IPAC2014 - List of Keywords (experiment)

Paper	Title	Other Keywords	Page
MOZB02	Advances in Photocathodes for Accelerators	electron, emittance, cathode, laser	48
	L. Cultrera Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	This talk reviews advances in photocathode technology for accelerators: cathodes demonstrating record average currents and deliverable charge, possessing ultra-low intrinsic emittance and sub-picosecond response time. It addresses the grand challenge to combine all these useful properties into a single photoemitter - one that is being actively pursued by the research community.
	Slides MOZB02 [4.354 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZB02
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MOOCB01	Beam-induced Quench Tests of LHC Magnets	simulation, quadrupole, collimation, beam-losses	52
	M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto CERN, Geneva, Switzerland
	At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.
	Slides MOOCB01 [2.737 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01
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MOOCB02	A Common Operation Metrics for Third Generation Light Sources	operation, feedback, survey, insertion	56
	A. Lüdeke PSI, Villigen PSI, Switzerland M. Bieler DESY, Hamburg, Germany J.-F. Lamarre SOLEIL, Gif-sur-Yvette, France M. Pont CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	High reliability is a very important goal for third generation light sources. Very often the beam availability is used as the operation metrics to measure the reliability of the accelerator. A survey at several light sources revealed that the calculation of this statistics varies significantly between facilities. This prevents a useful comparison of their reliabilities. The authors propose a specific metrics for the reliability of third generation light sources; a metrics that will allow a detailed and meaningful comparison of these particle accelerators.
	Slides MOOCB02 [0.701 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB02
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MOPRO013	Present Status of Coherent Electron Cooling Proof-of-Principle Experiment	electron, ion, cavity, gun	87
	V. Litvinenko, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C. Brutus, A.J. Curcio, L. DeSanto, C. Folz, D.M. Gassner, H. Hahn, Y. Hao, C. Ho, Y. Huang, R.L. Hulsart, M. Ilardo, J.P. Jamilkowski, Y.C. Jing, F.X. Karl, D. Kayran, R. Kellermann, N. Laloudakis, R.F. Lambiase, G.J. Mahler, M. Mapes, W. Meng, R.J. Michnoff, T.A. Miller, M.G. Minty, P. Orfin, A. Pendzick, I. Pinayev, F. Randazzo, T. Rao, J. Reich, T. Roser, J. Sandberg, T. Seda, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, A.N. Steszyn, R. Than, C. Theisen, R.J. Todd, J.E. Tuozzolo, E. Wang, G. Wang, D. Weiss, M. Wilinski, T. Xin, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA G.I. Bell, J.R. Cary, K. Paul, I.V. Pogorelov, B.T. Schwartz, A.V. Sobol, S.D. Webb Tech-X, Boulder, Colorado, USA C.H. Boulware, T.L. Grimm, R. Jecks, N. Miller Niowave, Inc., Lansing, Michigan, USA A. Elizarov SUNY SB, Stony Brook, New York, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia P.A. McIntosh, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Work supported by Stony Brook University and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The Coherent Electron Cooling Proof of Principle (CeC PoP) system is being installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. This technique may increase the beam luminosity by as much as tenfold. Within the scope of this experiment, a 112 MHz 2 MeV Superconducting Radio Frequency (SRF) electron gun coupled with a cathode stalk mechanism, two normal conducting 500 MHz single-cell bunching cavities, a 704 MHz 20 MeV 5-cell SRF cavity and a helical undulator will be used. In this paper, we provide an overview of the engineering design for this project, test results and discuss project status and plansd.
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MOPRO024	The Beam Test for the Ti Extraction Window Damage	extraction, radiation, electron, kicker	119
	T. Mimashi, N. Iida, M. Kikuchi KEK, Ibaraki, Japan
	For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.
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MOPRO057	Undulator Photon Beams with Orbital Angular Momentum	undulator, emittance, photon, storage-ring	213
	J. Bahrdt, K. Holldack, P. Kuske, R. Müller, M. Scheer, P.O. Schmid HZB, Berlin, Germany
	Photons carrying orbital angular momentum (OAM) are present in the off-axis radiation of higher harmonics of helical undulators. Usually, the purity and visibility of OAM photons is blurred by electron beam emittance. However, high brightness OAM beams are expected in ultimate storage rings and FELs, and they may trigger a new class of experiments utilizing the variability of the topological charge, a 3rd degree of freedom besides wavelength and polarization. We report on the first detection of OAM photons in helical undulator radiation in the 3rd generation storage ring BESSY II. Measurements and simulations are compared and the impact of emittance and energy spread is discussed.
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MOPRO108	Lattice and Start-to-end Simulation of the Mainz Energy Recovering Superconducting Accelerator MESA	lattice, linac, simulation, optics	346
	R.G. Heine, K. Aulenbacher, F. Schlander, D. Simon IKP, Mainz, Germany
	Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA" The institute for nuclear physics (IKPH) at Mainz University is designing a multi turn energy recovery linac for particle physics experiments . We present the current status of the lattice development of MESA together with a PARMELA start to end simulation. R. Heine, K. Aulenbacher, and R. Eichhorn: MESA-Sketch of an Energy Recovery LINAC for Nuclear Physics Experiments at Mainz, Proc. of the IPAC2012, New Orleans, Louisiana, USA, p. 1993-1995.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO108
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MOPRO116	Mechanical Engineering and Design of Novel Collimators for HL-LHC	impedance, operation, proton, collimation	369
	F. Carra, A. Bertarelli, A. Dallocchio, L. Gentini, P. Gradassi, A. Manousos, N. Mariani, G. Maîtrejean, N. Mounet, E. Quaranta, S. Redaelli, V. Vlachoudis CERN, Geneva, Switzerland
	In view of LHC intensity upgrades, collimator materials may become a limit to the machine performance: the high RF impedance of Carbon-Carbon composites can lead to beam instabilities, while the Tungsten alloy adopted in tertiary collimators exhibits low robustness in case of beam-induced accidents. An R&D program has been pursued to develop new materials overcoming such limitations. Molybdenum-Graphite, in addition to its outstanding thermal conductivity, can be coated with pure molybdenum, reducing collimator impedance by a factor of 10. A new secondary collimator is being designed around this novel composite. New high-melting materials are also proposed to improve the robustness of tertiary collimators. All the new collimators will be equipped with BPMs, significantly enhancing the alignment speed and the beta-star reach. This implies additional constraints of space, as well as detailed static and fatigue calculations on cables and connectors. This paper describes the mechanical design and the engineering calculations of such future collimators, focusing on the study via state-of-the-art numerical methods of interactions between the particle beams and the new materials adopted.
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MOPME001	Commissioning of the Double Electrostatic Storage Ring DESIREE	ion, storage-ring, injection, pick-up	373
	A. Källberg, M. Björkhage, M. Blom, E. Bäckström, H. Cederquist, O.M. Hole, M. Kaminska, P. Löfgren, S. Mannervik, R. Nascimento, P. Reinhed, H.T. Schmidt, A. Simonsson Stockholm University, Stockholm, Sweden S. Rosén Stockholm University, Department of Physics, Stockholm, Sweden
	DESIREE, the double electrostatic storage rings in Stockholm, is now commissioned and used for experiments. The two 9 m circumference storage rings, which are constructed inside a double walled cryostat, are now cooled to 13 K and routinely used for storage of both negative and positive ions with lifetimes of several minutes. The main properties of DESIREE are presented as well as results from the commissioning and the first experiments.
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MOPME012	A New Tool for Automated Orbit and Spin Motion Analysis	lattice, software, storage-ring, simulation	403
	D. Zyuzin FZJ, Jülich, Germany
	There are a lot of tools to simulate beam dynamics in accelerators of various types. Many of them are intended to use for specific purposes, and there are universal codes that can simulate both orbit and spin motion in magnetic and electrostatic structures. To start using these codes beam physicist first should have learn syntax, know features and methods how to describe lattice and beams in this particular code. Output data structures of different simulation programs are also vary and depend on peculiarities of each program. This paper proposes a new tool for automated generation and execution of input files for simulation programs and for data analysis of output data. The developed tool allows to describe a lattice, calculate different lattice parameters (like tunes) using simulation program, track particles inside the lattice and analyze various parameters of output data (like beam depolarization). Simulations and analysis can be done in parallel using built-in parallelization mechanisms, and all results can be stored in the database and can be easily fetched when needed. The tool is used to simulate beam and spin dynamics in different lattices to increase spin coherence time.
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MOPME022	Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna	plasma, ion, operation, simulation	424
	H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu USTC/NSRL, Hefei, Anhui, People's Republic of China
	A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME022
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MOPME023	A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma	electron, simulation, cyclotron, plasma	427
	X.F. Li, D.Z. Chen, D. Li, H.K. Yue HUST, Wuhan, People's Republic of China
	A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.
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MOPME024	Progress of the RF Negative Ion Source Research at HUST	plasma, ion, ion-source, extraction	430
	D.Z. Chen, M. Fan, J. Huang, X.F. Li, K.F. Liu, C. Wang, H.K. Yue, C. Zhou HUST, Wuhan, People's Republic of China J.C. Huang, D. Li, D.W. Liu, Z. Zhang Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People's Republic of China
	Funding: Ministry of Science and Technology of China To promote the research and talent cultivation for ITER negative ion sources, Huazhong University of Science and Technology (HUST) has started to develop an experimental facility since 2011 under the support of Ministry of Science and Technology of China. As the first stage, we are building a radio frequency (RF) driver which will produce the plasma for yielding negative ions in the next stage. A deal of experimental research has been carried out on the setup.
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MOPME047	Comparison of the Results of a Hydrodynamic Tunneling Experiment with Iterative FLUKA and BIG2 Simulations	target, simulation, proton, collider	479
	F. Burkart, J. Blanco, D. Grenier, R. Schmidt, D. Wollmann CERN, Geneva, Switzerland N.A. Tahir GSI, Darmstadt, Germany
	In 2012, a novel experiment has been performed at the CERN HiRadMat facility to study the impact of a 440 GeV proton beam generated by the Super Proton Synchrotron (SPS), on extended solid copper cylindrical targets. Substantial hydrodynamic tunneling of the protons in the target material has been observed. Iterative FLUKA and BIG2 simulations with the parameters of the actual experiment have been performed. In this paper the results of these simulations will be discussed and compared to the experimental measurements. Furthermore, the implication on the machine protection design for high intensity hadron accelerators as the current LHC and the future High Luminosity LHC will be addressed.
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MOPME070	Investigation of a High Power, Low Impedance Pulse Forming Network based on Ceramic Capacitors	impedance, network, simulation, laser	529
	J. Gao, X.J. Ge, J. He, J. Liu NUDT, Changsha, People's Republic of China
	Solid state is one of the most important development directions for pulsed power technologies. For GW level pulse generators, switches and pulse forming units are difficult to implement with solid state components restricted by high power tolerance and high voltage insulation. Under certain pulse power, operation voltage is decided by impedance of the pulse forming unit, which means that pulse modulation with low impedance method should help improve insulation strength of a pulsed power system. Therefore, a high power, low impedance pulse forming network is developed based on solid components of ceramic capacitors in this research. It is designed that the impedance is 1.6 Ω, the pulse width is about 150 ns, and the output power is above 1 GW. Low impedance is accomplished via several pulse forming units connected in parallel with a circumferential structure, which could reduce the stray inductance due to good symmetrical characteristics. Key factors influencing pulse modulation process are investigated, stray parameters are examined by electromagnetic calculations and preliminary experiments are carried out, with results giving reasonable agreement with the theoretical cases.
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MOPME071	Configurations and Applications of Saturable Pulse Transformers in High Power Pulse Modulation	high-voltage, coupling, plasma, controls	532
	J. Liu, J. Gao, X.J. Ge, J. He, Y. Zhang NUDT, Changsha, People's Republic of China
	Saturable pulse transformers (SPTs) based on multiple batches of windings in parallel combination and coaxial cylindrical conductors are presented. The proposed SPT can be employed as the transformer and magnetic switch simultaneously for pulse capacitor or high-voltage pulse modulator of several hundred kV range. The SPT, with important features such as auto-resetting of core, high step-up ratio and low saturation inductance, achieves a compact integration of common transformer and magnetic switch. In the SPT, The physical suppression effect caused by reversed magnetic coupling mechanism among primary and secondary windings can reduce the saturation inductance of the SPT windings to a level lower than their structure inductances, which helps to achieve a magnetic switch with low saturation inductance. The proposed SPTs were applied in a high power pulse modulator based on a helical Blumlein pulse forming line (HBPFL). When the SPT played as a pulse transformer, the HBPFL can be charged to 200 kV. When the SPT played as a main magnetic switch of the HBPFL, it helped to form a quasi-square voltage pulse with amplitude of 180 kV，pulse duration of 130 ns, rise time of 60 ns.
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MOPRI005	The AWAKE Experimental Facility at CERN	electron, proton, plasma, laser	582
	E. Gschwendtner, T. Bohl, C. Bracco, A.C. Butterworth, S. Cipiccia, S. Döbert, V. Fedosseev, E. Feldbaumer, C. Heßler, W. Höfle, M. Martyanov, M. Meddahi, J.A. Osborne, A. Pardons, A.V. Petrenko, H. Vincke CERN, Geneva, Switzerland
	AWAKE, an Advanced Wakefield Experiment is launched at CERN to verify the proton driven plasma wakefield acceleration concept. Proton bunches at 400 GeV/c will be extracted from the CERN SPS and sent along a 750m long proton line to the plasma cell, a Rubidium vapour source, where the proton beam drives wakefields reaching accelerating gradients at the order of gigavolt per meter. A high power laser pulse will co-propagate within the proton bunch creating the plasma by ionizing the (initially) neutral gas. An electron beam will be injected into the plasma cell to probe the accelerating wakefield. The AWAKE experiment will be installed in the CNGS facility. First proton beam to the plasma cell is expected by end 2016. The design of the experimental area and the integration of the new beam-lines as well as the experimental equipment will be shown. The needed modifications of the infrastructure in the facility will be presented.
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MOPRI016	Hydrogen and Cesium Monitor for H⁻ Magnetron Sources	plasma, cathode, ion, controls	617
	C.-Y. Tan, D.S. Bollinger, B.A. Schupbach, K. Seiya Fermilab, Batavia, Illinois, USA
	Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energ The relative concentration of cesium to hydrogen in the plasma of a H⁻ magnetron source is an important parameter for reliable operations. If there is too much cesium, the surfaces of the source become contaminated with it and sparking occurs. If there is too little cesium then the plasma cannot be sustained. In order to monitor these two elements, a spectrometer has been built and installed on a test and operating source that looks at the plasma. It is hypothesized that the concentration of each element in the plasma is proportional to the intensity of their spectral lines.
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MOPRI018	Influence of Growth Method on K3Sb Photocathode Structure and Performance	cathode, synchrotron, scattering, emittance	624
	S.G. Schubert, T. Kamps, M. Schmeißer HZB, Berlin, Germany K. Attenkofer, J. Smedley BNL, Upton, Long Island, New York, USA E.M. Muller SBU, Stony Brook, New York, USA H.A. Padmore, J.J. Wong LBNL, Berkeley, California, USA M. Ruiz-Osés Stony Brook University, Stony Brook, USA J. Xie ANL, Argonne, Illinois, USA
	Funding: Supported by Director, OoS., OBES of US DOE, Contract DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNTI0013, DE-SC0005713, germ. BMBF, Land Berlin, Helmholtz Assoc.. Use of CHESS by NSF, DMR-0936384. Future high brightness photoelectron sources delivering >100 mA average current call for a new generation of photocathodes. Materials which qualify for this purpose should exhibit low intrinsic emittance, long lifetime and high quantum efficiency at photon energies in the visible range of the spectrum to relax drive laser requirements. A combination of material science techniques are used to determine the influence of the growth parameters on structure and performance of photocathode materials . In-situ XRR, XRD and GiSAXS measurements were performed at the synchrotron radiation sources, NSLS and CHESS. The growth of K3Sb, a precursor material of one of the prime candidates CsK2Sb, was studied intensively to optimize this intermediate growth step in terms of quantum efficiency and roughness. Three methods, a “layer by layer” type and a “super-lattice type” were examined. K3Sb exists in two crystallographic phases, namely cubic and hexagonal. The cubic phase exhibits a higher quantum efficiency at 532 nm than the hexagonal phase and transforms more easily into CsK2Sb, tuning this phase is believed to be one of the key parameters in the CsK2Sb growth.
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MOPRI021	Laser Systems Generating Short Polarized Electron Bunches at the S-DALINAC	laser, electron, operation, cathode	633
	M. Espig, J. Enders, Y. Fritzsche, A. Kaiser, M. Wagner TU Darmstadt, Darmstadt, Germany
	Funding: Supported by DFG within CRC634 and by the state of Hesse through the LOEWE center HIC for FAIR. The source of polarized electrons at the superconducting Darmstadt electron linear accelerator S-DALINAC uses photo-emission from strained-layer superlattice-GaAs and bulk-GaAs photocathodes. This system is driven by either 3 GHz gain-switched diode lasers or a short-pulse Ti:Sapphire laser system. Highly polarized electrons are generated with laser light at 780 nm, while blue laser light is used for unpolarized high-current experiments. We present the existing pulsed laser systems and the planned developments for the diode laser system, including, e.g., impedance matching of the diode lasers, gain switching with short electrical pulses and pulsing with a Mach-Zehnder modulator. The pulsed operation is aimed at generating short electron bunches (< 50 ps) at the S-DALINAC with variable repetition rates from some MHz to 3 GHz.
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MOPRI031	Multi-alkali Photocathode R&D	cathode, laser, electron, vacuum	661
	Y. Seimiya, M. Kuriki, N. Yamamoto HU/AdSM, Higashi-Hiroshima, Japan
	Multi-alkali photocathode has excellent features: high quantum efficiency, long lifetime, and excitation by visible light, for example green laser. The multi-alkali cathode is considered to be one of the best candidate of the high brightness electron source of the advanced electron accelerator such as ERL and FEL. We study conditions of multi-alkali evaporations, such as thicknesses, substrate temperature, and evaporation rate, and examine the cathode performances, such as quantum efficiency and extractable current density. Antimony (Sb), potassium (K), and cesium (Cs) are used in our evaporation system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI031
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MOPRI032	A STUDY ON ROBUSTNESS OF NEA-GAAS PHOTOCATHODE*	cathode, electron, vacuum, emittance	664
	K. Uchida, R. Kaku, M. Kuriki, K. Miyoshi, Y. Seimiya, N. Yamamoto HU/AdSM, Higashi-Hiroshima, Japan H. Iijima Tokyo University of Science, Tokyo, Japan
	Electron source is one of the most important component in the advanced linac. There is a strong demand on the high performance cathode, such as small emittance, high brightness, and short pulse generation. NEA-GaAs photo-cathode is a unique technology which is capable for generating highly polarized and extremely low emittance beam. Quantum efficiency (QE) of the cathode is high in near IR region, so it is favor to generate a high current density beam. These advantages are originated to the Negative Electron Affinity (NEA) surface, but it is fragile so the operational lifetime is limited. A study on a robust NEA surface cathode is reported. According to the hetero-junction model, Cs-Te thin film deposited on GaAs forms a robust NEA surface. We performed the Cs-Te evaporation experiment on a clean GaAs cathode and measured QE spectra. We found that some sample showed a high quantum efficiency up to 900nm wavelength which strongly suggested a NEA surface formation.
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MOPRI038	Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment.	electron, ion, site, vacuum	682
	K. Hayase, R. Chiba, H. Iijima, Y. Inagaki, T. Meguro Tokyo University of Science, Tokyo, Japan
	Negative electron affinity (NEA) surface are formed by deposition of Cs atoms on p-GaAs, and the drastic increase in the electron emission is observed by the Yo-Yo method. It is necessary to remove oxide layers of GaAs surface for the NEA surface formation, therefore the thermal treatment was carried out prior to the NEA activation. We have discussed the quantum efficiency (QE) with different thermal history. GaAs surfaces cleaned with organic solvents were thermally treated with the temperature sequence of 773K, 823K, and 723K. The NEA activation was carried out at every temperature. The QE less than 1% was obtained with 773K of treatment temperature on the initial surface. Then the QE increased at 10% after treatment at higher 823K. Successive increase of the QE to 13% was observed with a reduced temperature treatment at 723K. The GaAs surfaces after the thermal treatment in the high temperature region with the NEA activation are different from the as-cleaned-GaAs surfaces probably in stoichiometry or morphology due to desorption of As and Ga atoms. The role of thermal treatment with NEA activation is the modification of surface properties important for elevating the QE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI038
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MOPRI051	Measurements of the Longitudinal Energy Distribution of Low Energy Electrons	cathode, electron, laser, simulation	720
	L.J. Devlin, O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom L.J. Devlin, O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Work supported by STFC Cockcroft Core Grant No.ST/G008248/1 The Transverse Energy Spread Spectrometer (TESS) is an ASTeC experiment designed to measure the energy of electrons from different cathode materials. It is a dedicated test stand for future light sources. A full particle tracking code has been developed in the QUASAR Group, which simulates particle trajectories through TESS. Using this code it is possible to simulate different operational conditions of the experiment and cathode materials. The simulation results can then be benchmarked against experimental data to test the validity of the emission and beam transport model. Within this paper, results from simulation studies are presented and compared against experimental data as a collaboration within the Cockcroft Institute between ASTeC and the QUASAR Group for the case of measuring the longitudinal velocity distribution of electrons emitted from a gallium arsenide cathode using a grid structure as an energy filter.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI051
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MOPRI053	High Repetition Rate Ultrafast Electron Diffraction at LBNL	electron, emittance, gun, laser	724
	D. Filippetto, M. Mellado Munoz, H.J. Qian, F. Sannibale, W. Wan, R.P. Wells, M.S. Zolotorev LBNL, Berkeley, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231" Here we propose to use the APEX photo-gun as novel source for time-resolved electron diffraction studies. The electron source has been designed, built and successfully tested at LBNL. It combines a high accelerating field needed for bright beams, MeV electron energy essential for time resolution in gas-phase experiments and studies of bulk processes, together with continuous (CW) operations. Ultra-short electron pulses can be delivered with a maximum repetition rate of 186 MHz, enabling new science to be studied. We report the design of a dedicated electron diffraction beamline that fits in the space constraints of the APEX tunnel. Simulations of beam properties have been carried out with a genetic optimizer, showing 100 fs time resolution. Beam jitters in energy, time and position are currently being characterized, and a mitigation strategy via fast feedback loops is discussed.
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MOPRI065	The Development of a Low Energy Neutron Accelerator for Rebunching Pulsed Neutrons	neutron, impedance, controls, focusing	751
	S. Imajo Kyoto University, Kyoto, Japan Y. Arimoto KEK, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan M. Kitaguchi Kyoto University, Research Reactor Institute, Osaka, Japan Y. Seki RIKEN Nishina Center, Wako, Japan H.M. Shimizu Nagoya University, Nagoya, Japan S. Yamashita ICEPP, Tokyo, Japan T. Yoshioka Kyushu University, Fukuoka, Japan
	Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF in a gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons at the target, however, the pulsed neutrons with spread velocities are diffused in guide tubes during long beam transport. It is necessary to concentrate UCN temporally upon the bottle by controlling their velocities for nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured specification of the new rebuncher is described in detail.
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MOPRI066	External Neutron Source for Research Reactor Based on Linear Accelerator and Beryllium Target	target, neutron, electron, radiation	754
	V.P. Struev, A.A. Bogdanov, A.G. Golovkina, Yu.V. Kiselev, I.V. Kudinovich, A.I. Laikin, S.M. Rubanov KSRC, St. Petersburg, Russia A.G. Golovkina, I.V. Kudinovich St. Petersburg State University, St. Petersburg, Russia
	Nuclear research reactor “U-3” of Krylov State Research Center was operated as an experimental tool to study a radiation shield of small nuclear power plants, radiation resistance of its equipment including control system elements. Reactor thermal output power is 50 kW. Currently reactor modernization is being carried out, in the framework of which neutron lighting system that consists of a linear electron accelerator “UEL-10D” (10 MeV) and a beryllium target is implemented. At the present time the neutron yield from the target experiments are going on, some obtained experimental results are presented. Optimal target sizes with a view to neutron yield were defined.
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MOPRI067	Beam Cooling Systems and Activities at GSI and FAIR	electron, ion, pick-up, antiproton	757
	C. Dimopoulou GSI, Darmstadt, Germany
	Efficient and versatile beam cooling (electron and stochastic cooling) has been an indispensable ingredient for beam preparation and physics experiments at the GSI accelerator complex. The hot secondary beams emerging from the production targets can hardly be used, unless they are cooled. Beam stacking of low-abundant species relies on cooling. Cooling enables high-precision experiments with stored beams, counteracts the heating during internal target operation and controls decelerated beams. New challenges lie ahead within the FAIR project like (i) the ongoing integration downstream of the ESR of the low-energy CRYRING with its electron cooler, (ii) the developments for the demanding CR stochastic cooling system, (iii) the stacking scenarios with RF and stochastic cooling in the HESR/RESR. The function and parameters of the existing and future beam cooling systems are summarized. We report on the latest hardware developments as well as on improvements of the controls and operation software. Recent highlights and results from beam manipulations with cooling at GSI are shown. In focus are those benchmarking experiments, where the concepts for the new FAIR systems are verified. C. Dimopoulou on behalf of the GSI Beam Cooling Department, of the GSI Stored Beams Division and of the FAIR Project Team.
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MOPRI070	2MeV Electron Cooler for COSY and HESR – First Results	electron, proton, operation, heavy-ion	765
	V. Kamerdzhiev, U. Bechstedt, F.M. Esser, O. Felden, R. Gebel, A.J. Halama, F. Klehr, G. Langenberg, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, K. Reimers, M. Retzlaff, R. Stassen, H. Stockhorst, R. Tölle FZJ, Jülich, Germany N. Alinovskiy, T.V. Bedareva, E.A. Bekhtenev, O.V. Belikov, V.N. Bocharov, V.V. Borodich, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, V.G. Cheskidov, B.A. Dovzhenko, A.I. Erokhin, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.K. Gosteev, I.A. Gusev, G.V. Karpov, Y.I. Koisin, M.N. Kondaurov, V.R. Kozak, A.M. Kruchkov, A.D. Lisitsyn, I.A. Lopatkin, V.R. Mamkin, A.S. Medvedko, V.M. Panasyuk, V.V. Parkhomchuk, I.V. Poletaev, V.A. Polukhin, A.Yu. Protopopov, D.N. Pureskin, A.A. Putmakov, V.B. Reva, P.A. Selivanov, E.P. Semenov, D.V. Senkov, D.N. Skorobogatov, N.P. Zapiatkin BINP SB RAS, Novosibirsk, Russia J. Dietrich HIM, Mainz, Germany T. Katayama Nihon University, Narashino, Chiba, Japan L.J. Mao IMP, Lanzhou, People's Republic of China
	The 2 MeV electron cooler was installed in the COSY ring in the spring 2013. The new system enables electron cooling in the whole energy range of COSY. The electron beam is guided by longitudinal magnetic field all the way from the electron gun to the collector. This well-proven optics scheme was chosen because of the wide electron energy range of 0.025-2 MeV. The electrostatic accelerator consists of 33 individual sections of identical design. Electrical power to each section is provided by a cascade transformer. Electron beam commissioning and first studies using proton and deuteron beams were carried out. Electron cooling of proton beam up to 1662 MeV kinetic energy was demonstrated. Maximum electron beam energy achieved so far amounted to 1.25 MeV. Voltage up to 1.4 MV was demonstrated. The cooler was operated with electron current up to 0.5 A. The paper provides insights into the recent progress in high energy electron cooling at COSY and perspectives for the HESR ring at FAIR.
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MOPRI072	Simulation Study of Heavy Ion Beam Injection and Acceleration in the HESR for Internal Target Experiments with Cooling	target, ion, acceleration, cavity	768
	H. Stockhorst, B. Lorentz, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany T. Katayama Nihon University, Narashino, Chiba, Japan
