japan
H. Nakano
Tohoku University, Graduate School of Science, Sendai, Japan

At SuperKEKB, beam particles which are Coulomb-scattered by the residual gas molecular change direction and will be eventually lost by hitting beam pipe inner wall. Due to large vertical beta function and small beam pipe radius just before IP, most of Coulomb-scattered particles are lost there and are very dangerous for the Belle-II detector. To stop such particles before the IP, vertical collimators are installed in the ring. However, such vertical collimators should be placed very close (few mm) to the beam and therefore induce transverse mode coupling instability. To avoid beam instability and achieve collimation at the same time, we need to install vertical collimators where vertical beta function is SMALL, since maximum collimator width determined by aperture condition is proportional to β^1/2, and minimum collimator width determined by instability is proportional to β^2/3. We present our strategy to stop beam-gas scattered particles and simulated loss rate in the interaction region. We will also show dedicated vertical collimator design to achieve less instability.

Slides TUOBC02 [2.196 MB]

TUPPC003

Analytical Methods for Statistical Analysis for the Correction of Coupling Due to Errors

quadrupole, emittance, sextupole, betatron

1152

A. Chancé, J. Payet
CEA/DSM/IRFU, France
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

The statistical evaluation of the coupling induced by magnets errors and misalignments on the optics design of a machine are done by tracking and Monte Carlo methods. These techniques are CPU demanding and time consuming. During the preliminary optics design phase a faster technique can be useful to evaluate the order of magnitude and the effectiveness of the correction system. Analytical expression for the transport along the machine of the magnets errors and misalignment are derived at first order. A perturbative approach is used to take into account the effect of a non zero central trajectory in the multipoles. The coupling correction is obtained by minimizing the cross-talk central trajectory matrix response.

TUPPC016

Progress of Emittance Coupling Correction at the SPring-8 Storage Ring

resonance, betatron, storage-ring, survey

1191

M. Takao, M. Masaki, Y. Shimosaki, K. Soutome, S. Takano, C. Zhang
JASRI/SPring-8, Hyogo-ken, Japan

The vertical beam spread, or the emittance coupling, is one of the most important parameters for the high brilliance light source storage ring. By the precise alignment of the magnets and the proper COD correction, at the commissioning phase of the SPring-8 storage ring we succeeded in achieving the very small coupling ~0.2 % without correction. However, the coupling had grown large with the years, so recently we have corrected it and recovered the initial performance. The scheme of the coupling correction at the SPring-8 storage ring is the global one, which is based on the perturbation theory with single resonance approximation. In the beginning of the correction the coupling was corrected by means of minimizing the vertical beam size. Then the performance of the coupling correction has been further improved by changing the scheme to minimizing the betatron coupling mode in the vertical oscillation of the horizontally kicked beam. This result implies that the higher order coupling contributes to the emittance coupling, which can be corrected by the higher skew multi-pole magnet. The present status of the coupling correction at the SPring-8 storage ring will be reported.

TUPPC018

Estimation of Orbit and Optics Distortion of SuperKEKB by Tunnel Deformation

emittance, quadrupole, optics, luminosity

1197

A. Morita, H. Koiso, Y. Ohnishi, K. Oide, H. Sugimoto
KEK, Ibaraki, Japan

The tunnel which was used for the KEKB B-factory is reused for the accelerator tunnel of the SuperKEKB. The total vertical displacement of the tunnel subsidence reached almost 30mm during 10 years KEKB operation. In order to operate the SuperKEKB which might be more delicate machine than the previous KEKB B-factory, we are evaluating the optics distortion by the tunnel deformation and studying the machine performance after the orbit and optics correction. We report the estimation of the machine performance degradation by the tunnel subsidence and the requirement of the correction.

TUPPC020

A Scheme for Horizontal-vertical Coupling Correction at SuperKEKB

simulation, optics, lattice, target

1203

H. Sugimoto, H. Koiso, A. Morita, Y. Ohnishi, K. Oide
KEK, Ibaraki, Japan

SuperKEKB is an 7 GeV electron and 4 GeV positron double ring collider project based on the nano beam scheme and is aimed to break the world's luminosity record. A horizontal flat beam is essential to realize the nano beam collisions. One of critical effect that induces unexpected coupling is machine error, such as magnet misalignment and field imperfection. Coupling correction, therefore, plays key role in the actual beam operation. In this study, we numerically explore a possible scheme for coupling correction in the SuperKEKB lattice. Some coupling measurement and correction methods are applied to the model lattice considering magnet misalignments and finite BPM resolution. Based on the results, the attainable smallest coupling in the actual SuperKEKB is discussed.

TUPPC023

Waist Corrections at the Interaction Point of ATF2 in the Presence of IPBSM Fringe Rotations and Input Beam Sigma13, Sigma24

sextupole, simulation, quadrupole, alignment

1212

S. Bai, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. In beam tuning towards the goal beam size, the presence of a tilt of the IP Shintake monitor fringe pattern with respect to the x-y coordinate system of the beam (or equivalently a σ13 correlation), as well as a σ24 correlation, can break the orthogonality in the main σ34 and σ32 waist corrections during the minimization and result in larger vertical beam sizes at IP. Both effects are studied, analytically and in simulation, and a practical procedure is suggested for diagnosing the presence of a residual fringe tilt, by measuring the influence of the horizontal waist correction on the minimum vertical beam size.

TUPPC026

Design of Compact C-Band Standing-Wave Accelerating Structure Enhancing RF Phase Focusing

bunching, cavity, focusing, simulation

1221

H.R. Yang, M.-H. Cho, J. Jang, S.H. Kim, W. Namkung, S.J. Park
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.-S. Oh
NFRI, Daejon, Republic of Korea

Funding: Work supported by POSTECH Physics BK21 Program.
We design a C-band standing-wave accelerating structure for an X-ray source of the imaging and medical applications. It is capable of producing 6-MeV, 100-mA pulsed electron beams which is focused by less than 1.5 mm without external magnets. As an RF source, we use peak 1.5-MW magnetron with duty factor of 0.08%. The accelerating structure is a bi-periodic and on-axis-coupled structure with a built-in bunching section, which consists 3 bunching cells, 13 normal cells and a coupler cell. It operated with π/2-mode standing-waves. The bunching section is designed to enhance the RF phase focusing in order to achieve 1.2-mm beam spot size. Each cavity is designed with the MWS code to maximize the effective shunt impedance within 3.5% inter-cell coupling. In this paper, we present design details of RF cavities and the beam dynamics simulation by the PARMELA code.

TUPPC040

Model Calibration and Optics Correction Using Orbit Response Matrix in the Fermilab Booster

booster, optics, dipole, acceleration

1251

M.J. McAteer, S.E. Kopp
The University of Texas at Austin, Austin, Texas, USA
V.A. Lebedev, E. Prebys
Fermilab, Batavia, USA
A.V. Petrenko
BINP SB RAS, Novosibirsk, Russia

A beam-based method of optical model calibration using the measured orbit response matrix, known as the LOCO method, was successfully applied to Fermilab's rapid-cycling Booster synchrotron. Orbit responses were measured by individually changing the strength of each dipole corrector throughout the acceleration cycle, and dispersion was measured by changing the beam's radial offset. The model calibration procedure revealed large calibration errors for all elements in the Booster's recently-installed multipole corrector packages and beam position monitors. The resulting model was used to correct coupling and beta beating.

TUPPC045

Modeling Investigation on a Deflecting-Accelerating Composite RF-cavity System for Phase Space Beam Control

cavity, simulation, klystron, electron

1266

Y.-M. Shin, M.D. Church, P. Piot
Fermilab, Batavia, USA

Phase space manipulations between the longitudinal and transverse degree of freedoms hold great promise toward the precise control of electron beams. Such transverse-to-longitudinal phase space exchange have been shown to be capable of exchanging the transverse and horizontal emittance or controlling the charge distribution of an electron bunch, for beam-driven advanced accelerator methods. The main limitation impinging on the performance of this exchange mechanism stems from the external coupling nature of a realistic deflecting cavity, compared to a thin-lens model. As an extended idea from *, this paper presents the design of a composite 3.9-GHz RF-system consisting of a deflecting- and accelerating-mode cavities. The system design analysis is discussed with particle-in-cell (PIC) simulations of the device performance.
* A. Zholents, PAC'11.

TUPPC046

Further Analysis of Real Beam Line Optics from a Synthetic Beam

optics, linac, closed-orbit, electron

1269

R.M. Bodenstein
UVa, Charlottesville, Virginia, USA
Y. Roblin, M.G. Tiefenback
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript for U.S. Government purposes.
Standard closed-orbit techniques for Twiss parameter measurement are not applicable to the open-ended Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. The evolution of selected sets of real orbits in the accelerator models the behavior of a “synthetic” beam. This process will be validated against beam profile-based Twiss parameter measurements and should provide the distributed optical information needed to optimize beamline tuning for an open-ended system. This work will discuss the current and future states of this technique, as well as an example of its use in the CEBAF machine.

TUPPC082

Non-linear Beam Dynamics Tests at the CERN PS in the Framework of the Multi-turn Extraction

pick-up, synchrotron, extraction, betatron

1365

M. Giovannozzi, G. Arduini, J.M. Belleman, S.S. Gilardoni, C. Hernalsteens, A. Lachaize, G. Métral, Y. Papaphilippou
CERN, Geneva, Switzerland

In the framework of the CERN PS Multi-Turn Extraction several campaigns of measurements probing the non-linear beam dynamics have been carried out. These measurements range from the measurement of non-linear chromaticity to phase space portraits, de-coherence and re-coherence measurements, secondary island tune etc. In this paper these measurements will be reviewed and the results presented and discussed in details.

