IPAC2014 - List of Keywords (laser)

Paper	Title	Other Keywords	Page
MOZA01	Ultralow Emittance Beam Production based on Doppler Laser Cooling and Coupling Resonance	ion, simulation, coupling, solenoid	28
	A. Noda, M. Nakao NIRS, Chiba-shi, Japan M. Grieser MPI-K, Heidelberg, Germany Z.Q. He FRIB, East Lansing, Michigan, USA Z.Q. He TUB, Beijing, People's Republic of China K. Jimbo Kyoto University, Kyoto, Japan H. Okamoto, K. Osaki HU/AdSM, Higashi-Hiroshima, Japan A.V. Smirnov JINR, Dubna, Moscow Region, Russia H. Souda Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan H. Tongu Kyoto ICR, Uji, Kyoto, Japan Y. Yuri JAEA/TARRI, Gunma-ken, Japan
	Funding: Work supported by Advanced Compact Accelerator Development project by MEXT of Japan. It is also supported by GCOE project at Kyoto University, “The next generation of Physics-Spun from Universality" Doppler laser cooling has been applied to low-energy (40 keV) Mg ions together with the resonant coupling method* at the S-LSR at ICR, Kyoto University,. The S-LSR storage ring has a high super periodicity of 6, which is preferable from the beam dynamical point of view. At S-LSR one dimensional ordering of proton beam was already realized for the first time*. Active three dimensional laser cooling has been experimentally demonstrated for ions with un-negligible velocity (v/c=0.0019, where c is the light velocity) for the first time. Utilizing the above mentioned characteristics of S-LSR, an approach to realize ultralow emittances has been pursuit. To suppress heating effects, due to intra-beam scattering, the circulating ion beam intensity was reduced by scraping and beam emittances of 1.3·10^-11 pi m·rad and 8.5·10^-12 pi m·rad (normalized) have been realized for the horizontal and vertical directions, respectively with the 40 keV Mg ion beam at a beam intensity of ~10⁴, which is the lowest emittance ever attained by laser cooling. From MD computer simulations, it is predicted that reduction of the ion number to about 10³ is needed to realize a crystalline string. H. Okamoto, A.M. Sessler, D. Moehl, Phys. Rev. Lett. 72, 397 (1994). ** T. Shirai et. al., Phys. Rev. Lett. 98, 204801 (2007).
	Slides MOZA01 [13.336 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOZB01	Superconducting RF Guns: Emerging Technology for Future Accelerators	gun, cathode, SRF, cavity	4085
	J. Teichert HZDR, Dresden, Germany
	This talk should give an overview of Superconducting photo injectors (SRF guns) and focus on the present status of SRF gun development, the technical requirements and the critical issues like cavity design, photocathode integration, and emittance compensation methods.
	Slides MOZB01 [22.198 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOZB02	Advances in Photocathodes for Accelerators	electron, emittance, cathode, experiment	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO054	Commissioning progress of the Femto-slicing Project at SOLEIL	electron, wiggler, radiation, synchrotron	206
	M. Labat, H.B. Abualrob, P. Betinelli-Deck, A. Buteau, N. Béchu, L. Cassinari, M.-E. Couprie, F. Dohou, C. Herbeaux, Ph. Hollander, J.-F. Lamarre, C. Laulhé, A. Lestrade, J. Lüning, O. Marcouillé, J.L. Marlats, T. Moreno, P. Morin, A. Nadji, L.S. Nadolski, D. Pédeau, P. Prigent, S. Ravy, J.P. Ricaud, M. Ros, P. Roy, M.G. Silly, F. Sirotti, K. Tavakoli, M.-A. Tordeux, D. Zerbib SOLEIL, Gif-sur-Yvette, France
	The femtoslicing project at SOLEIL is currently under commissioning. It will enable to serve several beamlines with 100 fs FWHM long pulses of soft and hard X-rays with reasonable flux and with a 1 kHz repetition rate. It is based on the interaction of a femtosecond Ti:Sa laser with electrons circulating in the magnetic field of a modulator wiggler, that provides the electron beam energy modulation on the length scale of the laser pulse. The optimization of the interaction is performed using two dedicated diagnostics stations. The first one, operating in the Infra-Red (IR) is installed in the tunnel and allows the adjustment of the temporal, spectral and spatial overlap between the laser and the electron beam. The second one, located in the IR-THz AILES beamline, measures the intensity of the terahertz (THz) radiation emitted by the local dip structure produced in the core electron beam after interaction. This second setup provides refined optimization of the interaction. This paper describes the layout of these diagnostics and gives first results and characterization of the slicing experiment at SOLEIL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO054
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO066	Status of FLUTE	gun, electron, linac, diagnostics	231
	M. Schuh, I. Birkel, A. Borysenko, A. Böhm, N. Hiller, E. Huttel, S. Höninger, V. Judin, S. Marsching, A.-S. Müller, A.-S. Müller, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schwarz, M. Weber, P. Wesolowski KIT, Karlsruhe, Germany R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb DESY, Hamburg, Germany H.-H. Braun, R. Ganter, V. Schlott, L. Stingelin PSI, Villigen PSI, Switzerland
	FLUTE, a new linac-based test facility and THz source is currently being built at the Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It consists of an RF photo gun and a traveling wave linac accelerating electrons to beam energies of ~41 MeV in the charge range from a few pC up to 3 nC. The electron bunch will then be compressed in a magnetic chicane in the range of 1 - 300 fs, depending on the charge, in order to generate coherent THz radiation with high peak power. An overview of the simulation and hardware status is given in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO066
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO078	The SPARC_LAB Thomson Source Commissioning	electron, photon, linac, emittance	267
	C. Vaccarezza, D. Alesini, M.P. Anania, M. Bellaveglia, E. Chiadroni, D. Di Giovenale, G. Di Pirro, M. Ferrario, A. Gallo, G. Gatti, R. Pompili, S. Romeo, F. Villa INFN/LNF, Frascati (Roma), Italy A. Bacci, C. Curatolo, D.T. Palmer, V. Petrillo, A.R. Rossi, L. Serafini, P. Tomassini Istituto Nazionale di Fisica Nucleare, Milano, Italy P. Cardarelli, G. Di Domenico, M. Gambaccini INFN-Ferrara, Ferrara, Italy A. Cianchi INFN-Roma II, Roma, Italy P. Delogu INFN-Pisa, Pisa, Italy F. Filippi, A. Giribono INFN-Roma, Roma, Italy B. Golosio, P. Oliva INFN-Cagliari, Monserrato (Cagliari), Italy A. Mostacci Rome University La Sapienza, Roma, Italy
	The SPARC_LAB Thomson source is presently under commissioning at LNF. An electron beam of energy between 30-150 MeV collides head-on with the laser pulse provided by the Ti:Sapphire laser FLAME, characterized in this phase by a length of 6 ps FWHM and by an energy ranging between 1 and 5 J. The key features of this system are the wide range of tunability of the X-rays yield energy, i.e. 20-500 keV, and the availability of a coupled quadrupole and solenoid focusing system, allowing to reach an electron beam size of 10-20 microns at the interaction point. The experimental results obtained in the February 2014 shifts are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO078
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO110	Present Status of the Compact ERL at KEK	recirculation, linac, dipole, injection	353
	N. Nakamura, M. Adachi, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan R. Hajima, S. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma JAEA, Ibaraki-ken, Japan J.G. Hwang KNU, Deagu, Republic of Korea M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan Y. Seimiya HU/AdSM, Higashi-Hiroshima, Japan
	The Compact Energy Recovery Linac (cERL) project is ongoing at KEK in order to demonstrate excellent ERL performance as a future light source. The cERL injector was already constructed with its diagnostic beamline and successfully commissioned from April to June in 2013. In the next step, the cERL recirculation loop with a main superconducting linac and merger and dump sections has been constructed and its commissioning is scheduled to start in December 2013. Significant progress is expected by the IPAC14 conference date. In this presentation, we will describe the present status of the cERL including future developments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO110
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME008	3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector	simulation, cathode, gun, emittance	391
	Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: work supported by DESY, Hamburg and Zeuthen sites The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra *. Computer Simulation Technology AG, website: http://www.cst.com/ ** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME008
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME070	Investigation of a High Power, Low Impedance Pulse Forming Network based on Ceramic Capacitors	impedance, network, simulation, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME070
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI005	The AWAKE Experimental Facility at CERN	electron, proton, plasma, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI009	Study on New Method for Generating Highly Charged Ions with Double Pulse Laser Ion Source	ion, plasma, ion-source, controls	595
	T. Shibuya TIT, Tokyo, Japan N. Hayashizaki RLNR, Tokyo, Japan M. Yoshida KEK, Ibaraki, Japan
	Laser ion source capable of generating high intensity ions is best for the ion source of RI beam facilities. A great deal of effort has been made on particle number as DPIS. Only few attempts have so far been made at generating highly charged ions. One of previous research has reported that Au+53 ions are produced by PALS laser. "Nonlinear process" mechanisms such as resonance absorption and self-focusing were used for this. However, these methods have limitation due to low repetition rate of the laser. Nd (λ=1064nm, E<1.2J, t~10ns) and Yb laser(λ=1030nm, E<10J, t~500fs) systems is possible to operate at 10 - 50Hz repetition rate. This double pulse laser system, with attainable laser intensity up to about 1017[W/cm²], was used to generate highly charged ions of solid target. First, the Nd laser creates a plasma plume. Next, the Yb laser reheats plasma plume by high intensity pulse at delay time of nanosecond. The properties of ions were investigated mainly on the base of time-of-flight method.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI010	Laser Ablation Ion Source for the KEK Digital Accelerator	ion, extraction, space-charge, simulation	598
	N. Munemoto Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan Y. Fuwa Kyoto ICR, Uji, Kyoto, Japan S. Ikeda, K. Takayama TIT, Yokohama, Japan M. Kumaki RISE, Tokyo, Japan M. Okamura BNL, Upton, Long Island, New York, USA S. Takano, K. Takayama KEK, Ibaraki, Japan K. Takayama Sokendai, Ibaraki, Japan
	KEK Digital Accelerator (DA) is a small scale induction synchrotron and operated at 10Hz and recently has succeeded to accelerate gaseous ions. There is a strong demand of fully striped carbon ions because the DA is regarded as the second generation of cancer therapy driver, which does not require an injector and electron stripper. We need a novel carbon ion source providing C⁶⁺ beams, which are directly injected into the DA and accelerated up to required energy. For this purpose, a laser ablation ion source(LAIS) is promising. To obtain high yield C⁶⁺ ions from ablation plasma, the laser irradiation condition has been evaluated and relationship between beam properties of charge spectrum, intensity, and temperature, and carbon target materials were examined. Two laser systems, long pulse (6 ns) and short pulse (170 ps), were employed to irradiate a graphite and amorphous carbon target. The current densities and profile of the generated plasmas in time were measured and charge state distributions were analyzed. In addition we will report a full design integrating this LAIS, the extraction system, the longitudinal chopper system, and the low energy beam transport line. T.Yoshimoto et al., presented in this conference ** N.Munemoto et al., Proceedings of ICIS2013, published in Rev. Sci. Inst.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI011	Control of Plasma Flux with Pulsed Solenoid for Laser Ion Source	ion, plasma, electron, ion-source	601
	S. Ikeda, K. Horioka TIT, Yokohama, Japan Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan T. Kanesue, M. Okamura BNL, Upton, Long Island, New York, USA
	We discuss the behavior of laser-ablation plasma spreading through a pulsed solenoidal field to minimize the beam emittance of laser-ablation ion source (LIS). LIS is expected to produce high-flux and low emittance ion beams from various solid materials in vacuum because of the high drift velocity and low temperature of the ablation plasma due to the adiabatic expansion. However, the ion flux level from the ablation plasma into an extraction gap changes within a pulse and then the shape of the sheath boundary changes transiently. Then, the integrated emittance is larger than the stroboscopic emittance at a certain time slice. To prevent the transient effect, we tried to control the plasma flux with a pulsed solenoidal magnetic field. The field is expected to change the direction of the plasma flow like a lens. By changing the magnetic flux density according to the transient flux level of ablation plasma, we can expect to control the plasma flux at the extraction gap. To investigate the controllability of the plasma flow, we measured the plasma flux as a function of parameters of the pulsed magnetic field. We scanned ion probes along the beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI017	Status of AREAL RF Photogun Test Facility	gun, electron, operation, emittance	620
	B. Grigoryan, G.A. Amatuni, V.S. Avagyan, H. Avdishyan, H. Davtyan, A.A. Gevorgyan, L.H. Hakobyan, M. Ivanyan, V.G. Khachatryan, E.M. Laziev, A. Lorsabyan, M. Manukyan, I.N. Margaryan, N. Martirosyan, T.H. Mkrtchyan, S. Naghdalyan, V.H. Petrosyan, H. Poladyan, V. Sahakyan, A. Sargsyan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan, V. V. Vardanyan, G.S. Zanyan CANDLE SRI, Yerevan, Armenia T.K. Sargsyan LT-PYRKAL cjsc, Yerevan, Armenia
	Advanced Research Electron Accelerator Laboratory (AREAL) is a 20 MeV laser driven RF linear accelerator which is being constructed in the CANDLE institute. The construction of phase-1 is finished and at present the machine commissioning is in progress. In phase-1 a photocathode RF gun provides a 5 MeV small emittance electron beam with the 100 pC bunch charge and variable electron bunch length from 0.5 to 8 ps. Two main operation modes are foreseen for this phase – single and multibunch regimes to satisfy experimental demands. We report the status of linac, first experience and nearest machine run schedule. The brief review of the facility, main parameters, performance and first results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI019	In-situ Characterization of K2CsSb Photocathodes	cathode, electron, vacuum, ion	627
	M. Schmeißer, A. Jankowiak, T. Kamps, S.G. Schubert HZB, Berlin, Germany S.G. Schubert BNL, Upton, Long Island, New York, USA
	Funding: Work supported by German Bundesministerium für Bildung und Forschung contract 05K12CB2 PCHB and Land Berlin. Alkali antimonide photocathodes with high quantum efficiency hold the promise of delivering electrons for high-brightness injectors. A drift type spectrometer (momentatron) was attached to the HZB preparation system to allow in-situ characterization within short time after fabrication and possibly identify correlations between growth process and cathode performance parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI020	Introducing GunLab – A Compact Test Facility for SRF Photoinjectors	gun, electron, SRF, cathode	630
	J. Völker, R. Barday, A. Jankowiak, T. Kamps, J. Rudolph, S.G. Schubert, S. Wesch HZB, Berlin, Germany A. Ferrarotto, T. Weis DELTA, Dortmund, Germany V.I. Shvedunov MSU, Moscow, Russia I.Yu. Vladimirov MSU SINP, Moscow, Russia
	Funding: Work supported by German Bundesministerium für Bildung und Forschung (BMBF contract 05K12CB2 PCHB and 05K10PEA), Land Berlin and grants of Helmholtz Association Superconducting radio-frequency photoelectron injectors (SRF photoinjectors) are a promising electron source for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the upcoming ERL project BERLinPro we want to test and commission different SRF photoinjectors and examine the beam performance of photocathode materials in an independent test facility. Therefore we designed GunLab to characterize the beam parameters from the SRF photoinjectors in a compact diagnostics beamline. In GunLab we want to investigate the complete 6 dimensional phase space as a function of drive laser and RF setup parameters. In this work we present the design and the estimated performance of GunLab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI020
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI021	Laser Systems Generating Short Polarized Electron Bunches at the S-DALINAC	electron, operation, experiment, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI023	Simulation of the ELBE SRF Gun II	gun, simulation, emittance, SRF	636
	P.N. Lu, A. Arnold, U. Lehnert, P. Murcek, J. Teichert, H. Vennekate, R. Xiang HZDR, Dresden, Germany
	Funding: EuCARD, contract number 227579 German Federal Ministry of Education and Research grant 05 ES4BR1/8 LA³NET, Grant Agreement Number GA-ITN-2011-289191 By combining the code of ASTRA and elegant in a user-friendly interface, a simulation tool is developed for the ELBE SRF Gun II. The photoelectric emission and first acceleration to several MeV in the gun cavity are simulated by ASTRA with a 1D Model, where the space charge effect is considered. The dependence of the beam quality on key parameters is studied, and a compromised optimization for a 77 pC beam is used for further elegant simulation of the beam transport through a dogleg and ELBE Linacs. Proper settings of the magnets and RF phases are the main targets of improving the beam quality. Up to now the best simulation result is an electron bunch with the energy of 47 MeV, energy spread of 66 keV, bunch length of 0.35 ps and transverse emittance of 1.9 μm and 2.7 μm in the two perpendicular directions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI023
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI024	NEA-GaAs (Cs, O) Photocathodes for the ELBE SRF Gun	gun, vacuum, SRF, cathode	639
	R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate HZDR, Dresden, Germany
	Funding: supported by the European Community under the FP7 programme (EuCARD-2, contract number 312453, and LA3NET, contract number 289191), and by the BMBF grant 05K12CR1. At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and commissioned. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te layer in last years. GaAs At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and tested. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te photocathode in last years. GaAs photocathodes are advantageous because of their high quantum efficiency (QE) with visible light and the extensive experiences of their use in DC guns. Furthermore, GaAs photocathodes provide the possibility to realize a polarized SRF gun in the future. In this presentation we will introduce the new preparation system and the first results of the GaAs tests. The new transfer system under construction will be also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI026	Complete Simulation of Laser Induced Field Emission from Nanostructures Using a DGTD, PIC and FEM Code	electron, simulation, cathode, space-charge	645
	A. Fallahi, F.X. Kärtner CFEL, Hamburg, Germany K.K. Berggren, R. Hobbs, F.X. Kärtner, P.D. Keathley, M.E. Swanwick, L.F. Velasquez-Garcia, Y. Yang MIT, Cambridge, Massachusetts, USA
	Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg. We present a general and efficient numerical algorithm for studying laser induced field emission from nanostructures. The method combines the Discontinuous Galerkin Time Domain (DGTD) method for solving the optical field profile, the Particle-In-Cell (PIC) method for capturing the electron dynamics and the Finite Element Method (FEM) for solving the static field distribution. The charge distribution is introduced to the time-domain method based on a modified Fowler-Nordheim field emission model, which accounts for the band-bending of the charge carriers at the emitter surface. This algorithm is capable of considering various effects in the emission process such as space-charge, Coulomb blockade and image charge. Simulation results are compared with experimental findings for optically driven electron emission from nanosharp Si-tips.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI029	Spectrometer for Laser-pulsed Electrons from Field Emission Cathodes	electron, cathode, detector, controls	655
	S. Mingels, B. Bornmann, D. Lützenkirchen-Hecht, G. Müller, V. Porshyn Bergische Universität Wuppertal, Wuppertal, Germany
	Funding: German Federal Ministry of Education and Research (BMBF). Project number: 05K13PX2. In order to develop highly brilliant, pulsed electron sources based on photo-induced field emission (PFE), which combines advantages of photo and field emission (FE), a new measurement system was constructed at BUW. In an UHV system the electrons are extracted from a cold cathode by a mesh electrode under pulsed laser illumination (3.5 ns, 10 Hz, 0.5 – 5.9 eV, > 0.3 mJ) and so far analyzed by a CW-spectrometer. Quantum efficiency investigations of flat metal (Au, Ag of different surface orientations) and semiconductor crystals (n- and p-Si, GaN) yielded the expected work functions and revealed first hints for PFE effects. However, the kinetic energy of the electrons could not be measured with the CW-spectrometer. In addition, the achievable electric field (< 20 MV/m) was limited by parasitic FE. Hence, the system is presently upgraded with a spectrometer (resolution < 3 meV) that can handle electron pulses and a dust reduced environment is installed at the load lock. First results acquired with the upgraded apparatus on PFE cathodes will be presented at the conference. B. Bornmann et al., Rev. Sci. Instrum. 83, 013302 (2012). ** S. Mingels et al., Proc. FEL2013, New York, USA, p. 339.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI031	Multi-alkali Photocathode R&D	cathode, electron, vacuum, experiment	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI034	Development of temporal response measurement system for transmission-type spin-polarized photocathodes	electron, cavity, resonance, linear-collider	670
	T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan M. Adachi KEK, Ibaraki, Japan X.G. Jin Institute for Advanced Research, Nagoya, Japan M. Katoh, T. Konomi UVSOR, Okazaki, Japan Y. Okano IMS, Okazaki, Japan
	Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved,. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode*. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results. T. Nakanishi, The XXI International LINAC Conference(1998) Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004 * Xiuguang Jin, Applied Physics Express 6 (2013) 015801
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI035	Development of the Photocathode LiTi2O4 and Evaluations of the Initial Emittance	cathode, electron, emittance, cavity	673
	R. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan T. Hitosugi, S. Shiraki Tohoku Uneversity, WPI-AIMR, Sendai, Japan E. Kako, Y. Kobayashi, S. Yamaguchi KEK, Ibaraki, Japan M. Katoh, T. Konomi, T. Tokushi UVSOR, Okazaki, Japan Y. Okano IMS, Okazaki, Japan
	In UVSOR, the X-ray free electron laser (XFEL) based on linear accelerator with high pulse repetition about 1MHz has been designed as a candidate for the next radiation sources. We thought a combination of superconducting RF cavity and photocathode is an optimal electron gun for the new accelerator. For this electron gun, we propose a back-illuminated multi-alkali* photocathode with transparent superconductor LiTi2O4*. The reason for using LiTi2O4 is to reflect RF by using feature of penetration depth of superconductor, which is defined from London equation. This feature protects optical components from RF damage. However, LiTi2O4 is a new material and properties are not clear. We have measured the basic properties of this photocathode, such as magnetic susceptibility measurement and photoelectron spectrometry, etc. In this conference, we will explain the detail of the concept and advantage of this cathode, and show the result measured about the basic properties of this photocathode focusing on the initial emittance measurement. A. V. Lyashenko et al. JINST 4 P07005 (2009) ** Kumatani et al. APL 101 (2012) 123103″
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI036	Pulse Radiolysis Using Terahertz Probe Pulses	electron, radiation, gun, linac	676
	K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Pulse radiolysis, which utilizes a pump electron beam and a probe pulse, is a powerful tool that can be used for the time-resolved observation of ultrafast radiation-induced phenomena. Recently, double-decker pulse radiolysis* using visible probe pulses were demonstrated based on a photocathode RF gun driven by two UV pulses, which enabled synchronized pump electron beam and visible probe pulses. In this study, pulse radiolysis using terahertz (THz) probe pulses which were realized by the “double-decker” electron beams and dynamics of transient quasi-free electrons in semiconductors are presented. * K. Kan et al., Rev. Sci. Instrum. 83, 073302 (2012).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI037	Development of Iridium Cerium Photocathode for the Generation of High-Charge Electron Beam	electron, cathode, gun, linac	679
	D. Satoh TIT, Tokyo, Japan N. Hayashizaki RLNR, Tokyo, Japan T. Natsui, M. Yoshida KEK, Ibaraki, Japan
	We developed an iridium cerium cathode material made by new production method for multi-purpose electron source. For multi-purpose electron source, we focused on the Ir5Ce compound which has a high melting point (> 2100 K) and a low work function (2.57 eV). This material has some excellent properties as both a thermionic cathode and a photocathode. For example, Ir5Ce thermionic cathode can generate one-order higher electrical current than a LaB6 cathode at the same temperature. Another advantage is that an Ir5Ce thermionic cathode has a lifetime two orders longer than that of a LaB6 thermionic cathode under the same conditions. Moreover, we discovered that this material has a reasonably high quantum efficiency (2.70 × 10−3 @213nm at 1000°C) and long-lifetime (> LaB6) as a photocathode. Our research shows that Ir5Ce compound is optimum material for a thermionic cathode and photocathode. We focused on this good emission properties under the high temperature and we tried to develop a backside electron beam heating system and demonstrate a laser pre-pulse heating for a high current thermionic gun system or high charge photocathode gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI042	Recent Developments at the High-charge PHIN Photoinjector and the CERN Photoemission Laboratory	cathode, vacuum, feedback, operation	695
	C. Heßler, E. Chevallay, S. Döbert, V. Fedosseev, I. Martini, M. Martyanov, A. Perillo Marcone, Sz. Sroka CERN, Geneva, Switzerland
	The high-charge PHIN photoinjector has originally been developed to study the feasibility of a photoinjector option for the drive beam of the CLIC Test Facility 3 (CTF3) at CERN and is now being used to investigate the feasibility of a drive beam photoinjector for CLIC. In this paper recent R&D efforts to improve the parameters of the existing system towards CLIC requirements will be discussed. This includes studies of a feedback loop for intensity stabilization, the upgrade of the PHIN vacuum system and the planned upgrade of the driving laser system. For photocathode production and R&D a dedicated photoemission laboratory is available at CERN. To increase the production rate of photocathodes and the availability of the photoemission lab for other studies, an upgrade of the photocathode preparation system with a load-lock system is under study and will also be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI046	The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State	electron, detector, cathode, brightness	707
	L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.E. Scheibler, A.S. Terekhov ISP, Novosibirsk, Russia
	The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and the electron beam brightness is increased significantly if the mean values of these quantities are reduced. ASTeC have commissioned a Transverse Energy Spread Spectrometer (TESS – an experimental facility designed to measure these transverse and longitudinal energy distributions) which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research. GaAs photocathodes were activated in our photocathode preparation facility (PPF), then transferred to TESS under XHV conditions and progressively degraded through controlled exposure to oxygen. We present commissioning data and initial measurements showing the evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state. Proc. FEL ’13, TUPPS033, 290-293 ** Proc. IPAC ’11, THPC129, 3185-3187
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI046
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI047	The Preparation of Atomically Clean Metal Surfaces for use as Photocathodes in Normally Conducting RF Guns	ion, gun, plasma, electron	711
	T.C.Q. Noakes, A.N. Hannah, K.J. Middleman, B.L. Militsyn, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S. Mistry Loughborough University, Leicestershre, United Kingdom
	Funding: Research supported by FP7 EuCard2 http://cern.ch/eucard2 This work reports a study of various alternative metal samples as candidate materials for use as photocathodes in normally conducting RF guns. Clean surfaces were prepared using Argon ion bombardment and quantum efficiency measured using a 265 nm UV LED light source with a picoammeter for drain current monitoring. Surface composition was studied using X-ray photoelectron spectroscopy and a Kelvin probe apparatus provided work function measurements. Data was taken both before and after annealing to 200°C, a temperature that is routinely achieved during RF gun vacuum baking. Ion bombardment typically leaves a very rough surface that can have a detrimental effect on beam emittance, so further work will focus on the use of Oxygen plasma cleaning of the best candidate alternative metals. An oxygen plasma treated Copper photocathode has been shown to produce an acceptable level of quantum efficiency in the VELA accelerator at Daresbury Laboratory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI049	An Ultracold Electron Facility in Manchester	electron, emittance, space-charge, extraction	714
	Ö. Mete, R. Appleby, W. Bertsche, M.A. Harvey, G.X. Xia UMAN, Manchester, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom A.J. Murray The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
	An ultra-cold atom based electron source (UCAE) facility has been built in the Photon Science Institute (PSI), University of Manchester. In this paper, the key components and working principles of this source are introduced. Pre-commissioning status of this facility and the preliminary simulations results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI049
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI050	Preliminary Study for an RF Photocathode based Electron Injector for AWAKE Project	emittance, electron, focusing, plasma	717
	Ö. Mete, G.X. Xia UMAN, Manchester, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom
	AWAKE project, a proton driven plasma wakefield acceleration (PDPWA) experiment is approved by CERN. The PDPWA scheme consists of a seeding laser, a drive beam to establish the accelerating wakefields within the plasma cell; and a witness beam to be accelerated. The drive beam protons will be provided by the CERN's SPS. The plasma ionisation will be performed by a seeding laser and the drive beam protons to produce the accelerating wakefields. After establishing the wakefields, witness beam, namely, electron beam from a dedicated source should be injected into the plasma cell. The primary goal of this experiment is to demonstrate acceleration of a 5-15 MeV single bunch electron beam up to 1 GeV in a 10 m of plasma. This paper explores the possibility of an RF photocathode as the electron source for this PDPWA scheme based on the existing PHIN photoinjector at CERN. The modifications to the existing design, preliminary beam dynamics simulations in order to provide the required electron beam are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI050
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI051	Measurements of the Longitudinal Energy Distribution of Low Energy Electrons	cathode, electron, experiment, 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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI053	High Repetition Rate Ultrafast Electron Diffraction at LBNL	electron, emittance, gun, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI053
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI055	APEX Present Experimental Results	cathode, gun, electron, emittance	730
	D. Filippetto, C.W. Cork, S. De Santis, L.R. Doolittle, G. Huang, R. Huang, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, F. Sannibale, J.W. Staples, R.P. Wells LBNL, Berkeley, California, USA J. Yang TUB, Beijing, People's Republic of China
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The APEX electron source at LBNL combines high-repetition-rate and high beam brightness typical of photo-guns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI055
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI059	Fabrication of Alkali Antimonide Photocathode for SRF Gun	cathode, gun, vacuum, SRF	742
	E. Wang, S.A. Belomestnykh, I. Ben-Zvi, D. Kayran, G.T. McIntyre, T. Rao, J. Smedley, D. Weiss, W. Xu BNL, Upton, Long Island, New York, USA I. Ben-Zvi, M. Ruiz-Osés Stony Brook University, Stony Brook, USA X. Liang SBU, Stony Brook, New York, USA H.M. Xie PKU, Beijing, People's Republic of China
	Funding: * This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant The first alkali antimonide photocathode was prepared and inserted into the BNL 704 MHz SRF gun. An excimer laser cleaning system was installed in a cathode deposition chamber and the cleaning technique developed previously was used in the first cathode preparation. We also demonstrated that oxidized cathode can be removed by exposing it to the same excimer laser. In this paper, we show the set up of the incorporated laser cleaning system and the QE enhancement of alkali antimony photocathode. The vacuum evolution at transport cart and QE measurement system are also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI069	Computing Angularly-resolved Far Field Emission Spectra in Particle-in-cell Codes using GPUs	radiation, plasma, simulation, GPU	761
	R.G. Pausch, H. Burau, M.H. Bussmann, J.P. Couperus, A.D. Debus, A. Huebl, A. Irman, A. Köhler, U. Schramm, K. Steiniger, R. Widera Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany T.E. Cowan HZDR, Dresden, Germany
	Angularly resolved far field radiation spectra computed from the Lienard Wiechert Potentials of accelerated electrons give information on the microscopic particle dynamics. We present recent results using our many-GPU, fully relativistic 3D3V particle-in-cell code PIConGPU for which we have developed fully synthetic radiation diagnostics that is capable of computing angularly-resolved radiation spectra of more than 10¹⁰ electrons for several hundred to a thousand wavelengths and directions in a single simulation in less than a day on large-scale supercomputers. With such a technique it is possible to use precision spectroscopic methods for understanding the dynamics of electron acceleration in scenarios where other diagnostics fail. We present studies on laser-driven wakefield acceleration and astrophysical jet dynamics to underline the power of this new technique.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI069
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI103	Longitudinal Bunch Shortening for the Laser Stripping Project	cavity, focusing, linac, acceleration	861
	T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, V.V. Danilov, Y. Liu, M.A. Plum 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. Realization of high efficiency laser stripping at the SNS accelerator needs good longitudinal overlap between H⁻ bunch and laser pulse. The default H⁻ bunch length at the interaction point is 5 times bigger than needed in order to achieve 90% stripping efficiency. Theoretical and experimental studies of longitudinal H⁻ bunch shortening are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI103
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZA01	Advanced Concepts and Challenges in Compton Radiation Sources	electron, plasma, cavity, photon	928
	I. Pogorelsky BNL, Upton, Long Island, New York, USA
	Ongoing developments in Compton radiation sources are aimed toward a diversity of potential applications, ranging from university-scale compact x-ray light sources and metrology tools for EUV lithography, to positron sources for e⁻e⁺ colliders. Novel conceptual approaches are pursued on different routes: One research direction lies in multiplying the source’s repetition rate and increasing its average brightness by placing the point of Compton interaction inside an optical cavity. High-gradient plasma-wakefield accelerators are fast becoming a practical reality, offering a new paradigm to compact all-optical Compton sources operating in x-ray- and gamma-regions. Continuing improvement in the quality of the beam of plasma accelerators promises the achievement of fully coherent Compton x-rays, thereby prompting the evolution of the Compton source to an all-optical free-electron laser.
	Slides TUZA01 [22.419 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUZA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA01	The Linac Coherent Light Source-II Project	linac, electron, undulator, cryomodule	935
	J.N. Galayda SLAC, Menlo Park, California, USA
	Funding: Work supported by US DOE Contract DE-AC02-766SF00515 The “Linac Coherent Light Source–II” Project, initiated in September 2010, has gone through a radical transformation beginning in August 2013. In its new form, LCLS-II will construct a 4 GeV CW superconducting linac in the first kilometre of the existing linac tunnel. A new undulator, optimized as a soft x-ray (200-1,300 eV) source, will receive electrons from the new SC linac. The existing undulator system will be replaced with a new variable gap device, which will receive electrons from either the new SC linac (providing 1-5 keV photons) or the copper linac presently used by LCLS (providing 1-25 keV x-rays). First light from the new facility is expected in September 2019. galayda@slac.stanford.edu
	Slides TUOCA01 [9.380 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA02	Status of the Free Electron Laser User Facility FLASH	FEL, flattop, gun, linac	938
	M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch DESY, Hamburg, Germany
	FLASH, the Free Electron Laser User Facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft X-ray FEL radiation to photon experiments. After a shutdown to connect the second undulator beamline FLASH2 to the FLASH linac, re-commissioning of FLASH started in autumn 2013. The year 2014 is dedicated to FLASH1 user experiments. The commissioning of the FLASH2 beamline takes place in 2014 in parallel to FLASH1 operation.
	Slides TUOCA02 [9.156 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA03	Production of Quasi-monochromatic GeV Photons by Compton Scattering using Undulator X-ray Radiation at SPring-8	photon, electron, undulator, experiment	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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBB01	Accelerator Physics Challenges towards a Plasma Accelerator with Usable Beam Quality	plasma, electron, acceleration, wakefield	961
	R.W. Aßmann, J. Grebenyuk DESY, Hamburg, Germany
	Enormous progress in compact plasma accelerators has been demonstrated over the recent years in various experiments. These experiments rely on high power, pulsed lasers or short electron bunches to excite ultra-strong wakefields in plasmas. Accelerating gradients have reached several 10 GV/m up to 100 GV/m and the absolute energy gain of electron beams is in the regime of several GeV to 30 GeV. The principle and potential of plasma accelerators has been proven impressively and performance parameters are steadily improving. It is noted that particle accelerators are powerful tools that are ultimately justified by their applications in science, medicine or industry. The demonstration of useable beam quality and a realistic use case remains to be achieved for plasma accelerators. The accelerator physics challenges to arrive at this goal are analyzed and discussed.