	Recently, the feature of ion beam injection, storage and acceleration assisted by a barrier bucket and cooling has been investigated in the High Energy Storage Ring HESR at the new facility FAIR which will be built at the GSI Darmstadt. A bare uranium beam is injected from the collector ring CR into the HESR at 740 MeV/u. The simulation studies are now improved to include different injection schemes applying either the barrier cavity or the h = 1 cavity in the HESR. It is outlined how the new 2.5 MeV electron cooler at COSY Jülich or stochastic cooling can support the injection mechanism. The beam preparation for an internal target experiment with cooling is outlined. The acceleration of the ion beam is extended to 5 GeV/u under the mandatory condition of the available cavity voltages and the maximum magnetic field ramp rate in the HESR. The flexibility of the HESR ring lattice is utilized to avoid transition energy crossing during ramping up to 5 GeV/u and to adjust the rings’ frequency slip factor for optimal stochastic cooling. The cooling simulations include the beam-target interaction due to a hydrogen target. H. Stockhorst et al., MOPEA018, IPAC13
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MOPRI078	High Power Cyclotrons for Neutrino Experiments	cyclotron, extraction, proton, vacuum	788
	D. Winklehner, J.R. Alonso, W.A. Barletta, A. Calanna, J.M. Conrad MIT, Cambridge, Massachusetts, USA A. Adelmann PSI, Villigen PSI, Switzerland L. Calabretta, D. Campo INFN/LNS, Catania, Italy M. Shaevitz Columbia University, New York, USA J.J. Yang CIAE, Beijing, People's Republic of China
	DAEδALUS* and IsoDAR** experiments needs large intense neutrino fluxes to investigate respectively the CP-Violation in the neutrino sector and the existence of sterile neutrino. DAEδALUS requires three neutrino sources driven by proton beams of ~800 MeV at powers of several megawatts placed at distances of 1.5, 8 and 20 km from the detector. Two cyclotrons working in cascade are chosen to deliver these high power beams. The first cyclotron accelerates the H²⁺ ions beam up to 60 MeV/amu. The beam is then extracted with an electrostatic deflector and reaccelerated up to 800 MeV/amu through a superconducting ring cyclotron. The acceleration of H²⁺ has two advantages: it reduces the space charge effect along the injection and acceleration inside the first cyclotron and allows the extraction of the beam from the last accelerator using a stripper foil. The injector cyclotron can be used in stand-alone mode to drive the IsoDAR experiment, which needs the accelerator placed near an underground neutrino detector. The design and the results of beam dynamic simulations will be shown. the results of preliminary injection and acceleration tests into a cyclotron test bench will be presented. * J. Alonso et al., arXiv:1006.0260[physics.ins-det] (2010). ** A. Bungau et al., Phys. Rev. Lett. 109 141802 (2012).
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MOPRI081	Beam Simulation for Improved Operation of Cyclotron NIRS-930	simulation, cyclotron, injection, extraction	797
	M. Nakao, S. Hojo, K. Katagiri, A. Noda, K. Noda, A. Sugiura NIRS, Chiba-shi, Japan A. Goto Yamagata University, Yamagata, Japan T. Honma, A.K. Komiyama, T. Okada, Y. Takahashi AEC, Chiba, Japan V.L. Smirnov, S.B. Vorozhtsov JINR, Dubna, Moscow Region, Russia
	Beam simulation using SNOP* code has been performed for the cyclotron NIRS-930 at NIRS in order to study beam dynamics in a cyclotron and to improve beam intensity. Each electric or magnetic field (main coil, trim coils, harmonic coils, magnetic channel, gradient corrector, grazer lens, dee electrode, inflector) were calculated by OPERA-3d, and simulated injection, acceleration, and extraction. The simulation of proton with 30 MeV extracting energy with harmonic 1 was already performed and well simulated RF phase and extraction efficiency*. Then we tried to apply SNOP to 18 MeV protons with harmonic 2. We first formed isochronous magnetic field with main and trim coils for simulating single particle. Next we optimized electric deflector and magnetic channel in order to maximize extracted particles simulating the bunch of particles. Beam loss of the simulation was compared to the experiment. And then we are optimizing position and rotation of inflector and position of puller to improve injection. We intend to apply optimized simulation parameter to actual cyclotron operation to improve beam intensity and quality. V.L. Smirnov, S.B. Vorozhtsov, Proc. of RUPAC2012 TUPPB008 325 (2012) ** V.L. Smirnov et al., Proc. of IPAC2012 292 (2012)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI081
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MOPRI088	Beam Transport Experiments Using Gabor Lenses	electron, beam-transport, focusing, space-charge	818
	K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger IAP, Frankfurt am Main, Germany
	A prototype Gabor lens has successfully been tested at the GSI High Current Test Injector (HOSTI). The experiments comprised the investigation of an emittance dominated and a space-charge dominated beam transport. In particular, the high-current measurements represent a necessary step towards evaluating the focusing performance of the lens and to gain experience in a real accelerator environment. Besides the evaluation of the technical feasibility, the behavior of the electron cloud was characterized by the parameter analysis of the confined non-neutral plasma during beam transport measurements as well as subsequently performed diagnostic experiments. This contribution will present experimental results as well as numerical studies on an improved Gabor lens design for the possible application at the GSI High Current Injector (HSI) in the context of an upgrade program for FAIR. K. Schulte et al., Proc. of IPAC'13, Shanghai, China, 2013, THPWO021 **L. Dahl, Proc. of HIAT’09, Venice, Italy, 2009, FR-01
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MOPRI101	Field Simulations and Mechanical Implementation of Electrostatic Elements for the ELENA Transfer Lines	quadrupole, ion, proton, vacuum	855
	D. Barna University of Tokyo, Tokyo, Japan W. Bartmann, J. Borburgh, C. Carli, G. Vanbavinckhove CERN, Geneva, Switzerland
	The Antiproton Decelerator (AD) complex at CERN will be extended by an extra low energy anti-proton ring (ELENA) further decelerating the anti-protons thus improving their trapping. The kinetic energy of 100 keV at ELENA extraction facilitates the use of electrostatic transfer lines to the experiments. The mechanical implementation of the electrostatic devices are presented with focus on their alignment, bakeout compatibility, ultra-high vacuum compatibility and polarity switching. Field optimisations for an electrostatic crossing device of three beam lines are shown.
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TUOAA03	Extra Low ENergy Antiproton ring ELENA: From the Conception to the Implementation Phase	antiproton, electron, emittance, extraction	910
	C. Carli, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, T. Eriksson, S. Maury, S. Pasinelli, G. Tranquille CERN, Geneva, Switzerland W. Oelert Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany
	The Extra Low Energy Antiproton ring (ELENA) is a CERN project aiming at constructing a small 30 m circumference synchrotron to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The ELENA design is now well advanced and the project is moving to the implementation phase. Component design and construction are taking place at present for installation foreseen during the second half of 2015 and beginning of 2016 followed by ring commissioning until the end of 2016. New electrostatic transfer lines to the experiments will be installed and commissioned during the first half of 2017 followed by the first physics operation with ELENA. Basic limitations like Intra Beam Scattering limiting the emittances obtained under electron cooling and direct space charge effects will be reviewed and the status of the project will be reported.
	Slides TUOAA03 [4.963 MB]
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TUOCA03	Production of Quasi-monochromatic GeV Photons by Compton Scattering using Undulator X-ray Radiation at SPring-8	photon, electron, undulator, laser	941
	H. Ohkuma, A. Mochihashi, M. Oishi, S. Suzuki, K. Tamura JASRI/SPring-8, Hyogo-ken, Japan N. Muramatsu, H. Shimizu Tohoku University, Research Center for Electron Photon Science, Sendai, Japan T. Nakano RCNP, Osaka, Japan
	Funding: This work is supported by JSPS KAKENHI (Grant-in-Aid for Scientific Research) Grant Number 24241035. Backward Compton scattering (BCS) of X-ray photons emitted by undulator and reflected back by a single crystal from the electron beam can produce a quasi-monochromatic gamma-ray beam up to an energy very close to the electron beam energy. The SPring-8 beam diagnostics beamline (BL05SS) is used to inject a reflected undulator X-ray radiation against 8 GeV stored electron beam and to extract a quasi-monochromatic 8 GeV gamma-ray produced by BCS. BL05SS has conditions to do a pilot experiment to obtain the gamma-ray beam using BCS of X-ray photons from existing undulator. Experimental setup including a Bragg mirror system is now under construction. Preliminary reflectivity measurement of a silicon Bragg mirror using around 10keV photons has been done. Status of the experimental preparation and the future outlook is presented.
	Slides TUOCA03 [1.889 MB]
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TUOBB02	Demonstration of Gigavolt-per-meter Accelerating Gradients using Cylindrical Dielectric-lined Waveguides	wakefield, radiation, electron, laser	965
	B.D. O'Shea, G. Andonian, K.L. Fitzmorris, J. Harrison, J.B. Rosenzweig, O. Williams UCLA, Los Angeles, California, USA M.J. Hogan, V. Yakimenko SLAC, Menlo Park, California, USA
	We present here the results of measurements made showing ~1 GV/m accelerating fields using a hollow dielectric-lined waveguide. The results are comprised of measurement of the energy loss of a high charge (~3 nC) ultrashort (~200 fs), ultra relativistic (20 GeV) beam and concomitant auto-correlation interferometeric techniques to obtain the frequency content of simultaneously generated coherent Cherenkov radiation (CCR). Experiments were conducted at the Facility for Advanced aCcelerator Experimental Tests (FACET) at the SLAC National Laboratory using metal-coated sub-millimeter diameter, ten-centimeter long fused silica tubes. We present simulation and theoretical results in support of the conclusions reached through experiment. These results build on previous work to provide a path towards high gradient accelerating structures for use in compact accelerator schemes, future linear colliders and free-electron lasers.
	Slides TUOBB02 [2.349 MB]
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TUPRO005	Status of the NICA Project at JINR	ion, collider, booster, electron	1003
	G.V. Trubnikov, N.N. Agapov, A.V. Butenko, D.E. Donets, E.D. Donets, E.E. Donets, A.V. Eliseev, E.V. Gorbachev, A. Govorov, E.V. Ivanov, V. Karpinsky, V.D. Kekelidze, H.G. Khodzhibagiyan, S.A. Kostromin, A.D. Kovalenko, O.S. Kozlov, V.A. Matveev, I.N. Meshkov, V.A. Mikhailov, V. Monchinsky, N. Shurkhno, A.O. Sidorin, I. Slepnev, V. Slepnev, A.V. Smirnov, A. Sorin, N.D. Topilin, A. Tuzikov, V. Volkov JINR, Dubna, Moscow Region, Russia O.I. Brovko, A.V. Philippov, N.V. Semin JINR/VBLHEP, Moscow, Russia
	Nuclotron-based Ion Collider fAcility (NICA) is the new accelerator complex being constructed in Joint Institute for Nuclear Research. General goal of the project is to provide experimental study of hot and dense strongly interacting QCD matter. The development of NICA injection complex is actively performed. Construction of new 3.2 MeV/u heavy-ion linear accelerator (HILac) is now under way in Germany. Construction of booster has been started. In this report the present status of the NICA accelerator complex are presented.
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TUPRO019	Localisation of Beam Offset Jitter Sources at ATF2	quadrupole, simulation, EPICS, damping	1049
	J. Pfingstner, H. Garcia, A. Latina, M. Patecki, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	For the commissioning and operation of modern particle accelerators, automated error detection and diagnostics methods are becoming increasingly important. In this paper, we present two such methods, which are capable of localising sources of beam offset jitter with a combination of correlation studies and so called degree of freedom plots. The methods were applied to the ATF2 beam line at KEK, where one of the major goals is the reduction of the beam offset jitter. Results of this localisation are shown in this paper. A big advantage of the presented method is its high robustness especially to varying optics parameters. Therefore, we believe that the developed beam offset jitter localisation methods can be easily applied to other accelerators.
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TUPRO021	Preliminary Study of Risks and Failure Scenarios for the High Luminosity Experiments in HL-LHC	luminosity, simulation, detector, cavity	1055
	F. Bouly LPSC, Grenoble Cedex, France R. Alemany-Fernández, H. Burkhardt, D. Wollmann CERN, Geneva, Switzerland B. Yee-Rendón CINVESTAV, Mexico City, Mexico
	For the HL-LHC it is planned to basically double the diameter of the triplet quadruple magnets around the high luminosity insertions of the LHC. The high luminosity experiments ATLAS and CMS would like to keep a small central chamber radius close the interaction point. In the context of collider-experiment studies for the high-luminosity upgrade of the LHC, we present a first study of the possible consequences of these changes for the experimental running conditions based on detailed simulations with tracking. We have started to implement crab cavity failures and discuss first results from these simulations.
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TUPRO022	Implementation of Luminosity Leveling by Betatron Function Adjustment at the LHC Interaction Points	luminosity, optics, operation, betatron	1058
	J. Wenninger, A.A. Gorzawski CERN, Geneva, Switzerland
	Growing expectations for integrated luminosity during upcoming LHC runs introduce new challenges for LHC beam operation in the scope of online luminosity control. Because some LHC experiments are limited in the maximum event rates, their luminosity is leveled to a constant value. Various techniques may be used for luminosity leveling, changing the betatron function at the interaction point is one of them. This paper explains the main operational requirements of a betatron function leveling scheme for the upcoming LHC run. Issues concerning the beam optics, orbits and collimator settings are discussed. The proposed architecture for control system integration will be discussed. A few operational scenarios with different beam configurations foreseen for the next LHC run will be presented.
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TUPRO023	Beam-beam Effects in Different Luminosity Levelling Scenarios for the LHC	luminosity, dynamic-aperture, beam-beam-effects, emittance	1061
	X. Buffat, D. Banfi, G.R. Coombs EPFL, Lausanne, Switzerland W. Herr, T. Pieloni CERN, Geneva, Switzerland
	Adjusting luminosity and optimizing the luminous region in each interaction point of the LHC according to the experiments needs has become a requirement to maximize the efficiency of the different detectors. Several techniques are envisaged, most importantly by varying β* or a transverse offset at the interaction point. Coherent and incoherent stability in the presence of beam-beam effects will be discussed in realistic luminosity levelling scenarios for the LHC.
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TUPRO031	RHIC Performance during the 7.5 GeV Low Energy Run in FY 2014	luminosity, ion, target, injection	1087
	C. Montag, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, S. Nemesure, J. Piacentino, P.H. Pile, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, P. Thieberger, J.E. Tuozzolo, M. Wilinski, K. Yip, A. Zaltsman, K. Zeno, W. Zhang 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. As the last missing step in phase 1 of the beam energy scan (BES-I), aimed at the search for the critical point in the QCD phase diagram, RHIC collided gold ions at a beam energy of 7.3 GeV/nucleon during the FY 2014 run. While this particular energy is close to the nominal RHIC injection energy of 9.8 GeV/nucleon, it is nevertheless challenging because it happens to be close to the AGS transition energy, which makes longitudinal beam dynamics during transfer from the AGS to RHIC difficult. We report on machine performance, obstacles and solutions during the FY 2014 low energy run.
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TUPRO034	Beam-beam Interaction in the Asymmetric Energy Gold-gold Collision in RHIC	simulation, ion, emittance, collider	1093
	Y. Luo, M. Blaskiewicz, M.R. Costanzo, W. Fischer, X. Gu, V.H. Ranjbar, S.M. White 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. In this article, we study the beam-beam interaction in the possible future gold-gold collision with different particle energies in the Relativistic Heavy Ion Collider (RHIC). With different particle energies, the center-of-mass of collision is moving in the longitudinal direction during collision. Since the RF harmonic numbers are different for the two RHIC rings, bunches collide in 110 turns followed by 10 turns without collision. In this study, the stability of particles and the beam emittance growth are calculated through numeric simulations based on a 6-D weak-strong beam-beam interaction model.
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TUPRO042	Ion Optics of the HESR Storage Ring at FAIR for Operation with Heavy Ions	ion, heavy-ion, target, optics	1117
	O.A. Kovalenko, A. Dolinskyy, T. Katayama, Yu.A. Litvinov, T. Stöhlker GSI, Darmstadt, Germany B. Lorentz, R. Maier, D. Prasuhn, H. Stockhorst FZJ, Jülich, Germany
	The High Energy Storage Ring (HESR) of the FAIR project is primarily designed for internal target experiments with stored and cooled antiprotons, which is the main objective of the PANDA collaboration. However, the HESR storage ring also appears to have remarkable properties to carry out physics experiments with heavy ions. In this paper a new ion optical design allowing the heavy ion operation mode of the HESR is presented. The main goal was to provide an optics which meets the requirements of the future experiments with heavy ion beams. Closed orbit correction, dynamic aperture as well as other characteristics of beam dynamics of the ion optical setup are under analysis in this study.
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TUPRO045	Simulation Studies on Beam Injection into a Figure-8 Type Storage Ring	simulation, injection, kicker, storage-ring	1126
	M. Droba, A. Ates, O. Meusel, H. Niebuhr, D. Noll, U. Ratzinger, J.F. Wagner IAP, Frankfurt am Main, Germany
	The proposed figure-8 storage ring at Frankfurt University [1, 2] is based on longitudinal guiding magnetic fields and will have special features with respect to the beam dynamics. A crucial part of the ring is the injection section, where the low energy beams have to cross an area of steeply rising field – up to B = 6 T into the main ring field. An optimized magnetic channel is designed to bring the injected beam close enough to the magnetic ring flux. An ExB kicker is needed to move the injected beam from the injection channel to the main magnetic field flux allowing multi turn injection. Simulation studies concentrate on this part and will be presented, results will be discussed. A comparison with simulations for prepared scaled down experiments with existing room temperature toroids will be done.
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TUPRO099	Development of a Method for Measuring the Radial Component of the Magnetic Field in AVF Cyclotrons	cyclotron, simulation, proton, extraction	1274
	N.A. Morozov, G.A. Karamysheva, S.A. Kostromin, E. Samsonov, N.G. Shakun, E. Syresin JINR, Dubna, Moscow Region, Russia
	In AVF cyclotrons the median plane of the magnetic field rather often does not coincide with the mid-plane of their magnetic system. To measure the radial component of the magnetic field, equipment based on search coils is developed and used to correct the median plane of the magnetic field. The equipment for Br mapping is described. The Br mapping and shimming results are presented for two proton therapy IBA C230 cyclotrons.
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TUPRO117	Magnet Design for the SNS Laser Stripping Experiment	laser, electron, ion, operation	1328
	A.V. Aleksandrov, A.A. Menshov ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation. The first step in the three-step laser assisted H⁻ beam stripping for charge exchange injection is to remove one electron in a strong magnetic field. In order to preserve the beam emittance for the subsequent laser induced stripping of the second electron the magnetic field has to have large gradient of about 40 T/m along the beam trajectory. The required magnetic field strength for stripping 1GeV H⁻ beam is 1.2 T in 29 mm aperture. In order to allow for undisturbed passage of high power beam during the nominal SNS operation the stripping magnet made of permanent magnet material resides in vacuum chamber and can move in and out of the beam line. This presentation describes requirements and design and the magnetic field calculation results for a stripping magnet for the Laser Stripping Experiment at SNS.
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TUPME006	Considerations for a QD0 with Hybrid Technology in ILC	alignment, quadrupole, luminosity, collider	1346
	M. Modena, A.V. Aloev, H. Garcia, L. Gatignon, R. Tomás CERN, Geneva, Switzerland
	The baseline design of the QD0 magnet for ILC, the International Linear Collider, is a very compact superconducting quadrupole (coil-dominated magnet). A prototype of this quadrupole is under construction at Brookhaven National Laboratory (USA). In CLIC, the Compact Linear Collider under study at CERN, we are studying another conceptual solution for the QD0. This is due to two main reasons: all the magnets of the Beam Delivery System will need to be stabilized in the nano-meter range and extremely tight alignment tolerances are required. The proposed solution, now baseline for CLIC, is a room temperature hybrid quadrupole based on electromagnetic coils and permanent magnet blocks (iron-dominated magnet). In this paper we present a conceptual design for a hybrid solution studied and adapted also to the ILC project. A special super-ferric solution is proposed to make the cross section compatible with the experiments layout. This design matches the compactness requirement with the advantages of stability and alignment precision, aspects critical also for ILC in order to achieve the design luminosity. Final Focus optics design considerations for this solution are also presented.
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TUPME010	The Physics Programme of next MICE Step IV	emittance, scattering, factory, simulation	1361
	J.C. Nugent University of Glasgow, Glasgow, United Kingdom V.C. Palladino INFN-Napoli, Napoli, Italy
	Funding: DOE, NSF, STFC, INFN, CHIPP and several others The International Muon Ionization Cooling Experiment is progressing towards a full demonstration of the feasibility of ionization cooling technology decisive for neutrino physics and muon colliders. Step IV should provide the first precise measurements of emittances and first evidence of cooling. The components required for Step IV, including spectrometer solenoids, muon trackers and absorber-FC (focus coil) modules have been assembled with data collection expected in 2015. The physics programme of this Step will be described in detail, with LiH and a few other promising absorber materials of different shapes. Abstract presented by the chair of the speaker bureau of the MICE collaboration, that would next select a MICE member to prepare and present the poster
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TUPME011	The Status of the Construction of MICE Step IV	solenoid, emittance, coupling, cavity	1364
	P. Snopok IIT, Chicago, Illinois, USA E. Overton Sheffield University, Sheffield, United Kingdom
	Funding: DOE, NSF, STFC, INFN, CHIPP and several others The International Muon Ionization Cooling Experiment will provide the demonstration ionization cooling. The experiment is being built in a series of Steps. Step IV, which consists of a tracking spectrometer upstream and downstream of an absorber/focus-coil (AFC) module will be completed in early in 2015. In this configuration, the emittance of the muon beam upstream and downstream of the absorber will be measured precisely allowing the emittance reduction and the factors that determine the ionization cooling effect to be studied in detail. The AFC module is a 22 liter volume of liquid hydrogen placed inside a superconducting focusing coil. The properties of lithium hydride, and possibly other absorber materials, will also be studied. All the components of Step IV have been manufactured and integration of the experiment in the MICE Hall at the Rutherford Appleton Laboratory is underway. A full study of ionization cooling will be carried out with Step V, which will include a short 201 MHz linac module in which beam transport is achieved with a superconducting “coupling coil”. The status of the preparation of the components of Step V of the experiment will be described briefly.
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TUPME013	Thermo-mechanical Tests for the CLIC Two-beam Module Study	operation, alignment, vacuum, linac	1370
	A. Xydou, G. Riddone, A.L. Vamvakas CERN, Geneva, Switzerland E. Daskalaki NTUA, Athens, Greece
	The luminosity goal of CLIC requires micron level precision with respect to the alignment of the components on its two-meter long modules, composing the two main linacs. The power dissipated inside the module components introduces mechanical deformations affecting their alignment and therefore the resulting machine performance. Several two-beam prototype modules must be assembled to extensively measure their thermo-mechanical behavior under different operation modes. In parallel, the real environmental conditions present in the CLIC tunnel should be studied. The air conditioning and ventilation system providing specified air temperature and flow has been installed in the dedicated laboratory. The power dissipation occurring in the modules is being reproduced by the electrical heaters inserted inside the RF structure mock-ups and the quadrupoles. The efficiency of the cooling systems is being verified and the alignment of module components is monitored. The measurement results will be compared to finite element analysis model and propagated back to engineering design. Finally, simulation of the most possible CLIC machine cycles is accomplished and preliminary results are analysed.
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TUPME027	Analysis of the Electron Cloud Observations with 25 ns Bunch Spacing at the LHC	dipole, emittance, injection, quadrupole	1410
	G. Iadarola Naples University Federico II, Science and Technology Pole, Napoli, Italy G. Arduini, V. Baglin, D. Banfi, H. Bartosik, S.D. Claudet, C.O. Domínguez, J. F. Esteban Müller, G. Iadarola, T. Pieloni, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, C. Zannini, F. Zimmermann CERN, Geneva, Switzerland
	Electron Cloud (EC) effects have been identified as a major performance limitation for the Large Hadron Collider (LHC) when operating with the nominal bunch spacing of 25 ns. During the LHC Run 1 (2010 - 2013) the luminosity production mainly used beams with 50 ns spacing, while 25 ns beams were only employed for short periods in 2011 and 2012 for test purposes. On these occasions, observables such as pressure rise, heat load in the cold sections as well as clear signatures on bunch-by-bunch emittance blow up, particle loss and energy loss indicated the presence of an EC in a large portion of the LHC. The analysis of the recorded data, together with EC build up simulations, has led to a significant improvement of our understanding of the EC effect in the different components of the LHC. Studies were carried out both at injection energy (450 GeV) and at top energy (4 TeV) aiming at determining the energy dependence of the EC formation and its impact on the quality of the proton beam.
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TUPME033	Scaling of TNSA-accelerated Proton Beams with Laser Energy and Focal Spot Size	laser, target, proton, acceleration	4093
	L. Obst, S. Kraft, J. Metzkes, U. Schramm, K. Zeil Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
	By focusing an ultra-short high-intensity laser pulse on a solid target, pulses of protons and other positively charged ions with energies of several 10 MeV per nucleon are generated. The properties of these particle beams such as their energy and absolute number are highly dependent on experimental conditions like laser and target parameters. In order to achieve principal comparability between different experimental campaigns at the Draco laser system at the Helmholtz-Zentrum Dresden-Rossendorf, a reference setup for the laser ion acceleration experiment was established. A configuration is sought in which proton beams of reproducible characteristics are generated. To ensure a high stability of the proton spectra, the application of longer focal length parabolas (f ~ 1000 mm) will be tested for this setup, according preparatory studies being presented in this paper.
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TUPME039	System Integration of the Demonstration Siemens Electrostatic Accelerator	high-voltage, ion-source, ion, power-supply	1440
	H. von Jagwitz-Biegnitz JAI, Oxford, United Kingdom P. Beasley, S. Goßmann-Levchuk, O. Heid Siemens AG, Erlangen, Germany D.C. Faircloth STFC/RAL, Chilton, Didcot, Oxon, United Kingdom R.G. Selway Inspired Engineering Ltd, Climping, United Kingdom
	Siemens has proposed a novel compact DC electrostatic tandem accelerator to produce protons of a few MeV. Siemens is currently building a prototype of the accelerator at the Rutherford Appleton Laboratory. This paper reports on recent progress on the different components of the system as well as the commissioning of the whole machine.
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TUPME042	Planned High-gradient Flat-beam-driven Dielectric Wakefield Experiments at the Fermilab’s Advanced Superconducting Test Accelerator	acceleration, wakefield, emittance, controls	1451
	F. Lemery, D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot, J. Zhu Fermilab, Batavia, Illinois, USA J. Zhu CAEP/IFP, Mainyang, Sichuan, People's Republic of China
	In beam driven dielectric wakefield acceleration (DWA), high-gradient short-wavelength accelerating fields are generally achieved by employing dielectric-lined waveguides (DLWs) with small aperture which constraints the beam sizes. In this paper we investigate the possibility of using a low-energy (50-MeV) flat beams to induce high-gradient wakes in a slab-symmetric DLW. We demonstrate via numerical simulations the possibility to produce axial electric field with peak amplitude close to 0.5 GV/m. Our studies are carried out using the Fermilab's Advanced Superconducting Test Accelerator (ASTA) photoinjector beamline. We finally discuss a possible experiment that could be performed in the ASTA photoinjector and eventually at higher energies.
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TUPME044	Planned High-brightness Channeling Radiation Experiment at Fermilab's Advanced Superconducting Test Accelerator	electron, detector, radiation, photon	1457
	B.R. Blomberg, D. Mihalcea, H. Panuganti, P. Piot Northern Illinois University, DeKalb, Illinois, USA C.A. Brau, B.K. Choi, W.E. Gabella, B.L. Ivanov, M.H. Mendenhall Vanderbilt University, Nashville, Tennessee, USA C.W. Lynn Swarthmore College, Swarthmore, Pennsylvania, USA P. Piot, T. Sen Fermilab, Batavia, Illinois, USA W.S. Wagner Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
	Funding: Work supported by the DARPA Axis program under contract AXIS N66001-11-1-4196 In this contribution we describe the technical details and experimental setup of our study aimed at producing high-brightness channeling radiation (CR) at Fermilab’s new user facility the Advanced Superconducting Test Accelerator (ASTA). In the ASTA photoinjector area electrons are accelerated up to 40-MeV and focused to a sub-micron spot on a ~40 micron thick carbon diamond, the electrons channel through the crystal and emit CR up to 80-KeV. Our study utilizes ASTA’s long pulse train capabilities and ability to preserve ultra-low emittance, to produce the desired high average brightness.
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TUPME047	SINBAD - A Proposal for a Dedicated Accelerator Research Facility at DESY	plasma, electron, laser, linac	1466