TUPPD065

An Electron Gun Test Stand to Prepare for the MAX IV Project

gun, cathode, injection, linac

1551

S. Werin, E. Elafifi, M. Eriksson, D. Kumbaro, F. Lindau, S. Thorin
MAX-lab, Lund, Sweden
E. Mansten
Lund University, Division of Atomic Physics, Lund, Sweden

The MAX IV facility, currently under construction, will include a 3 GeV linac injector with two RF guns providing beams for the two operations modes: ring injection and the Short Pulse Facility. The ring injection will be done by a thermionic 3 GHz RF gun developing from the current MAX-lab RF gun. The SPF gun will be a laser driven photo cathode 3 GHz RF gun based on the 1.6 cell BNL/SLAC type. The guns will be operated with short (0.7 us) RF pulses from a SLED system. A test stand to fine tune the operation of the two different systems has been assembled at the MAX IV laboratory (former MAX-lab). The experience in RF commissioning and initial measurements of energy, charge and quantum efficiency will be reported and the extension of the test stand for full emittance characterization will be outlined.

TUPPP004

Low-alpha Operation for the SOLEIL Storage Ring

optics, injection, radiation, photon

1608

M.-A. Tordeux, J. Barros, A. Bence, P. Brunelle, N. Hubert, M. Labat, P. Lebasque, A. Nadji, L.S. Nadolski, J.-P. Pollina
SOLEIL, Gif-sur-Yvette, France
C. Evain
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France

The low momentum compaction factor (alpha) operation has been recently established on the SOLEIL Storage Ring. Both time resolved X-ray and THz radiation user communities are taking benefit from a hybrid filling pattern with a 4.7 ps RMS bunch length. At a value of 1.7 10^-5 (nominal alpha /25) and a current per bunch of 65 μA, stable THz radiation is produced in the range of 8 - 20 cm^-1 (measurements and comparison with Coherent Synchrotron Radiation (CSR) modeling are reported elsewhere*, **). Several low-alpha optics have been investigated and the optics presented at IPAC’11 has been selected for the operation. This paper presents the comprehensive experimental characterization of this optics. Specificities of the low-alpha operation, driven by the very demanding user experiments, are reviewed: closed orbit stability issues, extremely tight injected current step when refilling which implies a specific Linac tuning, low current diagnostics optimization, short bunch measurements, insertion devices effect on the CSR characteristics and radiation safety aspects justified by beam losses at injection.
* C. Evain, A. Loulergue et al., this conference.
** E. Roussel et al., this conference.

TUPPP015

Status and Recent Progress of SPring-8

emittance, lattice, storage-ring, optics

1638

H. Ohkuma
JASRI/SPring-8, Hyogo-ken, Japan

The SPring-8 is an 8 GeV synchrotron radiation facility that has been in operation since 1997. The SPring-8 has been operated well and total user time has reached more than 53,700 hours, 75% of the total operation time. The average user time per year is about 4,000 hours. The average availability is about 98% in the past 15 years. The operational status and recent progress overview of SPring-8 is presented: the local lattice modification of 30-m long straight section for installing small gap (min. gap is 5.2 mm) in-vacuum undulators, the emittance coupling correction for the vertical beam size reduction, the test operation of low energy operation for the energy saving, and the study of lower emittance optics for the present SPring-8 storage ring. An outline of a future upgrade with a full-scale major lattice modification is also presented. We also present a little about recent progress of SPring-8 injecting accelerators.

TUPPP039

Vertical Dispersion Bump Design for Femto-second Slicing Beamline at the ALS

lattice, quadrupole, emittance, radiation

1698

C. Sun, C. Steier, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Femto-second (fs) slicing beamline has been brought to the operation at the Advanced Light Source (ALS) since 2002. It employs the resonant interaction of an electron bunch with a fs laser beam in a wiggler to energy-modulate a short section of the bunch. The induced energy modulation is then converted to a transverse displacement using a vertical dispersion bump downstream of the wiggler. Thus, the radiation from the fs pulse can be separated from the main bunch radiation. The current dispersion bump design has proved to be an effective and reliable one. However, the ALS storage ring lattice is under an upgrade to improve its brightness. After the completion of the upgrade, a new low emittance will be implemented, and the current dispersion bump design needs to be modified to provide the adequate vertical displacement, while minimizing the vertical emittance and spurious dispersion. In this paper, we present the new design of a vertical dispersion bump using Multi-Objective Genetic Algorithm (MOGA) for the ALS upgrade lattice.

TUPPP086

A Synchronized FIR/VUV Light Source at Jefferson Lab

FEL, laser, wiggler, electron

1789

S.V. Benson, D. Douglas, G. Neil, M.D. Shinn, G.P. Williams
JLAB, Newport News, Virginia, USA

Funding: This work was supported by U.S. DOE Contract No. DE-AC05-84-ER40150, the Air Force Office of Scientific Research, DOE Basic Energy Sciences.
We describe a dual FEL configuration on the UV Demo FEL at Jefferson Lab that would allow simultaneous lasing at THz and UV wavelengths. The THz source would be an FEL oscillator with a short wiggler providing diffraction-limited pulses with pulse energy exceeding 50 microJoules. The THz source would use the exhaust beam from a UVFEL. The coherent harmonics in the VUV from the UVFEL are outcoupled through a hole. The THz source uses a shorter resonator with either hole or edge coupling to provide very high power THz pulses. Simulations indicate excellent spectral brightness in the THz region with over 100 W/cm^-1 output.

TUPPR018

Beam Impedance Study of the Stripline Kicker for the CLIC Damping Ring

impedance, kicker, damping, simulation

1849

C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
M.J. Barnes
CERN, Geneva, Switzerland
I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: FPA2010-21456-C02-01
CLIC Pre-Damping (PDR) and Damping Rings (DR) are required for reducing the emittance of the electron and positron beams before being accelerated in the main linac. Several stripline kicker systems are used to inject and extract the beam from the PDR and DR. Wakefields produced by the charged particles when passing through the aperture of the stripline kickers may become an important source of emittance growth; for this reason, simulations of longitudinal and transverse beam impedance in the frequency domain, and their equivalent in the time domain are needed. First analytical approaches, future simulations and tests planned are presented in this paper.

TUPPR025

Higher-Order Modes and Beam Loading Compensation in CLIC Main Linac

impedance, beam-loading, HOM, higher-order-mode

1867

O. Kononenko, A. Grudiev
CERN, Geneva, Switzerland

Compensation of transient beam loading is one of the major performance issues of the future compact linear collider (CLIC). Recent calculations, which consider only the most important fundamental mode, have shown that the 0.03% limit on the rms relative bunch-to-bunch energy spread in the main beam can be reached by optimizing the RF power pulse shape for the TD26, the CLIC baseline accelerating structure. Here, using HFSS and massively parallel ACE3P codes developed at SLAC, we perform an additional dedicated study of the influence of higher-order modes on the energy spread compensation scheme. It is shown that taking these modes into account in the accelerating structure does not increase the rms energy spread in the main beam above the CLIC specification level. Results of the HFSS and ACE3P simulations are also in a good agreement.

TUPPR026

Conceptual Design of the CLIC Damping Ring RF System

cavity, damping, beam-loading, linac

1870

A. Grudiev
CERN, Geneva, Switzerland

In order to achieve high luminosity in CLIC, ultra-low emittance bunches have to be generated in both electron and positron damping rings. To achieve this goal, big energy loss per turn in the wigglers has to be compensated by the RF system. This results in very strong beam loading transients affecting the longitudinal bunch position and bunch length. In this paper, conceptual design of the RF system for the CLIC damping ring is presented. Baseline and several alternatives are discussed and the corresponding requirements for the cavities and the RF power sources are presented in order to meet stringent tolerances on the bunch-to-bunch phase and bunch length variations.

TUPPR027

Study of Multipolar RF Kicks from the Main Deflecting Mode in Compact Crab Cavities for LHC

cavity, multipole, dipole, simulation

1873

A. Grudiev, J. Barranco, R. Calaga, R. De Maria, M. Giovannozzi, R. Tomás
CERN, Geneva, Switzerland

A crab cavity system is under design in the frame work of the High Luminosity LHC project. Due to transverse space constraints on one hand and the RF frequency requirements on the other hand, the design of the crab cavities has to be compact. This results in the crab cavity shape being far from axially symmetric and, as a consequence, higher order multipolar components of the main deflecting mode are non-zero. In this paper, multipolar RF kicks from the main deflecting mode have been calculated in the compact crab cavities for LHC. They are compared to the multipolar error in magnetic elements of LHC. The influence of the RF kicks on the beam dynamics has been investigated and possible acceptable tolerances are presented.

TUPPR047

Vibration Model Validation for Linear Collider Detector Platforms

simulation, luminosity, damping, ground-motion

1921

K.J. Bertsche, J.W. Amann, T.W. Markiewicz, M. Oriunno, A.W. Weidemann, G.R. White
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
The ILC and CLIC reference designs incorporate reinforced-concrete platforms underneath the detectors so that the two detectors can each be moved onto and off of the beamline in a Push-Pull configuration. These platforms could potentially amplify ground vibrations which would reduce luminosity. In this paper we compare vibration models to experimental data on reinforced concrete structures, estimate the impact on luminosity, and summarize implications for the design of a reinforced concrete platform for the ILC or CLIC detectors.