	Slides TUOBB01 [12.407 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBB02	Demonstration of Gigavolt-per-meter Accelerating Gradients using Cylindrical Dielectric-lined Waveguides	experiment, wakefield, radiation, electron	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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBB02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO038	Beam Positioning Concept and Tolerance Considerations for BERLinPro	emittance, linac, gun, timing	1105
	B.C. Kuske, J. Rudolph HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association BERLinPro is an ERL project at Helmholtz-Zentrum Berlin, with the goal to illuminate the challenges and promises of a high brightness 100 mA superconducting RF gun in combination with a 50 MeV return loop and energy recovery [1, 2]. The precision of the beam position in a single turn machine might be relaxed compared to the demands in storage rings. Still, a trajectory correction concept has to be developed and the influence of trajectory offsets on the goal parameters, its dependence on fluctuating injection parameters or effects related to the low energy of 6.5-50 MeV have to be investigated. This paper covers the initial trajectory correction studies and first tolerance scenarios of BERLinPro using the projected hardware concept.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO038
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO117	Magnet Design for the SNS Laser Stripping Experiment	electron, ion, experiment, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO117
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME030	The LIGHT Beamline at GSI: Shaping Intense MeV Proton Bunches from a Compact Laser-driven Source	proton, cavity, focusing, ion	1419
	S. Busold, O. Deppert, M. Roth TU Darmstadt, Darmstadt, Germany V. Bagnoud, A. Blazevic, S. Busold HIJ, Jena, Germany V. Bagnoud, A. Blazevic, S. Busold, D. Schumacher GSI, Darmstadt, Germany C. Brabetz IAP, Frankfurt am Main, Germany F. Kroll TU Dresden, Dresden, Germany F. Kroll Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
	Laser-based proton acceleration as a source of high intensity multi-MeV-range proton bunches became subject of extensive research during the last 15 years and is discussed as potential candidate for various applications. However, their usage often requires special ways of beam shaping first, as the particles are emitted in a wide energy spectrum and with a large divergence angle from the laser matter interaction point. To handle these characteristics, a test stand has been build at GSI Darmstadt, using a pulsed high field solenoid and a radiofrequency cavity to produce intense collimated proton bunches with low energy spread from a TNSA source. In recent experiments, energy compression of an intense proton bunch around 10 MeV central energy to an energy spread of less than 3% could be demonstrated. The particle numbers were in access of 10⁹ protons and the bunch duration was only a few nanoseconds. Even shorter bunches and thus higher particle intensities are possible. This compact laser-driven proton beamline, available now at GSI, will be introduced and latest experimental results presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME031	Radiation Pressure Acceleration and Transport Methods	plasma, simulation, acceleration, target	1422
	P. Schmidt, O. Boine-Frankenheim TEMF, TU Darmstadt, Darmstadt, Germany O. Boine-Frankenheim, O. Boine-Frankenheim, I. Hofmann GSI, Darmstadt, Germany I. Hofmann HIJ, Jena, Germany I. Hofmann IAP, Frankfurt am Main, Germany
	Funding: HGS-HIRe for FAIR, HIC for FAIR, Technische Universität Darmstadt, FB 18 TEMF Several projects worldwide such as LIGHT at GSI focus on laser ion acceleration. With the development of new laser systems and advances in the target production a new acceleration mechanism has become of interest: The Radiation Pressure Acceleration (RPA). An ultra short high intense laser pulse hits a very thin foil target and the emerging plasma is ideally accelerated as one piece (light sail regime). The ions reach kinetic energies up to GeV and nearly solid body densities. In this work, the distribution and transport of a RPA plasma is studied. 1D and 2D PIC simulations (software: VSim) are carried out to obtain the phase space distribution of the plasma. The results are compared to fluid models (software: FiPy and USim). A reference model an RPA plasma is obtained which is then used for advanced transport studies. Transport mechanisms (active and passive) are studied, such asμlenses and foil stacks.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME031
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME033	Scaling of TNSA-accelerated Proton Beams with Laser Energy and Focal Spot Size	target, proton, acceleration, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME034	Transport and Energy Selection of Laser Produced Beams for Medical Research and Multidisciplinary Applications	quadrupole, target, solenoid, focusing	1425
	M.M. Maggiore INFN/LNL, Legnaro (PD), Italy G.A.P. Cirrone, F. Romano, F. Schillaci, A. Tramontana INFN/LNS, Catania, Italy V. Scuderi ELI-BEAMS, Prague, Czech Republic
	Ion beams produced by the interaction of high-power laser with thin targets are being characterized experimentally around the world in order to get a reasonable amount of particles with low divergence and narrow energy spread for medical and multidisciplinary applications. Several schemes about the energy selection and transport of laser accelerated beams have been considered and tested, however the energy spread of the selected particles remains rather high and the reproducibility has not been yet achieved. In the framework of the ELIMED network, we present a study of a possible layout to capture and transport in an efficient and reproducible way, the beams generated by the laser-target interaction. It consists of a combination of quadrupoles based on permanent magnets placed just downstream the target, coupled with a system composed by a series of 4 dipole magnets of inverted polarity, which provides the final energy selection of the previously focused beam. Such a system will be tested in 2014 at TARANIS facility to select proton beams in the energy range of 4-8 MeV; the main scheme can be scaled for the high energy beam that are expected at ELI-beamlines facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME035	Design Study of the Laser-driven Dielectric Accelerator	electron, acceleration, simulation, focusing	1428
	K. Koyama, M. Yoshida KEK, Ibaraki, Japan Y. Matsumura University of Tokyo, Tokyo, Japan S. Otsuki The University of Tokyo, Tokyo, Japan M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
	Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120. Laser driven dielectric accelerators (LDA) are vigorously studied in order to apply to various fields in recent years. Characteristics of the LDA output such as sub-micron diameter, atto-second bunch and high acceleration field are suitable for in-situ investigating the biological effects of low doses of radiation in a living cell. The output energy of 1 MeV is sufficient for sniping a cell nucleus or DNA. Although the electronic charge in the bunch is in the order of 10 fC, the tightly focused beam enable to cause a local damage in the cell. We have reported optimum structure parameters of dielectric in the nonrelativistic regime. The low acceleration efficiency of slow electrons by short laser pulses is the serious problem. The accelerator length, laser intensity, pulse width, and optical system must be adjusted to design the practical LDA. We present the design principle of the LDA for nonrelativistic electrons and present status of the pumping laser of us.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME036	Simulation Study on Electron Beam Acceleration using Coherent Cherenkov Radiation	electron, acceleration, simulation, radiation	1431
	K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan M. Hangyo ILE Osaka, Suita, Japan R. Kuroda, H. Toyokawa AIST, Tsukuba, Ibaraki, Japan
	Beam diagnostics for electron bunch length using spectrum analysis of multimode terahertz (THz) -wave have been studied in ISIR, Osaka University. The multimode THz-wave was generated by coherent Cherenkov radiation (CCR)* using hollow dielectric tubes and femtosecond/picosecond electron bunches. In this study, numerical calculation of acceleration and deceleration of electron beam using multimode THz-wave was carried out. * K. Kan et al., Appl. Phys. Lett. 99, 231503 (2011). ** A. M. Cook et al., Phys. Rev. Lett. 103, 095003 (2009).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME037	Development on On-chip Radiation Source using Dielectric Laser Accelerator	electron, acceleration, radiation, simulation	1434
	S. Otsuki The University of Tokyo, Tokyo, Japan K. Koyama, M. Yoshida KEK, Ibaraki, Japan Y. Matsumura University of Tokyo, Tokyo, Japan S. Mima RIKEN, Japan M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
	Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120. One of the state-of-the-art acceleration schemes, where high intensity laser pulses are modulated by dielectric grating structure such as quartz to accelerate charged particles, is dielectric laser acceleration (DLA). The difference of our DLA concept from other schemes is installation of a prism: the tilted wave-front in a prism shape refractive medium leads the suitable delay to match the phase advance of the electron beam. We plan to apply this method to build an on-chip radiation source which can hit and damage target elements of the cells. Such an application is useful in radiation biology, i.e., for investigation on bystander effects. The x-rays with small radius and adequate intensity required for this goal can be obtained using sub-micron beams from the small accelerating structure at high repetition rate (such as 50 kHz). In addition, the mass productivity of the DLA based on the consumer-grade laser and the photolithography has advantage compared to the conventional RF accelerator using high power klystrons. We will present field simulation and preliminary experimental results for demonstration on our concept of DLA. Demonstration of electron acceleration in a laser-driven dielectric microstructure, Nature 2013 ** Laser-Based Acceleration of Nonrelativistic Electrons at a Dielectric Structure, Phys. Rev. 2013
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME041	The Advanced Superconducting Test Accelerator at Fermilab: Science Program	SRF, electron, linac, emittance	1447
	P. Piot, E.R. Harms, S. Henderson, J.R. Leibfritz, S. Nagaitsev, V.D. Shiltsev, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: This work is supported by DOE contract DE-AC02-07CH11359 to the Fermi Research Alliance LLC The Advanced Superconducting Test Accelerator (ASTA) currently in commissioning phase at Fermilab is foreseen to support a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop novel approaches to particle-beam generation, acceleration and manipulation. ASTA incorporates a superconducting radiofrequency (SCRF) linac coupled to a flexible high-brightness photoinjector. The facility also includes a small-circumference storage ring capable of storing electrons or protons. This report summarizes the facility capabilities, and provide an overview of the accelerator-science researches to be enabled.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME043	Temporal Electron-bunch Shaping from a Photoinjector for Advanced Accelerator Applications	space-charge, wakefield, acceleration, gun	1454
	F. Lemery, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	Advanced-accelerator applications often require the production of bunches with shaped temporal distributions. An example of sought-after shape is a linearly-ramped current profile that can be improve the transformer ratio in beam-driven acceleration, or produce energy-modulated pulse for, e.g., the subsequent generation of THz radiation. Typically, such a shaping is achieved by manipulating ultra-relativistic electron bunches. In this contribution we discuss the possibility of shaping the bunch via photoemission and demonstrate using particle-in-cell simulations the production of MeV electron bunches with quasi-ramped current profile.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME043
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME045	Development of a High-Energy Short-pulse 5-μm Parametric Source for Dielectric Laser Acceleration	acceleration, detector, operation, optics	1460
	G. Xu, I. Jovanovic, S.F. Wandel Penn State University, University Park, Pennsylvania, USA
	A compact, high-peak-power 5-μm laser source with pulse duration of sub-100 fs has been designed and being constructed for pumping a dielectric photonic structure to produce an acceleration gradient of order GV/m in dielectric laser acceleration. Breakdown of dielectric structure induced by multiphoton ionization can be mitigated by adopting long wavelength driver laser. Since the dielectric structure scales with the laser wavelength, fabrication tolerances for dielectric structure are relaxed as well. The 5-μm laser source is based on two cascaded optical parametric amplifiers (OPA): a 2-μm BBO OPA with a mixed phase matching scheme is used as a pump source, and a type-I phase-matched ZGP OPA is designed to produce sub-mJ, <100 fs 5-μm laser pulses. The two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~2.2 mJ with a pulse duration of 42 fs (~6 optical cycles), and excellent pulse stability and beam quality. Preliminary result of ~50 μJ pulse energy at 5-μm is demonstrated by using single-stage ZGP OPA, and an improved two-stage OPA scheme for production of higher pulse energy at 5-μm is under development.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME045
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME046	3-D Particle-in-cell Simulations for Quasi-phase Matched Direct Laser Electron Acceleration in Density-modulated Plasma Waveguides	electron, plasma, emittance, simulation	1463
	M.W. Lin The Pennsylvania State University, University Park, Pennsylvania, USA I. Jovanovic Penn State University, University Park, Pennsylvania, USA
	Funding: This work is supported by the Defense Threat Reduction Agency through contract HDTRA1-10-1-0034. Quasi-phase matched (QPM) direct laser acceleration (DLA) of electrons can be realized with guided, radially polarized laser pulses in density-modulated plasma waveguides,. A 3-D particle-in-cell (PIC) simulation model has been developed to study the scheme in which an electron bunch from a laser wakefield accelerator (LWFA) is injected into a plasma waveguide for the second-stage DLA to higher energies. In addition to being driven directly by the laser field, the electrons also experience the laser pondermotive force and the electrostatic force from the excited plasma waves. The results lead to better understanding of the interactions between the electron bunch, the laser pulse and the background plasma. Selected bunch lengths, bunch sizes and time delays with respect to the laser pulse are assigned for the injected electrons in a series of simulations. The energy spectrum and emittance of the accelerated electron bunch vary depending on those initial conditions, and they can be chosen to optimize the DLA performance. P. Serafim, et al., IEEE Trans. Plasma Sci. 28, 1155 (2000). ** M. -W. Lin and I. Jovanovic, Phys. Plasmas 19, 113104 (2012).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME046
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME047	SINBAD - A Proposal for a Dedicated Accelerator Research Facility at DESY	plasma, experiment, electron, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME048	Injection of a LWFA Electron Bunch in a PWFA Driven by a Self-modulated-proton-bunch	plasma, wakefield, electron, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME048
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME051	Self-Injection by Trapping of Plasma Electrons Oscillating in Rising Density Gradient at Vacuum-Plasma Interface	plasma, electron, injection, wakefield	1479
	A. A. Sahai, T.C. Katsouleas Duke ECE, Durham, North Carolina, USA P. Muggli MPI-P, München, Germany
	Funding: DE-SC0010012, NSF-PHY-0936278 We model the trapping of plasma electrons within the density structures excited by a propagating energy source in a rising plasma density gradient. Rising density gradient leads to spatially contiguous coupled up-chirped plasmons (d{ω²_pe(x)}/{dx}>0). Therefore phase mixing between plasmons can lead to trapping until the plasmon field is high enough such that e^- trajectories returning towards a longer wavelength see a trapping potential. Rising plasma density gradients are ubiquitous for confining the plasma within sources at the vacuum-plasma interfaces. Therefore trapping of plasma-e^- in a rising ramp is important for acceleration diagnostics and to understand the energy dissipation from the excited plasmon train [1]. Down-ramp in density [2][3] has been used for plasma-e^- trapping within the first bucket behind the driver. Here, in rising density gradient the trapping does not occur in the first plasmon bucket but in subsequent plasmon buckets behind the driver. Trapping reduces the Hamiltonian of each bucket where e^- are trapped, so it is a wakefield-decay probe. Preliminary computational results for beam and laser-driven wakefield are shown. 1.Sahai, A. A. et.al.,Proc of IPAC2013, MOPAC10, Oct2013 2.Suk, H. et.al.,Phys. Rev.Lett. 86 2001 10.1103/PhysRevLett.86.1011 3.Dawson, J, Phys Rev 113 1959 10.1103/PhysRev.113.383
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME051
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME052	Enhanced Laser Ion Acceleration based on Near-Critical Density Plasma Lens	plasma, target, acceleration, electron	1483
	Y.X. Geng, J.E. Chen, L.R.F. Li, Y.H. Li, Q. Liao, C. Lin, L.H.Y. Lu, Y.R. Lu, H. Wang, X.Q. Yan, Z.X. Yuan, S. Zhao, W.B. Zhao, Y.Y. Zhao, K. Zhu, B.Y. Zou PKU, Beijing, People's Republic of China
	The laser prepulse has large effect on ion acceleration driven by high power laser pulse. Recently, simulations show that with proper prepulse parameters, a near critical density pre-plasma can be generated in the front target. When the main laser pulse propagating in this pre-plasma, it can experience transverse Self-focusing, longitudinal profile steepening and prepluse cleaning at the same time, meaning its quality is spontaneously improved by this “plasma lens”.The effects can greatly improve the energy coupling efficiency of laser pulse into accelerated ions. A 3mJ Ti-Sapphire laser system has been built at PKU in order to experimentally study the pre-pulse effect on a solid target. Fluid simulation show that, after hundreds of picoseconds radiated with this laser pulse, the pre-plasma in front of the target will expand to near critical density with tens of micron scale length, which is suitable as a plasma lens to improve the ion acceleration. A laser interferometer system is built to measure the scale length and density evolution of plasma and the optimum condition of the pre-plasma has been searched using both Aluminum target and home-made DLC target. H.Y.Wang et al, Laser shaping of a relativistic intense, short Gaussian pulse by a plasma lens, PRL, 107,265002, 2011
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME052
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME055	Room-temperature Burst-mode GHz and THz Pulse-train Photoinjector	electron, cathode, bunching, acceleration	1492
	F.H. Chao, C.H. Chen, K.Y. Huang, Y.-C. Huang, Y.C. Wang, M.H. Wu NTHU, Hsinchu, Taiwan P.J. Chou NSRRC, Hsinchu, Taiwan
	A photoinjector usually generates an electron pulse with few ps pulse duration repeating at 10-100 Hz. The low-pulse rate limits the data rate in a number of applications. Although high-repetition-rate operation is possible from a superconducting accelerator, the high cost and complexity of a superconducting system prevent it from being widely used. In this paper, we present our study toward a burst-mode GHz/THz pulse train photoinjector operating at room temperature. For the GHz operation mode, we self-develop a driver laser system, generating tens of laser pulses at 2.856 GHz in an adjustable 5-10 ns temporal envelope repeating at 10 Hz. Upon illuminating the photocathode with the driver laser, our S-band photoinjector (supported by Tsing Hua University, Beijing) is to generate a GHz electron pulse train with the same temporal structure as that of the driver laser pulses. For the THz operation mode, we illuminate the photocathode with two lasers, one being a typical UV gun-driver laser at 260 nm and the other being a mid-infrared laser at 100 THz. The UV laser induces photoemission and the infrared laser gates the emission current at 100 THz by virtue of the Schottky effect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME055
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME056	Improving Ion and Electron Beam Characteristics within LA³NET	electron, acceleration, photon, simulation	1495
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191. Lasers are widely used at accelerator and light source facilities for beam generation, acceleration and optimization. Research within LA³NET focuses on laser-based particle sources (photo injectors and laser ion sources), laser acceleration, and laser-based beam diagnostics. This project was recently selected as a ‘success story’ by the European Commission for its research achievements. This paper presents selected numerical and experimental results. From HZDR results of electron transport simulations in their new SRF gun II cavity, super-conductive solenoid and downstream accelerators are shown. The results from optimization studies into asymmetric grating structures obtained at the University of Liverpool are also presented, along with initial results from studies into novel diagnostics for high intensity proton beams at CERN and low energy electron beams at KIT. Finally, the events organized by the consortium to date and future plans are summarized.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME056
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME058	The Argonne Wakefield Accelerator (AWA): Commissioning and Operation	wakefield, gun, electron, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME058
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME064	Laser-driven Acceleration with External Injection at SINBAD	plasma, injection, acceleration, simulation	1515
	J. Grebenyuk, R.W. Aßmann, U. Dorda, B. Marchetti DESY, Hamburg, Germany
	One of the important milestones to make plasma acceleration a realistic technology for user-applications is demonstration of bunch acceleration inside a plasma wake with minimal degradation of its quality. This can be achieved by external injection of beams into a plasma accelerator. SINBAD is a proposed dedicated accelerator research and development facility at DESY where amongst other topics laser-driven wakefield acceleration with external injection of ultra-short bunches will be exploited. To minimise energy-spread growth the bunch should occupy a small fraction of the plasma wavelength. In addition it has to be longitudinally synchronised with the laser driver to high accuracy. To avoid emittance growth the beam Twiss parameters have to be matched to the intrinsic beta-function of the plasma. To facilitate matching and synchronisation, acceleration at low plasma densities can be advantageous. We present a preparatory feasibility study for future plasma experiments at SINBAD using simulations with the particle-in-cell code OSIRIS. Field-gradient scaling laws are presented together with parameter scans of externally injected bunch, such as its injection phase, charge and length.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME064
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME073	A Novel Laser Ionized Rb Plasma Source for Plasma Wakefield Accelerators	plasma, wakefield, proton, electron	1522
	E. Öz, F. Batsch, P. Muggli MPI-P, München, Germany
	Funding: AWAKE collaboration A proton driven plasma wakefield accelerator* is to be conducted at CERN by the AWAKE collaboration. Externally injected electrons are accelerated in a large gradient (~GeV/m) wakefield. The large gradient is achieved by resonant formation of the wakefield by a train of micro-bunches. Transverse modulation of a long (~12 cm) proton bunch by the self modulation instability creates these plasma wavelength size (~1 mm) micro-bunches. This resonant mechanism brings a strict requirement on the plasma density uniformity, namely % 0.2, in order for the injected electron bunch to remain in the accelerating and focusing phase of the wakefields. We describe the plasma source* that satisfies this requirement during the beam plasma interaction. Rb vapor with ~10¹⁵ cm^-3 density is confined in a 10 m long 4 cm diameter, stainless-steel tube which is heated to ~200 Co by an oil heat exchanger. The access to the source during interaction is provided by custom built fast valves. The vapor is fully tunnel ionized (first e-) by a laser forming a 2 mm diameter plasma channel. * http://awake.web.cern.ch/awake/ http://link.aps.org/doi/10.1103/PhysRevLett.104.255003 * http://dx.doi.org/10.1016/j.nima.2013.10.093
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME073
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME075	Simulations on Laser Wakefield Generation in a Parabolic Magnetic-plasma Channel	plasma, wakefield, simulation, electron	1528
	D.N. Gupta, M. Singh University of Delhi, Delhi, India D. Jang, H. Suk APRI-GIST, Gwangju, Republic of Korea B.S. Sharma Kota University, Rajasthan, India
	To utilize the laser-plasma channel for laser wakefield acceleration, we have studied the non-paraxial theory of nonlinear propagation of ultra-intense relativistic Gaussian laser pulse in a preformed spatially tapered magneto-plasma channel having a parabolic density profile. A three-dimensional envelope equation for the laser field is derived, which includes the non-paraxial and applied magnetic field effects. An analytical expression for the wakefield is derived and analyzed the results with the help of particle-in-cell (PIC) simulations. It is shown that wakefield structures and the phase of axial component of the wakefield depend on applied external magnetic field. This aspect of theoretical observation can be used in the production of highly collimated mono-energetic x-rays.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME075
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME077	The Challenge of Interfacing the Primary Beam Lines for the AWAKE Project at CERN	proton, plasma, electron, injection	1534
	C. Bracco, B. Goddard, E. Gschwendtner, M. Meddahi, A.V. Petrenko CERN, Geneva, Switzerland P. Muggli MPI, Muenchen, Germany F.M. Velotti EPFL, Lausanne, Switzerland
	The Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN foresees the simultaneous operation of a proton, a laser and an electron beam. The first stage of the experiment will consist in proving the self-modulation, in the plasma, of a long proton bunch into micro-bunches. The success of this experiment requires an almost perfect concentricity of the proton and laser beams, over the full length of the plasma cell. The complexity of integrating the laser into the proton beam line and fulfilling the strict requirements in terms of pointing precision of the proton beam at the plasma cell are described. The second stage of the experiment foresees also the injection of electron bunches to probe the accelerating wakefields driven by the proton beam. Studies were performed to evaluate the possibility of injecting the electron beam parallel and with an offset to the proton beam axis. This option would imply that protons and electrons will have to share the last few meters of a common beam line. Issues and possible solutions for this case are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME077
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI090	Linac Alignment for SuperKEKB Injector	alignment, linac, emittance, positron	1781
	T. Higo, K. Kakihara, T. Kamitani, M. Satoh, R. Sugahara, T. Suwada, M. Tanaka KEK, Ibaraki, Japan
	The misalignment of the linac beamline components amounted to be a millimeter level during the operation of KEKB, though the requirement of 0.1mm in mind. The limited effort toward improving such big misalignments has long been pursued but could not finish especially after the earthquake in March 2011. This linac is now under upgrade to the SuperKEKB, where the required alignment is 0.1mm in σ for the short distance in 100m span, while 0.3mm through the whole linac for the emittance preservation. The straight line as a reference for the alignment was defined by laser beam over 500m. The actual hardwares are set with respect to this reference line by using a laser tracker. The alignment present status is reported in this paper. On the other hand, we noticed, through the alignment measurements over months, that the tunnel floor moved in the range of 0.1mm or maybe more. The evaluation of this movement is on-going to discuss about how to achieve the required emittance and how to keep the situation. Various measurements to evaluate the movement are presented also in the paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI090
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI091	Refinement of ARC Alignment between Two Straight Sections for Injector Linac of SuperKEKB	alignment, linac, emittance, quadrupole	1784
	M. Tanaka, T. Higo, K. Kakihara, T. Kamitani KEK, Ibaraki, Japan K. Kimura, K. Suzuki, N. Toyotomi, S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	The beam line of the KEKB injector linac is under realignment as the restoration after the big Earthquake in 2011, but with the refinement for the SuperKEKB in mind. The linac consists of two straight sections connected by a 180 degree ARC. Precise alignment of the ARC magnets is one of the key issues for the emittance preservation of the electron beam. The ARC beam line was defined by measuring these two straight lines. Then, the misalignment of the ARC magnets were reduced from 3 mm maximum down to 0.1mm in the errors perpendicular to the beam direction. This paper describes how we defined the ARC beam line and performed the alignment. The connection method of the laser tracker data needed for the definition of the ARC was also studied and described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI091
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI093	Determination of the Magnetic Axis of a CLIC Drive Beam Quadrupole with respect to External Alignment Targets using a Combination of WPS, CMM and Laser Tracker Measurements.	alignment, quadrupole, target, linear-collider	1790
	M. Duquenne, M. Anastasopoulos, D. Caiazza, G. Deferne, J. Garcia Perez, H. Mainaud Durand, M. Modena, V. Rude, J. Sandomierski, M. Sosin CERN, Geneva, Switzerland
	CERN is currently studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). One of the engineering challenges is the pre-alignment precision and accuracy requirement on the alignment of the linac components. For example, the magnetic axis of a Drive Beam Quadrupole will need to be aligned within 20 um rms with respect to a straight reference line of alignment. The fiducialisation process which is the determination of the magnetic axis with respect to external alignment targets, that is part of this error budget, will have to be performed at an accuracy never reached before. This paper presents the strategy proposed for the fiducialisation of the Drive Beam quadrupole, based on a combination of CMM measurements, WPS measurements and Laser tracker measurements. The results obtained on a dedicated test bench will be described as well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI093
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI094	Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor	vacuum, experiment, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI094
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI100	Present Status of the Cherenkov Beam Loss Monitor at SACLA	electron, undulator, detector, status	1808
	T. Itoga JASRI/SPring-8, Hyogo, Japan Y. Asano RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	Since 2011, high power lasers have been delivered stably to the users at SACLA, the SPring-8 Angstrom compact free electron laser, and the upgrades have been performing to obtain the high quality of the laser continuously. Optical fiber based Cherenkov beam loss monitors have been successfully operated from the commissioning phase. This monitor covers the undulator section of beam lines and the electron beam transporting tunnel from SACLA to SPring-8. This monitor is made good use of not only beam transport but also detection of the small beam loss such as electron halos hitting the magnets of undulator. In this presentation, we will report the present status of the Cherenkov beam loss monitor and its usage experience.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI100
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI107	Compact MTCA.4 Based Laser Synchronization	timing, FPGA, hardware, FEL	1823
	M. Felber, L. Butkowski, H.T. Duhme, M. Fenner, C. Gerth, U. Mavrič, P. Peier, H. Schlarb, B. Steffen DESY, Hamburg, Germany T. Kozak, P. Prędki, K.P. Przygoda TUL-DMCS, Łódź, Poland
	In this paper we present a compact and efficient approach for laser synchronization based on MTCA.4 platform. Laser pulses are converted to the RF signals using a photo-diode detector. The RF section performs filtering, amplification and down-conversion of a narrowband, CW signal. The resulting IF signal is sampled by a high resolution digitizer on the AMC (Advanced Mezzanine Card) side and transported via point-to-point links to an adjacent AMC board. The processing electronics on this board drives a digital-to-analog converter on the rear-side. The analog signal is then filtered and amplified by a high voltage power amplifier which drives the piezo stretcher in the laser. Some preliminary results of laser to RF locking with such a scheme are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI107
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI108	Development of New Tag Supply System for DAQ for SACLA User Experiments	experiment, 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).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI108
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAA03	Ultrashort and Coherent Radiation for Pump-probe Experiments at the DELTA Storage Ring	radiation, experiment, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBA03	Status of Preparations for a 10 μs Laser-Assisted H⁻ Beam Stripping Experiment	experiment, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEXB01	Breaking the 70 MeV Proton Energy Threshold in Laser Proton Acceleration and Guiding Beams to Applications	target, proton, ion, acceleration	1886
	M. Roth, S. Bedacht, S. Busold, O. Deppert, G. Schaumann, A. Tebartz, F. Wagner TU Darmstadt, Darmstadt, Germany V. Bagnoud, A. Blazevic, D. Schumacher GSI, Darmstadt, Germany C. Brabetz IAP, Frankfurt am Main, Germany T.E. Cowan HZDR, Dresden, Germany K. Falk, A. Favalli, J.C. Fernandez, C. Gautier, C.E. Hamilton, R.P. Johnson, K. Schoenberg, T. Shimada, G.A. Wurden LANL, Los Alamos, New Mexico, USA M. Geißel, M. Schollmeier Sandia National Laboratories, Albuquerque, New Mexico, USA D. Jung Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom F. Kroll Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
	This talk covers recent developments in laser plasma ion acceleration describing the technological challenges in breaking of energy threshold of 70 MeV. The presentation also highlights the recent experimental achievements towards laser ion acceleration and transport in the LIGHT collaboration.
	Slides WEXB01 [15.155 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEXB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB01	The Commissioning of the Laser Ion Source for RHIC-EBIS	ion, target, ion-source, injection	1890
	T. Kanesue, J.G. Alessi, E.N. Beebe, M.R. Costanzo, L. DeSanto, R.F. Lambiase, D. Lehn, C.J. Liaw, V. LoDestro, M. Okamura, R.H. Olsen, A.I. Pikin, D. Raparia, A.N. Steszyn BNL, Upton, Long Island, New York, USA S. Ikeda TIT, Yokohama, Japan K. Kondo, M. Sekine RLNR, Tokyo, Japan
	Funding: Work supported by NASA and Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy A new laser ion source (LIS) for low charge state ion production was installed on RHIC-EBIS. This is the first LIS to be combined with an Electron Beam Ion Source (EBIS) type heavy ion source. The LIS provides intense low charge state ions from any solid state material, with low emittance and narrow pulse length. These features make it suitable as an external source of 1+ ions that can be injected into the EBIS trap for charge breeding. In addition, a LIS is the only type ion source which can allow rapid switching among many ion species, even on pulse-by-pulse basis, by changing either laser path or target position, to strike the material of choice. The EBIS works as a charge breeder, with the extracted high charge state ions used in the following accelerators. The beams from LIS will be used for RHIC and NASA Space Radiation Laboratory (NSRL) at BNL. The rapid beam switching, which was not possible with existing ion sources, will expand the research field at NSRL as a galactic cosmic ray simulator. The results of commissioning will be shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB03	Linear Electron Acceleration in THz Waveguides	electron, linac, acceleration, accelerating-gradient	1896
	E.A. Nanni, W.S. Graves, K.-H. Hong, W.R. Huang, F.X. Kärtner, KR. Ravi, L.J. Wong MIT, Cambridge, Massachusetts, USA A. Fallahi, F.X. Kärtner CFEL, Hamburg, Germany R.J.D. Miller DESY, Hamburg, Germany G. Moriena University of Toronto, Toronto, Ontario, Canada
	Funding: Supported by DARPA N66001-11-1-4192, CFEL DESY, DOE DEFG02-10ER46745, DOE DE-FG02-08ER41532, ERC Synergy Grant 609920 and NSF DMR-1042342. We report the first experimental demonstration of linear electron acceleration using an optically generated single cycle THz pulse centered at 0.45 THz. 7 keV of acceleration is achieved using 10 microJ THz pulses in a 3 mm interaction length. The THz pulse is produced via optical rectification of a 1.2 mJ, 1 micron laser pulse with a 1 kHz repetition rate. The THz pulse is coupled into a dielectric-loaded circular waveguide with 10 MeV/m on-axis accelerating gradient. A 25 fC input electron bunch is produced with a 60 keV DC photo-emitting cathode. The achievable accelerating gradient in the THz structures being investigated will scale rapidly by increasing the IR pulse energy (100 mJ - 1 J) and correspondingly the THz pulse energy. Additionally, with recent advances in the generation of THz pulses via optical rectification, in particular improvements to efficiency and generation of multi-cycle pulses, GeV/m accelerating gradients could be achieved. An ultra-compact high-gradient THz accelerator would be of interest for a wide variety of applications.
	Slides WEOAB03 [7.185 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAB03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBB01	Design and Performance of the Optical Fiber Length Stabilization System for SACLA	controls, timing, feedback, experiment	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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBB02	Status of Single-shot EOSD Measurement at ANKA	wakefield, operation, electron, storage-ring	1909
	N. Hiller, A. Borysenko, E. Hertle, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh, P. Schönfeldt, N.J. Smale, J.L. Steinmann KIT, Karlsruhe, Germany P. Peier, B. Steffen DESY, Hamburg, Germany V. Schlott PSI, Villigen PSI, Switzerland
	Funding: This work is funded by the BMBF contract numbers: 05K10VKC, 05K13VKA. ANKA is the first storage ring in the world with a near-field single-shot electro-optical (EO) bunch profile monitor. The method of electro-optical spectral decoding (EOSD) uses the Pockels effect to modulate the longitudinal electron bunch profile onto a long, chirped laser pulse passing through an EO crystal. The laser pulse is then analyzed with a single-shot spectrometer and from the spectral modulation, the temporal modulation can be extracted. The setup has a sub-ps resolution (granularity) and can measure down to bunch lengths of 1.5 ps RMS for bunch charges as low as 30 pC. With this setup it is possible to study longitudinal beam dynamics (e. g. microbunching) occurring during ANKA's low-alpha-operation, an operation mode with compressed bunches to generate coherent synchrotron radiation in the THz range. In addition to measuring the longitudinal bunch profile, long-ranging wake-fields trailing the electron bunch can also be studied, revealing bunch-bunch interactions.
	Slides WEOBB02 [12.753 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBB02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOZA01