	R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, B. Foster, J. Grebenyuk, I. Hartl, M. Hüning, Y.C. Nie, J. Osterhoff, A. Rühl, H. Schlarb, B. Schmidt DESY, Hamburg, Germany M. Groß, B. Marchetti, F. Stephan DESY Zeuthen, Zeuthen, Germany F.J. Grüner, B. Hidding, A.R. Maier Uni HH, Hamburg, Germany F.X. Kärtner, B. Zeitler CFEL, Hamburg, Germany A.-S. Müller, M. Schuh KIT, Karlsruhe, Germany
	A new, dedicated accelerator research facility SINBAD (Short INnovative Bunches and Accelerators at DESY) is proposed. This facility is aimed at promoting two major goals: (1) Short electron bunches for ultra-fast science. (2) Construction of a plasma accelerator module with useable beam quality. Research and development on these topics is presently ongoing at various places at DESY, as add-on experiments at operational facilities. The two research goals are intimately connected: short bunches and precise femtosecond timing are requirements for developing a plasma accelerator module. The scientific case of a dedicated facility for accelerator research at DESY is discussed. Further options are mentioned, like the use of a 1 GeV beam from Linac2 for FEL studies and the setup of an attosecond radiation source with advanced technology. The presently planned conversion of the DORIS storage ring and its central halls into the SINBAD facility is described. The available space will allow setting up several independent experiments with a cost-effective use of the same infrastructure. National and international contributions and proposals can be envisaged.
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TUPME048	Injection of a LWFA Electron Bunch in a PWFA Driven by a Self-modulated-proton-bunch	plasma, wakefield, electron, laser	1470
	P. Muggli MPI, Muenchen, Germany L.D. Amorim IST, Lisboa, Portugal S. Karsch MPQ, Garching, Munich, Germany N.C. Lopes, J. Vieira Instituto Superior Tecnico, Lisbon, Portugal
	The AWAKE experiment recently approved at CERN will study the acceleration of an externally injected electron bunch in a plasma wakefield accelerator (PWFA) driven by a self-modulated proton bunch. We study the possibility of injecting a bunch created by a laser-driven plasma wakefield accelerator (LWFA). We consider a first plasma source used for self-modulation of the drive bunch and a gas discharge source for acceleration of the collinearly injected bunch. The LWFA produces an electron bunch very short when compared to the PWFA wavelength and with relatively large current, possibly allowing for loading of the wakefields. Short length and high current lead to a small final energy spread. Co-linear injection preserves the incoming bunch quality and insures trapping and acceleration of the whole bunch. The energy of the LWFA electron bunch can easily exceed the trapping energy and can be produced over only a few millimeters gas-jet plasma driven by a laser of relatively modest power by today’s standards. We explore the parameter space suitable for this injection scheme that is more compact, simpler to implement and more suitable for injection in the mm-size accelerator structure.
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TUPME049	Hosing Suppression in the Self-modulated Wakefield Accelerator	plasma, wakefield, flattop, controls	1473
	J. Vieira IPFN, Lisbon, Portugal W.B. Mori UCLA, Los Angeles, California, USA P. Muggli MPI, Muenchen, Germany
	Funding: FCT-Portugal contract no EXPL/FIS-PLA/0834/1012; European Research Council contract no ERC-2010-AdG Grant 267841; by DOE contract no DE-SC0008491, DE-SC0008316, and DE-FG02- 92-ER40727. The proton driven plasma wakefield accelerator (PDPWFA) uses short LHC proton (p⁺) bunches (shorter than the plasma wavelength) as drivers for strongly non-linear plasma waves. Simulations showed that the PDPWFA could be used to accelerate electrons to 600 GeVs in 600 m long plasmas. Currently available p⁺ bunches are much longer than the plasma wavelength, being ideal to excite intese wakefields through the self-modulation instability (SMI). An experiment is being prepared at CERN to demonstrate SMI of p⁺ bunches. In addition, lepton SMI experiments are also being prepared at SLAC, DESY-PITZ and RAL. The hosing instability (HI) is a competing instability that may lead to beam breakup, and needs to be controlled over the long propagation distances required for SMI growth and saturation. In this work we show that the HI can be suppressed after SMI saturation in the linear wakefield excitation regime. SMI saturation before beam-break up can be achieved by seeding SMI, and as long as the initial bunch centroid displacements are within the initial bunch transverse size. The HI suppression occurs via a plasma analogue of the BNS damping in conventional accelerators. A. Caldwell et al, Nat. Physics Nat. Phys. 5, 363 (2009).
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TUPME050	Electron Bunch Self-modulation in Long Plasmas at SLAC FACET	plasma, wakefield, electron, radiation	1476
	P. Muggli MPI, Muenchen, Germany E. Adli, V.K.B. Olsen University of Oslo, Oslo, Norway L.D. Amorim IST, Lisboa, Portugal S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos SLAC, Menlo Park, California, USA C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA N.C. Lopes, J. Vieira Instituto Superior Tecnico, Lisbon, Portugal O. Reimann MPI-P, München, Germany
	Funding: This work performed in part under DOE Contract DE-AC02-76SF00515. We study the physics of self-modulation instability (SMI) of long, when compared to the wake wavelength, electron and positron bunches in pre-formed plasmas at SLAC-FACET. Self-modulation is the result of the action of focusing/defocusing transverse wakefields on the bunch radius. Self-modulation leads to observables such as overall defocusing of the bunch, periodic modulation of the bunch radius at the wake period and multi-GeV energy gain/loss by drive bunch particles. Defocusing is observed from OTR images, radial self-modulation from CTR spectra and interferometric traces and energy gain/loss from energy spectra with sub-GeV resolution. The plasma density is varied by changing the vapor density ionized by a laser/axicon system. The bunch length, radius and charge can also be varied. The SMI can be seeded using a notch collimator system. Numerical simulations indicate that seeding the SMI mitigates the hose instability. Hose instability can also be seeded, for example by using the RF deflecting cavity to impart a tilt to the incoming bunch axis. The overall experimental plan as well as the latest experimental results obtained with electron bunches will be presented.
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TUPME058	The Argonne Wakefield Accelerator (AWA): Commissioning and Operation	wakefield, gun, electron, laser	1503
	M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, C.-J. Jing, C. Li, W. Liu, J.G. Power, J.Q. Qiu, J.H. Shao, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA S.P. Antipov, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA S. Cao IMP, Lanzhou, People's Republic of China C. Li, J.H. Shao TUB, Beijing, People's Republic of China E.E. Wisniewski Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. The commissioning of the upgraded AWA facility is well underway. The new L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of four bunches with up to 80 nC per bunch have been generated. The six new accelerating cavities (L-band, seven cells, pi mode) have been RF conditioned to 12 MW or more; their operation at 10 MW brings the beam energy up to 75 MeV. Measurements of the beam parameters are presently underway, and the use of this intense beam to drive high gradient wakefields will soon follow. One of the main goals of the facility is to generate RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.
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TUPME059	Longitudinal Bunch Shaping with a Double Dogleg based Emittance Exchange Beam Line	emittance, space-charge, controls, cavity	1506
	G. Ha, M.E. Conde, W. Gai, C.-J. Jing, K.-J. Kim, J.G. Power, A. Zholents ANL, Argonne, Illinois, USA M.-H. Cho, G. Ha, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	Funding: Work supported by High Energy Physics, Office of Science, US DOE. A new program is under development at Argonne National Laboratory (ANL) to use an emittance exchange (EEX) beamline to produce longitudinally shaped electron bunches. While the ultimate goal is to generate triangular shapes for high transformer ratio wakefield acceleration we are also exploring, in general, the capability of the double dogleg EEX beamline to control the bunch shape. We are studying effects that degrade the quality of the longitudinal current profile including: non-uniform particle distribution, emittance, the deflecting cavity thick-lens effect, 2nd order effects, space charge effects and coherent synchrotron radiation effects. We will present the double dogleg EEX beamline layout and the diagnostic design as well as give a progress report on the experimental status of the program.
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TUPME069	Proton Electron Accelerator at CERN	plasma, proton, electron, wakefield	1519
	R. Tarkeshian MPI, Muenchen, Germany
	AWAKE is a proton driven plasma-wakefield acceleration at CERN, that uses long proton bunches ~ 400 ps from the SPS. In a dense plasma, a long proton bunch is subject toμbunching at plasma period due to the self-modulation instability, SMI. The self-modulated proton bunch generates large amplitude charge separation through resonant wakefield excitation. Numerical simulations show that when seeded the SMI can grow and saturate over ~4 m in a plasma with density in the (1-10) 10¹⁴/cc range. Seeding also allows for deterministic injection of witness bunches in the focusing and accelerating phase of the wakefields. The SPS proton bunch carrying kJ of energy is a unique driver for generation of ~ GeV/m wakefields through 10’s of meters of plasma. The side-injected electrons ~15 MeV can reach GeV energies. The AWAKE experimental layout, the physics of self-modulation, simulation results, plasma source under study, diagnostics plan for bunch modulation measurement using transverse coherent transition radiation*, and phasing of the witness bunch respect to the wave and synchronisation with diagnostics will be presented.** A. Caldwel, et. al, Nature Physics 5, 2009 N. Kumar, A. Pukhov, PRL, 104, 2010 O. Reimann, R. Tarkeshian, Proc. of IBIC, 2013 ** The work is submitted on behalf of AWAKE collaboration.
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TUPME074	First Experiences with the PITZ Plasma Cell for Electron Beam Self-modulation Studies	plasma, electron, proton, Windows	1525
	M. Groß, A. Donat, J.D. Good, M. Khojoyan, G. Koss, M. Krasilnikov, R. Schütze, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany R. Brinkmann DESY, Hamburg, Germany F.J. Grüner, G. Pathak Uni HH, Hamburg, Germany P. Muggli, E. Öz MPI-P, München, Germany D. Richter HZB, Berlin, Germany C.B. Schroeder LBNL, Berkeley, California, USA
	The self-modulation of long particle beams in a plasma has recently gained interest in light of the ongoing preparation for the plasma wakefield acceleration experiment of the AWAKE collaboration at CERN. Instrumental to the experiment is the self-modulation of a proton beam to generate bunches short enough for producing high acceleration fields. As electron bunches are easier to handle and the underlying physics is identical, it is judicious to first gain insight into the experimental conditions of the self-modulation of long particle beams in plasma by using electron bunches before progressing to the experiment with proton bunches. The experimental demonstration of self-modulation of an electron bunch is in preparation at the Photo Injector Test facility at DESY, location Zeuthen (PITZ). In this contribution the fabrication and first experimental tests towards a Lithium plasma cell are highlighted. The distinctive feature of this plasma cell is the addition of side ports for insertion of the ionization laser beam and for diagnostics purposes.
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TUPME076	Numerical modeling of the E-209 self-modulation experiment at SLAC - FACET	plasma, electron, wakefield, simulation	1531
	L.D. Amorim, L.O. Silva, J. Vieira IPFN, Lisbon, Portugal P. Muggli MPI, Muenchen, Germany
	The E-209 experiment currently running at SLAC- FACET used a long electron bunch (∼ 5 times the plasma wavelength) to drive plasma wakefields through the self- modulation instability. In this work we present and analyze numerical simulation results performed with the particle-in- cell (PIC) code OSIRIS. The results show that SMI saturates after 5cm of propagation in the plasma and that the maxi- mum acceleration wakefields, 15 − 20GV/m, are sustained over a 1m long plasma. Electron bunch energy loss of 4GeV was observed in the simulations.
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TUPRI003	Simulating the Production and Eﬀects of Dark Currents in MICE Steps V and VI	electron, cavity, solenoid, simulation	1556
	C. Hunt, J. Pasternak, M.A. Uchida Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Funding: STFC The completion of the international Muon Ionisation Cooling Experiment (MICE) Step V will involve the construction, commissioning and use of RF cavity and Coupling Coil (RFCC) Modules. The RFCCs consist of 4 RF cavities and a solenoid magnet, and are expected to act as a source of potentially damaging electrons (dark currents) and X-rays. Ongoing work to create a high-statistics simulation of the dark current production, within RF cavities, is described. Current results predict the energy and angular spectra of emitted electrons for an RFCC, and include particle tracking, realistic field maps and ionisation energy losses in cavity windows. Individual electron emitters, parametrised by the Fowler-Nordheim equation, are used and are user-definable, allowing potential worst-case scenarios to be simulated and upper/lower limits for the total dark current to be estimated. These data are being used within the MICE Analysis and User Software (MAUS) to estimate the potential detector backgrounds and the damage that may be inflicted upon the scintillating fibre trackers.
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TUPRI004	The Design and Implementation of The Radiation Monitors for the Protection of the MICE Tracker Detectors	radiation, detector, emittance, electron	1559
	M.A. Uchida, C. Hunt, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	A radiation monitor will be required for the Muon Ionisation Cooling experiment (MICE) beyond Step IV, when the RF cavities are installed. The role of the radiation monitors will be to protect the particle tracking detectors (Trackers) from dangerous levels of RF dark currents and the as- sociated photon fluxes that could potentially be produced in the RF cavities. If such levels of radiation should occur the radiation monitor will ensure that the radiation shields (shutters) are closed thereby protecting the Tracker modules. The radiation monitor will be positioned on these radiation shields and will monitor x-rays, gamma-rays and electrons up to a few MeV. It is expected that the spectrum will peak at very low energies, since the peak voltage across the cavities is 8 MV/m and so the maximum energy that an electron could gain is 12 MeV (maximally accelerated from all four RF cavities). The design, positioning and expected sensitivity of the radiation monitors will be described here along with their readout and inclusion into the MICE interlocking systems. The schedule for the work and progress so far will also be presented.
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TUPRI009	Study of Resonance Crossing in Non-scaling FFAGs using the S-POD Linear Paul Trap	resonance, ion, dipole, acceleration	1571
	D.J. Kelliher, S. Machida, C.R. Prior, S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom K. Fukushima, K. Ito, K. Moriya, H. Okamoto, T. Okano HU/AdSM, Higashi-Hiroshima, Japan
	Experiments on EMMA have shown that with rapid acceleration (~10 turns) a linear non-scaling FFAG can accelerate through several integer tunes without detrimental effects on the beam [1]. Proton and ion applications such as hadron therapy will necessarily have a slower acceleration rate, so their feasibility depends on how harmful resonance crossing is in this regime. A simple and useful tool to answer such fundamental questions is the S-POD linear Paul trap at Hiroshima University, which can be set up to simulate the dynamics of a beam in an FFAG. We report here results of experiments to explore different resonance crossing speeds, quantify beam loss and study nonlinear effects. We also discuss the implications of these experimental results in terms of limits on acceptable acceleration rates and alignment errors. [1] S.Machida et al, Nature Physics, N8, 243-257 (2012)
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TUPRI014	Modelling and Long Term Dynamics of Crab Cavities in the LHC	cavity, multipole, luminosity, hadron	1578
	R. Appleby, D.R. Brett UMAN, Manchester, United Kingdom J. Barranco García, R. De Maria, A. Grudiev, R. Tomás CERN, Geneva, Switzerland
	Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan. The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 250-300 fb-1 per year. This upgrade includes the use crab cavities to mitigate the geometric loss of luminosity arising from the beam crossing angle. The tight space constraints at the location of the cavities leads to cavity designs which are axially non-symmetric and have a potentially significant effect on the long term dynamics and dynamic aperture of the LHC. In this paper we present the current status of advanced modelling of crab cavities.
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TUPRI038	The Low Energy Particle Wakefield Radiation From the Open End of Internally Coated Metallic Tube	radiation, wakefield, vacuum, resonance	1644
	M. Ivanyan, A. Grigoryan, A. Sargsyan, A.V. Tsakanian CANDLE SRI, Yerevan, Armenia
	The radiation of the non-relativistic electron beam from the open end of the resistive circular waveguide is presented. The angular and spectral characteristics of the radiation are determined. The possibility of producing the focused guasi-monochromatic radiation is discussed. The principal scheme of the experiments for 5 and 20 MeV AREAL RF photogun linac is presented.
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TUPRI050	Numerical Calculation and Experiment of Ion Related Phenomenon in SPring-8 Storage Ring	ion, electron, simulation, storage-ring	1680
	A. Mochihashi, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	In the SPring-8 storage ring, various kinds of bunch filling pattern are available. Under some bunch filling patterns, residual gas ions created by scattering process between high energy electrons and residual gas molecules can be trapped stably around the electron beam and disturb the original motion of the beam. We have considered the stability of the electron beam due to the ion related phenomenon under several bunch filling patterns by computer simulation. In the simulation, we have modeled the electron bunch as single particle and the residual gas ions as macroparticles. The number of the trapped ions, size of the ion cloud and change in betatron oscillation amplitude of the beam under several filling pattern conditions will be discussed. We have also performed experiments for stability of the beam under equally spaced bunch filling patterns which give severe condition for the ion related instability. The numerical calculations and the experimental results will be discussed in the presentation.
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TUPRI054	FEM Analysis of Beam-coupling Impedance and RF Contacts Criticality on the LHC UA9 Piezo Goniometer	impedance, simulation, resonance, coupling	1692
	A. Danisi, R. Losito, A. Masi, A. Passarelli, B. Salvant, C. Zannini CERN, Geneva, Switzerland
	The UA9 piezo-goniometer has been designed to guarantee micro-radians-accuracy angular positioning of a silicon crystal for a crystal collimation experiment in the LHC, and to minimize the impact on the LHC beam-coupling impedance. This paper presents a Finite Element Method (FEM) study of the device, in both parking and operational positions, to evaluate its impact on the LHC impedance budget. The study has been a progressive simulation work, started from the simplification of the original detailed design, and aimed at highlighting the effect of single details (e.g. objects in confining chambers) on the longitudinal and transverse components of beam-coupling impedance. In addition, the shielding contribution of the RF gaskets has been carefully evaluated, with the objective to assess the consequences for operation in case of their failure. Sensitivity analyses to simulation parameters are also performed, in order to test the FEM model robustness. A final word is drawn on the overall device impedance criticality.
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TUPRI094	Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor	laser, vacuum, alignment, linear-collider	1793
	G. Stern, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin CERN, Geneva, Switzerland A. Geiger, S. Guillaume ETH, Zurich, Switzerland
	Aligning accelerator components over 200m with 10 μm accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The positions of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser pointing stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser pointing stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 μm at 35m) than in air (2000 μm at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric positioning over 35m. It also gives an estimation of the achievable precision.
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TUPRI108	Development of New Tag Supply System for DAQ for SACLA User Experiments	laser, controls, free-electron-laser, electron	1826
	T. Abe RIKEN SPring-8 Center, Innovative Light Sources Division, Hyogo, Japan A. Amselem, K. Okada, R. Tanaka, M. Yamaga JASRI/SPring-8, Hyogo-ken, Japan
	This paper presents development of a new tag supply system for the data-acquisition (DAQ) system for SACLA user experiments. The X-ray Free-Electron Laser facility in SPring-8, SACLA, has delivered X-ray laser beams to users since March 2012 [1]. For the user experiments at SACLA, a dedicated DAQ system has been developed. The DAQ system is currently capable to operate with maximum ten sensors of multiport Charge-Coupled Device (MPCCD) for X-ray detection. The data of ten sensors are read out with individual readout modules. We implement a new tag supply system to ensure the reconstruction of the diffraction image of the user experiments. The tag data are used to synchronize the data. One master server receives a signal given by accelerator and the delivery of the tag data follows to five experimental halls at SACLA and some of monitors at SACLA accelerator. We employ dedicated communication lines to deliver the tag data. The longest distance to deliver the tag data is about one kilometer. We need to update entire softwares of DAQ system for the implementation. We will implement the new system to the DAQ system by the spring 2014. [1] T. Ishikawa et al., "A compact X-ray free-electron laser emitting in the sub-angstrom region", Nature Photonics 6, 540-544 (2012).
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WEOAA03	Ultrashort and Coherent Radiation for Pump-probe Experiments at the DELTA Storage Ring	radiation, laser, electron, undulator	1848
	M. Huck, S. Hilbrich, H. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick, P. Ungelenk DELTA, Dortmund, Germany
	Funding: Work supported by DFG, BMBF, and by the Federal State NRW. A light source facility employing the coherent harmonic generation (CHG) principle is being commissioned and operated since 2011 at DELTA, a 1.5-GeV electron storage ring at the TU Dortmund University, with the purpose of providing ultrashort coherent VUV radiation for time-resolved experiments. CHG is based on the interaction of ultrashort laser pulses with electrons in an undulator to generate coherent harmonics of the laser wavelength. Different methods have been used to optimize, detect and characterize the CHG radiation. One example is the study of transverse and longitudinal coherence properties in double-slit and Michelson experiments. Moreover, final steps towards performing pump-probe experiments to study ultrafast magnetic phenomena have been taken.
	Slides WEOAA03 [4.139 MB]
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WEOBA03	Status of Preparations for a 10 μs Laser-Assisted H⁻ Beam Stripping Experiment	laser, ion, optics, injection	1864
	S.M. Cousineau, A.V. Aleksandrov, V.V. Danilov, T.V. Gorlov, Y. Liu, A.A. Menshov, M.A. Plum, A.P. Shishlo, Y. Wang ORNL, Oak Ridge, Tennessee, USA F.G. Garcia, N.F. Luttrell UTK, Knoxville, Tennessee, USA D.E. Johnson Fermilab, Batavia, Illinois, USA A. Rakhman ORNL RAD, Oak Ridge, Tennessee, USA Y. Takeda KEK, Ibaraki, Japan
	Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation. The concept of laser-assisted H⁻ stripping, originated over three decades ago, was successfully demonstrated for a 6 ns, 900 MeV H⁻ beam in 2006. Plans are underway to build on this foundation by performing laser-assisted H⁻ stripping of a 10 μs, 1 GeV H⁻ beam at the Spallation Neutron Source facility; this constitutes a three orders of magnitude improvement over the initial proof of principle demonstration. The central theme of the experiment is the reduction of the required laser power through ion beam manipulations and laser-ion beam temporal matching. This paper discusses the configuration of the experiment, the current and anticipated challenges, and the schedule.
	Slides WEOBA03 [2.549 MB]
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WEOCA02	Recent Results from CTF3 Two Beam Test Stand	HOM, wakefield, accelerating-gradient, diagnostics	1880
	W. Farabolini, F. Peauger CEA/DSM/IRFU, France Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden R. Corsini, D. Gamba, A. Grudiev, M.A. Khan, S. Mazzoni, J.L. Navarro Quirante, R. Pan, J.R. Towler, N. Vitoratou, K. Yaqub CERN, Geneva, Switzerland
	From mid-2012, the Two Beam Test Stand (TBTS) in the CTF3 Experimental Facility is hosting 2 high gradient accelerating structures powered by a single power extraction and transfer structure in a scheme very close to the CLIC basic cell. We report here about the results obtained with this configuration as: energy gain and energy spread in relation with RF phases and power, octupolar transverse beam effects compared with modeling predictions, breakdown rate and breakdown locations within the structures. These structures are the first to be fitted with Wake Field Monitors (WFM) that have been extensively tested and used to further improve the structures alignment on the beam line. These results show the unique capabilities of this test stand to conduct experiments with real beams.
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WEOAB02	Wide-band Induction Acceleration in the KEK Digital Accelerator	acceleration, induction, ion, synchrotron	1893
	T. Yoshimoto, X. Liu, K. Takayama TIT, Yokohama, Japan T. Adachi, K. Takayama Sokendai, Ibaraki, Japan T. Adachi, T. Arai, E. Kadokura, T. Kawakubo, X. Liu, K. Okamura, S. Takano, K. Takayama, T. Yoshimoto KEK, Ibaraki, Japan H. Asao, Y. Okada NETS, Fuchu-shi, Japan M. Hirose, H. Kobayashi Tokyo City University, Tokyo, Japan
	Induction synchrotron can accelerate any ion species directly to higher energy without a large pre-accelerator, due to its intrinsic nature that there is no frequency band-width limitation below 1 MHz. KEK digital accelerator (DA) is a small scale prototype of fast cycling induction synchrotron. Recently it has been confirmed that heavy ion beams of mass to charge ratio A/Q = 4 are stably accelerated from 200 keV to a few tens of MeV in this accelerator ring, where the revolution frequency changes from82 kHz to 1 MHz. Acceleration and beam confinement are separately realized by pulse voltages generated in induction cells (1 to 1 pulse transformers) driven by the switching power supply (SPS). Everything is simply maneuvered by controlling of gate signals of solid-state switching elements employed in the SPS. For this purpose, the fully programmed acceleration control system based on the FPGA has been developed. In this paper, the wide-band induction acceleration is presented with experimental results. Further possibilities of beam handling in the induction synchrotron, such as super bunch and novel beam handling techniques, are discussed. K.Takayama et al., to be submitted to Phys. Rev. Lett. (2013). ** T.Iwashita et al., Phys. Rev. ST-AB 14, 071301(2011).
	Slides WEOAB02 [8.935 MB]
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WEOBB01	Design and Performance of the Optical Fiber Length Stabilization System for SACLA	laser, controls, timing, feedback	1906
	H. Maesaka, T. Ohshima, Y. Otake RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. Matsubara JASRI/SPring-8, Hyogo, Japan
	The x-ray free electron laser facility, SACLA, requires timing synchronization accuracies of less than 50 fs for acceleration rf components and less than 10 fs for pump-and-probe user experiments. Although a stable timing distribution system with optical fiber cables was constructed, a timing drift of more than 100 fs has been observed after the transmission of about 100 m. In order to suppress optical fiber length drift, we developed and installed an optical fiber length stabilization system with a Michelson interferometer. A frequency-stabilized laser with a wavelength of 1.5 um is transmitted together with a timing signal and it is reflected back to the interferometer. The length signal from the interferometer is fed back to a fiber stretcher for fiber length control. A prototype system showed that the length of a 1km-long optical fiber in a feedback loop was stabilized within 0.1 um corresponding to 0.5 fs. From this result, a timing accuracy improvement of pump-and-probe experiments can be expected. In this presentation, the design and basic performance of the optical fiber length stabilization system and the operational experience at SACLA will be reported. H. Maesaka et al., Proceedings of FEL’08, 352 (2008). ** H. Maesaka et al., Proceedings of FEL’12, 325 (2012).
	Slides WEOBB01 [2.673 MB]
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WEPRO006	Beam-driven Terahertz Source based on Open Ended Waveguide with a Dielectric Layer	radiation, vacuum, wakefield, optics	1949
	A.V. Tyukhtin, S.N. Galyamin, V.V. Vorobev Saint-Petersburg State University, Saint-Petersburg, Russia S.P. Antipov Euclid TechLabs, LLC, Solon, Ohio, USA S. Baturin LETI, Saint-Petersburg, Russia
	Funding: Work is supported by the Grant of the President of Russian Federation (MK-273.2013.2) and the Russian Foundation for Basic Research (Grant No. 12-02-31258). Electromagnetic waves with frequencies from 0.1 THz to 10 THz (usually called the Terahertz gap) are of great importance for a number of scientific and practical applications. Different techniques are known allowing generating these frequencies. However, a current trend of physics and industry is to fill this gap with more powerful and efficient sources. For example, recent experiments have shown promising THz generation in dielectric loaded structures. Developing this area, we consider the THz emitting scheme where an ultrarelativistic charge exits the open end of a cylindrical waveguide with a dielectric layer and produces THz waves in a form of Cherenkov radiation. The end of the waveguide is supposed to be either orthogonal to the structure axis or skewed. To obtain THz frequencies from waveguides with centimeter or millimeter radii, we consider high order modes. We present typical field patterns (in the Fraunhofer zone) and show that the aperture of the vacuum channel gives, as a rule, the main contribution. We also give simple expressions for the angle of the main pattern lobe. S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012).
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WEPRO056	Development of an Optical Resonant Cavity for the LCS Experiment at cERL	cavity, laser, photon, resonance	2072
	T. Akagi, Y. Honda, A. Kosuge, J. Urakawa KEK, Ibaraki, Japan R. Hajima, M. Mori, R. Nagai, T. Shizuma JAEA, Ibaraki-ken, Japan
	A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays by laser Compton scattering (LCS) is under development. In order to demonstrate the accelerator and laser performance required for the gamma-ray source, an LCS experiment is planned at Compact ERL (cERL) at KEK. An optical resonant cavity is under construction for the LCS experiment. The new optical cavity is designed by combination of two bow-tie cavities to achieve fast optical polarization switching. The performance of the optical cavity is presented in detail.
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MOZB02