TUPPR049

An X-band Standing Wave Dielectric Loaded Accelerating Structure

multipactoring, cavity, simulation, resonance

1927

C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
S.H. Gold
NRL, Washington, DC, USA
S. Kazakov
Fermilab, Batavia, USA
R. Konecny
ANL, Argonne, USA

Funding: DOE SBIR Phase I grant #DE-SC0006303
An 11.4 GHz standing wave dielectric loaded accelerating structure was recently developed. We expect to achieve a 120 MV/m gradient powered by a 10 MW 200 ns rf pulse from the X-band Magnicon at the Naval Research Laboratory. The structure uses on-axis rf coupling, which helps to localize the maximum EM fields within the dielectric region. Bench testing shows excellent agreement with the simulation results. The high power rf test is scheduled for January 2012.

TUPPR050

Design and simulation of Prebuncher for S-band Traveling Linear Accelerator

cavity, simulation, electron, linac

1930

S. Zarei, F. AbbasiDavani, S. Ahmadiannamini, F. Ghasemi
sbu, Tehran, Iran
H. Shaker
IPM, Tehran, Iran

An S-band Traveling wave linear accelerator with an RF input peak power level up to 2.5 MW, for accelerating 1 mA beam of electron up to 15 MeV, is under construction in Iran. This article presents design procedure of a prebuncher for this accelerator. One standing-cavity type prebuncher is required for bunching electron beam for this accelerator. The intended prebuncher is driven by a coaxial line at 2 kW and operated at the same frequency of the other parts of the accelerator. The magnetic coupling applied has been applied for power coupling to the prebuncher cavity. The optimum dimensions of the prebuncher were obtained by using 2D and 3D electromagnetic codes in the frequency domain. Prebuncher cavity consists of a copper body and coupling loop feed.

TUPPR055

Upgrading the CEBAF Injector with a New Booster, Higher Voltage Gun, and Higher Final Energy

booster, gun, cryomodule, cavity

1945

R. Kazimi, A. Freyberger, F.E. Hannon, A.S. Hofler, A. Hutton
JLAB, Newport News, Virginia, USA

Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177. The U.S. Govt. retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this for U.S. Govt. purposes.
The CEBAF accelerator at Jefferson Lab will be upgraded from 6 GeV to 12 GeV in the next few years. To meet the requirement of the new machine and also to take the opportunity to improve the beam quality, the CEBAF injector will be upgraded with a higher voltage gun, a new booster, and a new accelerating RF module. The CEBAF injector creates and accelerates three beams at different currents simultaneously. The beams are interleaved, each at one third of RF frequency, traveling through the same beam line. The higher voltage gun will lower the space charge effects making it easier to operate at different current with the same setup. The new booster with optimized beam dynamics will complete the bunching process and provides initial acceleration matched to the new gun voltage. Using our latest SRF design, the new booster has significantly lower XY coupling effects that should improve our beam setup and operation for the highly sensitive parity experiments scheduled for the CEBAF’s future. Finally, the new accelerating RF module will roughly double the injector final energy to match the rest of the 12 GeV accelerator. In this paper we will provide more detail about this upgrade.

TUPPR070

High-Gradient Photonic Band-gap (PBG) Structure Breakdown Testing at Ku-Band

diagnostics, lattice, HOM, damping

1984

B.J. Munroe, A.M. Cook, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA

Photonic Band-gap (PBG) structures continue to be a promising area of research forfuture accelerator structures. Previous experiments at X-Band have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. Two single-cell standing-wave structures have been constructed at MIT to investigate breakdown performance of PBG structures. A metallic structure with small rods will be used to test performance with very high surface temperature rise, while an over-moded structure with dielectric rods will investigate alternative solutions to the issue of surface temperature rise. Both structures are expected to reach gradients of at least 100 MV/m and will utilize novel diagnostics, including fast camera imaging and optical spectroscopy of breakdowns.

TUPPR090

Analysis of Ferrite Heating of the LHC Injection Kickers and Proposals for Future Reduction of Temperature

kicker, injection, vacuum, impedance

2038

M.J. Barnes, L. Ducimetière, N. Garrel, B. Goddard, V. Mertens, W.J.M. Weterings
CERN, Geneva, Switzerland

The two LHC injection kicker magnet (MKI) systems produce a kick of 1.3 T-m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen, consisting of a ceramic tube with conductors on the inner wall, is placed in the aperture of the magnets. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against wake fields. The conductors initially used gave adequately low beam coupling impedance however inter-conductor discharges occurred during pulsing of the magnet; hence an alternative design was implemented to meet the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time and good high voltage behaviour. During 2011 the LHC has been operated with high intensity beam, coasting for many hours at a time, resulting in heating of both the ferrite yoke and beam impedance reduction ferrites, of the MKIs. This paper presents an analysis of thermal measurement data and an extrapolation of the heating for future operation; in addition means are discussed for reducing ferrite heating and improving cooling.

WEPPC022

Elliptical SRF Cavity Design for PEFP Extension

cavity, linac, SRF, proton

2251

H.S. Kim, Y.-S. Cho, J.-H. Jang, H.-J. Kwon
KAERI, Daejon, Republic of Korea

Funding: * This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
To increase the beam energy up to 1 GeV by extending a PEFP 100-MeV proton linac, a study on the superconducting RF linac is underway. SRF technology is chosen due to its operational flexibility and lower beam loss, as well as its high accelerating performance and low operating cost. Preliminary study on the beam dynamics shows that two types of cavity with geometrical beta of 0.50 and 0.74 can cover the entire energy range from 100 MeV to 1 GeV. Assuming the achievable peak surface electric field to be 30 MV/m and 35 MV/m for medium and high beta cavity, respectively, we designed the six-cell elliptical cavities by optimizing the cavity parameters such as peak field ratio, inter-cell coupling and r/Q through the geometrical parameter sweep. The details of the SRF cavity design for PEFP extension will be presented.

WEPPC028

Slim Elliptical Cavity at 800 MHz for Local Crab Crossing

cavity, damping, impedance, HOM

2263

L. Ficcadenti, J. Tückmantel
CERN, Geneva, Switzerland

A slim highly eccentric elliptical Crab cavity with vertical deflection at 800 MHz, compatible to beam line distances everywhere in the LHC ring, was designed. It is a good fall-back solution in case of problems with new compact 400 MHz designs. Simulated RF characteristics of the delfecting mode, HOM spectra and damping, tuning and multipacting effects are presented. First the most simple HOM coupling system was investigated. The rejection of the working mode was not sufficient and a notch filter was added. Results of both cases will be presented.

WEPPC057

Design of SSR1 Single Spoke Resonators for PXIE

cavity, SRF, niobium, cryomodule

2342

L. Ristori, M.H. Awida, I.V. Gonin, M. Merio, D. Passarelli, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Project X Injector Experiment (PXIE) at Fermilab contains one cryomodule of Single Spoke Resonators operating at 325 MHz with a geometrical beta of 0.2. Two prototypes have been tested successfully at high gradients in the Fermilab Vertical Test Stand (VTS). We have welded a Stainless Steel helium vessel on the first prototype and tested it in the spoke-dedicated Test Cryostat. With excellent results in hand, an order for ten bare resonators was placed with US industry. A new design for the helium vessel was developed for these resonators with the main goal of reducing the sensitivity of the resonator to variations of the helium pressure to meet the requirements of PXIE. A new tuner was developed despite the good results of the first prototype. The new design was inevitable due to the different behavior of the resonator in the new helium vessel. Other aspects were improved such as the maintainability of the tuner motor and piezoelectric actuators allowing their replacement from access ports on the cryomodule's vacuum vessel.

WEPPC058

Development at ANL of a Copper-brazed Joint for the Coupling of the Niobium Cavity End Wall to the Stainless Steel Helium Vessel in the Fermilab SSR1 Resonator

niobium, cavity, vacuum, SRF

2345

L. Ristori
Fermilab, Batavia, USA
W.F. Toter
ANL, Argonne, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
In order to reduce the sensitivity of the Fermilab SSR1 resonator to helium pressure variations, it was concluded that the cavity and helium vessel end-walls needed to be structurally coupled by means of a transition ring. With the materials to be connected being Niobium and Stainless Steel, it was decided to utilize the same technology already developed for the cavity flanges which consists of a furnace-brazed joint utilizing oxygen-free electrolytic copper. Small-scale and full-scale annular samples have been constructed at Argonne National Laboratory and subject to tensile tests, thermal cycling and visual inspections to qualify the joint. The transition ring is electron-beam welded to the cavity and TIG welded to the helium vessel, the process is explained in detail.

WEPPC082

First Results on Cornell TE-type Sample Host Cavities

cavity, niobium, vacuum, pick-up

2402

Y. Xie, M. Liepe
CLASSE, Ithaca, New York, USA

Funding: Work supported by NSF and Alfred P. Sloan Foundation.
In order to measure surface resistance of new materials other than niobium such as Nb3Sn and MgB2, two sample host niobium cavities operating at TE modes have been developed at Cornell University. The first one is a 6GHz pillbox TE011 cavity modified from an older vision enabling testing 2.75'' diameter flat sample plates. The second one is an optimized mushroom-shape niobium cavity operating at both 5GHz TE012 and 6GHz TE013 modes for 3.75'' diameter flat sample plates . First results from the commissioning of the two TE cavities will be reported.