Ultralow Emittance Beam Production based on Doppler Laser Cooling and Coupling Resonance

ion, simulation, coupling, solenoid

28

A. Noda, M. Nakao
NIRS, Chiba-shi, Japan
M. Grieser
MPI-K, Heidelberg, Germany
Z.Q. He
FRIB, East Lansing, Michigan, USA
Z.Q. He
TUB, Beijing, People's Republic of China
K. Jimbo
Kyoto University, Kyoto, Japan
H. Okamoto, K. Osaki
HU/AdSM, Higashi-Hiroshima, Japan
A.V. Smirnov
JINR, Dubna, Moscow Region, Russia
H. Souda
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
Y. Yuri
JAEA/TARRI, Gunma-ken, Japan

Funding: Work supported by Advanced Compact Accelerator Development project by MEXT of Japan. It is also supported by GCOE project at Kyoto University, “The next generation of Physics-Spun from Universality"
Doppler laser cooling has been applied to low-energy (40 keV) Mg ions together with the resonant coupling method* at the S-LSR at ICR, Kyoto University,. The S-LSR storage ring has a high super periodicity of 6, which is preferable from the beam dynamical point of view. At S-LSR one dimensional ordering of proton beam was already realized for the first time**. Active three dimensional laser cooling has been experimentally demonstrated for ions with un-negligible velocity (v/c=0.0019, where c is the light velocity) for the first time. Utilizing the above mentioned characteristics of S-LSR, an approach to realize ultralow emittances has been pursuit. To suppress heating effects, due to intra-beam scattering, the circulating ion beam intensity was reduced by scraping and beam emittances of 1.3·10^-11 pi m·rad and 8.5·10^-12 pi m·rad (normalized) have been realized for the horizontal and vertical directions, respectively with the 40 keV Mg ion beam at a beam intensity of ~10⁴, which is the lowest emittance ever attained by laser cooling. From MD computer simulations, it is predicted that reduction of the ion number to about 10³ is needed to realize a crystalline string.
* H. Okamoto, A.M. Sessler, D. Moehl, Phys. Rev. Lett. 72, 397 (1994).
** T. Shirai et. al., Phys. Rev. Lett. 98, 204801 (2007).

Slides MOZA01 [13.336 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOZB01

Superconducting RF Guns: Emerging Technology for Future Accelerators

gun, cathode, SRF, cavity

4085

J. Teichert
HZDR, Dresden, Germany

This talk should give an overview of Superconducting photo injectors (SRF guns) and focus on the present status of SRF gun development, the technical requirements and the critical issues like cavity design, photocathode integration, and emittance compensation methods.