Advances in Photocathodes for Accelerators

electron, emittance, cathode, laser

48

L. Cultrera
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

This talk reviews advances in photocathode technology for accelerators: cathodes demonstrating record average currents and deliverable charge, possessing ultra-low intrinsic emittance and sub-picosecond response time. It addresses the grand challenge to combine all these useful properties into a single photoemitter - one that is being actively pursued by the research community.

Slides MOZB02 [4.354 MB]

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MOOCB01

Beam-induced Quench Tests of LHC Magnets

simulation, quadrupole, collimation, beam-losses

52

M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto
CERN, Geneva, Switzerland

At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.

Slides MOOCB01 [2.737 MB]

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MOOCB02

A Common Operation Metrics for Third Generation Light Sources

operation, feedback, survey, insertion

56

A. Lüdeke
PSI, Villigen PSI, Switzerland
M. Bieler
DESY, Hamburg, Germany
J.-F. Lamarre
SOLEIL, Gif-sur-Yvette, France
M. Pont
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

High reliability is a very important goal for third generation light sources. Very often the beam availability is used as the operation metrics to measure the reliability of the accelerator. A survey at several light sources revealed that the calculation of this statistics varies significantly between facilities. This prevents a useful comparison of their reliabilities. The authors propose a specific metrics for the reliability of third generation light sources; a metrics that will allow a detailed and meaningful comparison of these particle accelerators.

Slides MOOCB02 [0.701 MB]

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MOPRO013

Present Status of Coherent Electron Cooling Proof-of-Principle Experiment

electron, ion, cavity, gun

87

V. Litvinenko, Z. Altinbas, D.R. Beavis, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C. Brutus, A.J. Curcio, L. DeSanto, C. Folz, D.M. Gassner, H. Hahn, Y. Hao, C. Ho, Y. Huang, R.L. Hulsart, M. Ilardo, J.P. Jamilkowski, Y.C. Jing, F.X. Karl, D. Kayran, R. Kellermann, N. Laloudakis, R.F. Lambiase, G.J. Mahler, M. Mapes, W. Meng, R.J. Michnoff, T.A. Miller, M.G. Minty, P. Orfin, A. Pendzick, I. Pinayev, F. Randazzo, T. Rao, J. Reich, T. Roser, J. Sandberg, T. Seda, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, L. Snydstrup, A.N. Steszyn, R. Than, C. Theisen, R.J. Todd, J.E. Tuozzolo, E. Wang, G. Wang, D. Weiss, M. Wilinski, T. Xin, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
G.I. Bell, J.R. Cary, K. Paul, I.V. Pogorelov, B.T. Schwartz, A.V. Sobol, S.D. Webb
Tech-X, Boulder, Colorado, USA
C.H. Boulware, T.L. Grimm, R. Jecks, N. Miller
Niowave, Inc., Lansing, Michigan, USA
A. Elizarov
SUNY SB, Stony Brook, New York, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia
P.A. McIntosh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work supported by Stony Brook University and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Coherent Electron Cooling Proof of Principle (CeC PoP) system is being installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. This technique may increase the beam luminosity by as much as tenfold. Within the scope of this experiment, a 112 MHz 2 MeV Superconducting Radio Frequency (SRF) electron gun coupled with a cathode stalk mechanism, two normal conducting 500 MHz single-cell bunching cavities, a 704 MHz 20 MeV 5-cell SRF cavity and a helical undulator will be used. In this paper, we provide an overview of the engineering design for this project, test results and discuss project status and plansd.

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MOPRO024

The Beam Test for the Ti Extraction Window Damage

extraction, radiation, electron, kicker

119

T. Mimashi, N. Iida, M. Kikuchi
KEK, Ibaraki, Japan

For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.

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MOPRO057

Undulator Photon Beams with Orbital Angular Momentum

undulator, emittance, photon, storage-ring

213

J. Bahrdt, K. Holldack, P. Kuske, R. Müller, M. Scheer, P.O. Schmid
HZB, Berlin, Germany

Photons carrying orbital angular momentum (OAM) are present in the off-axis radiation of higher harmonics of helical undulators. Usually, the purity and visibility of OAM photons is blurred by electron beam emittance. However, high brightness OAM beams are expected in ultimate storage rings and FELs, and they may trigger a new class of experiments utilizing the variability of the topological charge, a 3rd degree of freedom besides wavelength and polarization. We report on the first detection of OAM photons in helical undulator radiation in the 3rd generation storage ring BESSY II. Measurements and simulations are compared and the impact of emittance and energy spread is discussed.

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MOPRO108

Lattice and Start-to-end Simulation of the Mainz Energy Recovering Superconducting Accelerator MESA

lattice, linac, simulation, optics

346

R.G. Heine, K. Aulenbacher, F. Schlander, D. Simon
IKP, Mainz, Germany

Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA"
The institute for nuclear physics (IKPH) at Mainz University is designing a multi turn energy recovery linac for particle physics experiments *. We present the current status of the lattice development of MESA together with a PARMELA start to end simulation.
* R. Heine, K. Aulenbacher, and R. Eichhorn: MESA-Sketch of an Energy Recovery LINAC for Nuclear Physics Experiments at Mainz, Proc. of the IPAC2012, New Orleans, Louisiana, USA, p. 1993-1995.

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MOPRO116

Mechanical Engineering and Design of Novel Collimators for HL-LHC

impedance, operation, proton, collimation

369

F. Carra, A. Bertarelli, A. Dallocchio, L. Gentini, P. Gradassi, A. Manousos, N. Mariani, G. Maîtrejean, N. Mounet, E. Quaranta, S. Redaelli, V. Vlachoudis
CERN, Geneva, Switzerland

In view of LHC intensity upgrades, collimator materials may become a limit to the machine performance: the high RF impedance of Carbon-Carbon composites can lead to beam instabilities, while the Tungsten alloy adopted in tertiary collimators exhibits low robustness in case of beam-induced accidents. An R&D program has been pursued to develop new materials overcoming such limitations. Molybdenum-Graphite, in addition to its outstanding thermal conductivity, can be coated with pure molybdenum, reducing collimator impedance by a factor of 10. A new secondary collimator is being designed around this novel composite. New high-melting materials are also proposed to improve the robustness of tertiary collimators. All the new collimators will be equipped with BPMs, significantly enhancing the alignment speed and the beta-star reach. This implies additional constraints of space, as well as detailed static and fatigue calculations on cables and connectors. This paper describes the mechanical design and the engineering calculations of such future collimators, focusing on the study via state-of-the-art numerical methods of interactions between the particle beams and the new materials adopted.

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MOPME001

Commissioning of the Double Electrostatic Storage Ring DESIREE

ion, storage-ring, injection, pick-up

373

A. Källberg, M. Björkhage, M. Blom, E. Bäckström, H. Cederquist, O.M. Hole, M. Kaminska, P. Löfgren, S. Mannervik, R. Nascimento, P. Reinhed, H.T. Schmidt, A. Simonsson
Stockholm University, Stockholm, Sweden
S. Rosén
Stockholm University, Department of Physics, Stockholm, Sweden

DESIREE, the double electrostatic storage rings in Stockholm, is now commissioned and used for experiments. The two 9 m circumference storage rings, which are constructed inside a double walled cryostat, are now cooled to 13 K and routinely used for storage of both negative and positive ions with lifetimes of several minutes. The main properties of DESIREE are presented as well as results from the commissioning and the first experiments.

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MOPME012

A New Tool for Automated Orbit and Spin Motion Analysis

lattice, software, storage-ring, simulation

403

D. Zyuzin
FZJ, Jülich, Germany

There are a lot of tools to simulate beam dynamics in accelerators of various types. Many of them are intended to use for specific purposes, and there are universal codes that can simulate both orbit and spin motion in magnetic and electrostatic structures. To start using these codes beam physicist first should have learn syntax, know features and methods how to describe lattice and beams in this particular code. Output data structures of different simulation programs are also vary and depend on peculiarities of each program. This paper proposes a new tool for automated generation and execution of input files for simulation programs and for data analysis of output data. The developed tool allows to describe a lattice, calculate different lattice parameters (like tunes) using simulation program, track particles inside the lattice and analyze various parameters of output data (like beam depolarization). Simulations and analysis can be done in parallel using built-in parallelization mechanisms, and all results can be stored in the database and can be easily fetched when needed. The tool is used to simulate beam and spin dynamics in different lattices to increase spin coherence time.

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MOPME022

Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna

plasma, ion, operation, simulation

424

H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.

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MOPME023

A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma

electron, simulation, cyclotron, plasma

427

X.F. Li, D.Z. Chen, D. Li, H.K. Yue
HUST, Wuhan, People's Republic of China

A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.

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MOPME024

Progress of the RF Negative Ion Source Research at HUST

plasma, ion, ion-source, extraction

430

D.Z. Chen, M. Fan, J. Huang, X.F. Li, K.F. Liu, C. Wang, H.K. Yue, C. Zhou
HUST, Wuhan, People's Republic of China
J.C. Huang, D. Li, D.W. Liu, Z. Zhang
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People's Republic of China

Funding: Ministry of Science and Technology of China
To promote the research and talent cultivation for ITER negative ion sources, Huazhong University of Science and Technology (HUST) has started to develop an experimental facility since 2011 under the support of Ministry of Science and Technology of China. As the first stage, we are building a radio frequency (RF) driver which will produce the plasma for yielding negative ions in the next stage. A deal of experimental research has been carried out on the setup.

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MOPME047

Comparison of the Results of a Hydrodynamic Tunneling Experiment with Iterative FLUKA and BIG2 Simulations

target, simulation, proton, collider

479

F. Burkart, J. Blanco, D. Grenier, R. Schmidt, D. Wollmann
CERN, Geneva, Switzerland
N.A. Tahir
GSI, Darmstadt, Germany

In 2012, a novel experiment has been performed at the CERN HiRadMat facility to study the impact of a 440 GeV proton beam generated by the Super Proton Synchrotron (SPS), on extended solid copper cylindrical targets. Substantial hydrodynamic tunneling of the protons in the target material has been observed. Iterative FLUKA and BIG2 simulations with the parameters of the actual experiment have been performed. In this paper the results of these simulations will be discussed and compared to the experimental measurements. Furthermore, the implication on the machine protection design for high intensity hadron accelerators as the current LHC and the future High Luminosity LHC will be addressed.

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MOPME070

Investigation of a High Power, Low Impedance Pulse Forming Network based on Ceramic Capacitors

impedance, network, simulation, laser

529

J. Gao, X.J. Ge, J. He, J. Liu
NUDT, Changsha, People's Republic of China

Solid state is one of the most important development directions for pulsed power technologies. For GW level pulse generators, switches and pulse forming units are difficult to implement with solid state components restricted by high power tolerance and high voltage insulation. Under certain pulse power, operation voltage is decided by impedance of the pulse forming unit, which means that pulse modulation with low impedance method should help improve insulation strength of a pulsed power system. Therefore, a high power, low impedance pulse forming network is developed based on solid components of ceramic capacitors in this research. It is designed that the impedance is 1.6 Ω, the pulse width is about 150 ns, and the output power is above 1 GW. Low impedance is accomplished via several pulse forming units connected in parallel with a circumferential structure, which could reduce the stray inductance due to good symmetrical characteristics. Key factors influencing pulse modulation process are investigated, stray parameters are examined by electromagnetic calculations and preliminary experiments are carried out, with results giving reasonable agreement with the theoretical cases.

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MOPME071

Configurations and Applications of Saturable Pulse Transformers in High Power Pulse Modulation

high-voltage, coupling, plasma, controls

532

J. Liu, J. Gao, X.J. Ge, J. He, Y. Zhang
NUDT, Changsha, People's Republic of China

Saturable pulse transformers (SPTs) based on multiple batches of windings in parallel combination and coaxial cylindrical conductors are presented. The proposed SPT can be employed as the transformer and magnetic switch simultaneously for pulse capacitor or high-voltage pulse modulator of several hundred kV range. The SPT, with important features such as auto-resetting of core, high step-up ratio and low saturation inductance, achieves a compact integration of common transformer and magnetic switch. In the SPT, The physical suppression effect caused by reversed magnetic coupling mechanism among primary and secondary windings can reduce the saturation inductance of the SPT windings to a level lower than their structure inductances, which helps to achieve a magnetic switch with low saturation inductance. The proposed SPTs were applied in a high power pulse modulator based on a helical Blumlein pulse forming line (HBPFL). When the SPT played as a pulse transformer, the HBPFL can be charged to 200 kV. When the SPT played as a main magnetic switch of the HBPFL, it helped to form a quasi-square voltage pulse with amplitude of 180 kV，pulse duration of 130 ns, rise time of 60 ns.

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MOPRI005

The AWAKE Experimental Facility at CERN

electron, proton, plasma, laser

582

E. Gschwendtner, T. Bohl, C. Bracco, A.C. Butterworth, S. Cipiccia, S. Döbert, V. Fedosseev, E. Feldbaumer, C. Heßler, W. Höfle, M. Martyanov, M. Meddahi, J.A. Osborne, A. Pardons, A.V. Petrenko, H. Vincke
CERN, Geneva, Switzerland

AWAKE, an Advanced Wakefield Experiment is launched at CERN to verify the proton driven plasma wakefield acceleration concept. Proton bunches at 400 GeV/c will be extracted from the CERN SPS and sent along a 750m long proton line to the plasma cell, a Rubidium vapour source, where the proton beam drives wakefields reaching accelerating gradients at the order of gigavolt per meter. A high power laser pulse will co-propagate within the proton bunch creating the plasma by ionizing the (initially) neutral gas. An electron beam will be injected into the plasma cell to probe the accelerating wakefield. The AWAKE experiment will be installed in the CNGS facility. First proton beam to the plasma cell is expected by end 2016. The design of the experimental area and the integration of the new beam-lines as well as the experimental equipment will be shown. The needed modifications of the infrastructure in the facility will be presented.

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MOPRI016

Hydrogen and Cesium Monitor for H⁻ Magnetron Sources

plasma, cathode, ion, controls

617

C.-Y. Tan, D.S. Bollinger, B.A. Schupbach, K. Seiya
Fermilab, Batavia, Illinois, USA

Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energ
The relative concentration of cesium to hydrogen in the plasma of a H⁻ magnetron source is an important parameter for reliable operations. If there is too much cesium, the surfaces of the source become contaminated with it and sparking occurs. If there is too little cesium then the plasma cannot be sustained. In order to monitor these two elements, a spectrometer has been built and installed on a test and operating source that looks at the plasma. It is hypothesized that the concentration of each element in the plasma is proportional to the intensity of their spectral lines.

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MOPRI018

Influence of Growth Method on K3Sb Photocathode Structure and Performance

cathode, synchrotron, scattering, emittance

624

S.G. Schubert, T. Kamps, M. Schmeißer
HZB, Berlin, Germany
K. Attenkofer, J. Smedley
BNL, Upton, Long Island, New York, USA
E.M. Muller
SBU, Stony Brook, New York, USA
H.A. Padmore, J.J. Wong
LBNL, Berkeley, California, USA
M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
J. Xie
ANL, Argonne, Illinois, USA

Funding: Supported by Director, OoS., OBES of US DOE, Contract DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNTI0013, DE-SC0005713, germ. BMBF, Land Berlin, Helmholtz Assoc.. Use of CHESS by NSF, DMR-0936384.
Future high brightness photoelectron sources delivering >100 mA average current call for a new generation of photocathodes. Materials which qualify for this purpose should exhibit low intrinsic emittance, long lifetime and high quantum efficiency at photon energies in the visible range of the spectrum to relax drive laser requirements. A combination of material science techniques are used to determine the influence of the growth parameters on structure and performance of photocathode materials . In-situ XRR, XRD and GiSAXS measurements were performed at the synchrotron radiation sources, NSLS and CHESS. The growth of K3Sb, a precursor material of one of the prime candidates CsK2Sb, was studied intensively to optimize this intermediate growth step in terms of quantum efficiency and roughness. Three methods, a “layer by layer” type and a “super-lattice type” were examined. K3Sb exists in two crystallographic phases, namely cubic and hexagonal. The cubic phase exhibits a higher quantum efficiency at 532 nm than the hexagonal phase and transforms more easily into CsK2Sb, tuning this phase is believed to be one of the key parameters in the CsK2Sb growth.

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MOPRI021

Laser Systems Generating Short Polarized Electron Bunches at the S-DALINAC

laser, electron, operation, cathode

633

M. Espig, J. Enders, Y. Fritzsche, A. Kaiser, M. Wagner
TU Darmstadt, Darmstadt, Germany

Funding: Supported by DFG within CRC634 and by the state of Hesse through the LOEWE center HIC for FAIR.
The source of polarized electrons at the superconducting Darmstadt electron linear accelerator S-DALINAC uses photo-emission from strained-layer superlattice-GaAs and bulk-GaAs photocathodes. This system is driven by either 3 GHz gain-switched diode lasers or a short-pulse Ti:Sapphire laser system. Highly polarized electrons are generated with laser light at 780 nm, while blue laser light is used for unpolarized high-current experiments. We present the existing pulsed laser systems and the planned developments for the diode laser system, including, e.g., impedance matching of the diode lasers, gain switching with short electrical pulses and pulsing with a Mach-Zehnder modulator. The pulsed operation is aimed at generating short electron bunches (< 50 ps) at the S-DALINAC with variable repetition rates from some MHz to 3 GHz.

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MOPRI031

Multi-alkali Photocathode R&D

cathode, laser, electron, vacuum

661

Y. Seimiya, M. Kuriki, N. Yamamoto
HU/AdSM, Higashi-Hiroshima, Japan

Multi-alkali photocathode has excellent features: high quantum efficiency, long lifetime, and excitation by visible light, for example green laser. The multi-alkali cathode is considered to be one of the best candidate of the high brightness electron source of the advanced electron accelerator such as ERL and FEL. We study conditions of multi-alkali evaporations, such as thicknesses, substrate temperature, and evaporation rate, and examine the cathode performances, such as quantum efficiency and extractable current density. Antimony (Sb), potassium (K), and cesium (Cs) are used in our evaporation system.

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MOPRI032

A STUDY ON ROBUSTNESS OF NEA-GAAS PHOTOCATHODE*

cathode, electron, vacuum, emittance

664

K. Uchida, R. Kaku, M. Kuriki, K. Miyoshi, Y. Seimiya, N. Yamamoto
HU/AdSM, Higashi-Hiroshima, Japan
H. Iijima
Tokyo University of Science, Tokyo, Japan

Electron source is one of the most important component in the advanced linac. There is a strong demand on the high performance cathode, such as small emittance, high brightness, and short pulse generation. NEA-GaAs photo-cathode is a unique technology which is capable for generating highly polarized and extremely low emittance beam. Quantum efficiency (QE) of the cathode is high in near IR region, so it is favor to generate a high current density beam. These advantages are originated to the Negative Electron Affinity (NEA) surface, but it is fragile so the operational lifetime is limited. A study on a robust NEA surface cathode is reported. According to the hetero-junction model, Cs-Te thin film deposited on GaAs forms a robust NEA surface. We performed the Cs-Te evaporation experiment on a clean GaAs cathode and measured QE spectra. We found that some sample showed a high quantum efficiency up to 900nm wavelength which strongly suggested a NEA surface formation.

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MOPRI038

Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment.

electron, ion, site, vacuum

682

K. Hayase, R. Chiba, H. Iijima, Y. Inagaki, T. Meguro
Tokyo University of Science, Tokyo, Japan

Negative electron affinity (NEA) surface are formed by deposition of Cs atoms on p-GaAs, and the drastic increase in the electron emission is observed by the Yo-Yo method. It is necessary to remove oxide layers of GaAs surface for the NEA surface formation, therefore the thermal treatment was carried out prior to the NEA activation. We have discussed the quantum efficiency (QE) with different thermal history. GaAs surfaces cleaned with organic solvents were thermally treated with the temperature sequence of 773K, 823K, and 723K. The NEA activation was carried out at every temperature. The QE less than 1% was obtained with 773K of treatment temperature on the initial surface. Then the QE increased at 10% after treatment at higher 823K. Successive increase of the QE to 13% was observed with a reduced temperature treatment at 723K. The GaAs surfaces after the thermal treatment in the high temperature region with the NEA activation are different from the as-cleaned-GaAs surfaces probably in stoichiometry or morphology due to desorption of As and Ga atoms. The role of thermal treatment with NEA activation is the modification of surface properties important for elevating the QE.

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MOPRI051

Measurements of the Longitudinal Energy Distribution of Low Energy Electrons

cathode, electron, laser, simulation

720

L.J. Devlin, O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L.J. Devlin, O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work supported by STFC Cockcroft Core Grant No.ST/G008248/1
The Transverse Energy Spread Spectrometer (TESS) is an ASTeC experiment designed to measure the energy of electrons from different cathode materials. It is a dedicated test stand for future light sources. A full particle tracking code has been developed in the QUASAR Group, which simulates particle trajectories through TESS. Using this code it is possible to simulate different operational conditions of the experiment and cathode materials. The simulation results can then be benchmarked against experimental data to test the validity of the emission and beam transport model. Within this paper, results from simulation studies are presented and compared against experimental data as a collaboration within the Cockcroft Institute between ASTeC and the QUASAR Group for the case of measuring the longitudinal velocity distribution of electrons emitted from a gallium arsenide cathode using a grid structure as an energy filter.

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MOPRI053

High Repetition Rate Ultrafast Electron Diffraction at LBNL

electron, emittance, gun, laser

724

D. Filippetto, M. Mellado Munoz, H.J. Qian, F. Sannibale, W. Wan, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231"
Here we propose to use the APEX photo-gun as novel source for time-resolved electron diffraction studies. The electron source has been designed, built and successfully tested at LBNL. It combines a high accelerating field needed for bright beams, MeV electron energy essential for time resolution in gas-phase experiments and studies of bulk processes, together with continuous (CW) operations. Ultra-short electron pulses can be delivered with a maximum repetition rate of 186 MHz, enabling new science to be studied. We report the design of a dedicated electron diffraction beamline that fits in the space constraints of the APEX tunnel. Simulations of beam properties have been carried out with a genetic optimizer, showing 100 fs time resolution. Beam jitters in energy, time and position are currently being characterized, and a mitigation strategy via fast feedback loops is discussed.

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MOPRI065

The Development of a Low Energy Neutron Accelerator for Rebunching Pulsed Neutrons

neutron, impedance, controls, focusing

751

S. Imajo
Kyoto University, Kyoto, Japan
Y. Arimoto
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
M. Kitaguchi
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Seki
RIKEN Nishina Center, Wako, Japan
H.M. Shimizu
Nagoya University, Nagoya, Japan
S. Yamashita
ICEPP, Tokyo, Japan
T. Yoshioka
Kyushu University, Fukuoka, Japan

Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF in a gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons at the target, however, the pulsed neutrons with spread velocities are diffused in guide tubes during long beam transport. It is necessary to concentrate UCN temporally upon the bottle by controlling their velocities for nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured specification of the new rebuncher is described in detail.

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MOPRI066

External Neutron Source for Research Reactor Based on Linear Accelerator and Beryllium Target

target, neutron, electron, radiation

754

V.P. Struev, A.A. Bogdanov, A.G. Golovkina, Yu.V. Kiselev, I.V. Kudinovich, A.I. Laikin, S.M. Rubanov
KSRC, St. Petersburg, Russia
A.G. Golovkina, I.V. Kudinovich
St. Petersburg State University, St. Petersburg, Russia

Nuclear research reactor “U-3” of Krylov State Research Center was operated as an experimental tool to study a radiation shield of small nuclear power plants, radiation resistance of its equipment including control system elements. Reactor thermal output power is 50 kW. Currently reactor modernization is being carried out, in the framework of which neutron lighting system that consists of a linear electron accelerator “UEL-10D” (10 MeV) and a beryllium target is implemented. At the present time the neutron yield from the target experiments are going on, some obtained experimental results are presented. Optimal target sizes with a view to neutron yield were defined.

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MOPRI067

Beam Cooling Systems and Activities at GSI and FAIR

electron, ion, pick-up, antiproton

757

C. Dimopoulou
GSI, Darmstadt, Germany

Efficient and versatile beam cooling (electron and stochastic cooling) has been an indispensable ingredient for beam preparation and physics experiments at the GSI accelerator complex. The hot secondary beams emerging from the production targets can hardly be used, unless they are cooled. Beam stacking of low-abundant species relies on cooling. Cooling enables high-precision experiments with stored beams, counteracts the heating during internal target operation and controls decelerated beams. New challenges lie ahead within the FAIR project like (i) the ongoing integration downstream of the ESR of the low-energy CRYRING with its electron cooler, (ii) the developments for the demanding CR stochastic cooling system, (iii) the stacking scenarios with RF and stochastic cooling in the HESR/RESR. The function and parameters of the existing and future beam cooling systems are summarized. We report on the latest hardware developments as well as on improvements of the controls and operation software. Recent highlights and results from beam manipulations with cooling at GSI are shown. In focus are those benchmarking experiments, where the concepts for the new FAIR systems are verified.
C. Dimopoulou on behalf of the GSI Beam Cooling Department, of the GSI Stored Beams Division and of the FAIR Project Team.

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MOPRI070

2MeV Electron Cooler for COSY and HESR – First Results

electron, proton, operation, heavy-ion

765

V. Kamerdzhiev, U. Bechstedt, F.M. Esser, O. Felden, R. Gebel, A.J. Halama, F. Klehr, G. Langenberg, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, K. Reimers, M. Retzlaff, R. Stassen, H. Stockhorst, R. Tölle
FZJ, Jülich, Germany
N. Alinovskiy, T.V. Bedareva, E.A. Bekhtenev, O.V. Belikov, V.N. Bocharov, V.V. Borodich, M.I. Bryzgunov, A.V. Bubley, V.A. Chekavinskiy, V.G. Cheskidov, B.A. Dovzhenko, A.I. Erokhin, M.G. Fedotov, A.D. Goncharov, K. Gorchakov, V.K. Gosteev, I.A. Gusev, G.V. Karpov, Y.I. Koisin, M.N. Kondaurov, V.R. Kozak, A.M. Kruchkov, A.D. Lisitsyn, I.A. Lopatkin, V.R. Mamkin, A.S. Medvedko, V.M. Panasyuk, V.V. Parkhomchuk, I.V. Poletaev, V.A. Polukhin, A.Yu. Protopopov, D.N. Pureskin, A.A. Putmakov, V.B. Reva, P.A. Selivanov, E.P. Semenov, D.V. Senkov, D.N. Skorobogatov, N.P. Zapiatkin
BINP SB RAS, Novosibirsk, Russia
J. Dietrich
HIM, Mainz, Germany
T. Katayama
Nihon University, Narashino, Chiba, Japan
L.J. Mao
IMP, Lanzhou, People's Republic of China

The 2 MeV electron cooler was installed in the COSY ring in the spring 2013. The new system enables electron cooling in the whole energy range of COSY. The electron beam is guided by longitudinal magnetic field all the way from the electron gun to the collector. This well-proven optics scheme was chosen because of the wide electron energy range of 0.025-2 MeV. The electrostatic accelerator consists of 33 individual sections of identical design. Electrical power to each section is provided by a cascade transformer. Electron beam commissioning and first studies using proton and deuteron beams were carried out. Electron cooling of proton beam up to 1662 MeV kinetic energy was demonstrated. Maximum electron beam energy achieved so far amounted to 1.25 MeV. Voltage up to 1.4 MV was demonstrated. The cooler was operated with electron current up to 0.5 A. The paper provides insights into the recent progress in high energy electron cooling at COSY and perspectives for the HESR ring at FAIR.