WEPPC105

Study of Etching Rate Uniformity in SRF Cavities

cavity, plasma, electron, SRF

2462

J. Upadhyay, S. Popović, L. Vušković
ODU, Norfolk, Virginia, USA
H.L. Phillips, A-M. Valente-Feliciano
JLAB, Newport News, Virginia, USA

Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The crucial aspect of the technology development is dependence of the etching rate and surface roughness on the frequency of the power supply, pressure, power level, driven electrode shape and chlorine concentration in gas mixture during plasma processing. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders are used as diagnostic ports for the measurement of the plasma parameters and as holders for the samples to be etched. The plasma properties are highly correlated with the shape of the driven electrode and the percentage of chlorine concentration in Argon/chlorine gas mixtures. The effect of the plasma parameters and chlorine gas concentration are investigated at RF (100 MHz) and microwave (2.45 GHz) frequencies.

WEPPD043

The Studies of Power System Harmonics at TLS

power-supply, cryogenics, dipole, controls

2609

T.-S. Ueng, J.-C. Chang, Y.F. Chiu, K.C. Kuo, Y.-C. Lin
NSRRC, Hsinchu, Taiwan

The power system harmonic distortion in the utility system of NSRRC is investigated for improving the power system performance. The monitored power quality data at the point of common coupling is examined and compared with industrial standards. In addition, the harmonic characteristics of electric power for the accelerator magnets and adjustable speed drives which contribute the most harmonics are analyzed. Furthermore, the approach to mitigate the harmonic effects for improving the power quality is studied.

WEPPD063

Construction of Disk-loaded Buncher for S-Band Low Energy TW Electron Linear Accelerator

electron, linac, impedance, cavity

2666

F. Ghasemi, F. AbbasiDavani, S. Ahmadiannamini, M.Sh. Shafiee
sbu, Tehran, Iran
M.L. Lamehi Rashti, H. Shaker
IPM, Tehran, Iran

The project of design and construction of Traveling linear electron accelerator is being performed by the Institute for Research in Fundamental Sciences (IPM) and Shahid Beheshti University in Iran. By using the results of the calculations and by dynamic simulation of electron beam in the designed buncher, the dimensions of the designed sample have been obtained. This paper discuss construction of this buncher.

WEPPD072

Frequency Fine-tuning of a Spin-flip Cavity for Antihydrogen Atoms

cavity, resonance, antiproton, vacuum

2690

S. Federmann, F. Caspers, E. Mahner
CERN, Geneva, Switzerland
B. Juhasz, E. Widmann
SMI, Vienna, Austria

As part of the ASACUSA collaboration physics program a spin-flip cavity for measurements of the ground-state hyperfine transition frequency of anti-hydrogen atoms is needed. The purpose of the cavity is to excite anti-hydrogen atoms depending on their polarisation by a microwave field operating at 1.42 GHz. The delicacy of designing such a cavity lies in achieving and maintaining the required properties of this field over a large aperture of 10cm and for a long period of time (required amplitude stability is 1% within 12h). The present paper presents the frequency fine tuning techniques to obtain the desired centre frequency of 1.42 GHz with a Q value below 500 as well as the tuning circuit used for the frequency sweep over the desired bandwidth of 6 MHz.

WEPPD075

A Novel Planar Balun Structure for Continuous Wave 1 kW, 500 MHz Solid-state Amplifier Design

simulation, synchrotron, impedance, HOM

2699

T.-C. Yu, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, C.H. Lo, M.H. Tsai, Ch. Wang, T.-T. Yang, M.-S. Yeh
NSRRC, Hsinchu, Taiwan

In general, the coaxial type balun plays key role in push-pull amplifier design in the increasing high power solid-state technique transmitter design for accelerator application. However, the coaxial baluns not only increase the complexity in manufacturing procedure but also introduce additional tolerance variation between modules. The variation between parallel power modules would decreases combining efficiency and thus increase the operation cost. Here, a novel planar balun has been proposed and successfully implemented on 1kW solid-state amplifier design for continuous operation with newly designed water cooling plates. The long-term CW test has demonstrated the feasibility of the newly designed planar is quite suitable for CW operation with its excellent low loss, balance property and also low tolerance between modules in mass production.

WEPPD078

Progress with PXIE MEBT Chopper

kicker, simulation, vacuum, radio-frequency

2708

V.A. Lebedev, A.Z. Chen, R.J. Pasquinelli, D.W. Peterson, G.W. Saewert, A.V. Shemyakin, D. Sun, M. Wendt
Fermilab, Batavia, USA
T. Tang
SLAC, Menlo Park, California, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
A capability to provide a large variety of bunch patterns is crucial for the concept of the Project X serving MW-range beam to several experiments simultaneously. This capability will be realized by the Medium Energy Beam Transport’s (MEBT) chopping system that will divert 80% of all bunches of the initially 5mA, 2.1 MeV CW 162.5 MHz beam to an absorber according to a pre-programmed bunch-by-bunch selection. Being considered one of the most challenging components, the chopping system will be tested at the Project X Injector Experiment (PXIE) facility that will be built at Fermilab as a prototype of the Project X front end. The bunch deflection will be made by two identical sets of travelling-wave kickers working in sync. Presently, two versions of the kickers are being investigated: a helical 200 Ω structure with a switching-type 500 V driver and a planar 50 Ω structure with a linear ±250 V amplifier. This paper will describe the chopping system scheme and functional specifications for the kickers, present results of electromagnetic measurements of the models, discuss possible driver schemes, and show a conceptual mechanical design.

WEPPP006

Using Simulations to Understand Particle Dynamics and Resonance in the Micro-accelerator Platform

laser, resonance, electron, acceleration

2732

J.C. McNeur, G. Travish
UCLA, Los Angeles, USA
H. Hairong
UESTC, Chengdu, Sichuan, People's Republic of China
R.B. Yoder
Manhattanville College, Purchase, New York, USA

Funding: Work funded in part by grant HDTRA1-09-1-0043 from the US Defense Threat Reduction Agency and under a grant from NNSA/NA-221 Office of Nonproliferation and Verification Research and Development.
The Micro-Accelerator Platform (MAP) is a slab-symmetric micron-scale electron accelerator. Electrons gain energy via a standing wave electromagnetic resonance powered by a side coupled Ti:Sapphire laser. In this paper, we will discuss simulations of resonance and particle dynamics in this structure. Three-dimensional simulations showing evidence of stable 1 GeV/m acceleration are detailed along with simulations studying defocusing and wakefield effects in the MAP. Additionally, optimization of the structure and the coupling of laser power into the cavity will be explored.

WEPPR038

Independent Component Analysis (ICA) Applied to Long Bunch Beams in the Los Alamos Proton Storage Ring

betatron, linac, injection, extraction

3018

J.S. Kolski, R.J. Macek, R.C. McCrady, X. Pang
LANL, Los Alamos, New Mexico, USA

Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis (PCA), which is the BSS foundation of the well known model independent analysis (MIA), ICA is more robust to noise, coupling, and nonlinearity. ICA of turn-by-turn beam position data has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch and discuss the source signals identified as betatron motion and longitudinal beam structure.

WEPPR062

The Mode Matching Method Applied to Beam Coupling Impedance Calculations of Finite Length Devices

impedance, simulation, cavity, resonance

3069

N. Biancacci, E. Métral, B. Salvant
CERN, Geneva, Switzerland
M. Migliorati, L. Palumbo
URLS, Rome, Italy
V.G. Vaccaro
Naples University Federico II and INFN, Napoli, Italy

The infinite length approximation is often used to simplify the calculation of the beam coupling impedance of accelerator elements. This is expected to be a reasonable assumption for devices whose length is greater than the transverse dimension but may be less accurate approximation for segmented devices. This contribution presents the study of the beam coupling impedance in the case of a finite length device: a cylindrical cavity loaded with a toroidal slab of material. In order to take into account the finite length we will decompose the field in the cavity and in the beam pipe into a set of orthonormal modes and apply the mode matching method to obtain the impedance. To validate our method, we will present comparisons between analytical formulas and 3D electromagnetic CST simulations as well as applications to the impedance of short beam pipe inserts, where the longitudinal and transverse dimensions are difficult to model in numerical simulations.

WEPPR070

Beam Coupling Impedance Simulations of the LHC TCTP Collimators

impedance, simulation, cavity, vacuum

3090

H.A. Day, R.M. Jones
UMAN, Manchester, United Kingdom
F. Caspers, A. Dallocchio, L. Gentini, A. Grudiev, E. Métral, B. Salvant
CERN, Geneva, Switzerland

As part of an upgrade to the LHC collimation system, 8 TCTP and 1 TCSG collimators are proposed to replace existing collimators in the collimation system. In an effort to review all equipment placed in the accelerator complex for potential side effects due to collective effects and beam-equipment interactions, beam coupling impedance simulations are carried out in both the time-domain and frequency-domain of the full TCTP design. Particular attention is paid to trapped modes that may induce beam instabilities and beam-induced heating due to cavity modes of the device.

WEPPR071

Evaluation of the Beam Coupling Impedance of New Beam Screen Designs for the LHC Injection Kicker Magnets

impedance, kicker, simulation, injection

3093

H.A. Day, R.M. Jones
UMAN, Manchester, United Kingdom
M.J. Barnes, F. Caspers, H.A. Day, E. Métral, B. Salvant
CERN, Geneva, Switzerland

During the 2011 run of the LHC there was a measured temperature increase in the LHC Injection Kicker Magnets (LHC-MKI) during operation with 50ns bunch spacing. This was suspected to be due to increased beam-induced heating of the magnet due to beam impedance. Due to concerns about future heating with the increased total intensity to nominal and ultimate luminosities a review of the impedance reduction techniques within the magnet was required. A number of new beam screen designs are proposed and their impedance evaluated. Heating estimates are also given with a particular attention paid to future intensity upgrades to ultimate and HL-LHC parameters.