Slides MOZB01 [22.198 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOZB02

Advances in Photocathodes for Accelerators

electron, emittance, cathode, experiment

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO054

Commissioning progress of the Femto-slicing Project at SOLEIL

electron, wiggler, radiation, synchrotron

206

M. Labat, H.B. Abualrob, P. Betinelli-Deck, A. Buteau, N. Béchu, L. Cassinari, M.-E. Couprie, F. Dohou, C. Herbeaux, Ph. Hollander, J.-F. Lamarre, C. Laulhé, A. Lestrade, J. Lüning, O. Marcouillé, J.L. Marlats, T. Moreno, P. Morin, A. Nadji, L.S. Nadolski, D. Pédeau, P. Prigent, S. Ravy, J.P. Ricaud, M. Ros, P. Roy, M.G. Silly, F. Sirotti, K. Tavakoli, M.-A. Tordeux, D. Zerbib
SOLEIL, Gif-sur-Yvette, France

The femtoslicing project at SOLEIL is currently under commissioning. It will enable to serve several beamlines with 100 fs FWHM long pulses of soft and hard X-rays with reasonable flux and with a 1 kHz repetition rate. It is based on the interaction of a femtosecond Ti:Sa laser with electrons circulating in the magnetic field of a modulator wiggler, that provides the electron beam energy modulation on the length scale of the laser pulse. The optimization of the interaction is performed using two dedicated diagnostics stations. The first one, operating in the Infra-Red (IR) is installed in the tunnel and allows the adjustment of the temporal, spectral and spatial overlap between the laser and the electron beam. The second one, located in the IR-THz AILES beamline, measures the intensity of the terahertz (THz) radiation emitted by the local dip structure produced in the core electron beam after interaction. This second setup provides refined optimization of the interaction. This paper describes the layout of these diagnostics and gives first results and characterization of the slicing experiment at SOLEIL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO066

Status of FLUTE

gun, electron, linac, diagnostics

231

M. Schuh, I. Birkel, A. Borysenko, A. Böhm, N. Hiller, E. Huttel, S. Höninger, V. Judin, S. Marsching, A.-S. Müller, A.-S. Müller, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schwarz, M. Weber, P. Wesolowski
KIT, Karlsruhe, Germany
R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
H.-H. Braun, R. Ganter, V. Schlott, L. Stingelin
PSI, Villigen PSI, Switzerland

FLUTE, a new linac-based test facility and THz source is currently being built at the Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It consists of an RF photo gun and a traveling wave linac accelerating electrons to beam energies of ~41 MeV in the charge range from a few pC up to 3 nC. The electron bunch will then be compressed in a magnetic chicane in the range of 1 - 300 fs, depending on the charge, in order to generate coherent THz radiation with high peak power. An overview of the simulation and hardware status is given in this contribution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO066

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO078

The SPARC_LAB Thomson Source Commissioning

electron, photon, linac, emittance

267

C. Vaccarezza, D. Alesini, M.P. Anania, M. Bellaveglia, E. Chiadroni, D. Di Giovenale, G. Di Pirro, M. Ferrario, A. Gallo, G. Gatti, R. Pompili, S. Romeo, F. Villa
INFN/LNF, Frascati (Roma), Italy
A. Bacci, C. Curatolo, D.T. Palmer, V. Petrillo, A.R. Rossi, L. Serafini, P. Tomassini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
P. Cardarelli, G. Di Domenico, M. Gambaccini
INFN-Ferrara, Ferrara, Italy
A. Cianchi
INFN-Roma II, Roma, Italy
P. Delogu
INFN-Pisa, Pisa, Italy
F. Filippi, A. Giribono
INFN-Roma, Roma, Italy
B. Golosio, P. Oliva
INFN-Cagliari, Monserrato (Cagliari), Italy
A. Mostacci
Rome University La Sapienza, Roma, Italy

The SPARC_LAB Thomson source is presently under commissioning at LNF. An electron beam of energy between 30-150 MeV collides head-on with the laser pulse provided by the Ti:Sapphire laser FLAME, characterized in this phase by a length of 6 ps FWHM and by an energy ranging between 1 and 5 J. The key features of this system are the wide range of tunability of the X-rays yield energy, i.e. 20-500 keV, and the availability of a coupled quadrupole and solenoid focusing system, allowing to reach an electron beam size of 10-20 microns at the interaction point. The experimental results obtained in the February 2014 shifts are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO078

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO110

Present Status of the Compact ERL at KEK

recirculation, linac, dipole, injection

353

N. Nakamura, M. Adachi, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
R. Hajima, S. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
JAEA, Ibaraki-ken, Japan
J.G. Hwang
KNU, Deagu, Republic of Korea
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan

The Compact Energy Recovery Linac (cERL) project is ongoing at KEK in order to demonstrate excellent ERL performance as a future light source. The cERL injector was already constructed with its diagnostic beamline and successfully commissioned from April to June in 2013. In the next step, the cERL recirculation loop with a main superconducting linac and merger and dump sections has been constructed and its commissioning is scheduled to start in December 2013. Significant progress is expected by the IPAC14 conference date. In this presentation, we will describe the present status of the cERL including future developments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO110

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME008

3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector

simulation, cathode, gun, emittance

391

Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: work supported by DESY, Hamburg and Zeuthen sites
The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra **.
* Computer Simulation Technology AG, website: http://www.cst.com/
** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME070

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

impedance, network, simulation, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI005

The AWAKE Experimental Facility at CERN

electron, proton, plasma, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI009

Study on New Method for Generating Highly Charged Ions with Double Pulse Laser Ion Source

ion, plasma, ion-source, controls

595

T. Shibuya
TIT, Tokyo, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
M. Yoshida
KEK, Ibaraki, Japan

Laser ion source capable of generating high intensity ions is best for the ion source of RI beam facilities. A great deal of effort has been made on particle number as DPIS. Only few attempts have so far been made at generating highly charged ions. One of previous research has reported that Au+53 ions are produced by PALS laser. "Nonlinear process" mechanisms such as resonance absorption and self-focusing were used for this. However, these methods have limitation due to low repetition rate of the laser. Nd (λ=1064nm, E<1.2J, t~10ns) and Yb laser(λ=1030nm, E<10J, t~500fs) systems is possible to operate at 10 - 50Hz repetition rate. This double pulse laser system, with attainable laser intensity up to about 1017[W/cm²], was used to generate highly charged ions of solid target. First, the Nd laser creates a plasma plume. Next, the Yb laser reheats plasma plume by high intensity pulse at delay time of nanosecond. The properties of ions were investigated mainly on the base of time-of-flight method.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI010

Laser Ablation Ion Source for the KEK Digital Accelerator

ion, extraction, space-charge, simulation

598

N. Munemoto
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan
Y. Fuwa
Kyoto ICR, Uji, Kyoto, Japan
S. Ikeda, K. Takayama
TIT, Yokohama, Japan
M. Kumaki
RISE, Tokyo, Japan
M. Okamura
BNL, Upton, Long Island, New York, USA
S. Takano, K. Takayama
KEK, Ibaraki, Japan
K. Takayama
Sokendai, Ibaraki, Japan

KEK Digital Accelerator (DA) is a small scale induction synchrotron and operated at 10Hz and recently has succeeded to accelerate gaseous ions*. There is a strong demand of fully striped carbon ions because the DA is regarded as the second generation of cancer therapy driver, which does not require an injector and electron stripper. We need a novel carbon ion source providing C⁶⁺ beams, which are directly injected into the DA and accelerated up to required energy. For this purpose, a laser ablation ion source(LAIS) is promising**. To obtain high yield C⁶⁺ ions from ablation plasma, the laser irradiation condition has been evaluated and relationship between beam properties of charge spectrum, intensity, and temperature, and carbon target materials were examined. Two laser systems, long pulse (6 ns) and short pulse (170 ps), were employed to irradiate a graphite and amorphous carbon target. The current densities and profile of the generated plasmas in time were measured and charge state distributions were analyzed. In addition we will report a full design integrating this LAIS, the extraction system, the longitudinal chopper system, and the low energy beam transport line.
* T.Yoshimoto et al., presented in this conference
** N.Munemoto et al., Proceedings of ICIS2013, published in Rev. Sci. Inst.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI011

Control of Plasma Flux with Pulsed Solenoid for Laser Ion Source

ion, plasma, electron, ion-source

601

S. Ikeda, K. Horioka
TIT, Yokohama, Japan
Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan
T. Kanesue, M. Okamura
BNL, Upton, Long Island, New York, USA

We discuss the behavior of laser-ablation plasma spreading through a pulsed solenoidal field to minimize the beam emittance of laser-ablation ion source (LIS). LIS is expected to produce high-flux and low emittance ion beams from various solid materials in vacuum because of the high drift velocity and low temperature of the ablation plasma due to the adiabatic expansion. However, the ion flux level from the ablation plasma into an extraction gap changes within a pulse and then the shape of the sheath boundary changes transiently. Then, the integrated emittance is larger than the stroboscopic emittance at a certain time slice. To prevent the transient effect, we tried to control the plasma flux with a pulsed solenoidal magnetic field. The field is expected to change the direction of the plasma flow like a lens. By changing the magnetic flux density according to the transient flux level of ablation plasma, we can expect to control the plasma flux at the extraction gap. To investigate the controllability of the plasma flow, we measured the plasma flux as a function of parameters of the pulsed magnetic field. We scanned ion probes along the beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI017

Status of AREAL RF Photogun Test Facility

gun, electron, operation, emittance

620

B. Grigoryan, G.A. Amatuni, V.S. Avagyan, H. Avdishyan, H. Davtyan, A.A. Gevorgyan, L.H. Hakobyan, M. Ivanyan, V.G. Khachatryan, E.M. Laziev, A. Lorsabyan, M. Manukyan, I.N. Margaryan, N. Martirosyan, T.H. Mkrtchyan, S. Naghdalyan, V.H. Petrosyan, H. Poladyan, V. Sahakyan, A. Sargsyan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan, V. V. Vardanyan, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia
T.K. Sargsyan
LT-PYRKAL cjsc, Yerevan, Armenia

Advanced Research Electron Accelerator Laboratory (AREAL) is a 20 MeV laser driven RF linear accelerator which is being constructed in the CANDLE institute. The construction of phase-1 is finished and at present the machine commissioning is in progress. In phase-1 a photocathode RF gun provides a 5 MeV small emittance electron beam with the 100 pC bunch charge and variable electron bunch length from 0.5 to 8 ps. Two main operation modes are foreseen for this phase – single and multibunch regimes to satisfy experimental demands. We report the status of linac, first experience and nearest machine run schedule. The brief review of the facility, main parameters, performance and first results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI019

In-situ Characterization of K2CsSb Photocathodes

cathode, electron, vacuum, ion

627

M. Schmeißer, A. Jankowiak, T. Kamps, S.G. Schubert
HZB, Berlin, Germany
S.G. Schubert
BNL, Upton, Long Island, New York, USA

Funding: Work supported by German Bundesministerium für Bildung und Forschung contract 05K12CB2 PCHB and Land Berlin.
Alkali antimonide photocathodes with high quantum efficiency hold the promise of delivering electrons for high-brightness injectors. A drift type spectrometer (momentatron) was attached to the HZB preparation system to allow in-situ characterization within short time after fabrication and possibly identify correlations between growth process and cathode performance parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI020

Introducing GunLab – A Compact Test Facility for SRF Photoinjectors

gun, electron, SRF, cathode

630

J. Völker, R. Barday, A. Jankowiak, T. Kamps, J. Rudolph, S.G. Schubert, S. Wesch
HZB, Berlin, Germany
A. Ferrarotto, T. Weis
DELTA, Dortmund, Germany
V.I. Shvedunov
MSU, Moscow, Russia
I.Yu. Vladimirov
MSU SINP, Moscow, Russia

Funding: Work supported by German Bundesministerium für Bildung und Forschung (BMBF contract 05K12CB2 PCHB and 05K10PEA), Land Berlin and grants of Helmholtz Association
Superconducting radio-frequency photoelectron injectors (SRF photoinjectors) are a promising electron source for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the upcoming ERL project BERLinPro we want to test and commission different SRF photoinjectors and examine the beam performance of photocathode materials in an independent test facility. Therefore we designed GunLab to characterize the beam parameters from the SRF photoinjectors in a compact diagnostics beamline. In GunLab we want to investigate the complete 6 dimensional phase space as a function of drive laser and RF setup parameters. In this work we present the design and the estimated performance of GunLab.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI021

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

electron, operation, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI023

Simulation of the ELBE SRF Gun II

gun, simulation, emittance, SRF

636

P.N. Lu, A. Arnold, U. Lehnert, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
HZDR, Dresden, Germany

Funding: EuCARD, contract number 227579 German Federal Ministry of Education and Research grant 05 ES4BR1/8 LA³NET, Grant Agreement Number GA-ITN-2011-289191
By combining the code of ASTRA and elegant in a user-friendly interface, a simulation tool is developed for the ELBE SRF Gun II. The photoelectric emission and first acceleration to several MeV in the gun cavity are simulated by ASTRA with a 1D Model, where the space charge effect is considered. The dependence of the beam quality on key parameters is studied, and a compromised optimization for a 77 pC beam is used for further elegant simulation of the beam transport through a dogleg and ELBE Linacs. Proper settings of the magnets and RF phases are the main targets of improving the beam quality. Up to now the best simulation result is an electron bunch with the energy of 47 MeV, energy spread of 66 keV, bunch length of 0.35 ps and transverse emittance of 1.9 μm and 2.7 μm in the two perpendicular directions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI024

NEA-GaAs (Cs, O) Photocathodes for the ELBE SRF Gun

gun, vacuum, SRF, cathode

639

R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate
HZDR, Dresden, Germany

Funding: supported by the European Community under the FP7 programme (EuCARD-2, contract number 312453, and LA3NET, contract number 289191), and by the BMBF grant 05K12CR1.
At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and commissioned. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te layer in last years. GaAs At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and tested. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te photocathode in last years. GaAs photocathodes are advantageous because of their high quantum efficiency (QE) with visible light and the extensive experiences of their use in DC guns. Furthermore, GaAs photocathodes provide the possibility to realize a polarized SRF gun in the future. In this presentation we will introduce the new preparation system and the first results of the GaAs tests. The new transfer system under construction will be also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI026

Complete Simulation of Laser Induced Field Emission from Nanostructures Using a DGTD, PIC and FEM Code

electron, simulation, cathode, space-charge

645

A. Fallahi, F.X. Kärtner
CFEL, Hamburg, Germany
K.K. Berggren, R. Hobbs, F.X. Kärtner, P.D. Keathley, M.E. Swanwick, L.F. Velasquez-Garcia, Y. Yang
MIT, Cambridge, Massachusetts, USA

Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg.
We present a general and efficient numerical algorithm for studying laser induced field emission from nanostructures. The method combines the Discontinuous Galerkin Time Domain (DGTD) method for solving the optical field profile, the Particle-In-Cell (PIC) method for capturing the electron dynamics and the Finite Element Method (FEM) for solving the static field distribution. The charge distribution is introduced to the time-domain method based on a modified Fowler-Nordheim field emission model, which accounts for the band-bending of the charge carriers at the emitter surface. This algorithm is capable of considering various effects in the emission process such as space-charge, Coulomb blockade and image charge. Simulation results are compared with experimental findings for optically driven electron emission from nanosharp Si-tips.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI029

Spectrometer for Laser-pulsed Electrons from Field Emission Cathodes

electron, cathode, detector, controls

655

S. Mingels, B. Bornmann, D. Lützenkirchen-Hecht, G. Müller, V. Porshyn
Bergische Universität Wuppertal, Wuppertal, Germany

Funding: German Federal Ministry of Education and Research (BMBF). Project number: 05K13PX2.
In order to develop highly brilliant, pulsed electron sources based on photo-induced field emission (PFE), which combines advantages of photo and field emission (FE), a new measurement system was constructed at BUW*. In an UHV system the electrons are extracted from a cold cathode by a mesh electrode under pulsed laser illumination (3.5 ns, 10 Hz, 0.5 – 5.9 eV, > 0.3 mJ) and so far analyzed by a CW-spectrometer. Quantum efficiency investigations of flat metal (Au, Ag of different surface orientations) and semiconductor crystals (n- and p-Si**, GaN) yielded the expected work functions and revealed first hints for PFE effects. However, the kinetic energy of the electrons could not be measured with the CW-spectrometer. In addition, the achievable electric field (< 20 MV/m) was limited by parasitic FE. Hence, the system is presently upgraded with a spectrometer (resolution < 3 meV) that can handle electron pulses and a dust reduced environment is installed at the load lock. First results acquired with the upgraded apparatus on PFE cathodes will be presented at the conference.
* B. Bornmann et al., Rev. Sci. Instrum. 83, 013302 (2012).
** S. Mingels et al., Proc. FEL2013, New York, USA, p. 339.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI031

Multi-alkali Photocathode R&D

cathode, electron, vacuum, experiment

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI034

Development of temporal response measurement system for transmission-type spin-polarized photocathodes

electron, cavity, resonance, linear-collider

670

T. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
M. Adachi
KEK, Ibaraki, Japan
X.G. Jin
Institute for Advanced Research, Nagoya, Japan
M. Katoh, T. Konomi
UVSOR, Okazaki, Japan
Y. Okano
IMS, Okazaki, Japan

Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved*,**. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode***. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results.
* T. Nakanishi, The XXI International LINAC Conference(1998)
** Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004
*** Xiuguang Jin, Applied Physics Express 6 (2013) 015801

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI035

Development of the Photocathode LiTi2O4 and Evaluations of the Initial Emittance

cathode, electron, emittance, cavity

673

R. Inagaki, M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
T. Hitosugi, S. Shiraki
Tohoku Uneversity, WPI-AIMR, Sendai, Japan
E. Kako, Y. Kobayashi, S. Yamaguchi
KEK, Ibaraki, Japan
M. Katoh, T. Konomi, T. Tokushi
UVSOR, Okazaki, Japan
Y. Okano
IMS, Okazaki, Japan

In UVSOR, the X-ray free electron laser (XFEL) based on linear accelerator with high pulse repetition about 1MHz has been designed as a candidate for the next radiation sources. We thought a combination of superconducting RF cavity and photocathode is an optimal electron gun for the new accelerator. For this electron gun, we propose a back-illuminated multi-alkali* photocathode with transparent superconductor LiTi2O4**. The reason for using LiTi2O4 is to reflect RF by using feature of penetration depth of superconductor, which is defined from London equation. This feature protects optical components from RF damage. However, LiTi2O4 is a new material and properties are not clear. We have measured the basic properties of this photocathode, such as magnetic susceptibility measurement and photoelectron spectrometry, etc. In this conference, we will explain the detail of the concept and advantage of this cathode, and show the result measured about the basic properties of this photocathode focusing on the initial emittance measurement.
* A. V. Lyashenko et al. JINST 4 P07005 (2009)
** Kumatani et al. APL 101 (2012) 123103″

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI036

Pulse Radiolysis Using Terahertz Probe Pulses

electron, radiation, gun, linac

676

K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Pulse radiolysis, which utilizes a pump electron beam and a probe pulse, is a powerful tool that can be used for the time-resolved observation of ultrafast radiation-induced phenomena. Recently, double-decker pulse radiolysis* using visible probe pulses were demonstrated based on a photocathode RF gun driven by two UV pulses, which enabled synchronized pump electron beam and visible probe pulses. In this study, pulse radiolysis using terahertz (THz) probe pulses which were realized by the “double-decker” electron beams and dynamics of transient quasi-free electrons in semiconductors are presented.
* K. Kan et al., Rev. Sci. Instrum. 83, 073302 (2012).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI037

Development of Iridium Cerium Photocathode for the Generation of High-Charge Electron Beam

electron, cathode, gun, linac

679

D. Satoh
TIT, Tokyo, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
T. Natsui, M. Yoshida
KEK, Ibaraki, Japan

We developed an iridium cerium cathode material made by new production method for multi-purpose electron source. For multi-purpose electron source, we focused on the Ir5Ce compound which has a high melting point (> 2100 K) and a low work function (2.57 eV). This material has some excellent properties as both a thermionic cathode and a photocathode. For example, Ir5Ce thermionic cathode can generate one-order higher electrical current than a LaB6 cathode at the same temperature. Another advantage is that an Ir5Ce thermionic cathode has a lifetime two orders longer than that of a LaB6 thermionic cathode under the same conditions. Moreover, we discovered that this material has a reasonably high quantum efficiency (2.70 × 10−3 @213nm at 1000°C) and long-lifetime (> LaB6) as a photocathode. Our research shows that Ir5Ce compound is optimum material for a thermionic cathode and photocathode. We focused on this good emission properties under the high temperature and we tried to develop a backside electron beam heating system and demonstrate a laser pre-pulse heating for a high current thermionic gun system or high charge photocathode gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI042

Recent Developments at the High-charge PHIN Photoinjector and the CERN Photoemission Laboratory

cathode, vacuum, feedback, operation

695

C. Heßler, E. Chevallay, S. Döbert, V. Fedosseev, I. Martini, M. Martyanov, A. Perillo Marcone, Sz. Sroka
CERN, Geneva, Switzerland

The high-charge PHIN photoinjector has originally been developed to study the feasibility of a photoinjector option for the drive beam of the CLIC Test Facility 3 (CTF3) at CERN and is now being used to investigate the feasibility of a drive beam photoinjector for CLIC. In this paper recent R&D efforts to improve the parameters of the existing system towards CLIC requirements will be discussed. This includes studies of a feedback loop for intensity stabilization, the upgrade of the PHIN vacuum system and the planned upgrade of the driving laser system. For photocathode production and R&D a dedicated photoemission laboratory is available at CERN. To increase the production rate of photocathodes and the availability of the photoemission lab for other studies, an upgrade of the photocathode preparation system with a load-lock system is under study and will also be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI046

The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State

electron, detector, cathode, brightness

707

L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.E. Scheibler, A.S. Terekhov
ISP, Novosibirsk, Russia

The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and the electron beam brightness is increased significantly if the mean values of these quantities are reduced. ASTeC have commissioned a Transverse Energy Spread Spectrometer (TESS – an experimental facility designed to measure these transverse and longitudinal energy distributions) which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research*. GaAs photocathodes were activated in our photocathode preparation facility (PPF)**, then transferred to TESS under XHV conditions and progressively degraded through controlled exposure to oxygen. We present commissioning data and initial measurements showing the evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state.
* Proc. FEL ’13, TUPPS033, 290-293
** Proc. IPAC ’11, THPC129, 3185-3187

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI047

The Preparation of Atomically Clean Metal Surfaces for use as Photocathodes in Normally Conducting RF Guns

ion, gun, plasma, electron

711

T.C.Q. Noakes, A.N. Hannah, K.J. Middleman, B.L. Militsyn, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Mistry
Loughborough University, Leicestershre, United Kingdom

Funding: Research supported by FP7 EuCard2 http://cern.ch/eucard2
This work reports a study of various alternative metal samples as candidate materials for use as photocathodes in normally conducting RF guns. Clean surfaces were prepared using Argon ion bombardment and quantum efficiency measured using a 265 nm UV LED light source with a picoammeter for drain current monitoring. Surface composition was studied using X-ray photoelectron spectroscopy and a Kelvin probe apparatus provided work function measurements. Data was taken both before and after annealing to 200°C, a temperature that is routinely achieved during RF gun vacuum baking. Ion bombardment typically leaves a very rough surface that can have a detrimental effect on beam emittance, so further work will focus on the use of Oxygen plasma cleaning of the best candidate alternative metals. An oxygen plasma treated Copper photocathode has been shown to produce an acceptable level of quantum efficiency in the VELA accelerator at Daresbury Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI049

An Ultracold Electron Facility in Manchester

electron, emittance, space-charge, extraction

714

Ö. Mete, R. Appleby, W. Bertsche, M.A. Harvey, G.X. Xia
UMAN, Manchester, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.J. Murray
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom

An ultra-cold atom based electron source (UCAE) facility has been built in the Photon Science Institute (PSI), University of Manchester. In this paper, the key components and working principles of this source are introduced. Pre-commissioning status of this facility and the preliminary simulations results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI050

Preliminary Study for an RF Photocathode based Electron Injector for AWAKE Project

emittance, electron, focusing, plasma

717

Ö. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom

AWAKE project, a proton driven plasma wakefield acceleration (PDPWA) experiment is approved by CERN. The PDPWA scheme consists of a seeding laser, a drive beam to establish the accelerating wakefields within the plasma cell; and a witness beam to be accelerated. The drive beam protons will be provided by the CERN's SPS. The plasma ionisation will be performed by a seeding laser and the drive beam protons to produce the accelerating wakefields. After establishing the wakefields, witness beam, namely, electron beam from a dedicated source should be injected into the plasma cell. The primary goal of this experiment is to demonstrate acceleration of a 5-15 MeV single bunch electron beam up to 1 GeV in a 10 m of plasma. This paper explores the possibility of an RF photocathode as the electron source for this PDPWA scheme based on the existing PHIN photoinjector at CERN. The modifications to the existing design, preliminary beam dynamics simulations in order to provide the required electron beam are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI051

Measurements of the Longitudinal Energy Distribution of Low Energy Electrons

cathode, electron, experiment, 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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI053

High Repetition Rate Ultrafast Electron Diffraction at LBNL

electron, emittance, gun, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI055

APEX Present Experimental Results

cathode, gun, electron, emittance

730

D. Filippetto, C.W. Cork, S. De Santis, L.R. Doolittle, G. Huang, R. Huang, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, F. Sannibale, J.W. Staples, R.P. Wells
LBNL, Berkeley, California, USA
J. Yang
TUB, Beijing, People's Republic of China

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The APEX electron source at LBNL combines high-repetition-rate and high beam brightness typical of photo-guns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI059

Fabrication of Alkali Antimonide Photocathode for SRF Gun

cathode, gun, vacuum, SRF

742

E. Wang, S.A. Belomestnykh, I. Ben-Zvi, D. Kayran, G.T. McIntyre, T. Rao, J. Smedley, D. Weiss, W. Xu
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
X. Liang
SBU, Stony Brook, New York, USA
H.M. Xie
PKU, Beijing, People's Republic of China

Funding: * This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant
The first alkali antimonide photocathode was prepared and inserted into the BNL 704 MHz SRF gun. An excimer laser cleaning system was installed in a cathode deposition chamber and the cleaning technique developed previously was used in the first cathode preparation. We also demonstrated that oxidized cathode can be removed by exposing it to the same excimer laser. In this paper, we show the set up of the incorporated laser cleaning system and the QE enhancement of alkali antimony photocathode. The vacuum evolution at transport cart and QE measurement system are also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI069

Computing Angularly-resolved Far Field Emission Spectra in Particle-in-cell Codes using GPUs

radiation, plasma, simulation, GPU

761

R.G. Pausch, H. Burau, M.H. Bussmann, J.P. Couperus, A.D. Debus, A. Huebl, A. Irman, A. Köhler, U. Schramm, K. Steiniger, R. Widera
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T.E. Cowan
HZDR, Dresden, Germany

Angularly resolved far field radiation spectra computed from the Lienard Wiechert Potentials of accelerated electrons give information on the microscopic particle dynamics. We present recent results using our many-GPU, fully relativistic 3D3V particle-in-cell code PIConGPU for which we have developed fully synthetic radiation diagnostics that is capable of computing angularly-resolved radiation spectra of more than 10¹⁰ electrons for several hundred to a thousand wavelengths and directions in a single simulation in less than a day on large-scale supercomputers. With such a technique it is possible to use precision spectroscopic methods for understanding the dynamics of electron acceleration in scenarios where other diagnostics fail. We present studies on laser-driven wakefield acceleration and astrophysical jet dynamics to underline the power of this new technique.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI103

Longitudinal Bunch Shortening for the Laser Stripping Project

cavity, focusing, linac, acceleration

861

T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, V.V. Danilov, Y. Liu, M.A. Plum
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.
Realization of high efficiency laser stripping at the SNS accelerator needs good longitudinal overlap between H⁻ bunch and laser pulse. The default H⁻ bunch length at the interaction point is 5 times bigger than needed in order to achieve 90% stripping efficiency. Theoretical and experimental studies of longitudinal H⁻ bunch shortening are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI103

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZA01

Advanced Concepts and Challenges in Compton Radiation Sources

electron, plasma, cavity, photon

928

I. Pogorelsky
BNL, Upton, Long Island, New York, USA

Ongoing developments in Compton radiation sources are aimed toward a diversity of potential applications, ranging from university-scale compact x-ray light sources and metrology tools for EUV lithography, to positron sources for e⁻e⁺ colliders. Novel conceptual approaches are pursued on different routes: One research direction lies in multiplying the source’s repetition rate and increasing its average brightness by placing the point of Compton interaction inside an optical cavity. High-gradient plasma-wakefield accelerators are fast becoming a practical reality, offering a new paradigm to compact all-optical Compton sources operating in x-ray- and gamma-regions. Continuing improvement in the quality of the beam of plasma accelerators promises the achievement of fully coherent Compton x-rays, thereby prompting the evolution of the Compton source to an all-optical free-electron laser.

Slides TUZA01 [22.419 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUZA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA01

The Linac Coherent Light Source-II Project

linac, electron, undulator, cryomodule

935

J.N. Galayda
SLAC, Menlo Park, California, USA

Funding: Work supported by US DOE Contract DE-AC02-766SF00515
The “Linac Coherent Light Source–II” Project, initiated in September 2010, has gone through a radical transformation beginning in August 2013. In its new form, LCLS-II will construct a 4 GeV CW superconducting linac in the first kilometre of the existing linac tunnel. A new undulator, optimized as a soft x-ray (200-1,300 eV) source, will receive electrons from the new SC linac. The existing undulator system will be replaced with a new variable gap device, which will receive electrons from either the new SC linac (providing 1-5 keV photons) or the copper linac presently used by LCLS (providing 1-25 keV x-rays). First light from the new facility is expected in September 2019.
galayda@slac.stanford.edu

Slides TUOCA01 [9.380 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA02

Status of the Free Electron Laser User Facility FLASH

FEL, flattop, gun, linac

938

M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

FLASH, the Free Electron Laser User Facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft X-ray FEL radiation to photon experiments. After a shutdown to connect the second undulator beamline FLASH2 to the FLASH linac, re-commissioning of FLASH started in autumn 2013. The year 2014 is dedicated to FLASH1 user experiments. The commissioning of the FLASH2 beamline takes place in 2014 in parallel to FLASH1 operation.

Slides TUOCA02 [9.156 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOCA03

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

photon, electron, undulator, experiment

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]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBB01

Accelerator Physics Challenges towards a Plasma Accelerator with Usable Beam Quality

plasma, electron, acceleration, wakefield

961

R.W. Aßmann, J. Grebenyuk
DESY, Hamburg, Germany

Enormous progress in compact plasma accelerators has been demonstrated over the recent years in various experiments. These experiments rely on high power, pulsed lasers or short electron bunches to excite ultra-strong wakefields in plasmas. Accelerating gradients have reached several 10 GV/m up to 100 GV/m and the absolute energy gain of electron beams is in the regime of several GeV to 30 GeV. The principle and potential of plasma accelerators has been proven impressively and performance parameters are steadily improving. It is noted that particle accelerators are powerful tools that are ultimately justified by their applications in science, medicine or industry. The demonstration of useable beam quality and a realistic use case remains to be achieved for plasma accelerators. The accelerator physics challenges to arrive at this goal are analyzed and discussed.

Slides TUOBB01 [12.407 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOBB02

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

experiment, wakefield, radiation, electron

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]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO038

Beam Positioning Concept and Tolerance Considerations for BERLinPro

emittance, linac, gun, timing

1105

B.C. Kuske, J. Rudolph
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
BERLinPro is an ERL project at Helmholtz-Zentrum Berlin, with the goal to illuminate the challenges and promises of a high brightness 100 mA superconducting RF gun in combination with a 50 MeV return loop and energy recovery [1, 2]. The precision of the beam position in a single turn machine might be relaxed compared to the demands in storage rings. Still, a trajectory correction concept has to be developed and the influence of trajectory offsets on the goal parameters, its dependence on fluctuating injection parameters or effects related to the low energy of 6.5-50 MeV have to be investigated. This paper covers the initial trajectory correction studies and first tolerance scenarios of BERLinPro using the projected hardware concept.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO117

Magnet Design for the SNS Laser Stripping Experiment

electron, ion, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO117

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME030

The LIGHT Beamline at GSI: Shaping Intense MeV Proton Bunches from a Compact Laser-driven Source

proton, cavity, focusing, ion

1419

S. Busold, O. Deppert, M. Roth
TU Darmstadt, Darmstadt, Germany
V. Bagnoud, A. Blazevic, S. Busold
HIJ, Jena, Germany
V. Bagnoud, A. Blazevic, S. Busold, D. Schumacher
GSI, Darmstadt, Germany
C. Brabetz
IAP, Frankfurt am Main, Germany
F. Kroll
TU Dresden, Dresden, Germany
F. Kroll
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany

Laser-based proton acceleration as a source of high intensity multi-MeV-range proton bunches became subject of extensive research during the last 15 years and is discussed as potential candidate for various applications. However, their usage often requires special ways of beam shaping first, as the particles are emitted in a wide energy spectrum and with a large divergence angle from the laser matter interaction point. To handle these characteristics, a test stand has been build at GSI Darmstadt, using a pulsed high field solenoid and a radiofrequency cavity to produce intense collimated proton bunches with low energy spread from a TNSA source. In recent experiments, energy compression of an intense proton bunch around 10 MeV central energy to an energy spread of less than 3% could be demonstrated. The particle numbers were in access of 10⁹ protons and the bunch duration was only a few nanoseconds. Even shorter bunches and thus higher particle intensities are possible. This compact laser-driven proton beamline, available now at GSI, will be introduced and latest experimental results presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME031

Radiation Pressure Acceleration and Transport Methods

plasma, simulation, acceleration, target

1422

P. Schmidt, O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim, O. Boine-Frankenheim, I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
HIJ, Jena, Germany
I. Hofmann
IAP, Frankfurt am Main, Germany

Funding: HGS-HIRe for FAIR, HIC for FAIR, Technische Universität Darmstadt, FB 18 TEMF
Several projects worldwide such as LIGHT at GSI focus on laser ion acceleration. With the development of new laser systems and advances in the target production a new acceleration mechanism has become of interest: The Radiation Pressure Acceleration (RPA). An ultra short high intense laser pulse hits a very thin foil target and the emerging plasma is ideally accelerated as one piece (light sail regime). The ions reach kinetic energies up to GeV and nearly solid body densities. In this work, the distribution and transport of a RPA plasma is studied. 1D and 2D PIC simulations (software: VSim) are carried out to obtain the phase space distribution of the plasma. The results are compared to fluid models (software: FiPy and USim). A reference model an RPA plasma is obtained which is then used for advanced transport studies. Transport mechanisms (active and passive) are studied, such asμlenses and foil stacks.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME033

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

target, proton, acceleration, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME034

Transport and Energy Selection of Laser Produced Beams for Medical Research and Multidisciplinary Applications

quadrupole, target, solenoid, focusing

1425

M.M. Maggiore
INFN/LNL, Legnaro (PD), Italy
G.A.P. Cirrone, F. Romano, F. Schillaci, A. Tramontana
INFN/LNS, Catania, Italy
V. Scuderi
ELI-BEAMS, Prague, Czech Republic

Ion beams produced by the interaction of high-power laser with thin targets are being characterized experimentally around the world in order to get a reasonable amount of particles with low divergence and narrow energy spread for medical and multidisciplinary applications. Several schemes about the energy selection and transport of laser accelerated beams have been considered and tested, however the energy spread of the selected particles remains rather high and the reproducibility has not been yet achieved. In the framework of the ELIMED network, we present a study of a possible layout to capture and transport in an efficient and reproducible way, the beams generated by the laser-target interaction. It consists of a combination of quadrupoles based on permanent magnets placed just downstream the target, coupled with a system composed by a series of 4 dipole magnets of inverted polarity, which provides the final energy selection of the previously focused beam. Such a system will be tested in 2014 at TARANIS facility to select proton beams in the energy range of 4-8 MeV; the main scheme can be scaled for the high energy beam that are expected at ELI-beamlines facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME035

Design Study of the Laser-driven Dielectric Accelerator

electron, acceleration, simulation, focusing

1428

K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
S. Otsuki
The University of Tokyo, Tokyo, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
Laser driven dielectric accelerators (LDA) are vigorously studied in order to apply to various fields in recent years. Characteristics of the LDA output such as sub-micron diameter, atto-second bunch and high acceleration field are suitable for in-situ investigating the biological effects of low doses of radiation in a living cell. The output energy of 1 MeV is sufficient for sniping a cell nucleus or DNA. Although the electronic charge in the bunch is in the order of 10 fC, the tightly focused beam enable to cause a local damage in the cell. We have reported optimum structure parameters of dielectric in the nonrelativistic regime. The low acceleration efficiency of slow electrons by short laser pulses is the serious problem. The accelerator length, laser intensity, pulse width, and optical system must be adjusted to design the practical LDA. We present the design principle of the LDA for nonrelativistic electrons and present status of the pumping laser of us.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME036

Simulation Study on Electron Beam Acceleration using Coherent Cherenkov Radiation

electron, acceleration, simulation, radiation

1431

K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
M. Hangyo
ILE Osaka, Suita, Japan
R. Kuroda, H. Toyokawa
AIST, Tsukuba, Ibaraki, Japan

Beam diagnostics for electron bunch length using spectrum analysis of multimode terahertz (THz) -wave have been studied in ISIR, Osaka University*. The multimode THz-wave was generated by coherent Cherenkov radiation (CCR)** using hollow dielectric tubes and femtosecond/picosecond electron bunches. In this study, numerical calculation of acceleration and deceleration of electron beam using multimode THz-wave was carried out.
* K. Kan et al., Appl. Phys. Lett. 99, 231503 (2011).
** A. M. Cook et al., Phys. Rev. Lett. 103, 095003 (2009).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME037

Development on On-chip Radiation Source using Dielectric Laser Accelerator

electron, acceleration, radiation, simulation

1434

S. Otsuki
The University of Tokyo, Tokyo, Japan
K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
S. Mima
RIKEN, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
One of the state-of-the-art acceleration schemes, where high intensity laser pulses are modulated by dielectric grating structure such as quartz to accelerate charged particles, is dielectric laser acceleration (DLA)*. The difference of our DLA concept from other schemes is installation of a prism: the tilted wave-front in a prism shape refractive medium leads the suitable delay to match the phase advance of the electron beam. We plan to apply this method to build an on-chip radiation source which can hit and damage target elements of the cells. Such an application is useful in radiation biology, i.e., for investigation on bystander effects. The x-rays with small radius and adequate intensity required for this goal can be obtained using sub-micron beams from the small accelerating structure at high repetition rate (such as 50 kHz). In addition, the mass productivity of the DLA based on the consumer-grade laser and the photolithography has advantage compared to the conventional RF accelerator using high power klystrons. We will present field simulation and preliminary experimental results for demonstration on our concept of DLA.
* Demonstration of electron acceleration in a laser-driven dielectric microstructure, Nature 2013
** Laser-Based Acceleration of Nonrelativistic Electrons at a Dielectric Structure, Phys. Rev. 2013

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME041

The Advanced Superconducting Test Accelerator at Fermilab: Science Program

SRF, electron, linac, emittance

1447

P. Piot, E.R. Harms, S. Henderson, J.R. Leibfritz, S. Nagaitsev, V.D. Shiltsev, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This work is supported by DOE contract DE-AC02-07CH11359 to the Fermi Research Alliance LLC
The Advanced Superconducting Test Accelerator (ASTA) currently in commissioning phase at Fermilab is foreseen to support a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop novel approaches to particle-beam generation, acceleration and manipulation. ASTA incorporates a superconducting radiofrequency (SCRF) linac coupled to a flexible high-brightness photoinjector. The facility also includes a small-circumference storage ring capable of storing electrons or protons. This report summarizes the facility capabilities, and provide an overview of the accelerator-science researches to be enabled.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME043

Temporal Electron-bunch Shaping from a Photoinjector for Advanced Accelerator Applications

space-charge, wakefield, acceleration, gun

1454

F. Lemery, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Advanced-accelerator applications often require the production of bunches with shaped temporal distributions. An example of sought-after shape is a linearly-ramped current profile that can be improve the transformer ratio in beam-driven acceleration, or produce energy-modulated pulse for, e.g., the subsequent generation of THz radiation. Typically, such a shaping is achieved by manipulating ultra-relativistic electron bunches. In this contribution we discuss the possibility of shaping the bunch via photoemission and demonstrate using particle-in-cell simulations the production of MeV electron bunches with quasi-ramped current profile.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME045

Development of a High-Energy Short-pulse 5-μm Parametric Source for Dielectric Laser Acceleration

acceleration, detector, operation, optics

1460

G. Xu, I. Jovanovic, S.F. Wandel
Penn State University, University Park, Pennsylvania, USA

A compact, high-peak-power 5-μm laser source with pulse duration of sub-100 fs has been designed and being constructed for pumping a dielectric photonic structure to produce an acceleration gradient of order GV/m in dielectric laser acceleration. Breakdown of dielectric structure induced by multiphoton ionization can be mitigated by adopting long wavelength driver laser. Since the dielectric structure scales with the laser wavelength, fabrication tolerances for dielectric structure are relaxed as well. The 5-μm laser source is based on two cascaded optical parametric amplifiers (OPA): a 2-μm BBO OPA with a mixed phase matching scheme is used as a pump source, and a type-I phase-matched ZGP OPA is designed to produce sub-mJ, <100 fs 5-μm laser pulses. The two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~2.2 mJ with a pulse duration of 42 fs (~6 optical cycles), and excellent pulse stability and beam quality. Preliminary result of ~50 μJ pulse energy at 5-μm is demonstrated by using single-stage ZGP OPA, and an improved two-stage OPA scheme for production of higher pulse energy at 5-μm is under development.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME046

3-D Particle-in-cell Simulations for Quasi-phase Matched Direct Laser Electron Acceleration in Density-modulated Plasma Waveguides

electron, plasma, emittance, simulation

1463

M.W. Lin
The Pennsylvania State University, University Park, Pennsylvania, USA
I. Jovanovic
Penn State University, University Park, Pennsylvania, USA

Funding: This work is supported by the Defense Threat Reduction Agency through contract HDTRA1-10-1-0034.
Quasi-phase matched (QPM) direct laser acceleration (DLA) of electrons can be realized with guided, radially polarized laser pulses in density-modulated plasma waveguides*,**. A 3-D particle-in-cell (PIC) simulation model has been developed to study the scheme in which an electron bunch from a laser wakefield accelerator (LWFA) is injected into a plasma waveguide for the second-stage DLA to higher energies. In addition to being driven directly by the laser field, the electrons also experience the laser pondermotive force and the electrostatic force from the excited plasma waves. The results lead to better understanding of the interactions between the electron bunch, the laser pulse and the background plasma. Selected bunch lengths, bunch sizes and time delays with respect to the laser pulse are assigned for the injected electrons in a series of simulations. The energy spectrum and emittance of the accelerated electron bunch vary depending on those initial conditions, and they can be chosen to optimize the DLA performance.
* P. Serafim, et al., IEEE Trans. Plasma Sci. 28, 1155 (2000).
** M. -W. Lin and I. Jovanovic, Phys. Plasmas 19, 113104 (2012).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME047

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

plasma, experiment, electron, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME048

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

plasma, wakefield, electron, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME051

Self-Injection by Trapping of Plasma Electrons Oscillating in Rising Density Gradient at Vacuum-Plasma Interface

plasma, electron, injection, wakefield

1479

A. A. Sahai, T.C. Katsouleas
Duke ECE, Durham, North Carolina, USA
P. Muggli
MPI-P, München, Germany

Funding: DE-SC0010012, NSF-PHY-0936278
We model the trapping of plasma electrons within the density structures excited by a propagating energy source in a rising plasma density gradient. Rising density gradient leads to spatially contiguous coupled up-chirped plasmons (d{ω²_pe(x)}/{dx}>0). Therefore phase mixing between plasmons can lead to trapping until the plasmon field is high enough such that e^- trajectories returning towards a longer wavelength see a trapping potential. Rising plasma density gradients are ubiquitous for confining the plasma within sources at the vacuum-plasma interfaces. Therefore trapping of plasma-e^- in a rising ramp is important for acceleration diagnostics and to understand the energy dissipation from the excited plasmon train [1]. Down-ramp in density [2][3] has been used for plasma-e^- trapping within the first bucket behind the driver. Here, in rising density gradient the trapping does not occur in the first plasmon bucket but in subsequent plasmon buckets behind the driver. Trapping reduces the Hamiltonian of each bucket where e^- are trapped, so it is a wakefield-decay probe. Preliminary computational results for beam and laser-driven wakefield are shown.
1.Sahai, A. A. et.al.,Proc of IPAC2013, MOPAC10, Oct2013
2.Suk, H. et.al.,Phys. Rev.Lett. 86 2001 10.1103/PhysRevLett.86.1011
3.Dawson, J, Phys Rev 113 1959 10.1103/PhysRev.113.383

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME052

Enhanced Laser Ion Acceleration based on Near-Critical Density Plasma Lens

plasma, target, acceleration, electron

1483

Y.X. Geng, J.E. Chen, L.R.F. Li, Y.H. Li, Q. Liao, C. Lin, L.H.Y. Lu, Y.R. Lu, H. Wang, X.Q. Yan, Z.X. Yuan, S. Zhao, W.B. Zhao, Y.Y. Zhao, K. Zhu, B.Y. Zou
PKU, Beijing, People's Republic of China

The laser prepulse has large effect on ion acceleration driven by high power laser pulse. Recently, simulations show that with proper prepulse parameters, a near critical density pre-plasma can be generated in the front target. When the main laser pulse propagating in this pre-plasma, it can experience transverse Self-focusing, longitudinal profile steepening and prepluse cleaning at the same time, meaning its quality is spontaneously improved by this “plasma lens”.The effects can greatly improve the energy coupling efficiency of laser pulse into accelerated ions. A 3mJ Ti-Sapphire laser system has been built at PKU in order to experimentally study the pre-pulse effect on a solid target. Fluid simulation show that, after hundreds of picoseconds radiated with this laser pulse, the pre-plasma in front of the target will expand to near critical density with tens of micron scale length, which is suitable as a plasma lens to improve the ion acceleration. A laser interferometer system is built to measure the scale length and density evolution of plasma and the optimum condition of the pre-plasma has been searched using both Aluminum target and home-made DLC target.
H.Y.Wang et al, Laser shaping of a relativistic intense, short Gaussian pulse by a plasma lens, PRL, 107,265002, 2011

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME055

Room-temperature Burst-mode GHz and THz Pulse-train Photoinjector

electron, cathode, bunching, acceleration

1492

F.H. Chao, C.H. Chen, K.Y. Huang, Y.-C. Huang, Y.C. Wang, M.H. Wu
NTHU, Hsinchu, Taiwan
P.J. Chou
NSRRC, Hsinchu, Taiwan

A photoinjector usually generates an electron pulse with few ps pulse duration repeating at 10-100 Hz. The low-pulse rate limits the data rate in a number of applications. Although high-repetition-rate operation is possible from a superconducting accelerator, the high cost and complexity of a superconducting system prevent it from being widely used. In this paper, we present our study toward a burst-mode GHz/THz pulse train photoinjector operating at room temperature. For the GHz operation mode, we self-develop a driver laser system, generating tens of laser pulses at 2.856 GHz in an adjustable 5-10 ns temporal envelope repeating at 10 Hz. Upon illuminating the photocathode with the driver laser, our S-band photoinjector (supported by Tsing Hua University, Beijing) is to generate a GHz electron pulse train with the same temporal structure as that of the driver laser pulses. For the THz operation mode, we illuminate the photocathode with two lasers, one being a typical UV gun-driver laser at 260 nm and the other being a mid-infrared laser at 100 THz. The UV laser induces photoemission and the infrared laser gates the emission current at 100 THz by virtue of the Schottky effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME056