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MOPRI072

Simulation Study of Heavy Ion Beam Injection and Acceleration in the HESR for Internal Target Experiments with Cooling

target, ion, acceleration, cavity

768

H. Stockhorst, B. Lorentz, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
T. Katayama
Nihon University, Narashino, Chiba, Japan

Recently, the feature of ion beam injection, storage and acceleration assisted by a barrier bucket and cooling has been investigated in the High Energy Storage Ring HESR at the new facility FAIR which will be built at the GSI Darmstadt. A bare uranium beam is injected from the collector ring CR into the HESR at 740 MeV/u*. The simulation studies are now improved to include different injection schemes applying either the barrier cavity or the h = 1 cavity in the HESR. It is outlined how the new 2.5 MeV electron cooler at COSY Jülich or stochastic cooling can support the injection mechanism. The beam preparation for an internal target experiment with cooling is outlined. The acceleration of the ion beam is extended to 5 GeV/u under the mandatory condition of the available cavity voltages and the maximum magnetic field ramp rate in the HESR. The flexibility of the HESR ring lattice is utilized to avoid transition energy crossing during ramping up to 5 GeV/u and to adjust the rings’ frequency slip factor for optimal stochastic cooling. The cooling simulations include the beam-target interaction due to a hydrogen target.
* H. Stockhorst et al., MOPEA018, IPAC13

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MOPRI078

High Power Cyclotrons for Neutrino Experiments

cyclotron, extraction, proton, vacuum

788

D. Winklehner, J.R. Alonso, W.A. Barletta, A. Calanna, J.M. Conrad
MIT, Cambridge, Massachusetts, USA
A. Adelmann
PSI, Villigen PSI, Switzerland
L. Calabretta, D. Campo
INFN/LNS, Catania, Italy
M. Shaevitz
Columbia University, New York, USA
J.J. Yang
CIAE, Beijing, People's Republic of China

DAEδALUS* and IsoDAR** experiments needs large intense neutrino fluxes to investigate respectively the CP-Violation in the neutrino sector and the existence of sterile neutrino. DAEδALUS requires three neutrino sources driven by proton beams of ~800 MeV at powers of several megawatts placed at distances of 1.5, 8 and 20 km from the detector. Two cyclotrons working in cascade are chosen to deliver these high power beams. The first cyclotron accelerates the H²⁺ ions beam up to 60 MeV/amu. The beam is then extracted with an electrostatic deflector and reaccelerated up to 800 MeV/amu through a superconducting ring cyclotron. The acceleration of H²⁺ has two advantages: it reduces the space charge effect along the injection and acceleration inside the first cyclotron and allows the extraction of the beam from the last accelerator using a stripper foil. The injector cyclotron can be used in stand-alone mode to drive the IsoDAR experiment, which needs the accelerator placed near an underground neutrino detector. The design and the results of beam dynamic simulations will be shown. the results of preliminary injection and acceleration tests into a cyclotron test bench will be presented.
* J. Alonso et al., arXiv:1006.0260[physics.ins-det] (2010).
** A. Bungau et al., Phys. Rev. Lett. 109 141802 (2012).

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MOPRI081

Beam Simulation for Improved Operation of Cyclotron NIRS-930

simulation, cyclotron, injection, extraction

797

M. Nakao, S. Hojo, K. Katagiri, A. Noda, K. Noda, A. Sugiura
NIRS, Chiba-shi, Japan
A. Goto
Yamagata University, Yamagata, Japan
T. Honma, A.K. Komiyama, T. Okada, Y. Takahashi
AEC, Chiba, Japan
V.L. Smirnov, S.B. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

Beam simulation using SNOP* code has been performed for the cyclotron NIRS-930 at NIRS in order to study beam dynamics in a cyclotron and to improve beam intensity. Each electric or magnetic field (main coil, trim coils, harmonic coils, magnetic channel, gradient corrector, grazer lens, dee electrode, inflector) were calculated by OPERA-3d, and simulated injection, acceleration, and extraction. The simulation of proton with 30 MeV extracting energy with harmonic 1 was already performed and well simulated RF phase and extraction efficiency**. Then we tried to apply SNOP to 18 MeV protons with harmonic 2. We first formed isochronous magnetic field with main and trim coils for simulating single particle. Next we optimized electric deflector and magnetic channel in order to maximize extracted particles simulating the bunch of particles. Beam loss of the simulation was compared to the experiment. And then we are optimizing position and rotation of inflector and position of puller to improve injection. We intend to apply optimized simulation parameter to actual cyclotron operation to improve beam intensity and quality.
* V.L. Smirnov, S.B. Vorozhtsov, Proc. of RUPAC2012 TUPPB008 325 (2012)
** V.L. Smirnov et al., Proc. of IPAC2012 292 (2012)

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MOPRI088

Beam Transport Experiments Using Gabor Lenses

electron, beam-transport, focusing, space-charge

818

K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger
IAP, Frankfurt am Main, Germany

A prototype Gabor lens has successfully been tested at the GSI High Current Test Injector (HOSTI)*. The experiments comprised the investigation of an emittance dominated and a space-charge dominated beam transport. In particular, the high-current measurements represent a necessary step towards evaluating the focusing performance of the lens and to gain experience in a real accelerator environment. Besides the evaluation of the technical feasibility, the behavior of the electron cloud was characterized by the parameter analysis of the confined non-neutral plasma during beam transport measurements as well as subsequently performed diagnostic experiments. This contribution will present experimental results as well as numerical studies on an improved Gabor lens design for the possible application at the GSI High Current Injector (HSI) in the context of an upgrade program for FAIR**.
*K. Schulte et al., Proc. of IPAC'13, Shanghai, China, 2013, THPWO021
**L. Dahl, Proc. of HIAT’09, Venice, Italy, 2009, FR-01

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MOPRI101

Field Simulations and Mechanical Implementation of Electrostatic Elements for the ELENA Transfer Lines

quadrupole, ion, proton, vacuum

855

D. Barna
University of Tokyo, Tokyo, Japan
W. Bartmann, J. Borburgh, C. Carli, G. Vanbavinckhove
CERN, Geneva, Switzerland

The Antiproton Decelerator (AD) complex at CERN will be extended by an extra low energy anti-proton ring (ELENA) further decelerating the anti-protons thus improving their trapping. The kinetic energy of 100 keV at ELENA extraction facilitates the use of electrostatic transfer lines to the experiments. The mechanical implementation of the electrostatic devices are presented with focus on their alignment, bakeout compatibility, ultra-high vacuum compatibility and polarity switching. Field optimisations for an electrostatic crossing device of three beam lines are shown.

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TUOAA03

Extra Low ENergy Antiproton ring ELENA: From the Conception to the Implementation Phase

antiproton, electron, emittance, extraction

910

C. Carli, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, T. Eriksson, S. Maury, S. Pasinelli, G. Tranquille
CERN, Geneva, Switzerland
W. Oelert
Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany

The Extra Low Energy Antiproton ring (ELENA) is a CERN project aiming at constructing a small 30 m circumference synchrotron to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The ELENA design is now well advanced and the project is moving to the implementation phase. Component design and construction are taking place at present for installation foreseen during the second half of 2015 and beginning of 2016 followed by ring commissioning until the end of 2016. New electrostatic transfer lines to the experiments will be installed and commissioned during the first half of 2017 followed by the first physics operation with ELENA. Basic limitations like Intra Beam Scattering limiting the emittances obtained under electron cooling and direct space charge effects will be reviewed and the status of the project will be reported.

Slides TUOAA03 [4.963 MB]

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TUOCA03

Production of Quasi-monochromatic GeV Photons by Compton Scattering using Undulator X-ray Radiation at SPring-8

photon, electron, undulator, laser

941

H. Ohkuma, A. Mochihashi, M. Oishi, S. Suzuki, K. Tamura
JASRI/SPring-8, Hyogo-ken, Japan
N. Muramatsu, H. Shimizu
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
T. Nakano
RCNP, Osaka, Japan

Funding: This work is supported by JSPS KAKENHI (Grant-in-Aid for Scientific Research) Grant Number 24241035.
Backward Compton scattering (BCS) of X-ray photons emitted by undulator and reflected back by a single crystal from the electron beam can produce a quasi-monochromatic gamma-ray beam up to an energy very close to the electron beam energy. The SPring-8 beam diagnostics beamline (BL05SS) is used to inject a reflected undulator X-ray radiation against 8 GeV stored electron beam and to extract a quasi-monochromatic 8 GeV gamma-ray produced by BCS. BL05SS has conditions to do a pilot experiment to obtain the gamma-ray beam using BCS of X-ray photons from existing undulator. Experimental setup including a Bragg mirror system is now under construction. Preliminary reflectivity measurement of a silicon Bragg mirror using around 10keV photons has been done. Status of the experimental preparation and the future outlook is presented.

Slides TUOCA03 [1.889 MB]

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TUOBB02

Demonstration of Gigavolt-per-meter Accelerating Gradients using Cylindrical Dielectric-lined Waveguides

wakefield, radiation, electron, laser

965

B.D. O'Shea, G. Andonian, K.L. Fitzmorris, J. Harrison, J.B. Rosenzweig, O. Williams
UCLA, Los Angeles, California, USA
M.J. Hogan, V. Yakimenko
SLAC, Menlo Park, California, USA

We present here the results of measurements made showing ~1 GV/m accelerating fields using a hollow dielectric-lined waveguide. The results are comprised of measurement of the energy loss of a high charge (~3 nC) ultrashort (~200 fs), ultra relativistic (20 GeV) beam and concomitant auto-correlation interferometeric techniques to obtain the frequency content of simultaneously generated coherent Cherenkov radiation (CCR). Experiments were conducted at the Facility for Advanced aCcelerator Experimental Tests (FACET) at the SLAC National Laboratory using metal-coated sub-millimeter diameter, ten-centimeter long fused silica tubes. We present simulation and theoretical results in support of the conclusions reached through experiment. These results build on previous work to provide a path towards high gradient accelerating structures for use in compact accelerator schemes, future linear colliders and free-electron lasers.

Slides TUOBB02 [2.349 MB]

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TUPRO005

Status of the NICA Project at JINR

ion, collider, booster, electron

1003

G.V. Trubnikov, N.N. Agapov, A.V. Butenko, D.E. Donets, E.D. Donets, E.E. Donets, A.V. Eliseev, E.V. Gorbachev, A. Govorov, E.V. Ivanov, V. Karpinsky, V.D. Kekelidze, H.G. Khodzhibagiyan, S.A. Kostromin, A.D. Kovalenko, O.S. Kozlov, V.A. Matveev, I.N. Meshkov, V.A. Mikhailov, V. Monchinsky, N. Shurkhno, A.O. Sidorin, I. Slepnev, V. Slepnev, A.V. Smirnov, A. Sorin, N.D. Topilin, A. Tuzikov, V. Volkov
JINR, Dubna, Moscow Region, Russia
O.I. Brovko, A.V. Philippov, N.V. Semin
JINR/VBLHEP, Moscow, Russia

Nuclotron-based Ion Collider fAcility (NICA) is the new accelerator complex being constructed in Joint Institute for Nuclear Research. General goal of the project is to provide experimental study of hot and dense strongly interacting QCD matter. The development of NICA injection complex is actively performed. Construction of new 3.2 MeV/u heavy-ion linear accelerator (HILac) is now under way in Germany. Construction of booster has been started. In this report the present status of the NICA accelerator complex are presented.

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TUPRO019

Localisation of Beam Offset Jitter Sources at ATF2

quadrupole, simulation, EPICS, damping

1049

J. Pfingstner, H. Garcia, A. Latina, M. Patecki, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

For the commissioning and operation of modern particle accelerators, automated error detection and diagnostics methods are becoming increasingly important. In this paper, we present two such methods, which are capable of localising sources of beam offset jitter with a combination of correlation studies and so called degree of freedom plots. The methods were applied to the ATF2 beam line at KEK, where one of the major goals is the reduction of the beam offset jitter. Results of this localisation are shown in this paper. A big advantage of the presented method is its high robustness especially to varying optics parameters. Therefore, we believe that the developed beam offset jitter localisation methods can be easily applied to other accelerators.

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TUPRO021

Preliminary Study of Risks and Failure Scenarios for the High Luminosity Experiments in HL-LHC

luminosity, simulation, detector, cavity

1055

F. Bouly
LPSC, Grenoble Cedex, France
R. Alemany-Fernández, H. Burkhardt, D. Wollmann
CERN, Geneva, Switzerland
B. Yee-Rendón
CINVESTAV, Mexico City, Mexico

For the HL-LHC it is planned to basically double the diameter of the triplet quadruple magnets around the high luminosity insertions of the LHC. The high luminosity experiments ATLAS and CMS would like to keep a small central chamber radius close the interaction point. In the context of collider-experiment studies for the high-luminosity upgrade of the LHC, we present a first study of the possible consequences of these changes for the experimental running conditions based on detailed simulations with tracking. We have started to implement crab cavity failures and discuss first results from these simulations.

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TUPRO022

Implementation of Luminosity Leveling by Betatron Function Adjustment at the LHC Interaction Points

luminosity, optics, operation, betatron

1058

J. Wenninger, A.A. Gorzawski
CERN, Geneva, Switzerland

Growing expectations for integrated luminosity during upcoming LHC runs introduce new challenges for LHC beam operation in the scope of online luminosity control. Because some LHC experiments are limited in the maximum event rates, their luminosity is leveled to a constant value. Various techniques may be used for luminosity leveling, changing the betatron function at the interaction point is one of them. This paper explains the main operational requirements of a betatron function leveling scheme for the upcoming LHC run. Issues concerning the beam optics, orbits and collimator settings are discussed. The proposed architecture for control system integration will be discussed. A few operational scenarios with different beam configurations foreseen for the next LHC run will be presented.

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TUPRO023

Beam-beam Effects in Different Luminosity Levelling Scenarios for the LHC

luminosity, dynamic-aperture, beam-beam-effects, emittance

1061

X. Buffat, D. Banfi, G.R. Coombs
EPFL, Lausanne, Switzerland
W. Herr, T. Pieloni
CERN, Geneva, Switzerland

Adjusting luminosity and optimizing the luminous region in each interaction point of the LHC according to the experiments needs has become a requirement to maximize the efficiency of the different detectors. Several techniques are envisaged, most importantly by varying β* or a transverse offset at the interaction point. Coherent and incoherent stability in the presence of beam-beam effects will be discussed in realistic luminosity levelling scenarios for the LHC.

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TUPRO031

RHIC Performance during the 7.5 GeV Low Energy Run in FY 2014

luminosity, ion, target, injection

1087

C. Montag, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, S. Nemesure, J. Piacentino, P.H. Pile, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, P. Thieberger, J.E. Tuozzolo, M. Wilinski, K. Yip, A. Zaltsman, K. Zeno, W. Zhang
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.
As the last missing step in phase 1 of the beam energy scan (BES-I), aimed at the search for the critical point in the QCD phase diagram, RHIC collided gold ions at a beam energy of 7.3 GeV/nucleon during the FY 2014 run. While this particular energy is close to the nominal RHIC injection energy of 9.8 GeV/nucleon, it is nevertheless challenging because it happens to be close to the AGS transition energy, which makes longitudinal beam dynamics during transfer from the AGS to RHIC difficult. We report on machine performance, obstacles and solutions during the FY 2014 low energy run.

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TUPRO034

Beam-beam Interaction in the Asymmetric Energy Gold-gold Collision in RHIC

simulation, ion, emittance, collider

1093

Y. Luo, M. Blaskiewicz, M.R. Costanzo, W. Fischer, X. Gu, V.H. Ranjbar, S.M. White
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.
In this article, we study the beam-beam interaction in the possible future gold-gold collision with different particle energies in the Relativistic Heavy Ion Collider (RHIC). With different particle energies, the center-of-mass of collision is moving in the longitudinal direction during collision. Since the RF harmonic numbers are different for the two RHIC rings, bunches collide in 110 turns followed by 10 turns without collision. In this study, the stability of particles and the beam emittance growth are calculated through numeric simulations based on a 6-D weak-strong beam-beam interaction model.

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TUPRO042

Ion Optics of the HESR Storage Ring at FAIR for Operation with Heavy Ions

ion, heavy-ion, target, optics

1117

O.A. Kovalenko, A. Dolinskyy, T. Katayama, Yu.A. Litvinov, T. Stöhlker
GSI, Darmstadt, Germany
B. Lorentz, R. Maier, D. Prasuhn, H. Stockhorst
FZJ, Jülich, Germany

The High Energy Storage Ring (HESR) of the FAIR project is primarily designed for internal target experiments with stored and cooled antiprotons, which is the main objective of the PANDA collaboration. However, the HESR storage ring also appears to have remarkable properties to carry out physics experiments with heavy ions. In this paper a new ion optical design allowing the heavy ion operation mode of the HESR is presented. The main goal was to provide an optics which meets the requirements of the future experiments with heavy ion beams. Closed orbit correction, dynamic aperture as well as other characteristics of beam dynamics of the ion optical setup are under analysis in this study.

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TUPRO045

Simulation Studies on Beam Injection into a Figure-8 Type Storage Ring

simulation, injection, kicker, storage-ring

1126

M. Droba, A. Ates, O. Meusel, H. Niebuhr, D. Noll, U. Ratzinger, J.F. Wagner
IAP, Frankfurt am Main, Germany

The proposed figure-8 storage ring at Frankfurt University [1, 2] is based on longitudinal guiding magnetic fields and will have special features with respect to the beam dynamics. A crucial part of the ring is the injection section, where the low energy beams have to cross an area of steeply rising field – up to B = 6 T into the main ring field. An optimized magnetic channel is designed to bring the injected beam close enough to the magnetic ring flux. An ExB kicker is needed to move the injected beam from the injection channel to the main magnetic field flux allowing multi turn injection. Simulation studies concentrate on this part and will be presented, results will be discussed. A comparison with simulations for prepared scaled down experiments with existing room temperature toroids will be done.

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TUPRO099

Development of a Method for Measuring the Radial Component of the Magnetic Field in AVF Cyclotrons

cyclotron, simulation, proton, extraction

1274

N.A. Morozov, G.A. Karamysheva, S.A. Kostromin, E. Samsonov, N.G. Shakun, E. Syresin
JINR, Dubna, Moscow Region, Russia

In AVF cyclotrons the median plane of the magnetic field rather often does not coincide with the mid-plane of their magnetic system. To measure the radial component of the magnetic field, equipment based on search coils is developed and used to correct the median plane of the magnetic field. The equipment for Br mapping is described. The Br mapping and shimming results are presented for two proton therapy IBA C230 cyclotrons.

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TUPRO117

Magnet Design for the SNS Laser Stripping Experiment

laser, electron, ion, operation

1328

A.V. Aleksandrov, A.A. Menshov
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation.
The first step in the three-step laser assisted H⁻ beam stripping for charge exchange injection is to remove one electron in a strong magnetic field. In order to preserve the beam emittance for the subsequent laser induced stripping of the second electron the magnetic field has to have large gradient of about 40 T/m along the beam trajectory. The required magnetic field strength for stripping 1GeV H⁻ beam is 1.2 T in 29 mm aperture. In order to allow for undisturbed passage of high power beam during the nominal SNS operation the stripping magnet made of permanent magnet material resides in vacuum chamber and can move in and out of the beam line. This presentation describes requirements and design and the magnetic field calculation results for a stripping magnet for the Laser Stripping Experiment at SNS.

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TUPME006

Considerations for a QD0 with Hybrid Technology in ILC

alignment, quadrupole, luminosity, collider

1346

M. Modena, A.V. Aloev, H. Garcia, L. Gatignon, R. Tomás
CERN, Geneva, Switzerland

The baseline design of the QD0 magnet for ILC, the International Linear Collider, is a very compact superconducting quadrupole (coil-dominated magnet). A prototype of this quadrupole is under construction at Brookhaven National Laboratory (USA). In CLIC, the Compact Linear Collider under study at CERN, we are studying another conceptual solution for the QD0. This is due to two main reasons: all the magnets of the Beam Delivery System will need to be stabilized in the nano-meter range and extremely tight alignment tolerances are required. The proposed solution, now baseline for CLIC, is a room temperature hybrid quadrupole based on electromagnetic coils and permanent magnet blocks (iron-dominated magnet). In this paper we present a conceptual design for a hybrid solution studied and adapted also to the ILC project. A special super-ferric solution is proposed to make the cross section compatible with the experiments layout. This design matches the compactness requirement with the advantages of stability and alignment precision, aspects critical also for ILC in order to achieve the design luminosity. Final Focus optics design considerations for this solution are also presented.

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TUPME010

The Physics Programme of next MICE Step IV

emittance, scattering, factory, simulation

1361

J.C. Nugent
University of Glasgow, Glasgow, United Kingdom
V.C. Palladino
INFN-Napoli, Napoli, Italy

Funding: DOE, NSF, STFC, INFN, CHIPP and several others
The International Muon Ionization Cooling Experiment is progressing towards a full demonstration of the feasibility of ionization cooling technology decisive for neutrino physics and muon colliders. Step IV should provide the first precise measurements of emittances and first evidence of cooling. The components required for Step IV, including spectrometer solenoids, muon trackers and absorber-FC (focus coil) modules have been assembled with data collection expected in 2015. The physics programme of this Step will be described in detail, with LiH and a few other promising absorber materials of different shapes.
Abstract presented by the chair of the speaker bureau of the MICE collaboration, that would next select a MICE member to prepare and present the poster

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TUPME011

The Status of the Construction of MICE Step IV

solenoid, emittance, coupling, cavity

1364

P. Snopok
IIT, Chicago, Illinois, USA
E. Overton
Sheffield University, Sheffield, United Kingdom

Funding: DOE, NSF, STFC, INFN, CHIPP and several others
The International Muon Ionization Cooling Experiment will provide the demonstration ionization cooling. The experiment is being built in a series of Steps. Step IV, which consists of a tracking spectrometer upstream and downstream of an absorber/focus-coil (AFC) module will be completed in early in 2015. In this configuration, the emittance of the muon beam upstream and downstream of the absorber will be measured precisely allowing the emittance reduction and the factors that determine the ionization cooling effect to be studied in detail. The AFC module is a 22 liter volume of liquid hydrogen placed inside a superconducting focusing coil. The properties of lithium hydride, and possibly other absorber materials, will also be studied. All the components of Step IV have been manufactured and integration of the experiment in the MICE Hall at the Rutherford Appleton Laboratory is underway. A full study of ionization cooling will be carried out with Step V, which will include a short 201 MHz linac module in which beam transport is achieved with a superconducting “coupling coil”. The status of the preparation of the components of Step V of the experiment will be described briefly.

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TUPME013

Thermo-mechanical Tests for the CLIC Two-beam Module Study

operation, alignment, vacuum, linac

1370

A. Xydou, G. Riddone, A.L. Vamvakas
CERN, Geneva, Switzerland
E. Daskalaki
NTUA, Athens, Greece

The luminosity goal of CLIC requires micron level precision with respect to the alignment of the components on its two-meter long modules, composing the two main linacs. The power dissipated inside the module components introduces mechanical deformations affecting their alignment and therefore the resulting machine performance. Several two-beam prototype modules must be assembled to extensively measure their thermo-mechanical behavior under different operation modes. In parallel, the real environmental conditions present in the CLIC tunnel should be studied. The air conditioning and ventilation system providing specified air temperature and flow has been installed in the dedicated laboratory. The power dissipation occurring in the modules is being reproduced by the electrical heaters inserted inside the RF structure mock-ups and the quadrupoles. The efficiency of the cooling systems is being verified and the alignment of module components is monitored. The measurement results will be compared to finite element analysis model and propagated back to engineering design. Finally, simulation of the most possible CLIC machine cycles is accomplished and preliminary results are analysed.

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TUPME027

Analysis of the Electron Cloud Observations with 25 ns Bunch Spacing at the LHC

dipole, emittance, injection, quadrupole

1410

G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy
G. Arduini, V. Baglin, D. Banfi, H. Bartosik, S.D. Claudet, C.O. Domínguez, J. F. Esteban Müller, G. Iadarola, T. Pieloni, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, C. Zannini, F. Zimmermann
CERN, Geneva, Switzerland

Electron Cloud (EC) effects have been identified as a major performance limitation for the Large Hadron Collider (LHC) when operating with the nominal bunch spacing of 25 ns. During the LHC Run 1 (2010 - 2013) the luminosity production mainly used beams with 50 ns spacing, while 25 ns beams were only employed for short periods in 2011 and 2012 for test purposes. On these occasions, observables such as pressure rise, heat load in the cold sections as well as clear signatures on bunch-by-bunch emittance blow up, particle loss and energy loss indicated the presence of an EC in a large portion of the LHC. The analysis of the recorded data, together with EC build up simulations, has led to a significant improvement of our understanding of the EC effect in the different components of the LHC. Studies were carried out both at injection energy (450 GeV) and at top energy (4 TeV) aiming at determining the energy dependence of the EC formation and its impact on the quality of the proton beam.

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TUPME033

Scaling of TNSA-accelerated Proton Beams with Laser Energy and Focal Spot Size

laser, target, proton, acceleration

4093

L. Obst, S. Kraft, J. Metzkes, U. Schramm, K. Zeil
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany

By focusing an ultra-short high-intensity laser pulse on a solid target, pulses of protons and other positively charged ions with energies of several 10 MeV per nucleon are generated. The properties of these particle beams such as their energy and absolute number are highly dependent on experimental conditions like laser and target parameters. In order to achieve principal comparability between different experimental campaigns at the Draco laser system at the Helmholtz-Zentrum Dresden-Rossendorf, a reference setup for the laser ion acceleration experiment was established. A configuration is sought in which proton beams of reproducible characteristics are generated. To ensure a high stability of the proton spectra, the application of longer focal length parabolas (f ~ 1000 mm) will be tested for this setup, according preparatory studies being presented in this paper.

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TUPME039

System Integration of the Demonstration Siemens Electrostatic Accelerator

high-voltage, ion-source, ion, power-supply

1440

H. von Jagwitz-Biegnitz
JAI, Oxford, United Kingdom
P. Beasley, S. Goßmann-Levchuk, O. Heid
Siemens AG, Erlangen, Germany
D.C. Faircloth
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
R.G. Selway
Inspired Engineering Ltd, Climping, United Kingdom

Siemens has proposed a novel compact DC electrostatic tandem accelerator to produce protons of a few MeV. Siemens is currently building a prototype of the accelerator at the Rutherford Appleton Laboratory. This paper reports on recent progress on the different components of the system as well as the commissioning of the whole machine.