WEPPR072

Increasing Instability Thresholds in the SPS by Lowering Transition Energy

optics, emittance, injection, extraction

3096

H. Bartosik, G. Arduini, T. Argyropoulos, T. Bohl, S. Cettour-Cave, K. Cornelis, J. Esteban Muller, W. Höfle, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova
CERN, Geneva, Switzerland

A new optics for the SPS with lower transition energy was tested experimentally during 2010-2011, showing a significant increase of the single bunch instability thresholds at injection, due to the 3-fold increase of the slip factor. This paper summarizes the series of performed machine studies for different LHC bunch structures and intensities. In particular, the search of the TMCI threshold in the new optics is presented. Observations on the longitudinal multi-bunch stability are compared between the nominal and the low-transition optics. Finally, optics variants with higher vertical tunes are discussed, which can allow to further increase the TMCI and vertical instability thresholds by reducing the vertical beta function.

WEPPR074

Effect of the TEM Mode on the Kicker Impedance

impedance, kicker, simulation, vacuum

3102

C. Zannini, G. Rumolo, V.G. Vaccaro
CERN, Geneva, Switzerland
C. Zannini
EPFL, Lausanne, Switzerland

The kickers are major contributors to the CERN SPS beam coupling impedance. As such, they may represent a limitation to increasing the SPS bunch current in the frame of a luminosity upgrade of the LHC. The C-Magnet supports a transverse electromagnetic (TEM) mode due to the presence of two conductors. Due to the finite length of the structure this TEM mode affects the impedance below a certain frequency (when the penetration depth in the ferrite becomes comparable to the magnetic circuit length). A theoretical model was developed to take into account also the impedance contribution due to the TEM mode. The model is found to be in good agreement with CST 3D electromagnetic (EM) simulations. It allows for generic terminations in the longitudinal direction. An example of kicker is analyzed taking into account also the external cables.

WEPPR085

Observation of Instabilities of Coherent Transverse Ocillations in the Fermilab Booster

booster, damping, injection, space-charge

3129

Y. Alexahin, N. Eddy, E. Gianfelice-Wendt, V.A. Lebedev, W.L. Marsh, W. Pellico, A.K. Triplett
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Fermilab Booster - built more than 40 years ago - operates well above the design proton beam intensity of 4.e12 ppp. Still, the Fermilab neutrino experiments call for even higher intensity of 5.5·10¹² ppp. A multitude of intensity related effects must be overcome in order to meet this goal including suppression of coherent dipole instabilities of transverse oscillations which manifest themselves as a sudden drop in the beam current. In this report we present the results of observation of these instabilities at different tune, coupling and chromaticity settings and discuss possible cures.

WEPPR094

Large Volume Resonant Microwave Discharge for Plasma Cleaning of a CEBAF 5-Cell Srf Cavity

cavity, plasma, electron, SRF

3156

S. Ahmed, K. Macha, J.D. Mammosser
JLAB, Newport News, Virginia, USA
M. Nikolić, S. Popović, J. Upadhyay, L. Vušković
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S.
We report preliminary results on plasma generation in a 5-cell CEBAF SRF cavity for the application of cavity interior surface cleaning. CEBAF currently has ~300 of these five cell cavities installed in the JLab accelerator which are mostly limited by cavity surface contamination. The development of an in-situ cavity surface cleaning method utilizing a resonant microwave discharge could lead to significant performance improvement. This microwave discharge is currently being used for set of plasma cleaning procedures targeted to the removal of various organic, metal and metal oxide impurities. These contaminants are responsible for the increase of surface resistance and the reduction of RF performance in installed cavities. CEBAF five cell cavity volume is ~ 0.5 m2, which places the discharge in the category of large-volume plasmas. Our preliminary study includes microwave breakdown and optical spectroscopy, which was used to define the operating pressure range and the rate of removal of organic impurities.

WEPPR097

Comparing New Models of Transverse Instability with Simulations

space-charge, simulation, synchrotron, wakefield

3165

M. Blaskiewicz
BNL, Upton, Long Island, New York, USA

Recently, Balbekov* has produced an ordinary integro-differential equation that approximates the Vlasov equation for beams with wakefields and large space charge tune shift. The present work compares this model with simulations. In particular, the claim that certain types of transverse wakes cannot lead to mode coupling instabilities, which contradicts earlier work**, is explored
* V. Balbekov, PRSTAB, 14, 094401 (2011).
** M. Blaskiewicz, PRSTAB 1, 044201 (1998).

THEPPB005

Study on the Injection Optimization and Transverse Coupling for CSNS/RCS

injection, emittance, beam-losses, collimation

3240

M.Y. Huang, J. Qiu, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China

The injection system of the China Spallation Neutron Source uses H⁻ stripping and phase space painting method to fill large ring acceptance with the linac beam of small emittance. The emittance evolution, beam losses, and collimation efficiency during the injection procedures for different injection parameters, such as the injection emittances, starting injection time, twiss parameters and momentum spread, were studied, and then the optimized injection parameters was obtained. In addition, the phase space painting scheme which also affect the emittance evolution and beam losses were simulated and the optimization range of phase space painting were obtained. There will be wobble in the power supply of the injection bumps, and the wobble effects were presented. In order to study the transverse coupling, the injection procedures for different betatron tunes and momentum spreads were studied.

THPPC003

Development of a Broad-band Magnetic Alloy Cavity at GSI

cavity, impedance, storage-ring, ion

3275

T.S. Mohite, U. Ratzinger
IAP, Frankfurt am Main, Germany
R. Balß, P. Hülsmann
GSI, Darmstadt, Germany

FINEMET, a Magnetic Alloy material, is often used to build a broad-band cavity for an accelerator or a storage ring. A research on the broad-band FINEMET cavity is of prime importance not only for the present accelerator facility but also for the future storage rings and synchrotron in upcoming FAIR facility alongside the GSI, Darmstadt. In several measurements, high intensity rare-isotope beams, with lower life time, are demanded at injection energy in Experimental Storage Ring (ESR) at GSI. A longitudinal beam stacking of such beams by means of using a special barrier-bucket RF cavity is found appropriate to serve this purpose*. Additionally, this cavity is supposed to provide the compressed bunches at lower energies for HITRAP, an ion-trap facility for experiments with highly charged ions, in FAIR. Several measurements are being performed, along with the theoretical analysis, to achieve the designed parameters for the planned barrier-bucket cavity. 60 FINEMET ring cores have been tested to confirm their designed electrical properties. Some of these ring cores are then loaded, in steps, in a test cavity, which will further be used as the barrier-bucket cavity for the ESR.
* C. Dimopoulou et al., JACoW Proceedings of COOL 2007, Bad Kreuznach, Germany

THPPC007

Coupling Cavity Design of RF Input Coupler Tests for the IFMIF/EVEDA Prototype RFQ Linac

cavity, rfq, linac, beam-transport

3284

S. Maebara
JAEA, Ibaraki-ken, Japan
M. Ichikawa
Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan

In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a 175MHz RFQ, which has a longitudinal length of 9.78m, was proposed to accelerate deuteron beam up to 5MeV. The operation frequency of 175MHz was selected to accelerate a large current of 125mA in cw mode. The overall driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. For the transmitted RF power tests of RF couplers, a coupling cavity to connect with two RF couplers is needed. For this purpose, two types of coupling cavities for the 175MHz have been designed. One is a capacitive coupling cavity with a co-axial waveguide and double loop coupling structures, and the other one is a ridge cavity type with a rectangular waveguide. In this article, these RF designs and engineering designs will be presented in detail.

THPPC008

Coupling Factor Evaluation of the RF Input Coupler for the IFMIF/EVEDA RFQ Linac

rfq, beam-loading, linac, cavity

3287

S. Maebara
JAEA, Ibaraki-ken, Japan
M. Ichikawa
Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
A. Palmieri
INFN/LNL, Legnaro (PD), Italy

In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a 175 MHz RFQ, which has a longitudinal length of 9.78m, was proposed to accelerate deuteron beam up to 5MeV. The operation frequency of 175MHz was selected to accelerate a large current of 125mA in CW mode. The overall driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. As a part of the validation of the coupler design, the beta factor (coupling coefficient) was measured on Aluminum RFQ at INFN Legnaro with on-purpose, real-scale dummy aluminum couplers for the installed depths of L=27, 40, 45, 48 and 73 mm. In this article, measurement and calculation results performed with the 3D code HFSS for coupling factor evaluation will be presented in details.

THPPC021

A Microwave Paraphoton and Axion Detection Experiment with 300 dB Electromagnetic Shielding at 3 GHz

cavity, photon, shielding, pick-up

3320

M. Betz, F. Caspers
CERN, Geneva, Switzerland

Funding: Work supported by the Wolfgang-Gentner-Programme of the Bundesministerium für Bildung und Forschung (BMBF).
For the microwave equivalent of "light shining through the wall" (LSW) experiments, a sensitive microwave detector and very high electromagnetic shielding is required. The screening attenuation between the axion-generating cavity and the nearby detection-cavity should be greater than 300 dB, in order to push beyond the presently existing exclusion limits. To achieve these goals in practice, a "box in a box" concept was utilized for shielding the detection-cavity, while a vector signal analyzer was used as a microwave receiver with a very narrow resolution bandwidth in the order of a few micro-Hz. This contribution will present the experimental layout and show the results to date.