Improving Ion and Electron Beam Characteristics within LA³NET

electron, acceleration, photon, simulation

1495

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191.
Lasers are widely used at accelerator and light source facilities for beam generation, acceleration and optimization. Research within LA³NET focuses on laser-based particle sources (photo injectors and laser ion sources), laser acceleration, and laser-based beam diagnostics. This project was recently selected as a ‘success story’ by the European Commission for its research achievements. This paper presents selected numerical and experimental results. From HZDR results of electron transport simulations in their new SRF gun II cavity, super-conductive solenoid and downstream accelerators are shown. The results from optimization studies into asymmetric grating structures obtained at the University of Liverpool are also presented, along with initial results from studies into novel diagnostics for high intensity proton beams at CERN and low energy electron beams at KIT. Finally, the events organized by the consortium to date and future plans are summarized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME058

The Argonne Wakefield Accelerator (AWA): Commissioning and Operation

wakefield, gun, electron, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME064

Laser-driven Acceleration with External Injection at SINBAD

plasma, injection, acceleration, simulation

1515

J. Grebenyuk, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

One of the important milestones to make plasma acceleration a realistic technology for user-applications is demonstration of bunch acceleration inside a plasma wake with minimal degradation of its quality. This can be achieved by external injection of beams into a plasma accelerator. SINBAD is a proposed dedicated accelerator research and development facility at DESY where amongst other topics laser-driven wakefield acceleration with external injection of ultra-short bunches will be exploited. To minimise energy-spread growth the bunch should occupy a small fraction of the plasma wavelength. In addition it has to be longitudinally synchronised with the laser driver to high accuracy. To avoid emittance growth the beam Twiss parameters have to be matched to the intrinsic beta-function of the plasma. To facilitate matching and synchronisation, acceleration at low plasma densities can be advantageous. We present a preparatory feasibility study for future plasma experiments at SINBAD using simulations with the particle-in-cell code OSIRIS. Field-gradient scaling laws are presented together with parameter scans of externally injected bunch, such as its injection phase, charge and length.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME064

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME073

A Novel Laser Ionized Rb Plasma Source for Plasma Wakefield Accelerators

plasma, wakefield, proton, electron

1522

E. Öz, F. Batsch, P. Muggli
MPI-P, München, Germany

Funding: AWAKE collaboration
A proton driven plasma wakefield accelerator* is to be conducted at CERN by the AWAKE collaboration. Externally injected electrons are accelerated in a large gradient (~GeV/m) wakefield. The large gradient is achieved by resonant formation of the wakefield by a train of micro-bunches. Transverse modulation of a long (~12 cm) proton bunch by the self modulation instability** creates these plasma wavelength size (~1 mm) micro-bunches. This resonant mechanism brings a strict requirement on the plasma density uniformity, namely % 0.2, in order for the injected electron bunch to remain in the accelerating and focusing phase of the wakefields. We describe the plasma source*** that satisfies this requirement during the beam plasma interaction. Rb vapor with ~10¹⁵ cm^-3 density is confined in a 10 m long 4 cm diameter, stainless-steel tube which is heated to ~200 Co by an oil heat exchanger. The access to the source during interaction is provided by custom built fast valves. The vapor is fully tunnel ionized (first e-) by a laser forming a 2 mm diameter plasma channel.
* http://awake.web.cern.ch/awake/
** http://link.aps.org/doi/10.1103/PhysRevLett.104.255003
*** http://dx.doi.org/10.1016/j.nima.2013.10.093

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME073

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME075

Simulations on Laser Wakefield Generation in a Parabolic Magnetic-plasma Channel

plasma, wakefield, simulation, electron

1528

D.N. Gupta, M. Singh
University of Delhi, Delhi, India
D. Jang, H. Suk
APRI-GIST, Gwangju, Republic of Korea
B.S. Sharma
Kota University, Rajasthan, India

To utilize the laser-plasma channel for laser wakefield acceleration, we have studied the non-paraxial theory of nonlinear propagation of ultra-intense relativistic Gaussian laser pulse in a preformed spatially tapered magneto-plasma channel having a parabolic density profile. A three-dimensional envelope equation for the laser field is derived, which includes the non-paraxial and applied magnetic field effects. An analytical expression for the wakefield is derived and analyzed the results with the help of particle-in-cell (PIC) simulations. It is shown that wakefield structures and the phase of axial component of the wakefield depend on applied external magnetic field. This aspect of theoretical observation can be used in the production of highly collimated mono-energetic x-rays.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME075

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME077

The Challenge of Interfacing the Primary Beam Lines for the AWAKE Project at CERN

proton, plasma, electron, injection

1534

C. Bracco, B. Goddard, E. Gschwendtner, M. Meddahi, A.V. Petrenko
CERN, Geneva, Switzerland
P. Muggli
MPI, Muenchen, Germany
F.M. Velotti
EPFL, Lausanne, Switzerland

The Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN foresees the simultaneous operation of a proton, a laser and an electron beam. The first stage of the experiment will consist in proving the self-modulation, in the plasma, of a long proton bunch into micro-bunches. The success of this experiment requires an almost perfect concentricity of the proton and laser beams, over the full length of the plasma cell. The complexity of integrating the laser into the proton beam line and fulfilling the strict requirements in terms of pointing precision of the proton beam at the plasma cell are described. The second stage of the experiment foresees also the injection of electron bunches to probe the accelerating wakefields driven by the proton beam. Studies were performed to evaluate the possibility of injecting the electron beam parallel and with an offset to the proton beam axis. This option would imply that protons and electrons will have to share the last few meters of a common beam line. Issues and possible solutions for this case are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI090

Linac Alignment for SuperKEKB Injector

alignment, linac, emittance, positron

1781

T. Higo, K. Kakihara, T. Kamitani, M. Satoh, R. Sugahara, T. Suwada, M. Tanaka
KEK, Ibaraki, Japan

The misalignment of the linac beamline components amounted to be a millimeter level during the operation of KEKB, though the requirement of 0.1mm in mind. The limited effort toward improving such big misalignments has long been pursued but could not finish especially after the earthquake in March 2011. This linac is now under upgrade to the SuperKEKB, where the required alignment is 0.1mm in σ for the short distance in 100m span, while 0.3mm through the whole linac for the emittance preservation. The straight line as a reference for the alignment was defined by laser beam over 500m. The actual hardwares are set with respect to this reference line by using a laser tracker. The alignment present status is reported in this paper. On the other hand, we noticed, through the alignment measurements over months, that the tunnel floor moved in the range of 0.1mm or maybe more. The evaluation of this movement is on-going to discuss about how to achieve the required emittance and how to keep the situation. Various measurements to evaluate the movement are presented also in the paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI090

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI091

Refinement of ARC Alignment between Two Straight Sections for Injector Linac of SuperKEKB

alignment, linac, emittance, quadrupole

1784

M. Tanaka, T. Higo, K. Kakihara, T. Kamitani
KEK, Ibaraki, Japan
K. Kimura, K. Suzuki, N. Toyotomi, S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

The beam line of the KEKB injector linac is under realignment as the restoration after the big Earthquake in 2011, but with the refinement for the SuperKEKB in mind. The linac consists of two straight sections connected by a 180 degree ARC. Precise alignment of the ARC magnets is one of the key issues for the emittance preservation of the electron beam. The ARC beam line was defined by measuring these two straight lines. Then, the misalignment of the ARC magnets were reduced from 3 mm maximum down to 0.1mm in the errors perpendicular to the beam direction. This paper describes how we defined the ARC beam line and performed the alignment. The connection method of the laser tracker data needed for the definition of the ARC was also studied and described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI091

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI093

Determination of the Magnetic Axis of a CLIC Drive Beam Quadrupole with respect to External Alignment Targets using a Combination of WPS, CMM and Laser Tracker Measurements.

alignment, quadrupole, target, linear-collider

1790

M. Duquenne, M. Anastasopoulos, D. Caiazza, G. Deferne, J. Garcia Perez, H. Mainaud Durand, M. Modena, V. Rude, J. Sandomierski, M. Sosin
CERN, Geneva, Switzerland

CERN is currently studying the feasibility of building a high energy e⁺ e⁻ linear collider: the CLIC (Compact LInear Collider). One of the engineering challenges is the pre-alignment precision and accuracy requirement on the alignment of the linac components. For example, the magnetic axis of a Drive Beam Quadrupole will need to be aligned within 20 um rms with respect to a straight reference line of alignment. The fiducialisation process which is the determination of the magnetic axis with respect to external alignment targets, that is part of this error budget, will have to be performed at an accuracy never reached before. This paper presents the strategy proposed for the fiducialisation of the Drive Beam quadrupole, based on a combination of CMM measurements, WPS measurements and Laser tracker measurements. The results obtained on a dedicated test bench will be described as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI093

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI094

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

vacuum, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI094

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI100

Present Status of the Cherenkov Beam Loss Monitor at SACLA

electron, undulator, detector, status

1808

T. Itoga
JASRI/SPring-8, Hyogo, Japan
Y. Asano
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

Since 2011, high power lasers have been delivered stably to the users at SACLA, the SPring-8 Angstrom compact free electron laser, and the upgrades have been performing to obtain the high quality of the laser continuously. Optical fiber based Cherenkov beam loss monitors have been successfully operated from the commissioning phase. This monitor covers the undulator section of beam lines and the electron beam transporting tunnel from SACLA to SPring-8. This monitor is made good use of not only beam transport but also detection of the small beam loss such as electron halos hitting the magnets of undulator. In this presentation, we will report the present status of the Cherenkov beam loss monitor and its usage experience.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI100

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI107

Compact MTCA.4 Based Laser Synchronization

timing, FPGA, hardware, FEL

1823

M. Felber, L. Butkowski, H.T. Duhme, M. Fenner, C. Gerth, U. Mavrič, P. Peier, H. Schlarb, B. Steffen
DESY, Hamburg, Germany
T. Kozak, P. Prędki, K.P. Przygoda
TUL-DMCS, Łódź, Poland

In this paper we present a compact and efficient approach for laser synchronization based on MTCA.4 platform. Laser pulses are converted to the RF signals using a photo-diode detector. The RF section performs filtering, amplification and down-conversion of a narrowband, CW signal. The resulting IF signal is sampled by a high resolution digitizer on the AMC (Advanced Mezzanine Card) side and transported via point-to-point links to an adjacent AMC board. The processing electronics on this board drives a digital-to-analog converter on the rear-side. The analog signal is then filtered and amplified by a high voltage power amplifier which drives the piezo stretcher in the laser. Some preliminary results of laser to RF locking with such a scheme are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI107

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI108

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

experiment, 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).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI108

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAA03

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

radiation, experiment, 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]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBA03

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

experiment, 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]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEXB01

Breaking the 70 MeV Proton Energy Threshold in Laser Proton Acceleration and Guiding Beams to Applications

target, proton, ion, acceleration

1886

M. Roth, S. Bedacht, S. Busold, O. Deppert, G. Schaumann, A. Tebartz, F. Wagner
TU Darmstadt, Darmstadt, Germany
V. Bagnoud, A. Blazevic, D. Schumacher
GSI, Darmstadt, Germany
C. Brabetz
IAP, Frankfurt am Main, Germany
T.E. Cowan
HZDR, Dresden, Germany
K. Falk, A. Favalli, J.C. Fernandez, C. Gautier, C.E. Hamilton, R.P. Johnson, K. Schoenberg, T. Shimada, G.A. Wurden
LANL, Los Alamos, New Mexico, USA
M. Geißel, M. Schollmeier
Sandia National Laboratories, Albuquerque, New Mexico, USA
D. Jung
Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom
F. Kroll
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany

This talk covers recent developments in laser plasma ion acceleration describing the technological challenges in breaking of energy threshold of 70 MeV. The presentation also highlights the recent experimental achievements towards laser ion acceleration and transport in the LIGHT collaboration.

Slides WEXB01 [15.155 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEXB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB01

The Commissioning of the Laser Ion Source for RHIC-EBIS

ion, target, ion-source, injection

1890

T. Kanesue, J.G. Alessi, E.N. Beebe, M.R. Costanzo, L. DeSanto, R.F. Lambiase, D. Lehn, C.J. Liaw, V. LoDestro, M. Okamura, R.H. Olsen, A.I. Pikin, D. Raparia, A.N. Steszyn
BNL, Upton, Long Island, New York, USA
S. Ikeda
TIT, Yokohama, Japan
K. Kondo, M. Sekine
RLNR, Tokyo, Japan

Funding: Work supported by NASA and Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A new laser ion source (LIS) for low charge state ion production was installed on RHIC-EBIS. This is the first LIS to be combined with an Electron Beam Ion Source (EBIS) type heavy ion source. The LIS provides intense low charge state ions from any solid state material, with low emittance and narrow pulse length. These features make it suitable as an external source of 1+ ions that can be injected into the EBIS trap for charge breeding. In addition, a LIS is the only type ion source which can allow rapid switching among many ion species, even on pulse-by-pulse basis, by changing either laser path or target position, to strike the material of choice. The EBIS works as a charge breeder, with the extracted high charge state ions used in the following accelerators. The beams from LIS will be used for RHIC and NASA Space Radiation Laboratory (NSRL) at BNL. The rapid beam switching, which was not possible with existing ion sources, will expand the research field at NSRL as a galactic cosmic ray simulator. The results of commissioning will be shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOAB03

Linear Electron Acceleration in THz Waveguides

electron, linac, acceleration, accelerating-gradient

1896

E.A. Nanni, W.S. Graves, K.-H. Hong, W.R. Huang, F.X. Kärtner, KR. Ravi, L.J. Wong
MIT, Cambridge, Massachusetts, USA
A. Fallahi, F.X. Kärtner
CFEL, Hamburg, Germany
R.J.D. Miller
DESY, Hamburg, Germany
G. Moriena
University of Toronto, Toronto, Ontario, Canada

Funding: Supported by DARPA N66001-11-1-4192, CFEL DESY, DOE DEFG02-10ER46745, DOE DE-FG02-08ER41532, ERC Synergy Grant 609920 and NSF DMR-1042342.
We report the first experimental demonstration of linear electron acceleration using an optically generated single cycle THz pulse centered at 0.45 THz. 7 keV of acceleration is achieved using 10 microJ THz pulses in a 3 mm interaction length. The THz pulse is produced via optical rectification of a 1.2 mJ, 1 micron laser pulse with a 1 kHz repetition rate. The THz pulse is coupled into a dielectric-loaded circular waveguide with 10 MeV/m on-axis accelerating gradient. A 25 fC input electron bunch is produced with a 60 keV DC photo-emitting cathode. The achievable accelerating gradient in the THz structures being investigated will scale rapidly by increasing the IR pulse energy (100 mJ - 1 J) and correspondingly the THz pulse energy. Additionally, with recent advances in the generation of THz pulses via optical rectification, in particular improvements to efficiency and generation of multi-cycle pulses, GeV/m accelerating gradients could be achieved. An ultra-compact high-gradient THz accelerator would be of interest for a wide variety of applications.

Slides WEOAB03 [7.185 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAB03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBB01

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

controls, timing, feedback, experiment

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]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEOBB02

Status of Single-shot EOSD Measurement at ANKA

wakefield, operation, electron, storage-ring

1909

N. Hiller, A. Borysenko, E. Hertle, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh, P. Schönfeldt, N.J. Smale, J.L. Steinmann
KIT, Karlsruhe, Germany
P. Peier, B. Steffen
DESY, Hamburg, Germany
V. Schlott
PSI, Villigen PSI, Switzerland

Funding: This work is funded by the BMBF contract numbers: 05K10VKC, 05K13VKA.
ANKA is the first storage ring in the world with a near-field single-shot electro-optical (EO) bunch profile monitor. The method of electro-optical spectral decoding (EOSD) uses the Pockels effect to modulate the longitudinal electron bunch profile onto a long, chirped laser pulse passing through an EO crystal. The laser pulse is then analyzed with a single-shot spectrometer and from the spectral modulation, the temporal modulation can be extracted. The setup has a sub-ps resolution (granularity) and can measure down to bunch lengths of 1.5 ps RMS for bunch charges as low as 30 pC. With this setup it is possible to study longitudinal beam dynamics (e. g. microbunching) occurring during ANKA's low-alpha-operation, an operation mode with compressed bunches to generate coherent synchrotron radiation in the THz range. In addition to measuring the longitudinal bunch profile, long-ranging wake-fields trailing the electron bunch can also be studied, revealing bunch-bunch interactions.

Slides WEOBB02 [12.753 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO002

Studies of Ultrashort THz Pulses at DELTA

electron, detector, radiation, simulation

1936

P. Ungelenk, L.-G. Böttger, S. Hilbrich, H. Huck, M. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick
DELTA, Dortmund, Germany
S. Bielawski, C. Evain, M. Le Parquier, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
N. Hiller, V. Judin, J. Raasch, P. Thoma
KIT, Karlsruhe, Germany

Funding: Work supported by the DFG, the BMBF, and the state of NRW.
At DELTA, a 1.5-GeV electron storage ring operated as a light source by the Center for Synchrotron Radiation at the TU Dortmund University, coherent ultrashort THz pulses are routinely generated by density-modulated electron bunches. Tracking simulations as well as experimental studies using ultrafast THz detectors and an FT-IR spectrometer aim at understanding the turn-by-turn evolution of the density modulation after an initial laser-electron interaction. Furthermore, intensity-modulated laser pulses are applied to create narrow-band THz radiation. This setup is part of the new short-pulse facility based on coherent harmonic generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO003

Construction of a Laser Compton Scattered Photon Source at cERL

photon, electron, cavity, gun

1940

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

A nondestructive assay system of isotopes by quasi-monochromatic gamma-rays and nuclear resonance fluorescence is under development in JAEA. The quasi-monochromatic gamma-rays are generated by laser Compton scattering (LCS) based on energy-recovery linac accelerator and laser technologies. 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. A mode-locked fiber laser, laser enhancement cavity, beamline, and experimental hatch are under construction for the LCS experiment. Up-to-date construction status is presented in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO004

Status of Laser Compton Scattered Gamma-ray Source at JAEA 150-MeV Microtron

radiation, microtron, detector, electron

1943

R. Hajima
JAEA/ERL, Ibaraki, Japan
I. Daito, H. Negm, H. Ohgaki
Kyoto University, Kyoto, Japan
M. Ferdows, T. Hayakawa, M. Kando, T. Shizuma
JAEA, Ibaraki-ken, Japan

Funding: This work is supported by Funds for Integrated Promotion of Social System Reform and Research and Development.
We have developed a laser Compton scattered gamma-ray source based on a 150-MeV racetrack microtron at Japan Atomic Energy Agency. The microtron equipped with a photocathode RF gun accelerates a single bunch of electrons to collide with a laser pulse from a Nd:YAG laser. Such gamma-ray source realizes industrial application of nuclear material detection in a ship cargo, which is one of the urgent requests of international nuclear security. Recent status of gamma-ray generation experiments and design study of a practical machine is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO027

W164: A Wiggler Dedicated to the PUMA Beamline and the FEMTOSLICING Project at SOLEIL

wiggler, operation, electron, photon

1998

O. Marcouillé, H.B. Abualrob, P. Brunelle, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, M. Labat, J.L. Marlats, F. Marteau, A. Mary, A. Nadji, K. Tavakoli, M.-A. Tordeux, M. Valléau
SOLEIL, Gif-sur-Yvette, France

The W164 out-vacuum wiggler was designed and built at SOLEIL with the double goal of producing high energy photons for the PUMA beamline (10 keV to 70 keV) and to be used as a modulator for the FEMTOSLICING project. The insertion device requires simultaneously reaching low resonant energy (1.55 eV) and high critical energy of photons (above 10 keV), leading to the choice of high field and large periods. The 3.28 m long wiggler is composed of 20 periods of 164 mm made of NdFeB magnets and vanadium permendur poles. The required effective field for the FEMTOSLICING is 1.53 T and the maximum total field reaches 1.8T at the minimum gap of 14.5 mm. The small transverse size of the poles was optimized to minimize the magnetic forces (8 tons maximum) resulting, together with the large field produced at minimum gap, to a large vertical dynamic field integral (DFI) inside the horizontal physical aperture of the chamber. A dedicated permanent magnet system was designed, constructed and installed at both wiggler ends to cancel the DFI at minimum gap. The construction of the wiggler, the results of the magnetic measurements and the effects on dynamics measured on electron beam are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO033

Design and Magnetic Measurements on Bi-harmonic Undulators

undulator, free-electron-laser, electron, synchrotron

2013

G. Sharma, G. Mishra
Devi Ahilya University, Indore, India
S. Tripathi
DESY, Hamburg, Germany

In recent years there exists interests in harmonic lasing of free electron lasers for short wavelength operation with low energy electron beams. In a planar undulator , the electron radiates at odd harmonics on axis however the harmonic gain of the FEL is much less than that of fundamental. It has been shown in earlier works that it is possible to enhance the harmonic radiation by increasing the harmonic wiggler field to the fundamental by putting high permeability shims inside the undulator. The common material is the vanadium permendur (μ ~800) , which has been used effectively to design the harmonic undulator. In this paper, we report the design and fabrication of seventh and ninth harmonic undulator for free electron laser applications. We use CRGO shims with μ ~ 2-3. The permanent magnet undulator is a four block per period design. The undulator is a variable gap type and consists of NdFeB magnets with six periods, each period is of 5cm length. The undulator has been measured in hall probe and pulsed wire bench. It is shown that the pulsed wire magnetic measurements yields results in close agreement with hall probe results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO034

Magnetic Measurement Developments for Undulators

undulator, quadrupole, vacuum, alignment

2016

P. Vagin, P. Neumann, M. Tischer
DESY, Hamburg, Germany

FLASH2 is an extension of the present VUV-FEL facility at DESY. It includes a separate tunnel with a 12 x 2.5m = 30m long planar hybrid undulator. The undulators have 31.4mm period length and 1T field at a minimum gap of 9mm. The paper presents recent progress in the magnetic measurements of these undulators. Several specific details of the measurement tools will be discussed like peculiarities in the Hall probe calibration and noise, positioning accuracy and synchronization of voltage measurement with probes movement during scan, noise issues of various voltage integrators for stretched wire and search coil measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO036

Construction and First Magnetic Field Test of a Superconducting Transversal Gradient Undulator for the Laser Wakefield Accelerator in Jena.

undulator, electron, radiation, wakefield

2022

V. Afonso Rodríguez, A. Bernhard, A.W. Grau, P. Peiffer, R. Rossmanith, M. Weber, C. Widmann, A. Will
KIT, Karlsruhe, Germany
M. Kaluza, M. Nicolai, A. Sävert
IOQ, Jena, Germany
M. Reuter
HIJ, Jena, Germany

Funding: This work is funded by the German Federal Ministry for Education and Research under contract no. 05K10VK2 and 05K10SJ2.
A superconducting transversal gradient undulator (TGU), tailored to the particular beam properties of the laser wakefield accelerator (LWFA) at the University of Jena, has been designed and constructed at KIT. This undulator in combination with a specialized beam transport line will be employed to produce undulator radiation with natural bandwidth despite the relatively large energy spread of the electrons produced by the LWFA. The fabrication of this undulator and first results of the magnetic field measurement are discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO040