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TUPME042

Planned High-gradient Flat-beam-driven Dielectric Wakefield Experiments at the Fermilab’s Advanced Superconducting Test Accelerator

acceleration, wakefield, emittance, controls

1451

F. Lemery, D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot, J. Zhu
Fermilab, Batavia, Illinois, USA
J. Zhu
CAEP/IFP, Mainyang, Sichuan, People's Republic of China

In beam driven dielectric wakefield acceleration (DWA), high-gradient short-wavelength accelerating fields are generally achieved by employing dielectric-lined waveguides (DLWs) with small aperture which constraints the beam sizes. In this paper we investigate the possibility of using a low-energy (50-MeV) flat beams to induce high-gradient wakes in a slab-symmetric DLW. We demonstrate via numerical simulations the possibility to produce axial electric field with peak amplitude close to 0.5 GV/m. Our studies are carried out using the Fermilab's Advanced Superconducting Test Accelerator (ASTA) photoinjector beamline. We finally discuss a possible experiment that could be performed in the ASTA photoinjector and eventually at higher energies.

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TUPME044

Planned High-brightness Channeling Radiation Experiment at Fermilab's Advanced Superconducting Test Accelerator

electron, detector, radiation, photon

1457

B.R. Blomberg, D. Mihalcea, H. Panuganti, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
C.A. Brau, B.K. Choi, W.E. Gabella, B.L. Ivanov, M.H. Mendenhall
Vanderbilt University, Nashville, Tennessee, USA
C.W. Lynn
Swarthmore College, Swarthmore, Pennsylvania, USA
P. Piot, T. Sen
Fermilab, Batavia, Illinois, USA
W.S. Wagner
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany

Funding: Work supported by the DARPA Axis program under contract AXIS N66001-11-1-4196
In this contribution we describe the technical details and experimental setup of our study aimed at producing high-brightness channeling radiation (CR) at Fermilab’s new user facility the Advanced Superconducting Test Accelerator (ASTA). In the ASTA photoinjector area electrons are accelerated up to 40-MeV and focused to a sub-micron spot on a ~40 micron thick carbon diamond, the electrons channel through the crystal and emit CR up to 80-KeV. Our study utilizes ASTA’s long pulse train capabilities and ability to preserve ultra-low emittance, to produce the desired high average brightness.

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TUPME047

SINBAD - A Proposal for a Dedicated Accelerator Research Facility at DESY

plasma, electron, laser, linac

1466

R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, B. Foster, J. Grebenyuk, I. Hartl, M. Hüning, Y.C. Nie, J. Osterhoff, A. Rühl, H. Schlarb, B. Schmidt
DESY, Hamburg, Germany
M. Groß, B. Marchetti, F. Stephan
DESY Zeuthen, Zeuthen, Germany
F.J. Grüner, B. Hidding, A.R. Maier
Uni HH, Hamburg, Germany
F.X. Kärtner, B. Zeitler
CFEL, Hamburg, Germany
A.-S. Müller, M. Schuh
KIT, Karlsruhe, Germany

A new, dedicated accelerator research facility SINBAD (Short INnovative Bunches and Accelerators at DESY) is proposed. This facility is aimed at promoting two major goals: (1) Short electron bunches for ultra-fast science. (2) Construction of a plasma accelerator module with useable beam quality. Research and development on these topics is presently ongoing at various places at DESY, as add-on experiments at operational facilities. The two research goals are intimately connected: short bunches and precise femtosecond timing are requirements for developing a plasma accelerator module. The scientific case of a dedicated facility for accelerator research at DESY is discussed. Further options are mentioned, like the use of a 1 GeV beam from Linac2 for FEL studies and the setup of an attosecond radiation source with advanced technology. The presently planned conversion of the DORIS storage ring and its central halls into the SINBAD facility is described. The available space will allow setting up several independent experiments with a cost-effective use of the same infrastructure. National and international contributions and proposals can be envisaged.

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TUPME048

Injection of a LWFA Electron Bunch in a PWFA Driven by a Self-modulated-proton-bunch

plasma, wakefield, electron, laser

1470

P. Muggli
MPI, Muenchen, Germany
L.D. Amorim
IST, Lisboa, Portugal
S. Karsch
MPQ, Garching, Munich, Germany
N.C. Lopes, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal

The AWAKE experiment recently approved at CERN will study the acceleration of an externally injected electron bunch in a plasma wakefield accelerator (PWFA) driven by a self-modulated proton bunch. We study the possibility of injecting a bunch created by a laser-driven plasma wakefield accelerator (LWFA). We consider a first plasma source used for self-modulation of the drive bunch and a gas discharge source for acceleration of the collinearly injected bunch. The LWFA produces an electron bunch very short when compared to the PWFA wavelength and with relatively large current, possibly allowing for loading of the wakefields. Short length and high current lead to a small final energy spread. Co-linear injection preserves the incoming bunch quality and insures trapping and acceleration of the whole bunch. The energy of the LWFA electron bunch can easily exceed the trapping energy and can be produced over only a few millimeters gas-jet plasma driven by a laser of relatively modest power by today’s standards. We explore the parameter space suitable for this injection scheme that is more compact, simpler to implement and more suitable for injection in the mm-size accelerator structure.

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TUPME049

Hosing Suppression in the Self-modulated Wakefield Accelerator

plasma, wakefield, flattop, controls

1473

J. Vieira
IPFN, Lisbon, Portugal
W.B. Mori
UCLA, Los Angeles, California, USA
P. Muggli
MPI, Muenchen, Germany

Funding: FCT-Portugal contract no EXPL/FIS-PLA/0834/1012; European Research Council contract no ERC-2010-AdG Grant 267841; by DOE contract no DE-SC0008491, DE-SC0008316, and DE-FG02- 92-ER40727.
The proton driven plasma wakefield accelerator (PDPWFA) uses short LHC proton (p⁺) bunches (shorter than the plasma wavelength) as drivers for strongly non-linear plasma waves. Simulations showed that the PDPWFA could be used to accelerate electrons to 600 GeVs in 600 m long plasmas*. Currently available p⁺ bunches are much longer than the plasma wavelength, being ideal to excite intese wakefields through the self-modulation instability (SMI). An experiment is being prepared at CERN to demonstrate SMI of p⁺ bunches. In addition, lepton SMI experiments are also being prepared at SLAC, DESY-PITZ and RAL. The hosing instability (HI) is a competing instability that may lead to beam breakup, and needs to be controlled over the long propagation distances required for SMI growth and saturation. In this work we show that the HI can be suppressed after SMI saturation in the linear wakefield excitation regime. SMI saturation before beam-break up can be achieved by seeding SMI, and as long as the initial bunch centroid displacements are within the initial bunch transverse size. The HI suppression occurs via a plasma analogue of the BNS damping in conventional accelerators.
* A. Caldwell et al, Nat. Physics Nat. Phys. 5, 363 (2009).

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TUPME050

Electron Bunch Self-modulation in Long Plasmas at SLAC FACET

plasma, wakefield, electron, radiation

1476

P. Muggli
MPI, Muenchen, Germany
E. Adli, V.K.B. Olsen
University of Oslo, Oslo, Norway
L.D. Amorim
IST, Lisboa, Portugal
S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos
SLAC, Menlo Park, California, USA
C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
N.C. Lopes, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal
O. Reimann
MPI-P, München, Germany

Funding: This work performed in part under DOE Contract DE-AC02-76SF00515.
We study the physics of self-modulation instability (SMI) of long, when compared to the wake wavelength, electron and positron bunches in pre-formed plasmas at SLAC-FACET. Self-modulation is the result of the action of focusing/defocusing transverse wakefields on the bunch radius. Self-modulation leads to observables such as overall defocusing of the bunch, periodic modulation of the bunch radius at the wake period and multi-GeV energy gain/loss by drive bunch particles. Defocusing is observed from OTR images, radial self-modulation from CTR spectra and interferometric traces and energy gain/loss from energy spectra with sub-GeV resolution. The plasma density is varied by changing the vapor density ionized by a laser/axicon system. The bunch length, radius and charge can also be varied. The SMI can be seeded using a notch collimator system. Numerical simulations indicate that seeding the SMI mitigates the hose instability. Hose instability can also be seeded, for example by using the RF deflecting cavity to impart a tilt to the incoming bunch axis. The overall experimental plan as well as the latest experimental results obtained with electron bunches will be presented.

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TUPME058

The Argonne Wakefield Accelerator (AWA): Commissioning and Operation

wakefield, gun, electron, laser

1503

M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, C.-J. Jing, C. Li, W. Liu, J.G. Power, J.Q. Qiu, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Cao
IMP, Lanzhou, People's Republic of China
C. Li, J.H. Shao
TUB, Beijing, People's Republic of China
E.E. Wisniewski
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
The commissioning of the upgraded AWA facility is well underway. The new L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of four bunches with up to 80 nC per bunch have been generated. The six new accelerating cavities (L-band, seven cells, pi mode) have been RF conditioned to 12 MW or more; their operation at 10 MW brings the beam energy up to 75 MeV. Measurements of the beam parameters are presently underway, and the use of this intense beam to drive high gradient wakefields will soon follow. One of the main goals of the facility is to generate RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.

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TUPME059

Longitudinal Bunch Shaping with a Double Dogleg based Emittance Exchange Beam Line

emittance, space-charge, controls, cavity

1506

G. Ha, M.E. Conde, W. Gai, C.-J. Jing, K.-J. Kim, J.G. Power, A. Zholents
ANL, Argonne, Illinois, USA
M.-H. Cho, G. Ha, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: Work supported by High Energy Physics, Office of Science, US DOE.
A new program is under development at Argonne National Laboratory (ANL) to use an emittance exchange (EEX) beamline to produce longitudinally shaped electron bunches. While the ultimate goal is to generate triangular shapes for high transformer ratio wakefield acceleration we are also exploring, in general, the capability of the double dogleg EEX beamline to control the bunch shape. We are studying effects that degrade the quality of the longitudinal current profile including: non-uniform particle distribution, emittance, the deflecting cavity thick-lens effect, 2nd order effects, space charge effects and coherent synchrotron radiation effects. We will present the double dogleg EEX beamline layout and the diagnostic design as well as give a progress report on the experimental status of the program.

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TUPME069

Proton Electron Accelerator at CERN

plasma, proton, electron, wakefield

1519

R. Tarkeshian
MPI, Muenchen, Germany

AWAKE is a proton driven plasma-wakefield acceleration at CERN*, that uses long proton bunches ~ 400 ps from the SPS. In a dense plasma, a long proton bunch is subject toμbunching at plasma period due to the self-modulation instability, SMI**. The self-modulated proton bunch generates large amplitude charge separation through resonant wakefield excitation. Numerical simulations show that when seeded the SMI can grow and saturate over ~4 m in a plasma with density in the (1-10) *10¹⁴/cc range. Seeding also allows for deterministic injection of witness bunches in the focusing and accelerating phase of the wakefields. The SPS proton bunch carrying kJ of energy is a unique driver for generation of ~ GeV/m wakefields through 10’s of meters of plasma. The side-injected electrons ~15 MeV can reach GeV energies. The AWAKE experimental layout, the physics of self-modulation, simulation results, plasma source under study, diagnostics plan for bunch modulation measurement using transverse coherent transition radiation***, and phasing of the witness bunch respect to the wave and synchronisation with diagnostics will be presented.****
*A. Caldwel, et. al, Nature Physics 5, 2009
**N. Kumar, A. Pukhov, PRL, 104, 2010
***O. Reimann, R. Tarkeshian, Proc. of IBIC, 2013
**** The work is submitted on behalf of AWAKE collaboration.

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TUPME074

First Experiences with the PITZ Plasma Cell for Electron Beam Self-modulation Studies

plasma, electron, proton, Windows

1525

M. Groß, A. Donat, J.D. Good, M. Khojoyan, G. Koss, M. Krasilnikov, R. Schütze, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
R. Brinkmann
DESY, Hamburg, Germany
F.J. Grüner, G. Pathak
Uni HH, Hamburg, Germany
P. Muggli, E. Öz
MPI-P, München, Germany
D. Richter
HZB, Berlin, Germany
C.B. Schroeder
LBNL, Berkeley, California, USA

The self-modulation of long particle beams in a plasma has recently gained interest in light of the ongoing preparation for the plasma wakefield acceleration experiment of the AWAKE collaboration at CERN. Instrumental to the experiment is the self-modulation of a proton beam to generate bunches short enough for producing high acceleration fields. As electron bunches are easier to handle and the underlying physics is identical, it is judicious to first gain insight into the experimental conditions of the self-modulation of long particle beams in plasma by using electron bunches before progressing to the experiment with proton bunches. The experimental demonstration of self-modulation of an electron bunch is in preparation at the Photo Injector Test facility at DESY, location Zeuthen (PITZ). In this contribution the fabrication and first experimental tests towards a Lithium plasma cell are highlighted. The distinctive feature of this plasma cell is the addition of side ports for insertion of the ionization laser beam and for diagnostics purposes.

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TUPME076

Numerical modeling of the E-209 self-modulation experiment at SLAC - FACET

plasma, electron, wakefield, simulation

1531

L.D. Amorim, L.O. Silva, J. Vieira
IPFN, Lisbon, Portugal
P. Muggli
MPI, Muenchen, Germany

The E-209 experiment currently running at SLAC- FACET used a long electron bunch (∼ 5 times the plasma wavelength) to drive plasma wakefields through the self- modulation instability. In this work we present and analyze numerical simulation results performed with the particle-in- cell (PIC) code OSIRIS. The results show that SMI saturates after 5cm of propagation in the plasma and that the maxi- mum acceleration wakefields, 15 − 20GV/m, are sustained over a 1m long plasma. Electron bunch energy loss of 4GeV was observed in the simulations.

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TUPRI003

Simulating the Production and Eﬀects of Dark Currents in MICE Steps V and VI

electron, cavity, solenoid, simulation

1556

C. Hunt, J. Pasternak, M.A. Uchida
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: STFC
The completion of the international Muon Ionisation Cooling Experiment (MICE) Step V will involve the construction, commissioning and use of RF cavity and Coupling Coil (RFCC) Modules. The RFCCs consist of 4 RF cavities and a solenoid magnet, and are expected to act as a source of potentially damaging electrons (dark currents) and X-rays. Ongoing work to create a high-statistics simulation of the dark current production, within RF cavities, is described. Current results predict the energy and angular spectra of emitted electrons for an RFCC, and include particle tracking, realistic field maps and ionisation energy losses in cavity windows. Individual electron emitters, parametrised by the Fowler-Nordheim equation, are used and are user-definable, allowing potential worst-case scenarios to be simulated and upper/lower limits for the total dark current to be estimated. These data are being used within the MICE Analysis and User Software (MAUS) to estimate the potential detector backgrounds and the damage that may be inflicted upon the scintillating fibre trackers.

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TUPRI004

The Design and Implementation of The Radiation Monitors for the Protection of the MICE Tracker Detectors

radiation, detector, emittance, electron

1559

M.A. Uchida, C. Hunt, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

A radiation monitor will be required for the Muon Ionisation Cooling experiment (MICE) beyond Step IV, when the RF cavities are installed. The role of the radiation monitors will be to protect the particle tracking detectors (Trackers) from dangerous levels of RF dark currents and the as- sociated photon fluxes that could potentially be produced in the RF cavities. If such levels of radiation should occur the radiation monitor will ensure that the radiation shields (shutters) are closed thereby protecting the Tracker modules. The radiation monitor will be positioned on these radiation shields and will monitor x-rays, gamma-rays and electrons up to a few MeV. It is expected that the spectrum will peak at very low energies, since the peak voltage across the cavities is 8 MV/m and so the maximum energy that an electron could gain is 12 MeV (maximally accelerated from all four RF cavities). The design, positioning and expected sensitivity of the radiation monitors will be described here along with their readout and inclusion into the MICE interlocking systems. The schedule for the work and progress so far will also be presented.

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TUPRI009

Study of Resonance Crossing in Non-scaling FFAGs using the S-POD Linear Paul Trap

resonance, ion, dipole, acceleration

1571

D.J. Kelliher, S. Machida, C.R. Prior, S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
K. Fukushima, K. Ito, K. Moriya, H. Okamoto, T. Okano
HU/AdSM, Higashi-Hiroshima, Japan

Experiments on EMMA have shown that with rapid acceleration (~10 turns) a linear non-scaling FFAG can accelerate through several integer tunes without detrimental effects on the beam [1]. Proton and ion applications such as hadron therapy will necessarily have a slower acceleration rate, so their feasibility depends on how harmful resonance crossing is in this regime. A simple and useful tool to answer such fundamental questions is the S-POD linear Paul trap at Hiroshima University, which can be set up to simulate the dynamics of a beam in an FFAG. We report here results of experiments to explore different resonance crossing speeds, quantify beam loss and study nonlinear effects. We also discuss the implications of these experimental results in terms of limits on acceptable acceleration rates and alignment errors.
[1] S.Machida et al, Nature Physics, N8, 243-257 (2012)

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TUPRI014

Modelling and Long Term Dynamics of Crab Cavities in the LHC

cavity, multipole, luminosity, hadron

1578

R. Appleby, D.R. Brett
UMAN, Manchester, United Kingdom
J. Barranco García, R. De Maria, A. Grudiev, R. Tomás
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan.
The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 250-300 fb-1 per year. This upgrade includes the use crab cavities to mitigate the geometric loss of luminosity arising from the beam crossing angle. The tight space constraints at the location of the cavities leads to cavity designs which are axially non-symmetric and have a potentially significant effect on the long term dynamics and dynamic aperture of the LHC. In this paper we present the current status of advanced modelling of crab cavities.

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TUPRI038

The Low Energy Particle Wakefield Radiation From the Open End of Internally Coated Metallic Tube

radiation, wakefield, vacuum, resonance

1644

M. Ivanyan, A. Grigoryan, A. Sargsyan, A.V. Tsakanian
CANDLE SRI, Yerevan, Armenia

The radiation of the non-relativistic electron beam from the open end of the resistive circular waveguide is presented. The angular and spectral characteristics of the radiation are determined. The possibility of producing the focused guasi-monochromatic radiation is discussed. The principal scheme of the experiments for 5 and 20 MeV AREAL RF photogun linac is presented.

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TUPRI050

Numerical Calculation and Experiment of Ion Related Phenomenon in SPring-8 Storage Ring

ion, electron, simulation, storage-ring

1680

A. Mochihashi, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

In the SPring-8 storage ring, various kinds of bunch filling pattern are available. Under some bunch filling patterns, residual gas ions created by scattering process between high energy electrons and residual gas molecules can be trapped stably around the electron beam and disturb the original motion of the beam. We have considered the stability of the electron beam due to the ion related phenomenon under several bunch filling patterns by computer simulation. In the simulation, we have modeled the electron bunch as single particle and the residual gas ions as macroparticles. The number of the trapped ions, size of the ion cloud and change in betatron oscillation amplitude of the beam under several filling pattern conditions will be discussed. We have also performed experiments for stability of the beam under equally spaced bunch filling patterns which give severe condition for the ion related instability. The numerical calculations and the experimental results will be discussed in the presentation.

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TUPRI054

FEM Analysis of Beam-coupling Impedance and RF Contacts Criticality on the LHC UA9 Piezo Goniometer

impedance, simulation, resonance, coupling

1692

A. Danisi, R. Losito, A. Masi, A. Passarelli, B. Salvant, C. Zannini
CERN, Geneva, Switzerland

The UA9 piezo-goniometer has been designed to guarantee micro-radians-accuracy angular positioning of a silicon crystal for a crystal collimation experiment in the LHC, and to minimize the impact on the LHC beam-coupling impedance. This paper presents a Finite Element Method (FEM) study of the device, in both parking and operational positions, to evaluate its impact on the LHC impedance budget. The study has been a progressive simulation work, started from the simplification of the original detailed design, and aimed at highlighting the effect of single details (e.g. objects in confining chambers) on the longitudinal and transverse components of beam-coupling impedance. In addition, the shielding contribution of the RF gaskets has been carefully evaluated, with the objective to assess the consequences for operation in case of their failure. Sensitivity analyses to simulation parameters are also performed, in order to test the FEM model robustness. A final word is drawn on the overall device impedance criticality.

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TUPRI094

Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor

laser, vacuum, alignment, linear-collider

1793

G. Stern, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin
CERN, Geneva, Switzerland
A. Geiger, S. Guillaume
ETH, Zurich, Switzerland

Aligning accelerator components over 200m with 10 μm accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The positions of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser pointing stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser pointing stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 μm at 35m) than in air (2000 μm at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric positioning over 35m. It also gives an estimation of the achievable precision.

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TUPRI108

Development of New Tag Supply System for DAQ for SACLA User Experiments

laser, controls, free-electron-laser, electron

1826

T. Abe
RIKEN SPring-8 Center, Innovative Light Sources Division, Hyogo, Japan
A. Amselem, K. Okada, R. Tanaka, M. Yamaga
JASRI/SPring-8, Hyogo-ken, Japan

This paper presents development of a new tag supply system for the data-acquisition (DAQ) system for SACLA user experiments. The X-ray Free-Electron Laser facility in SPring-8, SACLA, has delivered X-ray laser beams to users since March 2012 [1]. For the user experiments at SACLA, a dedicated DAQ system has been developed. The DAQ system is currently capable to operate with maximum ten sensors of multiport Charge-Coupled Device (MPCCD) for X-ray detection. The data of ten sensors are read out with individual readout modules. We implement a new tag supply system to ensure the reconstruction of the diffraction image of the user experiments. The tag data are used to synchronize the data. One master server receives a signal given by accelerator and the delivery of the tag data follows to five experimental halls at SACLA and some of monitors at SACLA accelerator. We employ dedicated communication lines to deliver the tag data. The longest distance to deliver the tag data is about one kilometer. We need to update entire softwares of DAQ system for the implementation. We will implement the new system to the DAQ system by the spring 2014.
[1] T. Ishikawa et al., "A compact X-ray free-electron laser emitting
in the sub-angstrom region", Nature Photonics 6, 540-544 (2012).

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WEOAA03

Ultrashort and Coherent Radiation for Pump-probe Experiments at the DELTA Storage Ring

radiation, laser, electron, undulator

1848

M. Huck, S. Hilbrich, H. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Work supported by DFG, BMBF, and by the Federal State NRW.
A light source facility employing the coherent harmonic generation (CHG) principle is being commissioned and operated since 2011 at DELTA, a 1.5-GeV electron storage ring at the TU Dortmund University, with the purpose of providing ultrashort coherent VUV radiation for time-resolved experiments. CHG is based on the interaction of ultrashort laser pulses with electrons in an undulator to generate coherent harmonics of the laser wavelength. Different methods have been used to optimize, detect and characterize the CHG radiation. One example is the study of transverse and longitudinal coherence properties in double-slit and Michelson experiments. Moreover, final steps towards performing pump-probe experiments to study ultrafast magnetic phenomena have been taken.

Slides WEOAA03 [4.139 MB]

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WEOBA03

Status of Preparations for a 10 μs Laser-Assisted H⁻ Beam Stripping Experiment

laser, ion, optics, injection

1864

S.M. Cousineau, A.V. Aleksandrov, V.V. Danilov, T.V. Gorlov, Y. Liu, A.A. Menshov, M.A. Plum, A.P. Shishlo, Y. Wang
ORNL, Oak Ridge, Tennessee, USA
F.G. Garcia, N.F. Luttrell
UTK, Knoxville, Tennessee, USA
D.E. Johnson
Fermilab, Batavia, Illinois, USA
A. Rakhman
ORNL RAD, Oak Ridge, Tennessee, USA
Y. Takeda
KEK, Ibaraki, Japan

Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation.
The concept of laser-assisted H⁻ stripping, originated over three decades ago, was successfully demonstrated for a 6 ns, 900 MeV H⁻ beam in 2006. Plans are underway to build on this foundation by performing laser-assisted H⁻ stripping of a 10 μs, 1 GeV H⁻ beam at the Spallation Neutron Source facility; this constitutes a three orders of magnitude improvement over the initial proof of principle demonstration. The central theme of the experiment is the reduction of the required laser power through ion beam manipulations and laser-ion beam temporal matching. This paper discusses the configuration of the experiment, the current and anticipated challenges, and the schedule.

Slides WEOBA03 [2.549 MB]

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WEOCA02

Recent Results from CTF3 Two Beam Test Stand

HOM, wakefield, accelerating-gradient, diagnostics

1880

W. Farabolini, F. Peauger
CEA/DSM/IRFU, France
Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
R. Corsini, D. Gamba, A. Grudiev, M.A. Khan, S. Mazzoni, J.L. Navarro Quirante, R. Pan, J.R. Towler, N. Vitoratou, K. Yaqub
CERN, Geneva, Switzerland

From mid-2012, the Two Beam Test Stand (TBTS) in the CTF3 Experimental Facility is hosting 2 high gradient accelerating structures powered by a single power extraction and transfer structure in a scheme very close to the CLIC basic cell. We report here about the results obtained with this configuration as: energy gain and energy spread in relation with RF phases and power, octupolar transverse beam effects compared with modeling predictions, breakdown rate and breakdown locations within the structures. These structures are the first to be fitted with Wake Field Monitors (WFM) that have been extensively tested and used to further improve the structures alignment on the beam line. These results show the unique capabilities of this test stand to conduct experiments with real beams.

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WEOAB02

Wide-band Induction Acceleration in the KEK Digital Accelerator

acceleration, induction, ion, synchrotron

1893

T. Yoshimoto, X. Liu, K. Takayama
TIT, Yokohama, Japan
T. Adachi, K. Takayama
Sokendai, Ibaraki, Japan
T. Adachi, T. Arai, E. Kadokura, T. Kawakubo, X. Liu, K. Okamura, S. Takano, K. Takayama, T. Yoshimoto
KEK, Ibaraki, Japan
H. Asao, Y. Okada
NETS, Fuchu-shi, Japan
M. Hirose, H. Kobayashi
Tokyo City University, Tokyo, Japan

Induction synchrotron can accelerate any ion species directly to higher energy without a large pre-accelerator, due to its intrinsic nature that there is no frequency band-width limitation below 1 MHz. KEK digital accelerator (DA) is a small scale prototype of fast cycling induction synchrotron. Recently it has been confirmed that heavy ion beams of mass to charge ratio A/Q = 4 are stably accelerated from 200 keV to a few tens of MeV in this accelerator ring*, where the revolution frequency changes from82 kHz to 1 MHz. Acceleration and beam confinement are separately realized by pulse voltages generated in induction cells (1 to 1 pulse transformers) driven by the switching power supply (SPS)**. Everything is simply maneuvered by controlling of gate signals of solid-state switching elements employed in the SPS. For this purpose, the fully programmed acceleration control system based on the FPGA has been developed. In this paper, the wide-band induction acceleration is presented with experimental results. Further possibilities of beam handling in the induction synchrotron, such as super bunch and novel beam handling techniques, are discussed.
* K.Takayama et al., to be submitted to Phys. Rev. Lett. (2013).
** T.Iwashita et al., Phys. Rev. ST-AB 14, 071301(2011).

Slides WEOAB02 [8.935 MB]

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WEOBB01

Design and Performance of the Optical Fiber Length Stabilization System for SACLA

laser, controls, timing, feedback

1906

H. Maesaka, T. Ohshima, Y. Otake
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Matsubara
JASRI/SPring-8, Hyogo, Japan

The x-ray free electron laser facility, SACLA, requires timing synchronization accuracies of less than 50 fs for acceleration rf components and less than 10 fs for pump-and-probe user experiments. Although a stable timing distribution system with optical fiber cables was constructed*, a timing drift of more than 100 fs has been observed after the transmission of about 100 m**. In order to suppress optical fiber length drift, we developed and installed an optical fiber length stabilization system with a Michelson interferometer. A frequency-stabilized laser with a wavelength of 1.5 um is transmitted together with a timing signal and it is reflected back to the interferometer. The length signal from the interferometer is fed back to a fiber stretcher for fiber length control. A prototype system showed that the length of a 1km-long optical fiber in a feedback loop was stabilized within 0.1 um corresponding to 0.5 fs. From this result, a timing accuracy improvement of pump-and-probe experiments can be expected. In this presentation, the design and basic performance of the optical fiber length stabilization system and the operational experience at SACLA will be reported.
* H. Maesaka et al., Proceedings of FEL’08, 352 (2008).
** H. Maesaka et al., Proceedings of FEL’12, 325 (2012).