THPPC022

Enhanced Coupling Design of a Detuned Damped Structure for CLIC

wakefield, damping, simulation, dipole

3323

A. D'Elia, A. Grudiev, V.F. Khan, W. Wuensch
CERN, Geneva, Switzerland
T. Higo
KEK, Ibaraki, Japan
R.M. Jones
UMAN, Manchester, United Kingdom

The key feature of the improved coupling design in the Damped Detuned Structure (DDS) is focused on the four manifolds. Rectangular geometry slots and rectangular manifolds are used. This results in a significantly stronger coupling to the manifolds compared to the previous design. We describe the new design together with its wakefield damping properties.

THPPC023

RF Loads for Energy Recovery

cavity, synchrotron, vacuum, proton

3326

S. Federmann, M. Betz, F. Caspers
CERN, Geneva, Switzerland

Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ̊C) are discussed. Another design deals with a very high temperature (up to 800 ̊C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the actual microwave absorber and is not brazed to the metallic enclosure.

THPPC026

A Transverse Deflecting Cavity for the Measurement of Short Low Energy Bunches at EBTF

cavity, electron, simulation, impedance

3335

G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S.R. Buckley, P. Goudket, C. Hill, P.A. McIntosh, J.W. McKenzie, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The Electron Beam Test Facility (EBTF) at Daresbury Laboratory will deliver low energy (5/6 MeV) short bunches (~40 fs) to a number of industrial experimental stations and for scientific research. In order to measure the longitudinal profile of the bunch an S-band transverse deflecting cavity will be inserted into the beamline. A transverse kick of around 5 MV is required hence a 9 cell design has been chosen. The design of the transverse deflecting cavity has been influence by the competing demands of high RF efficiency and minimising the unwanted transverse kick at the entrance and exit of the cavity which cause the electrons to be displaced while traversing the cavity. This has led to a shortened end cell structure design to minimise the kick applied at the entrance and exit to the cavity. In order to minimise the impact of the input coupler a dummy waveguide has been placed on the opposing side of the cavity to minimise the monopole component of the RF fields in the coupling cell. The coupler is located at the central cell of the cavity to avoid exciting the nearby modes. Tracking of the beam is performed in GPT including space charge, due to the low energy of the electrons.

THPPC033

Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D

cavity, electron, vacuum, simulation

3356

D.L. Bowring, A.J. DeMello, A.R. Lambert, D. Li, S.P. Virostek, M.S. Zisman
LBNL, Berkeley, California, USA
D.M. Kaplan
Illinois Institute of Technology, Chicago, Illinois, USA
R.B. Palmer
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Muon Accelerator Program (MAP) collaboration is working to develop an ionization cooling channel for future muon colliders. The ionization cooling channel requires the operation of high-gradient, normal-conducting RF cavities in solenoidal magnetic fields up to 5 T. However, experiments conducted at Fermilab's MuCool Test Area (MTA) show that increasing the solenoidal field strength reduces the maximum achievable cavity gradient. This gradient limit is characterized by an RF breakdown process that has caused significant damage to copper cavity interiors. The damage is likely caused by field-emitted electrons, focused by the solenoidal magnetic field onto small areas of the inner cavity surface. Local heating may then induce material fatigue and surface damage. Fabricating a cavity with beryllium walls would mitigate this damage due to beryllium's low density, low thermal expansion, and high electrical and thermal conductivity. This poster addresses the design and fabrication of a pillbox RF cavity with beryllium walls, in order to evaluate the performance of high-gradient cavities in strong magnetic fields.

THPPC040

Improved RF Design for an 805 MHz Pillbox Cavity for the US MuCool Program

cavity, simulation, ion, multipactoring

3371

Z. Li, C. Adolphsen, L. Ge
SLAC, Menlo Park, California, USA
D.L. Bowring, D. Li
LBNL, Berkeley, California, USA

Funding: Work supported by US DOE under contract number DE-AC02-05CH11231, and DE-AC02-76SF00515.
Normal conducting RF cavities are required to operate at high gradient in the presence of strong magnetic field in muon ionization cooling channels for a Muon Collider. Experimental studies using an 805 MHz pillbox cavity at MTA of Fermilab has shown significant degradation in gradient performance and damage in the regions that are correlated with high RF fields in magnetic field up to 4 Tesla. These effects are believed to be related to the dark current and/or multipacting activities in the presence of external magnetic field. To improve the performance of the cavity, a new RF cavity with significantly lower surface field enhancement was designed, and will be built and tested in the near future. Numerical analyses of multipacting and dark current were performed using the 3D parallel code Track3P for both the original and new improved cavity profiles in order to gain more insight in understanding of the gradient issues under strong external magnetic field. In this paper, we will present the improved RF design and the dark current and multipacting analyses for the 805 MHz cavity.

THPPC041

704 MHz Fast High-power Ferroelectric Phase Shifter for Energy Recovery Linac Applications

cavity, controls, linac, pulsed-power

3374

S.V. Shchelkunov
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
J.L. Hirshfield
Omega-P, Inc., New Haven, USA
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Kazakov, V.P. Yakovlev
Fermilab, Batavia, USA
A.B. Kozyrev
LETI, Saint-Petersburg, Russia
E. Nenasheva
Ceramics Ltd., St. Petersburg, Russia

Funding: Research supported by the U.S. Department of Energy, Office of High Energy Physics
Development, tests, and evaluation of a fast electrically-controlled 704 MHz tuner for Energy Recovery Linacs that employs an electrically -controlled ferroelectric component are presented. The tuner is a refinement of an already tested prototype described elsewhere. In the new concept, a collection of ferroelectric assemblies behave as cavities configured as transmission components within a coaxial waveguide. Each assembly is based on a ring-like ferroelectric ceramic with its height, inner and outer diameters, and the shape of edges adjusted to insure a clean operating mode, and relatively low field strength. Several assemblies serve to widen the passband and increase tunability. The tuner is to deliver fast (~100-200 ns) phase adjustment from 0-to-100 degrees when biased by voltages from 0-to-15kV; the design promises to handle 50 kW CW and 900 kW of pulsed power. A scaled version is also considered to operate at 1300 MHz while handling 500 kW of pulsed power. Our latest findings, related issues, and plans for experiments are discussed.

THPPC044

Development of the Dual Slot Resonance Linac

linac, cavity, resonance, impedance

3383

N. Barov, X. Chang, R.H. Miller, D.J. Newsham
Far-Tech, Inc., San Diego, California, USA

Funding: Work supported by DOE Grant DE-FG02-08ER85034
We report the status of the Dual Slot Resonance (DSR) linac under development by FAR-TECH. In this linac type, cell-to-cell coupling is provided by a pair of close-coupled resonant slots, resulting in very strong coupling vs. a typical side-coupled linac design, as well as a much more compact radial space requirement. We discuss the status of the structure fabrication, the RF distribution system, and installation and testing at the UCLA Pegasus facility.

THPPC047

Fabrication and Initial Tests of an Ultra-High Gradient Compact S-Band (HGS) Accelerating Structure

klystron, linac, vacuum, accelerating-gradient

3392

L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh
RadiaBeam, Santa Monica, USA
V.A. Dolgashev
SLAC, Menlo Park, California, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: Work supported by US DOE grant # DE-SC000866.
RadiaBeam Technologies reports on the RF design and fabrication of a ultra-high gradient (50 MV/m) S-Band accelerating structure (HGS) operating in the pi-mode at 2.856 GHz. The compact HGS structure offers a drop-in replacement for conventional S-Band linacs in research and industrial applications such as drivers for compact light sources, medical and security systems. The electromagnetic design (optimization of the cell shape in order to maximize RF efficiency and minimize surface fields at very high accelerating gradients) has been carried out with the codes HFSS and SuperFish while the thermal analysis has been performed by using the code ANSYS. The initial cold tests are presented together with the plans for high-power tests currently ongoing at Lawrence Livermore National Laboratory (LLNL).

THPPC049

Progress on the MICE 201 MHz RF Cavity at LBNL

cavity, simulation, resonance, electron

3398

T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA
A.J. DeMello, D. Li, S.P. Virostek, M.S. Zisman
LBNL, Berkeley, California, USA

The international Muon Ionization Cooling Experiment (MICE) aims at demonstrating transverse cooling of muon beams by ionization. The ionization cooling channel of MICE requires eight 201-MHz normal conducting RF cavities to compensate for the longitudinal beam energy loss in the cooling channel. In this paper, we present recent progresses on MICE RF cavity at LBNL, which includes electro-polishing, intended to improve the cavity performance in the presence of strong external magnetic field; low power RF measurements on resonant frequency and Q value of each cavity with a pair of curved- beryllium windows to terminate the cavity irises. Multipacting simulations are conducted using SLAC’s ACE-3P code to study the effects in the cavity and coupler regions with the influence by external magnetic field.

THPPC057

S-band High Power RF System for 10 GeV PAL-XFEL

cavity, simulation, klystron, linac

3419

W.H. Hwang, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Kim, H.-S. Lee, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 120 Hz. In high power operation, it is important to decrease the rf electric field to protect rf break-down in high power rf components. To obtain the maximum beam, we must reduce the phase difference between waveguide branches including accelerating structure and minimize the environment influences. This paper describes the waveguide system and high power rf components for the PxFEL.