Field Measurement Facility for PAL-XFEL Undulators

undulator, controls, FEL, software

2032

K.-H. Park, Y.-G. Jung, D.E. Kim, S.N. Kim, I.S. Ko, B.H. Lee, H.-G. Lee, M.S. Lee, S.B. Lee, H.S. Suh, C.W. Sung
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) is developing the SASE based FEL for X-ray coherent photon sources. The PAL developed the prototype undulator that was 5.0 m magnetic length. The PAL has constructed the undulator field measurement facility to confirm the field qualities of the XFEL undulators in the assembly building. The temperature stability of the measurement rooms was controlled within ±0.1°C. Two field measurement benches that included Hall probe scan, flip coil and stretched wire system were installed and evaluated their performances. The field profile of the prototype undulator was characterized and shimmed using the installed measurement system. This paper described the field measurement facility with the performance test results of the two benches.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO045

Design of a System at NSRRC to Measure the Field for an In-vacuum Cryogenic Undulator with Permanent Magnet

vacuum, alignment, undulator, timing

2041

C.K. Yang, C.-H. Chang, T.Y. Chung, J.C. Huang, C.-S. Hwang, Y.Y. Lin
NSRRC, Hsinchu, Taiwan

A cryogenic undulator with a permanent magnet (CPMU) is an important insertion device now under construction at NSRRC. For an undulator of this kind, the distribution of the magnetic field must be measured along the axis; the phase error, trajectory and photon flux must be calculated after the magnetic arrays are installed in the vacuum chamber and cooled to cryogenic temperature. We developed a Hall-probe system to measure the magnetic field in an evacuated environment; this system uses lasers and stages to monitor and to correct dynamically the positions of the Hall probe. All components installed inside the vacuum chamber are compatible with an environment of high vacuum and low temperature. The details of the design and completed fabrication are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO050

Cryogenically Cooled 1J, ps Yb:YAG Slab Laser for High-brightness Laser-Compton X-Ray Source

photon, electron, booster, operation

2056

A. Endo, M. Chyla, T. Miura, T. Mocek, P. Sikocinski
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
K. Sakaue, M. Washio
RISE, Tokyo, Japan

Funding: This work benefitted from the support of the Czech Republic’s Ministry of Education, Youth and Sports to the HiLASE and DPSSLasers projects cofinanced from the European Regional Development Fund.
Laser Compton X-ray source is studied as an accelerator-laser hybrid technology to realize a compact source from soft X-ray to gamma ray*. It is critical to design a solid state laser of 1J pulse energy with 1ps pulse length, and a high beam quality for 10 microμm diameter interaction. The required M2 is less than 1.5 in a standard normal incidence configuration. X-ray total photon number is ~10⁹ with 1nC, 3ps 43MeV electron bunch for each shot. HiLASE project is committed to make a progress in the field of new generation solid state laser based on Yb-doped materials, to deliver 1J at 120Hz of 1-2ps with M2<1.5. The laser system consists of a seed fiber laser and two amplifier stages, an Yb:YAG thin disk regenerative amplifier, and a cryogenically cooled single slab booster amplifier. We have obtained output energy of 45mJ from the regenerative amplifier at 1 kHz with M2 <1.2. Booster amplifier is designed by a conduction cooling to build a compact system. Gain bandwidth was 1.2nm at 120K, enough to obtain 1-2ps pulses. Improvement of the crystal holder and the experimental results are presented to indicate the available pulse energy and M2.
*Endo, A. et.al. “Characterization of the monochromatic laser Compton X-ray beam with picosecond and femtosecond pulse widths”, Proceedings SPIE 4502, pp100-108 (2001)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO051

Commissioning of the Laser Beam Transport for the Femto-slicing Project at the Synchrotron SOLEIL

wiggler, beam-transport, diagnostics, electron

2059

P. Prigent, M.-E. Couprie, Ph. Hollander, M. Labat, C. Laulhé, A. Lestrade, J. Lüning, J.L. Marlats, P. Morin, A. Nadji, S. Ravy, J.P. Ricaud, M.G. Silly, F. Sirotti, M.-A. Tordeux, D. Zerbib
SOLEIL, Gif-sur-Yvette, France

The aim of the Femto-Slicing project at SOLEIL is to generate 100 fs X-rays pulses on two beamlines, CRISTAL and TEMPO in a first step, for pump-probe experiments in the hard and soft X-rays regions and possibly on two other beamlines in the future. Two fs lasers are currently in operation on TEMPO and CRISTAL for pump-probe experiments on the ps time scale enabling time resolved photoemission and photodiffraction studies. The Femto-Slicing project is based on the fs laser of the CRISTAL beamline, which can be adjusted to deliver 5 to 3 mJ pulses of 30 fs duration at 1 to 2.5 kHz respectively. The laser beam is separated in three branches: one delivering about 2 mJ to the modulator Wiggler and the other ones delivering the remaining energy to the TEMPO and CRISTAL experiments. This layout will yield natural synchronization between IR laser pump and X-ray probe pulses, only affected by drift associated with beam transport. In this paper, we present the current status of the Femto-Slicing project at SOLEIL, with particular emphasis on the characterization of the laser beam transport to the wiggler, to the CRISTAL beamline, and with the first results that will be obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO052

The ThomX Project Status

cavity, framework, synchrotron, gun

2062

A. Variola, D. Auguste, A. Blin, J. Bonis, S. Bouaziz, C. Bruni, K. Cassou, I. Chaikovska, S. Chancé, V. Chaumat, R. Chiche, P. Cornebise, O. Dalifard, N. Delerue, T. Demma, I.V. Drebot, K. Dupraz, N. El Kamchi, M. El Khaldi, P. Gauron, A. Gonnin, E. Guerard, J. Haissinski, M. Jacquet, D. Jehanno, M. Jouvin, E. Jules, F. Labaye, M. Lacroix, M. Langlet, D. Le Guidec, P. Lepercq, R. Marie, J.C. Marrucho, A. Martens, B. Mercier, E. Mistretta, H. Monard, Y. Peinaud, A. Pérus, B. Pieyre, E. Plaige, C. Prevost, T. Roulet, R. Roux, V. Soskov, A. Stocchi, C. Vallerand, A. Vermes, F. Wicek, Y. Yan, J.F. Zhang, Z.F. Zomer
LAL, Orsay, France
P. Alexandre, C. Benabderrahmane, F. Bouvet, L. Cassinari, M.-E. Couprie, P. Deblay, Y. Dietrich, M. Diop, M.E. El Ajjouri, M.P. Gacoin, C. Herbeaux, N. Hubert, M. Labat, P. Lebasque, A. Lestrade, R. Lopes, A. Loulergue, P. Marchand, F. Marteau, D. Muller, A. Nadji, R. Nagaoka, J.-P. Pollina, F. Ribeiro, M. Ros, R. Sreedharan
SOLEIL, Gif-sur-Yvette, France
A. Bravin, G. Le Duc, J. Susini
ESRF, Grenoble, France
C. Bruyère, A. Cobessi, W. Del Net, J.L. Hazemann, J.L. Hodeau, P. Jeantet, J. Lacipière, O. Proux
Institut NEEL, Grenoble, France
E. Cormier, J. Lhermite
CELIA, Talence, France
L. De Viguerie, H. Rousselière, P. Walter
LAMS, Universite Pierre et Marie Curie, Ivry Sur Seine, France
H. Elleaume, F. Esteve
INSERM, Grenoble Institut des Neurosciences, La Tronche, France
J.M. Horodinsky, N. Pauwels, P. Robert
CNRS (IRSD), Orsay, France
S. Sierra
TED, Velizy, France

Funding: Work supported by the French Agence Nationale de la Recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI
A collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay – France. After a period of study and definition of the machine performances a complete description of all the systems has been provided. The infrastructures work is started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different ongoing R&D on optical resonators, fast power supplies for the injection kickers and on the electron gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO053

All-optical Free Electron Lasers using Travelling-wave Thomson Scattering

electron, FEL, undulator, scattering

2065

K. Steiniger, M.H. Bussmann, A.D. Debus, A. Irman, A. Jochmann, R.G. Pausch, U. Schramm
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T.E. Cowan
HZDR, Dresden, Germany

In Travelling-Wave Thomson Scattering (TWTS) the pulse front of a high-power, short-pulse laser is tilted and the dispersion of the pulse is controlled in such a way that electrons can interact over a long distance with a quasi-monochromatic electromagnetic wave. We present a complete three dimensional analytic time-dependent description of the TWTS field and use this description to derive an analytic FEL equation that shows that TWTS indeed provides for an all-optical FEL. We further derive conditions for optimum operation of the TWTS FEL, showing that EUV and XUV FEL sources are in reach using Petawatt lasers and conventional few-hundred MeV electron sources. Future laser-wakefield accelerators could potentially drive all-optical TWTS-FELs in the X-ray and beyond. TWTS itself is optimum to provide full flexibility in terms of the wavelength and bandwidth of the scattered radiation, allowing for application-optimized, highly-brilliant Thomson Scattering sources for a broad range of wavelengths from the EUV to the gamma ray spectral region.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO055

Development of a Quasi 3-D Ellipsoidal Photo Cathode Laser System for PITZ

electron, emittance, simulation, cathode

2069

T. Rublack, M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia

Funding: Funded by the German Federal Ministry of Education and Research (BMBF) project 05K10CHE in the framework of the German-Russian collaboration "Development and Use of Accelerator-Based Photon Sources".
3-D ellipsoidal photo cathode laser pulses are considered as the next step in optimization of photo injectors required for a successful operation of linac based free electron lasers. Significant improvements in electron beam emittance obtained from the beam dynamics simulations using such laser pulses compared to the conventional cylindrical pulses motivated the experimental studies in order to develop a laser system for quasi 3-D ellipsoidal pulses. The Institute of Applied Physics (Nizhny Novgorod, Russia) in collaboration with the Joint Institute of Nuclear Research (Dubna, Russia) and the Photo Injector Test facility at DESY, Zeuthen site (PITZ) is developing such a photo cathode laser system. Experimental tests of the laser system with photoelectron beam production are planned at PITZ. The laser pulse shaping is realized using the spatial light modulator technique. The laser system is capable of pulse train generation. First cross-correlation measurements were done demonstrating in principle the ability to generate and measure quasi ellipsoidal laser pulses. In this contribution the overall set-up, working principle and the actual progress of the development will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO056

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

cavity, photon, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO093

Possibility of Application of THz Wiggler in Low Energy FEL for Measurements of Electron Bunch Longitudinal Structure

electron, wiggler, radiation, undulator

2177

E. Syresin, S.A. Kostromin, R.S. Makarov, N.A. Morozov, D. Petrov
JINR, Dubna, Moscow Region, Russia
M. Krasilnikov
DESY Zeuthen, Zeuthen, Germany

Funding: The work is funded by HGDF-RFBR Grant HRJRG-400
The infrared undulator constructed at JINR and installed at FLASH in 2007 is used for longitudinal bunch shape measurements in the range of several tenths of μm. The presented below electromagnetic wiggler is applied for a narrow-band THz radiation for measurements of electron bunch longitudinal structure in FEL with electron energy of several tenths of MeV. This is a planar electromagnetic device with 6 regular periods, each of 30 cm long. The K parameter is varied in the range 0.5- 7.12 corresponding to a range B=0.025- 0.356 T of the peak field on axis. The wiggler is simulated for 19.8 MeV/c FEL. The bunch compression scheme allows the whole wavelength range to be covered by super-radiant emission with a sufficient form factor. The wavelength range corresponds to 126 μm - 5.3 mm for the electron beam momentum of 19.8 MeV/c. The 3D Opera simulations of THz wiggler will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO093

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO103

Femtosecond Time-resolved Transmission Electron Microscopy using an RF Gun

electron, gun, emittance, cathode

2205

J. Yang, M. Gohdo, K. Kan, T. Kondoh, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

The first prototype of RF gun based relativistic-energy electron microscopy has been constructed at Osaka University to study ultrafast structural dynamic processes in matter. The RF gun driven by a femtosecond laser has generated a 100-fs-pulse MeV electron beam with emittance of 0.1 mm-mrad and energy spread of 10^-4. Both the electron diffraction and image measurements have been succeeded in the prototype using the femtosecond electron beam. In the diffraction measurement, an excellent quality of diffraction pattern was acquired with electron number of 10⁶. The single-shot measurement is available in the prototype. In the image measurement, the TEM image was acquired with a total electron number of 10⁸. The magnification was 3,000 times. In the next step, we will reduce further the emittance to increase the beam brightness on the sample, and then improve the spatial resolution to <10 nm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO103

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO108

Electron Diffraction on VELA at Daresbury

electron, gun, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO108

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO113

Status of the Radiation Source ELBE Upgrade

electron, operation, radiation, klystron

2233

P. Michel, T.E. Cowan, U. Lehnert, U. Schramm
HZDR, Dresden, Germany

ELBE is based on a 40 MeV superconducting Electron Linac able to operate in CW mode and provides manifold secondary user beams. The suite of secondary beams include: two free electron lasers operating in the IR/THz regime; a fast neutron beam; a Bremsstrahlung gamma-ray beam; a low-energy positron beam; and patented single-electron test beams. The primary electron beam is also used for radiobiology research, or in interaction with ultra-intense PW-class lasers. Through 2014 ELBE will be upgraded to a Centre for High Power Radiation Sources. The ELBE beam current was increased to 1.6 mA by using novel solid state RF amplifiers. The concept also contains additional broad and narrow band coherent THz sources and the development of a 500 TW TiSa Laser and even a 1.5 PW diode pumped laser system. Laser plasma electron acceleration and proton acceleration experiments for medical applications are planned. Additionally, coupled electron laser beam experiments like Thomson scattering or injection of ELBE electron into the laser plasma will be done.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO113

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO115

The Star Project

electron, photon, linac, scattering

2238

A. Bacci, D.T. Palmer, L. Serafini, V. Torri
Istituto Nazionale di Fisica Nucleare, Milano, Italy
R.G. Agostino, G. Borgese, M. Ghedini, F. Martire, C. Pace
UNICAL, Arcavacata di Rende, Italy
D. Alesini, M.P. Anania, M. Bellaveglia, F.G. Bisesto, G. Di Pirro, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, B. Spataro, C. Vaccarezza, F. Villa
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
G. D'Auria, A. Fabris, M. Marazzi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
T. Levato
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
E. Puppin
Politecnico/Milano, Milano, Italy
P. Tomassini
Università degli Studi di Milano, Milano, Italy

We present on overview of the STAR project (Southern european Thomson source for Applied Research), in progress at the Univ. of Calabria (Italy) aimed at the construction of an advanced Thomson source of monochromatic tunable, ps-long, polarized X-ray beams, ranging from 20 to 140 keV. The project is pursued in collaboration among: Univ. della Calabria, CNISM, INFN and Sincrotrone Trieste. The X-rays will be devoted to experiments of matter science, cultural heritage, advanced radiological imaging with micro-tomography capabilities. One S-band RF Gun at 100 Hz will produce electron bunches boosted up to 60 MeV by a 3m long S-band TW cavity. A dogleg will bring the beam on a parallel line, shielding the X-ray line from the background radiation due to Linac dark current. The peculiarity of the machine is the ability to produce high quality electron beams, with low emittance and high stability, allowing to reach spot sizes around 15-20 microns, with a pointing jitter of the order of a few microns. The collision laser will be based on a Yb:Yag 100 Hz J-class high quality laser system, synchronized to an external photo-cathode laser and to the RF system to better than 1 ps time jitter.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO115

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO116

Direct High Power Laser Diagnostic Technique Based on Focused Electron Bunch

electron, solenoid, scattering, experiment

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).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO116

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME001

Virtual Cathode Drive Laser Diagnostics with a Large Dynamic Range for a Continuous Wave SRF Photoinjector

cathode, electron, diagnostics, operation

2251

E. Panofski, A. Jankowiak, T. Kamps, G. Klemz
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
In a SRF photoinjector the close relationship between the laser pulse and the generated electron bunch parameters requires continuous monitoring of some of the laser pulse parameters. A laser diagnostic system, called virtual cathode, is a key part of a system that controls the stability of the laser. One of the main challenges for the virtual cathode is to cover the large dynamic range of the photocathode laser between commissioning at 120 Hz and operation at 1.3 GHz repetition rate with constant laser pulse parameters. The design of the virtual cathode as well as first measurements with a photocathode drive laser for the SRF injector test facility GunLab of BERLinPro will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME002

Laser System for SNS Laser Stripping Experiment

cavity, controls, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME060

Yb DOPED HIGH-ENERGY UV ULTRAFAST LASER FOR AREAL FACILITY

electron, gun, alignment, emittance

2412

A. Lorsabyan, A.A. Gevorgyan, B. Grigoryan, A.S. Simonyan
CANDLE SRI, Yerevan, Armenia
V. Clet, A. Courjaud
Amplitude Systemes, Pessac, France
T.K. Sargsyan
LT-PYRKAL cjsc, Yerevan, Armenia

For electron generation from photocathode the new laser system was developed for the AREAL linear accelerator laboratory. Besides generating electrons using the laser, we plan to provide a laser beam for other experimental stations running in parallel. The performance and capabilities of the laser system including operating frequency, electron generation in multi-bunch regime and other advantages are presented. The outlooks and steps for further upgrade are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME061

Ytterbium Fiber and Disk Laser of RF Gun for SuperKEKB

gun, cavity, background, emittance

2415

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida
KEK, Ibaraki, Japan

For SuperKEKB project, the electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun at the injector linac. An ytterbium (Yb)-doped laser system with a center wavelength of 259 nm and a pulse width of 30 ps is employed to obtain high peak energy pulses. Although, the pulse repetition of 25 Hz with double-bunch is required, more than 5 nC electron with single-bunch has so far been generated in the 2 Hz.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME061

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME067

Performance of the MTCA.4 Based LLRF System at FLASH

LLRF, electron, operation, free-electron-laser

2433

Ch. Schmidt, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, K.P. Przygoda, H. Schlarb, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
W. Cichalewski, D.R. Makowski, A. Piotrowski
TUL-DMCS, Łódź, Poland
K. Czuba, I. Rutkowski, D. Sikora, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
I.M. Kudla
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The Free Electron Laser in Hamburg (FLASH) is the first linac which is equipped with a MTCA.4 based low level RF control system. Precise regulation of RF fields is essential for stable and and reproducible photon generation. Flash benefits from the performance increase using the new developments like, accurate and precise field detection devices. Further enourmous increase of processing capabilities allow for more sophisticated controller applications which better the overall performance of the regulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME067

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI032

First Cryomodule Test at AMTF Hall for The European X-ray Free Electron Laser (XFEL)

cryomodule, vacuum, free-electron-laser, cavity

2546

K. Kasprzak, B. Dzieza, W. Gaj, D. Karolczyk, L.M. Kolwicz-Chodak, A. Kotarba, A. Krawczyk, K. Krzysik, W. Maciocha, A. Marendziak, K. Myalski, S. Myalski, T. Ostrowicz, B. Prochal, M. Sienkiewicz, M. Skiba, J. Świerbleski, M. Wiencek, J. Zbroja, P. Ziolkowski, A. Zwozniak
IFJ-PAN, Kraków, Poland

The Accelerator Module Test Facility (AMTF) at DESY in Hamburg is dedicated to the tests of RF cavities and accelerating cryomodules for the European X-ray Free Electron Laser (XFEL). The AMTF hall is equipped with two vertical cryostats, which are used for RF cavities testing and three test benches that will be used for tests of the accelerating cryomodules. Recently, the first cryomodule teststand (XATB3) was commissioned and the first XFEL cryomodule (XM-2) was tested by team of physicists, engineers and technicians from The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland, as a part of Polish in-kind contribution to XFEL. This paper describes the preparation for the cryomodule test, differences with the old teststands CryoModule Test Bench (CMTB), the cryomodule test and the test procedure updates done at the AMTF test bench. The first test of the accelerating cryomodule on the AMTF was successfully performed and the preliminary test results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI058

Commissioning Status of the Advanced Superconducting Test Accelerator at Fermilab

gun, cryomodule, cavity, cathode

2615

J. Ruan, R. Andrews, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B. Chase, M.D. Church, D.J. Crawford, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, A.S. Johnson, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P.S. Prieto, J. Reid, J.K. Santucci, G. Stancari, D. Sun, M. Wendt, S.J. Wesseln
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: *Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The Advanced Superconducting Test Accelerator (ASTA) is under construction at Fermilab. This accelerator will consist of a photo-electron gun, injector, ILC-type cryomodules, and multiple downstream beam-lines. Its purpose is to be a user-based facility for Advanced Accelerator R&D. . Following the successful commissioning of the photoinjector gun, a Tesla style 8-cavity cryomodule and a high gradient capture cavity have been cooled down to 2 K and powered commissioning and performance characterization has begun. We will report on the commissioning status and near-term future plans for the facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI059

Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end

optics, diagnostics, vacuum, gun

2618

D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, D. Snee
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. The Front-End consists of a 1.5 cell normal conducting RF Gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a diagnostic area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI115

Design and Integration of the Optical Reference Module at 1.3 GHz for FLASH and the European XFEL

electronics, detector, controls, LLRF

2768

E. Janas, K. Czuba, P. Kownacki, D. Sikora
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
M.K. Czwalinna, M. Felber, T. Lamb, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack
DESY, Hamburg, Germany
J. Szewiński
NCBJ, Świerk/Otwock, Poland

In this paper we present recent progress on the integration and implementation of the optical reference module (REFM-OPT) for the free-electron lasers FLASH and European XFEL. In order to achieve high energy stability and low arrival time jitter of the electron beam, the accelerator requires an accurate low-level RF (LLRF) field regulation and a sophisticated synchronization scheme for various devices along the facility. The REFM-OPT is a 19” module which is responsible for resynchronizing the 1.3 GHz reference signal for the LLRF distributed by coaxial cables to a phase-stable signal of the optical synchronization system. The module provides a 1.3 GHz output signal with low phase noise and high long-term stability. Several sub-components of the REFM-OPT designed specifically for this module are described in detail. The readout electronics of the high-precision Laser-to-RF phase detector are presented as well as the integration of this key component into the 19” module. Additionally, we focus on design solutions which assure phase stability and synchronization of the 1.3 GHz signal at several high power outputs of the module.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI115

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI116

Master Oscillator for the European XFEL

feedback, low-level-rf, timing, detector

2771

L.Z. Zembala, K. Czuba, B. Gąsowski, D. Sikora
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
J. Branlard, H. Schlarb, H.C. Weddig
DESY, Hamburg, Germany

The reference signal outage causes breakdown of the synchronisation in the entire accelerator, which could result in a multi-day break in the operation. Therefore, the Master Oscillator (MO) for the European XFEL has to be redundant, in order to achieve extremely high reliability. The redundancy concept, which provides no interruption in the reference signal, requires phase coherence, fast RF switching and sustaining the RF power with a high-Q filter. These features allow to keep possible signal transitions smooth. Furthermore, the MO has to generate a 1.3 GHz signal of exceptionally good phase noise performance – jitter < 35 fs RMS integrated from 10 Hz to1 MHz. One of the problems in the way are vibrations, which have to be properly isolated to avoid microphonics effects in oscillators. The proposed MO architecture and connection with the RF distribution system is described. A basic prototype is tested and results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI116

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THYA01

Control and Application of Beam Microbunching in High Brightness Linac-driven Free Electron Lasers

FEL, impedance, electron, radiation

2789

G.V. Stupakov
SLAC, Menlo Park, California, USA

The remarkable properties of coherent radiation from free-electron lasers (FELs) are due to the current modulation in the beam with the modulation period equal to the radiation wavelength. This modulation is developed as a result of a beam instability when the beam propagates in a long FEL undulator, and requires a beam with a high-peak current, small emittance and a small energy spread. Unfortunately the same beam qualities make it a subject to a so-called microbunching instability at a much longer scale than the radiation wavelength. It is driven by the space charge and CSR impedances in the machine and develops during the beam acceleration in the linac, compression, and transport to the undulator. If not controlled, the microbunching instability influences dramatically the FEL performance and in the worst case can even ruin the lasing. In the presentation we will review the mechanism behind the microbunching instability, the suppression methods used in existing facilities as well as possible future developments and concepts.