Slides WEOBB01 [2.673 MB]

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WEPRO006

Beam-driven Terahertz Source based on Open Ended Waveguide with a Dielectric Layer

radiation, vacuum, wakefield, optics

1949

A.V. Tyukhtin, S.N. Galyamin, V.V. Vorobev
Saint-Petersburg State University, Saint-Petersburg, Russia
S.P. Antipov
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia

Funding: Work is supported by the Grant of the President of Russian Federation (MK-273.2013.2) and the Russian Foundation for Basic Research (Grant No. 12-02-31258).
Electromagnetic waves with frequencies from 0.1 THz to 10 THz (usually called the Terahertz gap) are of great importance for a number of scientific and practical applications. Different techniques are known allowing generating these frequencies. However, a current trend of physics and industry is to fill this gap with more powerful and efficient sources. For example, recent experiments have shown promising THz generation in dielectric loaded structures*. Developing this area, we consider the THz emitting scheme where an ultrarelativistic charge exits the open end of a cylindrical waveguide with a dielectric layer and produces THz waves in a form of Cherenkov radiation. The end of the waveguide is supposed to be either orthogonal to the structure axis or skewed. To obtain THz frequencies from waveguides with centimeter or millimeter radii, we consider high order modes. We present typical field patterns (in the Fraunhofer zone) and show that the aperture of the vacuum channel gives, as a rule, the main contribution. We also give simple expressions for the angle of the main pattern lobe.
* S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012).

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WEPRO056

Development of an Optical Resonant Cavity for the LCS Experiment at cERL

cavity, laser, photon, resonance

2072

T. Akagi, Y. Honda, A. Kosuge, J. Urakawa
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, T. Shizuma
JAEA, Ibaraki-ken, Japan

A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays by laser Compton scattering (LCS) is under development. In order to demonstrate the accelerator and laser performance required for the gamma-ray source, an LCS experiment is planned at Compact ERL (cERL) at KEK. An optical resonant cavity is under construction for the LCS experiment. The new optical cavity is designed by combination of two bow-tie cavities to achieve fast optical polarization switching. The performance of the optical cavity is presented in detail.

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WEPRO059

Analysis and Design of a New Kirkpatrick-Baez Mirror System for Microbeams

focusing, operation

2081

K.H. Gil, H. J. Choi, J.Y. Huang, M.H. Jung, J.H. Lim
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This research is part of the results of the Basic Science Research Program performed by the support of the NRF of Korea funded by the Korean Ministry of Education (2013R1A1A2012390).
In this research, a new K-B mirror system was developed for focusing a microbeam to 1 μm x 1 μm at the 4B beamline of the Pohang Light Source-II. The new K-B mirror system consists of a pair of assemblage having three mechanisms that adjust the position, pitch, and curvature of each vertically and horizontally focusing mirrors and stages that support both the assemblages to enable translations along two orthogonal axes and rotation on the horizontal plane. Both the pitch- and curvature-adjusting mechanisms were designed as flexural mechanisms driven by their respective single actuators to minimize the movement of the mirror center even when the pitch or the curvature of each mirror was adjusted. The K-B mirror system with these features will be robust against possible disturbances and will help promote easy and simple mirror adjustment. This paper describes the whole design of the new K-B mirror system in detail and the structural analysis results of the pitch- and the curvature-adjusting mechanisms, and reports the operation principle of the curvature-adjusting mechanism.

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WEPRO061

Optimization of the SIS18 Injector Operation for FAIR

acceleration, operation, controls, space-charge

2088

D. Ondreka, H. Liebermann, B.R. Schlei
GSI, Darmstadt, Germany

In the FAIR accelerator complex, the existing synchrotron SIS18 will serve as an injector, supplying intense beams of heavy ions and protons for further acceleration in the synchrotron SIS100. In order to satisfy the intensity requirements for FAIR, SIS18 has to be operated routinely at the space charge limit. Particularly demanding requirements arise from the operation with medium charge state heavy ions due to the dynamic vacuum created by ions lost through charge exchange reactions. It is therefore crucial to avoid losses in SIS18 as much as possible while confining unavoidable losses onto low desorption surfaces. In this contribution we report on the ongoing activities related to minimizing the losses by means of a better quantitative understanding and control of the beam. This includes the development of more accurate theoretical models, benchmarked with machine experiments, as well as the practical integration of the models into the control system, using beam instrumentation data in the calculation of set values whenever possible.

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WEPRO086

Experimental Activity in the ENEA-Frascati Irradiation Facility with 3-7 MeV Protons

proton, detector, DTL, linac

2156

M. Vadrucci, A. Ampollini, F. Bonfigli, M.C. Carpanese, F. Marracino, R.M. Montereali, P. Nenzi, L. Picardi, M. Piccinini, C. Ronsivalle, V. Surrenti, M.A. Vincenti
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
URLS, Rome, Italy
M. Balduzzi, C. Marino, C. Snels
ENEA Casaccia, Roma, Italy
M. Balucani, A. Klyshko
University of Rome "La Sapienza", Rome, Italy
C. De Angelis, G. Esposito, M.A. Tabocchini
ISS, Rome, Italy

A variable energy (3-7 MeV) and pulsed current (0.1 – 100 μA) proton beam has been made available for different applications (radiobiology experiments, detectors development, material studies) in an irradiation facility at ENEA-Frascati based on the 7 MeV injector of the protontherapy linac under realization in the framework of the TOP-IMPLART Project. It is a 425 MHz linear accelerator consisting in a 3 MeV RFQ followed by a DTL up to 7 MeV (PL-7 ACCSYS-HITACHI model) followed by an horizontal and a vertical beam transport line. The latter one is particularly suitable for radiobiology in vitro studies allowing to irradiate besides cell monolayes also cell growing in suspension culture. The paper describes the facility and the recent results of the experimental activity.

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WEPRO089

Latest Developments of a C-band 2MeV Accelerator

operation, linac, status, detector

2165

W. Bai, M. Li, L.J. Shan, X.M. Shen, Z. Xu
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

A C-band 2MeV accelerator is developped at CAEP in China. This research is aimmed at developing an compact accelerator used as X ray source for industrial useage. At present, the C-band accelerator has been developed successfully. we have carried out a lot of research work based on the accelerator, including test of X ray energy, focus and dose rate etc. This paper shows the latest experimental results and application research status on the C-band accelerator.

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WEPRO108

Electron Diffraction on VELA at Daresbury

electron, gun, laser, space-charge

2218

M. Surman
STFC/DL/SRD, Warrington, Cheshire, United Kingdom
P. Aden, R.J. Cash, D.M.P. Holland, M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
W.A. Bryan
Swansea University, Swansea, Wales
J.A. Clarke, J.W. McKenzie
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P.D. Lane, D.A. Wann
University of York, York, United Kingdom
J.G. Underwood
UCL, London, United Kingdom

Accelerator based Ultrafast Electron Diffraction (UED) is a technique for static and dynamic structural studies in material and biological sciences. The recently commissioned VELA accelerator at the Daresbury Laboratory provides multi-MeV beams for science and industry and will provide a test bed for the UK electron diffraction community. We present the design of the diffractometer currently being installed on VELA which will allow capture of a single shot diffraction pattern with a 1 pC electron bunch and outline future options.

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WEPRO109

Experimental Determination of Heavy Nuclei Fission Cross-sections under Relativistic Deuterons Irradiation on the Accelerator Complex “Nuclotron” for Purposes of Transmutation and Energy Amplification

neutron, detector, target, simulation

2221

V.V. Bukhal, A.A. Patapenka, A.A. Safronava
JIPNR-Sosny NASB, Minsk, Belarus
M. Artiushenko
NSC/KIPT, Kharkov, Ukraine
K.V. Husak
The Joint Institute of Power and Nuclear Reserach - "SOSNY" NASB, Minsk, Belarus
S.I. Tyutyunnikov
JINR, Dubna, Moscow Region, Russia

Experimental studies of neutron spectra of three different subcritical assemblies driven by an accelerator (Accelerator Driven Systems – ADS) for investigation of the possibility of transmutation and energy amplification have been carried out. The assemblies were constructed in the framework of the international project “Energy and Transmutation of Radioactive Wastes” and experiments with them are running in the Veksler and Baldin Laboratory of High Energy Physics of the Joint Institute for Nuclear Research (Dubna, Russia) at the accelerator complex “Nuclotron”. In this paper the results of measurements of 239Pu(n, f), 235U(n, f), 238U(n, f) and 238U(n,γ) reactions cross-sections and reactions rates using solid state nuclear track detectors and activation gamma-spectroscopy are presented. A comparison of the experimental results with FLUKA calculations is given. The obtained experimental values characterize the neutron spectra in the experimental points and allow the efficiency of the ADS technology for the systems with similar parameters to be evaluated.

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WEPRO114

SALOME: An Accelerator for the Practical Course in Accelerator Physics

cathode, quadrupole, electron, emittance

2235

V. Miltchev, D. Riebesehl, J. Roßbach, M. Trunk
Uni HH, Hamburg, Germany
O. Stein
CERN, Geneva, Switzerland

SALOME (Simple Accelerator for Learning Optics and the Manipulation of Electrons) is a short low energy linear electron accelerator built by the University of Hamburg. The goal of this project is to give the students the possibility to obtain hands-on experience with the basics of accelerator physics. In this contribution the layout of the device will be presented. The most important components of the accelerator will be discussed and an overview of the planned demonstration experiments will be given.

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WEPRO116

Direct High Power Laser Diagnostic Technique Based on Focused Electron Bunch

electron, laser, solenoid, scattering

2242

R. Sato, A. Endo, K. Nonomura, K. Sakaue, M. Washio, Y. Yoshida
Waseda University, Tokyo, Japan

In laser produced plasma EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efficiency and stable EUV power, we desire to measure laser profile in collision point. However, focused laser profile has not been observed directory by existing techniques. We have been developing laser profiler based on laser Compton scattering. Laser profile can be measured by scanning focused electron beam while measuring Compton scattering signal. This method is suitable for a high intensity laser, but very small spot size of electron beam is required. To achieve small spot size, we use S-band photocathode rf gun and special design solenoid lens. The beam size was simulated by General particle tracer (GPT) and directory measured by Gafchromic film HD-810. We have succeeded in observing minimum beam size of about 20 μm rms. We are preparing beam scanning system, pulse CO2 laser and a detector for Compton signal. In this conference, we will report the results of focused electron beam measurement and future prospective.
Work supported by NEDO(New Energy and Industrial Technology Development Organization).

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WEPRO118

THz Radiation Generation in Multimode Wakefield Structures

radiation, wakefield, electron, linac

2248

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, Illinois, USA
D. Wang
TUB, Beijing, People's Republic of China

Funding: DOE SBIR
A number of methods for producing sub-picosecond electron bunches have been demonstrated in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We propose to use a bunch train like this to selectively excite a high order mode in a dielectric wakefield structure. This allows us to use wakefield structures that are geometrically larger and easier to fabricate for beam-based THz generation. In this paper we present a THz source design based on this concept and experimental progress to date.

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WEPME002

Laser System for SNS Laser Stripping Experiment

laser, cavity, controls, neutron

2254

Y. Liu, C. Huang, A. Rakhman
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation.
The Spallation Neutron Source (SNS) accelerator complex utilizes charge-exchange injection to stack a high-intensity proton beam in the accumulator ring for short-pulse neutron production. A foil-less charge exchange injection method was researched at SNS by using a laser assisted H⁻ beam stripping scheme. Following a proof-of-principle experiment using a Q-switched laser, a new experiment is being prepared to demonstrate laser stripping over a 10-us macropulse. In this talk, we will report the design and measurement results of the laser system for the next stage laser stripping experiment. The laser system adopts a master oscillator power amplifier (MOPA) configuration and contains an actively mode-locked fiber seeder, macropulse generator, multiple-stage Nd:YAG amplifiers, harmonic converters, and control electronics. The laser system generates 50 ps/402.5 MHz pulses (at a macropulse mode) with multiple megawatt peak power at a wavelength of 355 nm. The measurement results of laser pulse width, spectrum, spatial/temporal beam quality and their parameter dependence will be described.

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WEPME020

Commissioning of the MICE RF System

operation, power-supply, cavity, high-voltage

2297

A.J. Moss, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.M.H. Alsari
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
A.J. Dick, K. Ronald, D.C. Speirs, C.G. Whyte
USTRAT/SUPA, Glasgow, United Kingdom
T. Stanley
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C.J. White
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The Muon Ionisation Cooling Experiment (MICE) is being constructed at Rutherford Appleton Laboratory in the UK. The muon beam will be cooled using multiple hydrogen absorbers then reaccelerated using an RF cavity system operating at 201MHz. This paper describes recent progress in commissioning the amplifier systems at their design operation conditions, installation and operation within the Ionisation Cooling Test Facility (ICTF) as part of the MICE project.

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WEPME033

Search for New e-cloud Mitigator Materials for High Intensity Particle Accelerators

electron, vacuum, embedded, impedance

2332

R. Cimino, S.T. O'connor, A.L. Romano
INFN/LNF, Frascati (Roma), Italy
V. Baglin, G. Bregliozzi, R. Cimino
CERN, Geneva, Switzerland
M.R. Masullo
INFN-Napoli, Napoli, Italy
S. Petracca, A. Stabile
INFN-Salerno, Baronissi, Salerno, Italy

Electron cloud is an ubiquitous effect in positively charged particle accelerators and has been observed to induce unwanted detrimental impacts on beam quality, stability, vacuum etc. A great effort has been recently devoted to the search of new material morphology and/or coatings which can intrinsically mitigate beam instabilities deriving from electron cloud effects. In this context, we present some characterization of Cu foams, available from the market, and their qualification in terms of their vacuum behavior, impedance, secondary electron yield, gas desorption etc. More experimental effort is required to finally qualify foams as a mature technology to be integrated in accelerator environments. But, our preliminary results suggests that, when compatible with geometrical constrains, Cu foams can be utilized when low desorption yields are required and as e-cloud moderator in future particles accelerators.

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WEPME036

Simulation of the Trajectory of Electrons in a Magnetron Sputtering System of TiN with CST Particle Studio

vacuum, cathode, electron, simulation

2341

J. Wang, L. Fan, Y.Z. Hong, W.L. Liu, X.T. Pei, K. Tang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Nature Science Foundation of China under Grant Nos.11075157.
In the process of magnetron sputtering deposition, electromagnetic fields have an important influence on the trajectory of particle movement and the properties of the TiN thin film in many cases. Even for simple geometries, the analytical prediction for charged particles trajectories is extremely cumbersome, so numerical simulations are essential to obtain a better understanding of the possible effects and helpful to optimize the design of experimental facility and experimental process. A software of CST PARTICLE STUDIOTM has been used to simulate the effect of magnetic and electric fields on electrons trajectories in the process of film coating. According to the simulation results, the improvement measures of the system design and experimental process have been achieved. The author put forward the improvement measures on film coating process according to the simulation results. The result shows that it is feasible and convenient to use three dimensional tool in the simulation of trajectory of electrons in a magnetron sputtering system.

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WEPME040

Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN

vacuum, beam-losses, factory, electron

2354

M.A. Gallilee, P. Chiggiato, P. Costa Pinto, L.M.A. Ferreira, P. Lepeule, J. Perez Espinos, L. Prever-Loiri, A. Sapountzis
CERN, Geneva, Switzerland

Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity LHC, the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and NEG thin-film coating.

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WEPME043

Design and Qualification of Transparent Beam Vacuum Chamber Supports for the LHCb Experiment

operation, vacuum, factory, proton

2363

J.L. Bosch, P. Chiggiato, C. Garion
CERN, Geneva, Switzerland

Beryllium beam vacuum chambers pass through the aperture of the large dipole magnet and particle acceptance region of the LHCb experiment, coaxial to the LHC beam. At the interior of the magnet, a system of rods and cables supports the chambers, holding them rigidly in place, in opposition to the vacuum forces caused by their conical geometry. In the scope of the current upgrade program, the steel and aluminium structural components are replaced by a newly designed system, making use of Beryllium, in addition to a number of organic materials, and are optimized for overall transparency to incident particles. Presented in this paper are the design criteria, along with the unique design developments carried out at CERN, and furthermore, a description of the technologies procured from industrial partners, specifically in obtaining the best solution for the cable components.

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WEPME044

LHC Experimental Beam Pipe Upgrade during LS1

vacuum, detector, injection, simulation

2366

G. Lanza, V. Baglin, G. Bregliozzi, P. Chiggiato
CERN, Geneva, Switzerland

The LHC experimental beam pipes are being improved during the ongoing long shutdown 1 (LS1). Several vacuum chambers have been tested and validated before their installation inside the detectors. The validation tests include: leak tightness, ultimate vacuum pressure, material outgassing rate, and residual gas composition. NEG coatings are assessed by hydrogen sticking probability measurement with the help of Monte Carlo simulations. In this paper the motivation for the beam pipe upgrade, the validation tests of the components and the results are presented and discussed.

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WEPME045

Assessment of New Components to be Integrated in the LHC Room Temperature Vacuum System

vacuum, injection, ion, operation

2369

G. Bregliozzi, V. Baglin, P. Chiggiato
CERN, Geneva, Switzerland

Integration of new equipment in the long straight sections (LSS) of the LHC must be compatible with the TiZrV non-evaporable getter thin film that coats most of the 6-km-long room-temperature beam pipes. This paper focus on two innovative accelerator devices to be installed in the LSS during the long shutdown 1 (LS1): the beam gas vertex (BGV) and a beam bending experiment using crystal collimator (LUA9). The BGV necessitates a dedicated pressure bump, generated by local gas injection, in order to create the required rate of inelastic beam-gas interactions. The LAU9 experiments aims at improving beam cleaning efficiency with the use of a crystal collimator. New materials like fibre optics, piezoelectric components, and glues are proposed in the original design of the two devices. The integration feasibility of these set-ups in the LSS is presented. In particular outgassing tests of special components, X-rays photoelectron spectroscopy, analysis of NEG coating behaviour in presence of glues during bake-out, and pressure profile simulations will be presented.

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WEPME047

CERN Vacuum System Activities during the Long Shutdown 1: the LHC Beam Vacuum

vacuum, electron, cryogenics, collimation

2375

V. Baglin, G. Bregliozzi, P. Chiggiato, J.M. Jimenez, G. Lanza
CERN, Geneva, Switzerland

After the Long Shutdown 1 (LS1) and the consolidation of the magnet bus bars, the CERN Large Hadron Collider (LHC) will operate with nominal beam parameters. Larger beam energy, beam intensities and luminosity are expected. Despite the very good performance of the beam vacuum system during the 2010-12 physics run (Run 1), some particular areas require attention for repair, consolidation and upgrade. Among the main activities, a large campaign aiming at the repair of the RF bridges of some vacuum modules is conducted. Moreover, consolidation of the cryogenic beam vacuum systems with burst disk for safety reasons is implemented. In addition, NEG cartridges, NEG coated inserts and new instruments for the vacuum system upgrade are installed. Besides these activities, repair, consolidation and upgrades of other beam equipment such as collimators, kickers and beam instrumentations are carried out. In this paper, the motivation and the description for such activities, together with the expected beam vacuum performance after LS1, are described in detail.

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WEPME050

High Frequency Electromagnetic Characterization of NEG properties for the CLIC Damping Rings

simulation, damping, network, impedance

2384

E. Koukovini-Platia, G. Rumolo, C. Zannini
CERN, Geneva, Switzerland

Coating materials will be used in the CLIC damping rings (DR) to suppress two-stream effects. In particular, NEG coating is necessary to suppress fast beam ion instabilities in the electron damping ring (EDR). The electromagnetic (EM) characterization of the material properties up to high frequencies is required for the impedance modeling of the CLIC DR components. The EM properties for frequencies of few GHz are determined with the waveguide method, based on a combination of experimental measurements of the complex transmission coefficient S21 and CST 3D EM simulations. The results obtained from a NEG coated copper (Cu) waveguide are presented in this paper.

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WEPME056

Further Optimisation of NEG Coatings for Accelerator Beam Chamber

electron, vacuum, injection, photon

2399

O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The non-evaporable getter (NEG) coating, invented at CERN in 90s, is used nowadays in many accelerators around the world. The main advantages of using NEG coatings are evenly distributed pumping speed, low thermal outgassing rates and low photon and electron stimulated gas desorption. The only downside of the NEG is its selective pumping: it pumps H2, CO, CO2 and some other gas species, but does not pump noble gases and hydrocarbons. However, in the accelerators where NEG coating could be beneficial, there is synchrotron radiation and photoelectrons that bombard vacuum chamber walls, it was found in our study that hydrocarbons can be pumped by NEG coating under electron and, most likely, photon bombardment. The detail and the results of this study are reported in this paper.

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WEPME083

VELA: A New Accelerator Technology Development Platform for Industry

electron, FEL, cavity, target

2471

P.A. McIntosh, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, J.A. Clarke, P.A. Corlett, B.D. Fell, A.R. Goulden, C. Hill, F. Jackson, S.P. Jamison, J.K. Jones, L.B. Jones, A. Kalinin, L. Ma, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, S.L. Smith, T.T. Thakker, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Bliss, G. Cox, G.P. Diakun, A. Gleeson, T.J. Jones, K. Robertson, M.D. Roper, E. Snedden
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
S.T. Boogert
Royal Holloway, University of London, Surrey, United Kingdom
N.J. Boulding
FMB Oxford, Oxford, United Kingdom
A. Lyapin
JAI, Egham, Surrey, United Kingdom
E.J. Morton
CXR Ltd, Guildford, United Kingdom

The Versatile Electron Linear Accelerator (VELA) facility will provide enabling infrastructures targeted at the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications in medicine, health, security, energy and industrial processing. The facility has now been commissioned at Daresbury Laboratory and the facility is now being actively utilised by industrial groups who are able to take advantage of the variable electron beam parameters available on VELA to either demonstrate new techniques and/or processes or otherwise develop new technologies for future commercial realisation. Examples of which to be presented include; demonstration of a new cargo scanning process, characterisation of novel, high performance beam position monitors, as well as other technology development applications.

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WEPRI023

Review of the Multilayer Coating Model

vacuum, factory, interface

2522

T. Kubo, T. Saeki
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan

Structures of alternating layers of superconducting (Sc) and insulating films formed on a bulk Sc proposed by A. Gurevich in 2006 are actively discussed these years, because of their great possibility in reducing power consumptions and in enhancing RF breakdown field of the Sc RF cavity. On Apr. 2013, we submitted general formulae for the vortex penetration field of the Sc layer and the shielded magnetic field on the bulk Sc for a structure with a single Sc layer and a single insulator layer formed on a bulk Sc, by which a combination of the thicknesses of Sc and insulator layers that can realize the enhanced RF breakdown field can be found for any given materials. In this contribution, we will show progresses during the last year. Comparisons between the formulae and experimental results, and extended formulae for more realistic models, such as a model with surface defects, will be shown.
T. Kubo, Y. Iwashita, and T. Saeki, Appl. Phys. Lett. 104, 032603 (2014); arXiv:1304.6876 [physics.acc-ph]; arXiv:1306.4823 [physics.acc-ph]; arXiv:1307.0583 [physics.acc-ph].

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WEPRI029

Simulations and Measurements of Beam Pipe Modes excited in 9-cell Superconducting Cavities

cavity, HOM, dipole, simulation

2540

A. Kuramoto
Sokendai, Ibaraki, Japan
N. Baboi
DESY, Hamburg, Germany
H. Hayano
KEK, Ibaraki, Japan

Higher order modes (HOM) excited in 9-cell superconducting cavities have been studied to detect cavity alignment. Dipole modes have been monitored, since their magnitude is proportional to beam offsets from their electrical centers. Detection of cavity alignment is important for the ILC to confirm alignment accuracy and furthermore possible source of emittance growth. We are particularly interested in beam pipe modes because they are localized in both ends of the cavity. We measured beam-induced HOM in the STF accelerator at KEK in 2012 – 2013. From the results of the measurement, we found some modes whose behaviors are like dipole mode at around 2.1 GHz instead of 2.28 GHz as calculated by R. Wanzenberg for an ideal cavity [TESLA 2001-33, September 2001]. We also measured beam induced HOM in the TESLA superconducting cavities in FLASH at DESY. In order to identify beam pipe modes and to compare the measurement with the calculation, we calculate beam pipe modes of 9-cell superconducting cavity by CST MICROWAVE STUDIO 2012 and HFSS 12. We will discuss about these calculations and the measurement.

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WEPRI034

Analysis of BCP Characteristics for SRF Cavities

niobium, SRF, ion, cavity

2549

Y. Jung, H.J. Kim
IBS, Daejeon, Republic of Korea
H.H. Lee, H.C. Yang
KRICT, Daejoen, Republic of Korea

A chemical polishing process is well-known critical process for improving superconducting cavities such as a quality factor and an acceleration electric filed with additional temperature treatment. Especially, Buffered Chemical Polishing (BCP) has been widely used in SRF (Superconducting Radio Frequency) cavity processing. We performed BCP experiments with 1:1:1 and 1:1:2 of an etchant ratio (HF:HNO3:H3PO4). In fact, BCP experiments were carried out by using both undeformed (as-receoved) and deformed niobium samples. We will report baseline BCP results by analyzing surface states of niobium samples such as optical photographs, etch rates and AFM (Atomic Force Microscopy) depending on temperature and time.

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WEPRI081

Mechanical Design of the 704 MHz 5-cell SRF Cavity Cold Mass for CeC PoP Experiment

cavity, SRF, cryomodule, electron

2678

J.C. Brutus, S.A. Belomestnykh, I. Ben-Zvi, Y. Huang, V. Litvinenko, I. Pinayev, J. Skaritka, L. Snydstrup, R. Than, J.E. Tuozzolo, W. Xu
BNL, Upton, Long Island, New York, USA
T.L. Grimm, R. Jecks, J.A. Yancey
Niowave, Inc., Lansing, Michigan, USA

Funding: * Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
A 5-cell SRF cavity operating at 704 MHz will be used for the Coherent Electron Cooling Proof of Principle (CeC PoP) system under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the new technique of cooling proton and ion beams that may increase the beam luminosity in certain cases, by as much as tenfold. The 704 MHz cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up 22 MeV. Novel mechanical designs, including a super fluid heat exchanger, helium vessel, vacuum vessel and tuner mechanism are presented. Structural and thermal analysis, using ANSYS were performed to confirm the mechanical tuning system structural stability. This paper provides an overview of the design, the project status and schedule of the 704 MHz 5-cell SRF for CeC PoP experiment.

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WEPRI096

Mu2e Magnetic Measurements

solenoid, detector, electron, target

2719

M. Buehler, M.A. Tartaglia, J.C. Tompkins
Fermilab, Batavia, Illinois, USA
C.R. Orozco
University of Illinois at Urbana-Champaign, Illinois, USA

The Mu2e experiment at Fermilab is designed to explore charged lepton flavor violation by searching for muon-to-electron conversion. The magnetic field generated by a system of solenoids is crucial for Mu2e and requires accurate characterization to detect any flaws and to produce a detailed field map. Stringent physics goals are driving magnetic field specifications for the Mu2e solenoids. A field mapper is being designed, which will produce detailed magnetic field maps. The uniform field region of the spectrometer volume requires the highest level of precision (1 Gauss per 1 Tesla). During commissioning, multiple magnetic field maps will be generated to verify proper alignment of all magnet coils, and to create the final magnetic field map. In order to design and build a precise field mapping system consisting of Hall and NRM probes, tolerances and precision for such a system need to be evaluated. In this paper we present a design for the Mu2e field mapping hardware, and discuss results from OPERA-3D simulations to specify parameters for Hall and NMR probes. We also present a fitting procedure for the analytical treatment of our expected magnetic measurements.