THPPC059

Design of SLED System with Dual Side-wall Coupling Irises and Biplanar Power Splitter for PAL XFEL

simulation, klystron, cavity, factory

3425

Y.D. Joo, I. Hwang, C. Kim, B.-J. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

The SLED system of the PAL XFEL is required to be operated with the RF input power of 80 MW and the pulse width of 4 us. The high RF dose from the RF breakdown at the coupling holes and power splitter prohibits that the original design of the SLED serve this operation condition. To reduce the gradient at the cavity coupling structure, the concept of dual side-wall coupling irises is introduced. In addition, the 3dB splitter is modified with the concept of biplanar coupler structure.

THPPC066

Adjustable High Power Coax RF Coupler without Moving Parts

cavity, extraction, solenoid

3443

M.L. Neubauer, A. Dudas, R. Sah
Muons, Inc, Batavia, USA
A. Nassiri
ANL, Argonne, USA

A high power fundamental RF power coupler (FPC) with an adjustable in situ coupling factor would be highly desirable for a number of applications; for example, the 352 MHz light source at APS and Project X. A Phase I project has been completed with a prototype constructed and modeled. The prototype includes a coaxial TEE with two windows a quarter wavelength apart, and a ferrite tuner. Two materials were tested and their characteristics measured in terms of loss and magnetic field requirements to produce the desired change in coupling. A VSWR of better than 1.05:1 and a bandwidth of at least 8% at 1.15:1 was measured. The tradeoffs of a final design are proposed based upon these results.

THPPD039

Magnetic Analysis of a Single-Aperture 11T Nb3Sn Demonstrator Dipole for LHC Upgrades

dipole, injection, simulation, sextupole

3596

B. Auchmann, M. Karppinen
CERN, Geneva, Switzerland
V. Kashikhin, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The planned upgrade of the LHC collimation system foresees additional collimators to be installed in the dispersion suppressor areas around points 2, 3, and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33-T 15-m-long NbTi LHC main dipoles with shorter 11-T Nb3Sn dipoles compatible with the LHC lattice and main systems. To demonstrate this possibility, in 2011 Fermilab and CERN started a joint R&D program with the goal of building a 5.5-m-long twin-aperture dipole prototype suitable for installation in the LHC by 2014. The first step of this program is the development of a 2-m-long single-aperture demonstration dipole with the nominal field of 11 T at the LHC nominal current of ~11.85 kA and 60-mm bore with ~20% margin. This paper presents the results of magnetic analysis of the single-aperture Nb3Sn demonstrator dipole for the LHC collimation system upgrade.

THPPD058

Reduction of Conductive EMI Noise Resulted from the Commercial Power Supply

power-supply, high-voltage, vacuum, impedance

3644

C.S. Chen, C.K. Chan, J.-C. Chang, Y.L. Chu, K.H. Hsu, C.Y. Kuo, Y.-H. Liu, C.S. Yang
NSRRC, Hsinchu, Taiwan

Almost every electronic equipment must be connected to power system. Because of the complexity of power lines, the reduction of conductive electro-magnetic interference (C-EMI) plays an important role in precise measurements. In this paper, a line impedance stabilization network (LISN) was built up to get the spectrum from power lines. After several measurements by some commercial power supplies, it is found that some of these power supplies induce effectively C-EMI into power lines, even if a passive filter is bound in power line. These noises may influence numerous equipments in a local area near the sources. Therefore, how to choose a suitable filter is a decisive factor to reduce the magnitude of C-EMI.

THPPD072

Performance Optimization of the Stacked-Blumlein

simulation, impedance, high-voltage, induction

3680

L.W. Zhang, J. Li, W.D. Wang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
Y. Li
CAEP, Mainyang, Sichuan, People's Republic of China

Funding: This work was supported by the National Natural Science Foundation of China (11035004)
For the applications of the Dielectric Wall Accelerator (DWA), the stacked Blumlein pulse generator comprised of parallel-plate transmission lines is being developed. The peak output voltage of the stacked Blumlein will be much lower than expected due to the parasitic coupling among the individual pulse forming lines of the Blumlein stack. The finite difference time domain method is used to model the stacked Blumlein structure and determine the outputs. We present the optimization of a 20-Blumleins-stack in this paper. The results for different structures are discussed.

THPPP003

Coupling Impedance Study of the New Injection Kicker Magnets of the JPARC Main Ring

impedance, kicker, simulation, vacuum

3725

K. Fan, S. Fukuoka, H. Matsumoto, T. Sugimoto, T. Toyama
KEK, Ibaraki, Japan

New lumped inductance kicker magnets have been developed for the J-PARC main ring injection system. For high intensity beam operation, the beam coupling impedance of the new kickers is a critical issue, which not only generates significant heating inside the ferrite impairing the performance of the kickers, but also drives beam instability. Numerical simulations based on CST studio have been studied during the design stage to optimize the kicker structure. Impedance measurements based on wire method have been carried out. The measured results agree well with the simulation results.

THPPP004

Design and Test of Injection Kicker Magnets for the JPARC Main Ring

kicker, impedance, injection, proton

3728

K. Fan, S. Fukuoka, K. Ishii, H. Matsumoto, H. Someya, T. Sugimoto, T. Toyama
KEK, Ibaraki, Japan

The present injection kicker magnets of the JPARC main ring consists of three transmission type kickers. To overcome the operational problems, four lumped inductance kicker magnets have been developed for the simplicity and the high reliability. The tight requirements on the rise and fall time create difficulties for the new design. Magnetic field measurements, coupling impedance measurements and have been carried out. The measurement results show that the new kicker magnets can satisfy the requirements of beam injection.

THPPP005

Space Charge Effect in the Presence of x-y Coupling in J-PARC MR

lattice, space-charge, emittance, simulation

3731

K. Ohmi
KEK, Ibaraki, Japan
S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

It is crucial issue to suppress beam loss due to space charge force in J-PARC MR. We focus x-y coupling as a source of the beam loss. x-y coupling is measured by turn-by-turn beam position monitors in J-PARC MR. A space charge simulation under the measured x-y coupling evaluates the beam loss. Tolerance of x-y coupling and how to improve the beam loss are discussed.

THPPP019

Tune Determination of Strongly Coupled Betatron Oscillations in a Fast Ramping Synchrotron

booster, damping, betatron, quadrupole

3770

Y. Alexahin, E. Gianfelice-Wendt, W.L. Marsh, A.K. Triplett
Fermilab, Batavia, USA

Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Tune identification - i.e. attribution of the spectral peak to a particular normal mode of oscillations - can present a significant difficulty in the presence of strong transverse coupling when the normal mode with a lower damping rate dominates spectra of Turn-by-Turn oscillations in both planes. The introduced earlier phased sum algorithm* helped to recover the weaker normal mode signal from the noise, but by itself proved to be insufficient for automatic peak identification in the case of close phase advance distribution in both planes. To resolve this difficulty we modified the algorithm by taking and analyzing Turn-by-Turn data for two different ramps with the beam oscillation excited in each plane in turn. Comparison of the relative amplitudes of Fourier components allows for automatic correct tune identiﬁcation. The proposed algorithm was implemented in the Fermilab Booster B38 console application and successfully used in tune, coupling and chromaticity measurements.
* Y. Alexahin, E. Gianfelice-Wendt, W. Marsh, Proc. IPAC10, Kyoto, May 2010, p. 1179.

THPPP021

6 Batch Injection and Slipped Beam Tune Measurements in Fermilab’s Main Injector

injection, booster, proton, target

3776

D.J. Scott, D. Capista, I. Kourbanis, K. Seiya, M.-J. Yang
Fermilab, Batavia, USA

During Nova operations it is planned to run the Fermilab Recycler in a 12 batch slip stacking mode. In preparation for this, measurements of the tune during a six batch injection and then as the beam is slipped by changing the RF frequency, but without a 7th injection, have been carried out in the Main Injector. The coherent tune shifts due to the changing beam intensity were measured and compared well with the theoretically expected tune shift. The tune shifts due to changing RF frequency, required for slip stacking, also compare well with the linear theory, although some nonlinear affects are apparent at large frequency changes. These results give us confidence that the expected tunes shifts during 12 batch slip stacking Recycler operations can be accommodated.

THPPP029

Simultaneous Global Coupling and Vertical Dispersion Correction in RHIC

quadrupole, proton, polarization, heavy-ion

3794

C. Liu, Y. Luo, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Residual vertical dispersion on the order of ±0.2 m (peak to peak) has been measured at store energies for both polarized proton and heavy ion beams. The hypothesis is that this may have impact on the polarization transmission efficiency during the energy ramp, the beam lifetimes, and, especially for heavy ions, the dynamics aperture. An algorithm to correct global coupling and dispersion simultaneously using skew quads was developed for RHIC. Simulation results together with the measured coupling and dispersion functions before and after correction will be shown for both injection and store together with an assessment of overall collider performance improvement.