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THPRO013

FERMI Status Report

FEL, laser, electron, linac

2885

M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, L. Fröhlich, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI, the seeded Free Electron Laser (FEL) located at the Elettra laboratory in Trieste, Italy, consists of two FEL lines. The FEL-1 facility, covering the wavelength range between 20 and 100 nm, was officially opened to external users. The shorter wavelength range, between 20 and 4 nm, is covered by the FEL-2 line, a double stage cascade operating in the “fresh bunch injection” mode, which is still under commissioning. We will report on the different FEL-1 operation modes that can be offered for users and assess the performance of the facility. The progress in the commissioning of FEL-2 will then be addressed, in particular reporting the performance attained at the lower wavelength limit; this aspect is of great interest for the user’s community of the FERMI seeded FEL since it allows to carry out experiments below the carbon K-edge.

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THPRO056

Estimation of Systematic Errors for Deuteron Electric Dipole Moment (EDM) Search at a Storage Ring

simulation, polarization, dipole, extraction

2998

S. Chekmenev
RWTH, Aachen, Germany

An experimental method which is aimed to find a permanent EDM of a charged particle was proposed by JEDI (Jülich Electric Dipole moment Investigations) collaboration in 2012*. EDMs can be observed by their small influence on spin motion. The only possible way to perform a direct measurement is to use a storage ring. For this purpose it was decided to carry out the first precursor experiment at the Cooler Synchrotron (COSY). Since the EDM of a particle violates CP invariance and is expected to be tiny, treatment of all various sources of systematic errors should be done with a great level of precision. One should clearly understand how misalignments of the magnets affects the beam and the spin motion. In reality, one of the methods to investigate spin behavior in the presence of misalignments in a storage ring is to mimic their influence on the beam parameters using small orbit kicks with different amplitudes. In this talk the first simulations of orbit excitations will be discussed. The corresponding spin tune shifts will be considered. The influence of the distorted orbit on the polarization build-up caused by the EDM will be examined.
* A. Lehrach, F. Rathmann, J. Pretz et al., "Search for Permanent Electric Dipole Moments at COSY. Step 1: Spin coherence and systematic error studies", 2012

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THPRO063

Spin Tune Parametric Resonance Investigation

resonance, SRF, dipole, synchrotron

3020

Y. Senichev, A.N. Ivanov, A. Lehrach, R. Maier, D. Zyuzin
FZJ, Jülich, Germany
S.N. Andrianov
St. Petersburg State University, St. Petersburg, Russia

The idea of resonant spin oscillation method was modernized and improved in Forschungszentrum Julich in the proposed experiment at the COSY ring. The resonant method is based on spin tune parameterization using transverse RF magnetic or/and electric field. The spin orientation smearing due to the finite spin coherence time (SCT) plays a crucial in the proposed experiment to search for the electric dipole moment. Our analysis is based on the T-BMT differential equations for spin together with shorten motion equations. Using well developed theory of Mathieu's differential equations we have got simplified analytic solution for prediction of spin behavior. In this paper we have numerically evaluated all effects having fundamental contributions from our point of view.

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THPRO067

Modeling Slow Extraction Process For J-PARC Main Ring

extraction, controls, operation, quadrupole

3032

A.Y. Molodozhentsev
KEK, Ibaraki, Japan

J-PARC Main Ring has to deliver the proton beam to ‘hadron’ experiments by using ‘slow extraction’ technique, base on the 3rd order horizontal resonance. The spill quality during the full extraction period is one of the most important requirements as well as the beam quality. The computer modeling of the slow extraction process for J-PARC Main Ring is based on a realistic machine model, which includes measured imperfections of the machine in addition to dynamic variation of the machine elements to perform the slow extraction. In frame of this report we represent the results of the modeling the slow extraction process from J-PARC Main Ring by using the PTC-ORBIT combined code. The resonance extraction has been controlled by changing the betatron tune. Control the horizontal emittance of the extracted beam has been performed by using ‘dynamic’ bumps. Control the spill quality of the extracted beam has been performed by using dedicated quadrupole magnets and the transverse RF signal (RF knockout). In addition, the spill quality can be improved by suppressing effect of the power supply ripple. On the request, the collective effects can be introduced into the model.

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THPRO071

Control of Calculations in the Beam Dynamics using Approximate Invariants

controls, quadrupole, emittance, database

3041

S.N. Andrianov
St. Petersburg State University, St. Petersburg, Russia
D. Zyuzin
FZJ, Jülich, Germany

One of the important problems in the theory of dynamical systems is to find corresponding (invariants). In this article we are discussing some problems of computing of invariant functions (invariants) for dynamical systems. These invariants can be used for describing of particle beams systems. The suggested method is constructive and based on the matrix formalism for Lie algebraic tools. We discuss two types of invariants: kinematic and dynamic. All calculations can be realized in symbolic forms, in particular, kinematic invariants are based on the theory of representations of Lie algebras (in particular, using the Casimir’s operators). For the case of nonlinear kinematic invariants we propose a recursive scheme, which can be implemented in symbolic forms using instruments of computer algebra (for example, such packages as Maple or Mathematica). The corresponding expressions for invariants can be used to control the correctness of computational experiments, first of all for long time beam dynamics.

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THPRO095

The Design, Construction and Experiments of a RFQ Cold Model at Tsinghua University

rfq, cavity, dipole, insertion

3110

L. Du, Q.Z. Xing, Y. Yang
TUB, Beijing, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (Major Research Plan Grant No. 91126003 and Project 11175096).
The design, construction and experiments of a cold model of one high-current CW RFQ with ramped inter-vane voltage at Tsinghua University are presented in this paper. The 1-meter-long aluminium cold model is chosen to be the same as the low-energy part of the 3-meter-long RFQ. This cold model will be used mainly for the RFQ field study and education.

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THPRO112

Beam Dynamics Analysis in the Beam Halo Experiments at IHEP

simulation, focusing, quadrupole, proton

3159

H. Jiang, S. Fu, C. Meng, J. Peng, Y. Zou
IHEP, Beijing, People's Republic of China

We have measured the beam parameters properly, and also found the RMS matched beam. Now we simulate the matched beam and the mismatched beam using the IMPACT and TraceWin code. We find the simulations can succeed to reproduce the beam profiles without halo for both matched and mismatched beam, but there are some differences for the beam with halo.

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THPME056

A Space-charge Compatible "Tomography" of Beam Phase-space Distributions

simulation, space-charge, beam-transport, focusing

3358

N. Pichoff
CEA/DSM/IRFU, France
A. Lasheen
CERN, Geneva, Switzerland

The well-known 3-gradient method allows accessing to a beam RMS emittance and Twiss parameters at a position A by measuring its rms size at a downstream position B with at least 3 different transport conditions from A to B. We suggest extending this method to access to a beam phase-space distribution model at A from beam profiles measured at B. We propose to use an iterative method which consists in: - defining a parametric model describing the beam distribution in 4D transverse phase-space at a position A, - adjusting iteratively the model parameters by minimizing the difference between beam profiles measured at B and these obtained by transporting the beam generated according to the model with TraceWIN code from A to B. This method allows taking into account space-charge and other transport non-linearities.

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THPME076

Oscillating Wire as a “Resonant Target” for Beam Transversal Gradient Investigation

laser, photon, target, scattering

3412

S.G. Arutunian, A.V. Margaryan
ANSL, Yerevan, Armenia

Measurements of reflected/generated on oscillating wire secondary particles/photons in synchronism with oscillating wire frequency are proposed to done. The differential signal on wire maximal deviations at oscillation process can provide a fast signal proportional to beam profile gradient. Idea of usage of such “Resonant Target” for beam transversal gradient investigation was tested with lightening the oscillating wire by a laser.

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THPME083

BPM Data Correction at SOLEIL

electronics, vacuum, synchrotron, storage-ring

3430

N. Hubert, B. Béranger, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

In a synchrotron light source like SOLEIL, Beam Position Monitors (BPM) are optimized to have the highest sensitivity for an electron beam passing nearby their mechanical center. Nevertheless, this optimization is done to the detriment of the response linearity when the beam is off-centered for dedicated machine physic studies. To correct for the geometric non-linearity of the BPM, we have applied an algorithm using boundary element method. Moreover the BPM electronics is able to provide position data at a turn-by-turn rate. Unfortunately the filtering process in this electronics mixes the information from one turn to the neighboring turns. An additional demixing algorithm has been set-up to correct for this artefact. The paper reports on performance and limitations of those two algorithms that are used at SOLEIL to correct the BPM data.

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THPME091

Beam Halo Measurements using Wire Scanners at ATF2

background, detector, photon, collimation

3445

S. Liu, P. Bambade
LAL, Orsay, France
S. Bai, J. Gao, D. Wang
IHEP, Beijing, People's Republic of China
A. Faus-Golfe, N. Fuster-Martínez
IFIC, Valencia, Spain
T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

Funding: Chinese Scholarship Council, FPA2010-21456-C02-01 and i-link 0704
Beam halo hitting on the beam pipe after the Interaction Point (IP) can generate a large amount of background for the measurements of the nano meter beam size using the laser interferometer beam size monitor (Shintake monitor) at ATF2. In order to investigate the beam halo transverse distribution, a diamond detector will be installed downstream of the IP. A feasibility study of a transverse halo collimation system to reduce the background for these measurements is also in progress. Prior to the diamond detector installation, a first attempt of beam halo measurements have been performed in 2013 using the currently installed wire scanners. Modeling of the beam halo distribution in the extraction (EXT) line was done and compared with the old modeling for ATF. Beam halo measurements were also done using the post-IP wire scanner to investigate the beam halo distribution at post-IP.
Work supported by Chinese Scholarship Council, FPA2010-21456-C02-01 and i-link 0704

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THPME115

EUV Radiation Generated by a 5.7 MeV Electron Beam in Multilayer Periodical Structure

radiation, target, electron, photon

3503

S.R. Uglov, A. Potylitsyn, L.G. Sukhikh, A.V. Vukolov
TPU, Tomsk, Russia
G. Kube
DESY, Hamburg, Germany

Funding: This work was partly supported by the by the Ministry of Education Science of the Russian Federation, contract 2.1799.2011.
Recent experience from linac based FELs like LCLS or FLASH shows that transverse beam imaging based on optical transition radiation (OTR) might fail due to coherence effects in the OTR emission process. In order to overcome the problem it was proposed to use transition radiation (TR) in the EUV region*. For a reliable beam diagnostics however, an increase of the light output in the EUV region is required. One possibility to increase the radiation yield in the geometry of interest (target tilt angles 22.5 or 45 degrees) is to exchange the conventional monolayer target by a multilayer structure which acts as a multilayer X-ray mirror for EUV radiation. In this case, two radiation components are expected to contribute to the measured signal, diffracted transition radiation (DTR) and parametric radiation (PR)**. In this report we present results of an experimental investigation of EUV TR generated by a 5.7 MeV electron beam at monolayer and multilayer targets. The angular characteristics of the radiation was investigated and compared with theoretical models.
* L.G. Sukhikh, S. Bajt, G. Kube et al., in Proc. IPAC'12, MOPPR019, New Orleans, Louisiana, USA, p.819 (2012)
** N.Nasonov, V.Kaplin, S.Uglov, e al., Phys. Rev. E 68 (2003) 036504

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THPME116

Studies on a Diagnostic Pulse for FLASH

optics, betatron, diagnostics, linac

3506

F. Mayet, R.W. Aßmann, S. Schreiber, M. Vogt
DESY, Hamburg, Germany

The long-term stability of the beam optics at FLASH is crucial for all connected experiments and the operation of the new second beamline FLASH2. It is therefore desirable to have a simple procedure to monitor the beam optics routinely and at the same time minimally invasive. This way user operation is not disturbed. An automated procedure, which has been successfully employed at the SLAC linac is presented in the context of FLASH. The betatron oscillations of selectively kicked pulses are recorded using BPMs at a fixed time interval. An online algorithm is then used to extract the betatron phase advance, as well as potential growth of the betatron oscillation amplitude and the Twiss parameters beta and alpha. Using this method, the long-term beam optics stability can be monitored in order to identify potential sources of drifts.

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THPME120

An Intensity Measurement Method based on Inorganic Scintillators and Optoelectronic Sensors

ion, proton, heavy-ion, beam-transport

3518

A. Kechler, E. Feldmeier, Th. Haberer, A. Peters, C. Schömers
HIT, Heidelberg, Germany

The Heidelberg Ion Therapy Center (HIT) is a heavy ion accelerator facility located at the Heidelberg university hospital and intended for cancer treatment with heavy ions and protons. Currently ionization chambers with highly sensitive charge amplifiers are regularly used for intensity measurements of the high-energy ion beams. A new intensity measuring method will be presented based on the combination of fluorescent light from inorganic scintillators and an optoelectronic sensor with adjacent electronics as an alternative to the ionization chambers. A special measurement set-up with a large-area Si PIN-diode and adapted optics was investigated with respect to signal dynamics, resolution and linearity. The experimental results with proton and carbon beams will be presented in detail. Worth mentioning is a variation in sensitivity relating to the position of the beam spot, which could be reduced to some percent only.

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THPME146

Bunch Length Measurement by Using a 2-Cell Superconducting RF Cavity in cERL Injector at KEK

cavity, electron, gun, cathode

3596

J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
T. Miyajima
KEK, Ibaraki, Japan

The development of future light source and linear colliders require high quality electron beams with short bunch length. The measurement of the bunch length is important technique for future electron machine. In general, the bunch length was measured by using deflecting cavity which has the time dependent transverse electromagnetic field. However, the transverse electric field of 2-cell superconducting RF (SRF) cavity can also provide the correlation between the bunch length and beam size as like the role of the deflecting cavity in bunch length measurement. The deflection strength was calibrated by changing the RF phase and the beam offset because the strength of transverse electric field of RF cavity depends on the phase of RF field and the beam offset in the cavity. We will present new way to measure the bunch length by using 2-cell SRF cavity, which has the acceleration field of 15 MV/m, and the measured result with the bunch length of 3 ps in cERL injector.

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THPME158

Coherent Diffraction and Cherenkov Radiation from Short Electron Bunches in Fibers

radiation, electron, polarization, target

3632

G.A. Naumenko, V.V. Bleko, A. Potylitsyn, V.V. Soboleva
TPU, Tomsk, Russia

Funding: This work is particularly supported by grant of Russian MES Program "Nauka" number 2456
The ability to use a radiation of relativistic electrons in optical fibers for beam diagnostics was proposed by X. Artu recently *. In the cited work the properties of different types of radiation, such as diffraction and Cherenkov radiation in the visible region, induced in fibers by relativistic electron were considered. In our report we present the results of experimental investigation of such a phenomenon for millimeter wavelength radiation. The origin and properties of radiation in fibers were investigated for different geometries of fiber position in respect to the electron beam. The spectral characteristics and dependence on the orientation angle of fibers relative to the electron beam were investigated. One of the useful properties of fibers is the fiber flexibility. The characteristics of radiation accepted by flexible fiber with diameter D=11 mm and length L=600 mm were investigated as a function of curvature radius of the fiber R. The experimental results show the allowable transport factor of radiation for the condition L>R>>D. We believe that fibers for mm and submm range can be used for beam diagnostics also.
* X Artru and C. Ray, Nucl. Inst. Meth. B 309 (2013)

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THPME172

Experimental Results from the Characterization of Diamond Particle Detectors with a High Intensity Electron Beam

detector, electron, radiation, impedance

3671

F. Burkart, R. Schmidt, O. Stein, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

Understanding the sources of ultra-fast failures, with durations of less than 3 LHC turns, is important for a safe operation of the LHC, as only passive protection is possible in these time scales. Diamond particle detectors with bunch-by-bunch resolution and high dynamic range have been successfully used to improve the understanding of some new ultra-fast loss mechanisms discovered in the LHC. To fully exploit their potential, diamond detectors were characterized with a high-intensity electron beam (10⁵ to 1010 electrons per shot). For the first time their efficiency and linearity has been measured in such a wide range of intensities. In this paper the experimental setup will be described and the signals of the different detectors will be discussed. Finally, future applications of these detectors in high-radiation applications will be discussed.

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THPME183

Longitudinal Beam Profile Measurements of the Microbunching Instability

detector, radiation, lattice, synchrotron

3706

W. Shields, A. Finn, P. Karataev
JAI, Egham, Surrey, United Kingdom
R. Bartolini, I.P.S. Martin, G. Rehm
DLS, Oxfordshire, United Kingdom

The microbunching instability is a phenomenon characterized by the onset of radiation bursts above a threshold bunch current. These bursts consist of coherent emissions with wavelengths comparable to the bunch length and shorter. The instability has recently been observed at Diamond Light Source, a 3rd generation synchrotron. The operating conditions for triggering the instability at Diamond Light Source are well known, however measuring the spectral content of the resulting emissions is a more challenging investigation. A Michelson interferometer has been installed with the aim of recording the coherent spectrum from the bunches, using ultra-fast response Schottky Barrier Diode detectors. The longitudinal profile of the bunches can be estimated with subsequent analysis.

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THPME185

Design and First Operation of a Silicon-based Non–invasive Beam Monitor

detector, proton, operation, electronics

3712

T. Cybulski, L.J. Devlin, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T. Cybulski, L.J. Devlin, K.P. Hennessy, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
A. Kacperek, B. Marsland, I. Taylor, A. Wray
The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom

Funding: Work supported by the EU under contract PITN-GA-2008-215080 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
Non–invasive, highly accurate and reliable beam monitors are a desired aim of any beam diagnostics design. Knowledge of beam parameters is essential in fundamental research, industry or medical applications with varying demands. It is critical for the optimization of ion beams used for cancer treatment. Ocular tumor treatment at the Clatterbridge Cancer Center (CCC) uses a 60 MeV proton beam. Disturbances introduced to a beam by intercepting devices risk affecting its energy and energy spread, thereby limiting its effectiveness for treatment. The advantageous semi-circular structure of the LHCb Vertex Locator (VELO) detector has been investigated in the QUASAR Group. It is an interesting option for a non-invasive online beam monitor relying on beam ‘halo’ measurements without disturbing the part of the beam used for treatment. This contribution discusses the measurement method, setup design and integration within the CCC treatment beam line.

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THPRI028

Acoustic Spark Localization for the 201 MHz RF Cavity

cavity, Windows, vacuum, software

3828

P.G. Lane, Y. Torun
Illinois Institute of Technology, Chicago, Illinois, USA
E. Behnke, I.Y. Levine
Indiana University South Bend, South Bend, USA
D.W. Peterson
Fermilab, Batavia, Illinois, USA
P. Snopok
IIT, Chicago, Illinois, USA

Funding: Work supported by U.S. Department of Energy
Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on the experiment setup for localizing sparks in an RF cavity by using piezoelectric transducers and on preparation for data collection on a 201.25 MHz vacuum cavity.

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THPRI062

CW Room Temperature Re-buncher for the PIP-II Linac Front End

cavity, linac, proton, beam-transport

3914

I. Terechkine, M. Chen, I.V. Gonin, S. Kazakov, T.N. Khabiboulline, L. Ristori, G.V. Romanov
Fermilab, Batavia, Illinois, USA

At Fermilab there is a plan for improvements to the Fermilab accelerator complex aimed at providing a beam power capability of at least 1 MW on target. The essential element of the plan (the Proton Improvement Plan II – PIP-II) is a new 800 MeV superconducting linac. The PIP-II linac includes a room temperature front-end and high energy part based on five types of superconducting cavities used to cover the entire velocity range required for beam acceleration. The room temperature front end is composed of an ion source, low energy beam transport line (LEBT), radio frequency quadrupole (RFQ), and a medium energy beam transport line (MEBT). The paper reports RF design of the re-buncher for MEBT along with thermal analysis of the cavity.

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THPRI064

Plasma Chemistry in a High Pressure Gas Filled RF Test Cell for use in a Muon Cooling Channel

ion, electron, plasma, cavity

3917

B.T. Freemire, Y. Torun
IIT, Chicago, Illinois, USA
M. Chung, M.R. Jana, M.A. Leonova, A. Moretti, T.A. Schwarz, A.V. Tollestrup, Y. Torun, K. Yonehara
Fermilab, Batavia, Illinois, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Filling an RF cavity with a high pressure gas prevents breakdown when the cavity is placed in a multi-Tesla external magnetic field. A beam of particles traversing the cavity, be it muons or protons, ionizes the gas, creating an electron-ion plasma which absorbs energy from the cavity. In order to understand the nature of this plasma loading, a variety of gas species, gas pressures, dopants, and cavity electric fields were investigated. Plasma induced energy loss, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times were measured. The results for hydrogen, deuterium, helium, and nitrogen, doped with dry air will be presented.

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THPRI076

Laser Triggered RF Breakdown Study Using an S-band Photocathode Gun

laser, gun, HOM, cathode

3943

J.H. Shao, W. Gai
ANL, Argonne, Illinois, USA
H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, C.-X. Tang, L.X. Yan
TUB, Beijing, People's Republic of China
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

A laser triggered RF breakdown experiment was carried out with an S-band photocathode gun at Tsinghua University for attempting understanding of the RF breakdown processes. By systematic measurement of the time dependence of the breakdown current at the gun exit and the stored RF energy in the cavity, one might gain insight into the time evolution of RF breakdown physics. A correlation of the stored energy and field emission current has been analysed with an equivalent circuit model. Experimental details and analysis methods are reported.

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THPRI077

Electric Field Enhancement Study using an L-band Photocathode Gun

cathode, gun, simulation, pick-up

3946

J.H. Shao, W. Gai
ANL, Argonne, Illinois, USA
H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

RF breakdown in high gradient accelerating structures is a fundamental problem that is still needed better understanding. Past studies have indicated that field emission, which is usually represented by electric field enhancement (i.e. β) produced from the Fowler-Nordheim plot, is strongly coupled to the breakdown problem. A controlled surface study using a high gradient L-band RF gun is being carried out. With a flat cathode, the maximum electric field on the surface reached 10³ MV/m. And electric field as high as 565 MV/m on the surface was achieved by a pin-shaped cathode. The field enhancement factor was measured at different surface field during the conditioning process. Initial results of the study are presented in this paper.

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THPRI078

Experimental Study of Surface RF Magnetic Field Enhancement Caused by Closely Spaced Protrusions

cavity, klystron, vacuum, superconductivity

3949

F.Y. Wang, C. Adolphsen, J.P. Eichner, C.D. Nantista, L. Xiao
SLAC, Menlo Park, California, USA

The RF magnetic field enhancement between two closely spaced protrusions on a metallic surface has been studied theoretically. It is found that a large enhancement occurs when the field is perpendicular to the gap between the protrusions. This mechanism could help explain the melting that has been observed on cavity surfaces subjected to pulsed heating that would nominally be well below the melting temperature of the surface material. To test this possibility, an experiment was carried out in which a pair of copper “pins” was attached to the base plate of an X-band cavity normally used to study pulsed heating. Melting was observed between the pins when the predicted peak temperature was near or exceeded the copper melting temperature.

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THPRI084

Testing Results of the Prototype Beam Absorber for the PXIE MEBT

focusing, radiation, simulation, electron

3967

C.M. Baffes, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. A prototype of the absorber was manufactured from molybdenum alloy TZM, and tested with an electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototype and key testing results.

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THPRI094

MadX Tracking Simulations to Determine the Beam loss Distributions for the LHC Quench Tests with ADT Excitation

simulation, quadrupole, beam-losses, focusing

3991

V. Chetvertkova, B. Auchmann, T. Bär, W. Höfle, A. Priebe, M. Sapinski, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

Quench tests with stored beam were performed in 2013 with one of the LHC main focusing quadrupoles to experimentally verify the quench levels for beam losses in the time scales from a few milliseconds to several seconds. A novel technique combining a 3-corrector orbital bump and transverse-damper kicks was used for inducing the beam losses. MadX tracking simulations were an essential step for determining the spatial and angular beam loss distributions during the experiment. These were then used as input for further energy-deposition and quench-level calculations. In this paper the simulated beam-loss distributions for the respective time scales and experimental parameters are presented. Furthermore the sensitivity of the obtained loss-distributions to the variation of key input parameters, which were measured during the experiment, is discussed.

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THPRI103

Improvement of the Run-time of 35 mbar Helium Gas Pumping Units for the Superconducting Linear Accelerator S-DALINAC

operation, coupling, controls, vacuum

4019

J. Conrad, F. Hug, T. Kürzeder, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG through SFB 634
The superconducting Darmstadt linear accelerator S-DALINAC has been designed to provide electron beams of up to 130 MeV for nuclear and astrophysical experiments. The accelerating cavities are operated in a liquid helium bath at 2 K. To achieve this temperature the cryostat has to be pumped down to a pressure of 35 mbar which was done by a system of pumping units connected in series, when the accelerator started its operation in 1991. In 2005 this system was replaced by four parallel switched pumping stations. In the first three years of their operation, the reliability of the accelerator was very poor due to repeated breakdowns of the pumping stations caused by overheating. In addition the high temperatures lead to an early decay of the gaskets used. The problem was solved by installing oil cooling systems and more appropriate shaft sleeves at the pumping stations. We will report on the technical efforts we made and thereby further increased the availability of the accelerator significantly. Also we will give a review on our experiences in maintenance procedures.

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THPRI109

Auto-alignment Status of the Taiwan Photon Source

alignment, laser, controls, status

4034

M.H. Wu, J.-R. Chen, P.S.D. Chuang, H.C. Ho, K.H. Hsu, D.-G. Huang, W.Y. Lai, C.-S. Lin, C.J. Lin, H.C. Lin, H.M. Luo, S.Y. Perng, P.L. Sung, C.W. Tsai, T.C. Tseng, H.S. Wang
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) is a new 3-GeV ring under construction at NSRRC in Taiwan. There are hundreds of magnets placed on girders that must be aligned correctly to keep the electronic beam in the desire orbit. Due to the reasons of manpower, set up time, accuracy of adjustment, deformation of the floor, and limited space, an auto-alignment girder control system was designed to meet this requirement. The auto-alignment test was completed with one double-bend cell at NSRRC. The Auto-alignment process will be tested with some sections of magnet girders to confirm the control system and the algorithm in the TPS. The status and test results will be described in this paper.

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FRXAA01

Beam Dynamics Studies with Non-neutral Plasma Traps

plasma, ion, resonance, focusing

4052

H. Okamoto, K. Fukushima, H. Higaki, K. Ito, K. Moriya, T. Okano, K. Osaki
HU/AdSM, Higashi-Hiroshima, Japan

Both Paul ion traps and Penning traps have been employed at Hiroshima University to explore fundamental aspects of space-charge dominated beam dynamics. These compact accelerator-free experiments are based on an isomorphism between non-neutral plasmas in a trap and charged-particle beams traveling in a periodic focusing channel. This talk highlights the recent experimental results on coherent betatron resonances in various strong-focusing lattices, resonance crossing in non-scaling FFAG accelerators, ultra-low emittance beam stability, and halo formation.

Slides FRXAA01 [5.557 MB]

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FRXBA01

Imaging Systems for 800 MeV Proton Radiography

proton, scattering, quadrupole, permanent-magnet

4057

F.E. Merrill, D.B. Barlow, C.J. Espinoza, B.J. Hollander, K. Kwiatkowki, J.D. Lopez, F.G. Mariam, D.J. Morley, C.L. Morris, P. Nedrow, A. Saunders, A. Tainter, D. Tupa, J. Tybo
LANL, Los Alamos, New Mexico, USA

Los Alamos National Laboratory has developed the technique of proton radiography as a flash radiography system for the study of dynamic systems. Historically these studies have focused on measuring fundamental material properties of dynamic materials (equation of state, strength, phase transitions) as well as the physical processes important in predicting the hydrodynamic flow of these materials at high velocity pressure and density (instabilities such as Richtmyer-Meshkov, Rayleigh-Taylor and Kelvin-Helmholtz). Recently these techniques have been extended to new applications which benefit from the unique capabilities of 800 MeV proton radiography. These new applications range from the study of metal alloy solidification to medical imaging applications. In addition to extending the application of this capability performance improvements have been investigated for future implementation. The results of dynamic studies and new applications are presented along with a proposed plan for future radiographic improvements.

Slides FRXBA01 [8.667 MB]

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