THPPP031

RF Design of ESS RFQ

rfq, simulation, cavity, linac

3800

O. Piquet, M. Desmons, A. France
CEA/DSM/IRFU, France
O. Delferrière
CEA/IRFU, Gif-sur-Yvette, France

The low energy front end of ESS is based on a 352 MHz, 5-m long Radiofrequency Quadrupole (RFQ) cavity. It will accelerate and bunch proton beams from 75 keV to 3 MeV. The beam current is 50 mA (75 mA as an upgrade scenario) for 4% duty cycle. A complete RF analysis of the ESS RFQ has been performed using 3D RF simulating codes and a RFQ 4-wire transmission line model. Proposed RFQ is a 4 vane-type structure where 2D cross-section is optimized for lower power dissipation, while featuring simple geometrical shape suitable for easy machining. RF calculations are performed for the whole RFQ, and mainly for the following parts: end cells, vacuum port, tuners and RF coupling ports. Power losses are particularly calculated in order to achieve Thermo-mechanical calculations.

THPPP036

First Measurements of an Coupled CH Power Cavity for the FAIR Proton Injector

cavity, linac, proton, DTL

3812

R. M. Brodhage, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
G. Clemente, L. Groening
GSI, Darmstadt, Germany

For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. For this second tank technical and mechanical investigations have been performed to develop a complete technical concept for manufacturing. In Spring 2011, the construction of the first power prototype has started. The main components of this cavity were ready for measurements in fall 2011. At that time, the cavity was tested with a preliminary aluminum drift tube structure, which will allow precise frequency and field tuning. This paper will report on the recent technical developments and achievements. It will outline the main tuning and commissioning steps towards that novel type of proton DTL and it will show very promising results of the latest measurements.

THPPP049

Tuning Procedure for the LINAC4 PI Mode Structure (PIMS)

simulation, cavity, linac, electron

3850

P. Ugena Tirado, F. Gerigk, R. Wegner
CERN, Geneva, Switzerland

PI-Mode-Structure (PIMS) cavities will be used in the high energy section of LINAC4 (10²-160 MeV). Each cavity is made of 7 coupled cells, operated in the π-mode at a resonant frequency of 352.2 MHz. The cell length remains constant for each of the 12 cavities but changes from cavity to cavity to synchronise with the increased beam energy. This paper reports on the tuning process required to get a constant voltage in each cell at the resonant frequency and consisting in re-machining to the required level the tuning rings located on each cell-wall. An algorithm based on single cell detuning, equivalent circuit simulations and precise 3D simulations for the 3 different cell types of each cavity has been developed and successfully applied to the tuning of the first PIMS cavity. In order to reduce the simulation effort for the remaining 11 cavities, an interpolation algorithm based on 3 cavities has been developed and validated. In a second tuning step, after the electron beam welding of all cells, the final adjustment of single-cell frequencies and field flatness is achieved by cutting the length of one plunger tuner per cell.

THPPP066

Beam Tuning Strategy of the FRIB Linac Driver

linac, cavity, solenoid, ion

3889

Y. Zhang
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The FRIB linac driver will deliver heavy ion beams up to uranium, with an energy of 200 MeV/u and total power on target of 400 kW. To reach the design power for heaviest ions, multi-charge-state beams will be accelerated simultaneously in this SRF linac. Beam tuning of the linac driver is among the most challenging tasks. In this paper, we discuss the beam tuning strategy, which includes the cavity synchronous phase and acceleration gradient setup, beam trajectory correction, and transverse matching with horizontal-vertical coupled beams as superconducting solenoids are used for transverse focusing in the linac segments.

THPPP068

Investigation of a Multi-cell Cavity Structure Proposed for Improved Hydroforming

cavity, focusing, HOM, SRF

3895

K.R. Shin
ORNL RAD, Oak Ridge, Tennessee, USA
A.E. Fathy
University of Tennessee, Knoxville, Tennessee, USA
J.A. Holmes, Y.W. Kang
ORNL, Oak Ridge, Tennessee, USA

A multi-cell cavity structure with rectangular coupling aperture between cavity cells is proposed. This investigation is to study the RF properties of such structure that may provide high yield in hydroforming. In mechanical point of view, the rectangular aperture iris may provide much improved structure quality in hydroforming since it can help to reduce the stress incurring within the sheet metal with improved structural malleability. The necking procedure can be easier because of greater perimeter in the iris geometry. Peak electric and magnetic fields per accelerating gradient may increase however, compared to traditional TESLA type elliptical cavity structure. The rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing may be achieved. 3D simulations with CST MWS have been carried out to analyze EM field properties and the cavity parameters.

THPPP093

Progress on MICE RFCC Module

cavity, vacuum, solenoid, controls

3954

D. Li, D.L. Bowring, A.J. DeMello, S.A. Gourlay, M.A. Green, N. Li, T.O. Niinikoski, H. Pan, S. Prestemon, S.P. Virostek, M.S. Zisman
LBNL, Berkeley, California, USA
A.D. Bross, R.H. Carcagno, V. Kashikhin, C. Sylvester
Fermilab, Batavia, USA
Y. Cao, S. Sun, L. Wang, L. Yin
SINAP, Shanghai, People's Republic of China
A.B. Chen, B. Guo, L. Li, F.Y. Xu
ICST, Harbin, People's Republic of China
D.M. Kaplan
Illinois Institute of Technology, Chicago, Illinois, USA
T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA

Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231, US Muon Accelerator Program and NSF MRI award: 0959000.
Recent progress on the design and fabrication of the RFCC (RF and Coupling Coil) module for the international MICE (Muon Ionization Cooling Experiment) will be reported. The MICE ionization cooling channel has two RFCC modules; each having four 201-MHz normal conducting RF cavities surrounded by one superconducting coupling coil (solenoid) magnet. The magnet is designed to be cooled by 3 cryocoolers. Fabrication of the RF cavities is complete; preparation for the cavity electro-polishing, low power RF measurements and tuning are in progress at LBNL. Fabrication of the cold mass of the first coupling coil magnet has been completed in China and the cold mass arrived at LBNL in late 2011. Preparations for testing the cold mass are currently under way at Fermilab. Plans for the RFCC module assembly and integration are being developed and will be described.

THPPR030

High Power Test of RF Separator For 12 GeV Upgrade of CEBAF at Jefferson Lab

cavity, vacuum, ion, extraction

4032

S. Ahmed, C. Hovater, G.A. Krafft, J.D. Mammosser, M. Spata, M.J. Wissmann
JLAB, Newport News, Virginia, USA
J.R. Delayen
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate enough to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, several options including the extension of existing normal conducting (NC) and a potential 499 MHz TEM-type superconducting (SC) cavity design have been investigated using computer simulations. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test to 4 kW is required to confirm the cavity’s operate-ability at these elevated gradient and power levels. We have assembled a 2-cell cavity, pumped down to 2.0·10^-9 torr using ion pump and confirmed the low level RF performance. A high power test is in progress and will be completed soon. The detailed numerical and experimental results will be discussed in the paper.

THPPR043

Applications of X-band 950 keV and 3.95 MeV Linac X-ray Source for On-site Inspection

linac, radiation, focusing, shielding

4071

M. Uesaka, K. Demachi, K. Dobashi, T. Fujiwara, H.F. Jin, M. Jin, H. Zhu
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
Y. Hattori
Hitachi Engineering & Services Co.,Ltd., Japan
J. Kusano, N. Nakamura, M. Yamamoto
Accuthera Inc., Kawasaki, Kanagawa, Japan
I. Miura
Mitsubishi Chemical Corporation, Japan
E. Tanabe
AET, Kawasaki-City, Japan

Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of a 250 kW magnetron and a cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. We have also developed a portable X-band (9.3GHz) 3.95MeV linac for on-site bridge inspection. The system consists of a 62kg X-ray source part without 80kg target collimator, a 62kg RF power source and other utility box of 116kg. Designed X-ray dose rate is 2 Sv/min@1m with 200pps repetition rate and we have achieved 0.5 Sv/min@1m with 50pps repetition rate. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding by 950keV linac and degradation of reinforced concrete sample by 3.95MeV is under way. Updated measurement results will be presented.

THPPR050

Fabrication and High Power RF Test of A C-band 6MeV Standing-wave Linear Accelerating Structure

simulation, gun, electron, target

4089

J.H. Shao, H. Chen, H. Zha
TUB, Beijing, People's Republic of China

We have designed a C-band standing-wave bi-periodic on-axis coupled linear accelerating structure for industrial and medical applications [1]. The output electron energy is 6MeV and the pulse current intensity is 100mA. The structure has been fabricated and measured in cold test. The cold test results show a good agreement between the simulation and actual measurement. At present, it’s under high power RF test. In this paper, we illustrate the fabrication, the results of cold test and newly high power RF test.

THPPR069

Compact, Inexpensive X-Band Linacs as Radioactive Isotope Source Replacements

linac, simulation, radiation, electron

4136

S. Boucher, R.B. Agustsson, X.D. Ding, L. Faillace, P. Frigola, A.Y. Murokh, M. Ruelas, S. Storms
RadiaBeam, Santa Monica, USA

Funding: Work supported by DNDO Phase II SBIR HSHQDC-10-C-00148 and DOE Phase II SBIR DE-SC0000865.
Radioisotope sources are still commonly used in a variety of industrial and medical applications. The US National Research Council has identified as a priority the replacement of high-activity sources with alternative technologies, due to the risk of accidents and diversion by terrorists for use in radiological dispersal devices (“dirty bombs”). RadiaBeam Technologies is developing novel, compact, inexpensive linear accelerators for use in a variety of such applications as cost-effective replacements. The technology is based on the MicroLinac (originally developed at SLAC), an X-band linear accelerator powered by an inexpensive and commonly available magnetron. Prototypes are currently under construction. This paper will describe the design, engineering, fabrication and future testing of these linacs at RadiaBeam. Future development plans will also be discussed.