Slides THYA01 [5.631 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THYA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOBA01

A New Scheme for Electro-optic Sampling at Record Repetition Rates : Principle and Application to the First (turn-by-turn) Recordings of THz CSR Bursts at SOLEIL

synchrotron, real-time, storage-ring, detector

2794

E. Roussel, S. Bielawski, C. Evain, M. Le Parquier, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
J.B. Brubach, L. Cassinari, M.-E. Couprie, M. Labat, L. Manceron, J.P. Ricaud, P. Roy, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

The microbunching instability is an ubiquitous problem in storage rings at high current density. However, the involved fast time-scales hampered the possibility to make direct real-time recordings of theses structures. When the structures occur at a cm scale, recent works at UVSOR*, revealed that direct recording of the CSR electric field with ultra-high speed electronics (17 ps) provides extremely precious informations on the microbunching dynamics. However, when CSR occurs at THz frequencies (and is thus out of reach of electronics), the problem remained largely open. Here we present a new opto-electronic strategy that enabled to record series of successive electric field pulses shapes with picosecond resolution (including carrier and envelope), every 12 ns, over a total duration of several milliseconds. We also present the first experimental results obtained with this method at Synchrotron SOLEIL, above the microbunching instability threshold, and we present direct tests of Vlasov-Fokker-Planck and macroparticle models. The method can be applied to the detection of ps electric fields in other situations where high repetition rate is also an issue.
* First Direct, Real Time, Recording of the CSR Pulses Emitted During the
Microbunching Instability, using Thin Film YBCO Detectors at UVSOR-III, IPAC2014

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOBA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOBA03

Beam Transport System from a Laser Wakefield Accelerator to a Transverse Gradient Undulator

undulator, electron, beam-transport, radiation

2803

C. Widmann, V. Afonso Rodríguez, A. Bernhard, N. Braun, A.-S. Müller, A.I. Papash, R. Rossmanith, W. Werner
KIT, Karlsruhe, Germany
M. Kaluza, M. Reuter
HIJ, Jena, Germany
M. Kaluza, M. Nicolai, A. Sävert
IOQ, Jena, Germany

Funding: This work is funded by the German Federal Ministry for Education and Research under contract no. 05K10VK2.
The transport and matching of electron beams generated by a laser wakefield accelerator (LWFA) is a major challenge due to their large energy spread and divergence. Strong focussing magnets and a chromatic correction are required. This contribution discusses the layout of the beam transport optics for a diagnostic beamline at the LWFA in Jena, Germany. The aim of this optics is to match the betatron functions and the dispersion to the field of a transverse gradient undulator (TGU) such that monochromatic undulator radiation is generated despite the large energy spread.

Slides THOBA03 [2.891 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOBA03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPPA01

FEL R&D Initiatives at the SLAC National Accelerator Laboratory

undulator, FEL, electron, free-electron-laser

2842

A. Marinelli
SLAC, Menlo Park, California, USA

The successful lasing of the linac coherent light source in 2009, the first x-ray free-electron laser (xFEL) in the world, has opened a new era for x-ray photon science. The unprecedented intensity and coherence of the LCLS photon pulses have enabled groundbreaking experiments in a wide variety of fields ranging from coherent x-ray imaging to molecular and atomic physics. Despite the success of x-ray free-electron lasers, there is a steady push to extend and improve their capabilities fueled by the users' demands for new modes of operation and more precise photon and electron diagnostics. In my talk I will present several R&D initiatives at the SLAC National Accelerator Laboratory geared towards improving the performance and extending the capabilities of x-ray FELs. In particular I will focus on the spectral manipulation of FELs and our recent development of the multibunch and multicolor x-ray FEL modes at LCLS as well as our demonstration of the longitudinal space-charge amplifier as a broadband coherent light source at the NLCTA test accelerator.

Slides THPPA01 [10.793 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPPA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO003

Progress of the LUNEX5 demonstator Project

FEL, electron, operation, undulator

2856

M.-E. Couprie, C. Benabderrahmane, P. Berteaud, C. Bourassin-Bouchet, F. Bouvet, L. Cassinari, L. Chapuis, J. Daillant, M. Diop, M.E. El Ajjouri, C. Evain, C. Herbeaux, N. Hubert, M. Labat, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, J.L. Marlats, C. Miron, P. Morin, A. Nadji, F. Polack, F. Ribeiro, J.P. Ricaud, P. Roy, K. Tavakoli, M. Valléau, D. Zerbib
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Carré, D. Garzella
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
X. Davoine
CEA/DAM/DIF, Arpajon, France
N. Delerue
LAL, Orsay, France
G. Devanz
CEA/DSM/IRFU, France
A. Dubois, J. Lüning
CCPMR, Paris, France
G. Lambert, R. Lehé, V. Malka, A. Rousse, C. Thaury
LOA, Palaiseau, France
C. Madec, A. Mosnier
CEA/IRFU, Gif-sur-Yvette, France

LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, coherent pulses in the 40-4 nm spectral range [1]. It comprises two types of accelerators connected to a single Free Electron Laser (FEL) for advanced seeding configurations (seeding with High order Harmonic in Gas, echo). A 400 MeV superconducting Linear Accelerator, adapted for studies of advanced FEL schemes, will enable future upgrade towards high repetition rate and multi-user operation by splitting part of the macropulse to different FEL lines. A 0.4 - 1 GeV Laser Wake Field Accelerator (LWFA) [2] will also be qualified by the FEL application. After the Conceptual Design Report, R&D has been launched on different sub components. Following transport theoretical studies of longitudinal and transverse manipulation of a LWFA electron beam enabling to provide theoretical amplification, a test experiment is under preparation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO013

FERMI Status Report

FEL, electron, linac, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO017

Comparison of the Detection Performance of Three Nonlinear Crystals for the Electro-optic Sampling of a FEL-THz Source

FEL, detector, lattice, damping

2891

B. Wu, L. Cao, Q. Fu, P. Tan, Y.Q. Xiong
HUST, Wuhan, People's Republic of China

The detector of a FEL-THz source at HUST is now in the physical design stage. The electro-optic (EO) sampling method will be employed for the coherent detection. The performances of three widely used EO crystals will be evaluated and compared numerically in the time domain detection: zinc telluride (ZnTe), gallium arsenide (GaAs) and gallium phosphide (GaP). The phase matching properties are analyzed to find the appropriate probe wavelength. The EO detection response is calculated to select the suitable crystal thickness and to discuss the detection ability of each crystal.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO018

Electron-Magnetic-Phase Mixing in a Linac-driven FEL to Suppress Microbunching in the Optical Regime and Below

linac, electron, FEL, radiation

2894

S. Di Mitri, S. Spampinati
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Control of microbunching instability is a fundamental requirement in modern high brightness electron linacs, in order to prevent malfunction of beam optical diagnostics and contamination in the generation of coherent radiation, such as free electron lasers. We present experimental control and suppression of microbunching instability-induced optical transition radiation by means of particles’ longitudinal phase mixing in a magnetic chicane*. In presence of phase mixing, the intensity of the beam-emitted coherent optical transition radiation is reduced by one order of magnitude and brought to the same level provided, alternatively, by beam heating. The experimental results are in agreement with particle tracking and analytical evaluations of the instability gain. A discussion of applications of magnetic phase mixing to the generation of quasi-cold high-brightness ultra-relativistic electron beams is finally given.
* S. Di Mitri and S. Spampinati, Phys. Rev. Lett. 112, 134802 (2014)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO021

Results Produced after Measuring PAL-ITF Beam Diagnostic Instruments

pick-up, diagnostics, controls, klystron

2903

H. J. Choi, M.S. Chae, J.H. Hong, H.-S. Kang, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) built a PAL-ITF at the end of 2012 to successfully complete PAL-XFEL in 2015. The PAL-ITF is equipped with various kinds of diagnostic equipment to produce high-quality electron bunches. An ICT and a Turbo-ICT were installed in the PAL-ITF. A Faraday Cup is installed at the end of the linear accelerator. These days, the quantity of electric charge occasionally is measured using a BPM Sum value. This paper focuses on the processes and results of electric charge quantity measurements using ICT, Turbo-ICT, FC and BPM. The PAL-ITF is equipped with Stripline-BPM. It is important to find a way to minimize measurement errors that can appear in the process of installing or measuring the BPM. For this, PAL-ITF separately measured the BPM electrode sensitivity and minimized BPM measurement errors through generally calibrating BPM devices by applying Lambertson's Method. A plan was made to minimize BPM measurement errors through applying the BPM electrical calibration method for BPM devices to be used by the PAL-XFEL. This paper examines the processes for checking the performance of the S-BPM installed in the PAL-ITF and the results of its measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO022

JINR Powerful Laser Driver Applied for FEL Photoinjector

radiation, FEL, electron, ion

2906

E. Syresin, N. Balalykin, M.A. Nozdrin, G. Shirkov, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia
E. Gacheva, E. Khazanov, G. Luchinin, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia

Funding: The work is funded by the German Federal Ministry of education and Research, project 05K10CHE.
The JINR develops a project of superconducting linear accelerator complex, based on a superconducting linear accelerator, for applications in nanoindustry, mainly for extreme ultraviolet lithography at a wavelength of 13.5 nm using kW-scale Free Electron Laser (FEL) light source. The application of kW-scale FEL source permits realizing EUV lithography with 22 nm, 16 nm resolutions and beyond. JINR-IAP collaboration constructed powerful laser driver applied for photoinjector of FEL linear accelerator which can be used for EUV lithography. To provide FEL kW-scale EUV radiation the photoinjector laser driver should provide a high macropulse repetition rate of 10 Hz, a long macropulse time duration of 0.8 ms and 8000 pulses per macropulse. The laser driver operates at wavelength of 260-266 nm on forth harmonic in the mode locking on base of Nd ions or Yb ions The laser driver micropulse energy of 1.6 uJ should provide formation of electron beam in FEL photoinjector with the bunch charge about 1 nC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO024

Progress of the EU-XFEL Laser Heater

undulator, vacuum, electron, photon

2912

M. Hamberg, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: Swedish research council under Project number DNR-828-2008-1093 for financial support.
We describe the technical layout and report the status of the installation of the undulator, optical and vacuum systems of the laser heater for the EUXFEL. The laser heater is a device to increase the overall X-ray brightness stability. This is achieved by an optical laser system which induce an additional momentum spread in the electron bunches to reduce micro-bunching instabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO032

Studies on LPWA-based Light Sources driven by a Transverse Gradient Undulator

undulator, FEL, electron, simulation

2937

T. Chanwattana, R. Bartolini, A. Seryi
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom

The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a LPWA based light source driven by a transverse gradient undulator is being investigated. This report presents the accelerator physics, FEL studies and the performance expected from such a facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO033

Electron-bunch Shaping for Coherent Compton Scattering

electron, radiation, simulation, scattering

4107

J.E. Thorne, P. Piot, I. Viti
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Producing high-quality x rays could have important applications to high-precision medical imaging and national security. Inverse Compton scattering involving the head-on collision of a relativistic electron bunch with a high-power laser offers a viable path toward the realization of a compact x-ray source. A method consisting in reflecting a short-pulse laser onto a “relativistic mirror” (a moving thin sheet of electrons) has been proposed and recently demonstrated as a way to enhance the back-scattered photon flux by operating in the coherent regime. In this contribution we present particle-in-cell numerical simulations of the inverse Compton scattering process and especially investigate the impact of the laser-pulse and electron-beam distributions that could substantially improve the x-ray production via coherent emission.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO038

Energy-Silenced HGHG

FEL, bunching, electron, space-charge

2946

E. Hemsing, G. Marcus, A. Marinelli
SLAC, Menlo Park, California, USA
D. Xiang
Shanghai Jiao Tong University, Shanghai, People's Republic of China

We study the effect of longitudinal space charge on the correlated energy spread of a relativistic beam that has been microbunched for the emission of high harmonic radiation. We show that, in the case of microbunching induced by a laser modulator followed by a dispersive chicane, longitudinal space charge forces can act to significantly reduce the induced energy spread of the beam without a reduction in the harmonic bunching content. This effect may significantly relax constraints on the harmonic number achievable in HGHG FELs, which are otherwise limited by the induced energy spread from the laser.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO043

Studies on the Application of the 3D Ellipsoidal Cathode Laser Pulses at PITZ

booster, electron, emittance, flattop

2958

M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany

Funding: The work is funded by the German federal Ministry of education and Research, project 05K10CHE “development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses”.
The Photo Injector Test facility at DESY, Zeuthen Site (PITZ) characterizes and optimizes high brightness electron sources for FLASH and the European XFEL. At nominal conditions the electron bunches are created from a photocathode laser with flat-top temporal distribution and sharp rise and fall times. Beam dynamics simulations using a 3D ellipsoidal cathode laser shape yielded to a significant improvement of the electron beam quality compared to the traditionally used cylindrically shaped beams. The 3D ellipsoidal laser system is under development at the Institute of Applied Physics (IAP) and will be used at PITZ soon, to create high quality electron beams. The recent studies of electron beam simulations at PITZ have been devoted to the position optimization of the second accelerating cavity for the 3D ellipsoidal laser profile. Electron beam properties were compared for cylindrical and 3D ellipsoidal beams applying default and optimized booster positions. Beam tolerance studies revealed much better injector performance for the 3D ellipsoidal laser profile case with the optimized booster position. The outcome of such investigations is presented and discussed in this contribution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO050

Study of a THz/VUV Free Electron Laser Facility in Taiwan

FEL, radiation, undulator, linac

2980

N.Y. Huang, M.C. Chou, C.-S. Hwang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
A. Chao, J. Wu
SLAC, Menlo Park, California, USA
C.H. Chen, Y.-C. Huang
NTHU, Hsinchu, Taiwan
X.M. Yang
DICP, Dalian, People's Republic of China

A free electron laser (FEL) facility aimed for VUV and THz radiation is being studied at National Synchrotron Radiation Research Center (NSRRC) in Taiwan. Strong consideration has been given to minimize the cost by making maximum use of existing hardware at NSRRC. One unique consideration is to use an existing undulator for the dual functions of the THz radiator and the modulator of a HGHG section. Design emphasizes versatility of operation and beam quality control and compensation of nonlinearities, with a vision that it will allow as much as possible future upgrades as well as later R&D of FEL physics. The polarization control of the THz radiation provides novel application for the users. The facility is to be housed in the existing 38-m by 5-m tunnel of the TPS Linac Test Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO052

Beam Physics Commissioning of VELA at Daresbury Laboratory

gun, emittance, diagnostics, quadrupole

2986

B.L. Militsyn, D. Angal-Kalinin, A.D. Brynes, F. Jackson, J.K. Jones, A. Kalinin, J.W. McKenzie, B.D. Muratori, T.C.Q. Noakes, D.J. Scott, E.W. Snedden, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

A user facility VELA (Versatile Electron Linear Accelerator) based on an RF photoinjector has been commissioned at Daresbury Laboratory in April 2013, providing beam to first users in September 2013. Machine study runs in 2013-2014 have concentrated on characterisation of main beam parameters like bunch charge, its momentum, beam emittance and dependence of these parameters on the launching RF phase. Major efforts have been also concentrated on investigation of the dark current from the gun and its dependence on the RF amplitude. Significant time has been dedicated to investigation of relative stability of LLRF and drive laser having significant impact on the overall machine stability. We present here the results of these studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO054

LLNL X-band Test Station Commissioning and X-ray Status

gun, vacuum, alignment, emittance

2992

R.A. Marsh, G.G. Anderson, S.G. Anderson, C.P.J. Barty, M. Betts, S.E. Fisher, D.J. Gibson, F.V. Hartemann, S.S.Q. Wu
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station is being commissioned at LLNL to support inverse Compton-scattering x-ray and gamma-ray source development. The X-band test station has been built and this presentation will focus on its current status and the generation of first electron beam. Special focus will be placed on the high gradient conditioning of the T53 traveling wave accelerator and Mark 1 X-band standing wave RF gun. Design and installation of the inverse-Compton scattering interaction region, future upgrade paths and configuration for a variety of x-ray and gamma-ray applications will be discussed along with the status of theory and modeling efforts.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO055

Electron Beam Final Focus System for Thomson Scattering at ELBE

quadrupole, permanent-magnet, electron, focusing

2995

J.M. Krämer, F. Bødker, A. Baurichter, M. Budde
Danfysik A/S, Taastrup, Denmark
A. Irman, U. Schramm
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
U. Lehnert, P. Michel
HZDR, Dresden, Germany

Funding: This work is part of LA3NET and funded by European Commission under Grant Agreement Number 289191.
The design of an electron beam Final Focus System (FFS) aiming for high-flux laser-Thomson backscattering x-ray sources at ELBE* is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole triplet. This allows sub-ps electron beam focusing to match the laser spot size at the interaction point. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. Since the electron beam is chirped for bunch compression upstream, the rms energy spread is increased to one or two percent and second order chromatic effects must be taken into account. For an emittance of 13 pi mm mrad, we predict rms spot sizes of about 40 um and divergences of about 15 mrad. We also present the design of the permanent magnet quadrupoles to be used for the FFS. Ferromagnetic poles ensure a high field quality and adjustable shunts allow for fine adjustment of the field strength and compensation of deviations in the permanent magnet material.
*A. Jochmann et al., Phys. Rev. Lett. 111 (2013) 114803

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO064

Effect of Laser-plasma Channeling on Third-harmonic Radiation Generation

plasma, electron, radiation, focusing

3023

M. Singh, D.N. Gupta
University of Delhi, Delhi, India

An intense Gaussian laser beam, propagating through a magnetized plasma, becomes self-focused due to the ponderomotive force on the electrons. The magnetic field reduces the radius of the laser beam and enhances the self focusing of the laser beam. The self-sustained plasma channel can affect the efficiency of harmonic generation of the interacting laser beam. The radial density gradient of the channel beats with the oscillatory electron velocity to produce density perturbation at laser frequency. The ponderomotive force at second-harmonic frequency produces electrons density oscillations that beat with the oscillatory velocity to create a non-linear current, driving the third harmonic radiation. The velocity and density perturbation associated with the self-focused laser beam generates a nonlinear current at triple fold frequency of the fundamental laser. Our results show that the efficiency of third-harmonic generation of the laser beam is affected significantly due to the self-sustained plasma channel. The strength of magnetic field play a crucial role in efficiency enhancement of third-harmonic generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO064

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO086

Flat-beam Generation and Compression at Fermilab's Advanced Superconducting Test Accelerator

emittance, quadrupole, simulation, dipole

3086

J. Zhu, D. Mihalcea, P. Piot
Fermilab, Batavia, Illinois, USA
D. Mihalcea, P. Piot, C.R. Prokop
Northern Illinois University, DeKalb, Illinois, USA

An important asset of Fermilab’s Advanced Superconducting Test Accelerator (ASTA) is its ability to generate flat beams with high-transverse emittance ratios. In this paper, we present a practical design and simulation of flat beam generation and compression with various bunch charges up to 3.2 nC. Emittance growth within the round-to-flat beam transformer and the impact of low energy compression is discussed in detail. Finally, it is found that the compressed flat beam could provide exciting opportunities in the field of advanced acceleration techniques and accelerator-based light source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO086

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO093

Low Emittance Electron Beam Transportation in Compact ERL Injector

gun, cathode, focusing, solenoid

3104

T. Miyajima, K. Harada, Y. Honda, T. Kume, S. Nagahashi, N. Nakamura, T. Obina, S. Sakanaka, M. Shimada, R. Takai, T. Uchiyama, A. Ueda, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai, N. Nishimori
JAEA, Ibaraki-ken, Japan
J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea

For future light source based on Energy Recovery Linac (ERL), an injector, which consists of a photocathode DC gun and superconducting RF cavities, is a key part to generate a low emittance, short pulse and high bunch charge electron beam. In compact ERL (cERL) which is a test accelerator to develop key technologies for ERL, the generation of low emittance electron beam with 0.1 mm mrad normalized emittance and 390 keV beam energy from the photocathode DC gun, and the acceleration to 5.6 MeV by superconducting cavity, were demonstrated in the first beam commissioning. To keep the high quality in the beam transportation, understanding the beam optics, which is affected by not only the focusing effects due to the gun, solenoid magnets and RF cavities but also space charge effect, is required. In this presentation, we will show that how to measure and correct the focusing effect by experimental method. Using this method, we succeeded in correcting the analytical model to give the good agreement with the measured gun focusing for low charge beam. And, we will show the space charge effect for high bunch charge beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO093

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO105

MTCA.4 Module for Cavity and Laser Piezo Operation

cavity, high-voltage, controls, feedback

3140

K.P. Przygoda, J. Branlard, M. Felber, C. Gerth, M. Heuer, U. Mavrič, P. Peier, H. Schlarb, B. Steffen
DESY, Hamburg, Germany
T. Kozak, P. Prędki
TUL-DMCS, Łódź, Poland

A MicroTCA.4 (MTCA.4) compliant Piezo Driver (DRTM-PZT4)* has been developed to drive piezoelectric-based actuators used in accelerator instrumentation applications. More specifically, it is used for superconducting cavities fine tuning, synchronization of pulsed lasers and stabilization of fiber links. This paper briefly presents the designed system requirements and discusses the main hardware issues. The Piezo Driver performance measurements are also discussed. The first results of the prototype hardware usage for laser locking** to an external RF source and fiber link stabilization are summarized.
*K. Przygoda et all.,“MTCA.4 Compilant Piezo Driver RTM for Laser Synchronization”,MIXDES'13**U. Mavric et. all, "Precision Synchronization of Optical Lasers based on MTCA.4 Electronics", IBIC'13

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO105

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME071

Injection and Extraction Systems for a High-Power Proton Synchrotron at CERN

injection, extraction, septum, kicker

3400

W. Bartmann, V. Fedosseev, B. Goddard, T. Kramer
CERN, Geneva, Switzerland

A new High-Power Proton Synchrotron (HP-PS) is being studied at CERN for the second phase of the Long Baseline Neutrino facility (LAGUNA-LBNO) where a 2 MW beam power shall impinge onto a target. A 4 GeV H⁻ injection based on foil stripping and extendable to laser-assisted magnet stripping is described. The proposed laser-assisted stripping is assessed with regard to the laser power requirements. The feasibility of a fast extraction system at 75 GeV is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME071

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME076

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

photon, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME076

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME094

Measurement of Low-charged Electron Beam with a scintillator Screen

detector, electron, diagnostics, vacuum

3456

T. Vinatier, P. Bambade, C. Bruni, S. Liu
LAL, Orsay, France

Measuring electron beam charge lower than 1pC is very challenging since the traditional diagnostics, like Faraday Cup and ICT, are limited in resolution to a few pC. A way to simply measure lower charge would be to use the linear relation, existing before saturation regime, between the incident charge and the total light intensity emitted by a YAG screen. Measurement has been performed on PHIL accelerator at LAL, with charge lower than 50pC, with a YAG screen located just in front of a Faraday Cup. It shows a very good linear response of the YAG screen up to the Faraday Cup resolution limit (2pC) and therefore allows calibrating the YAG screen for lower charge measurement with an estimated precision of 4%. A noise analysis allows estimating the YAG screen resolution limit around 40fC. Results of low charge measurement on PHIL will be shown and compared to those coming from a diamond detector installed on PHIL, in order to validate the measurement principle and to determine its precision and resolution limit. Such simple measurement may thereafter be used as single-shot charge diagnostic for electron beam generated and accelerated by laser-plasma interaction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME094

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME095

Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method

gun, electron, booster, flattop

3459

T. Vinatier, C. Bruni, S. Chancé, P.M. Puzo
LAL, Orsay, France

The goal of 3-phase method is to determine the length of an electron beam without dedicated diagnostics by varying the measurement conditions of its energy spread, through a change in the RF phase of an accelerating structure. The originality here comes from the fact that it is applied on high-brightness electron beams of few MeV generated by RF photo-injectors. It allows testing the accuracy of 3-phase method, since the length to reconstruct is known as being that of the laser pulse generating the beam. It requires establishing the longitudinal transfer matrix of a RF photo-injector, which is difficult since the electron velocity vary from 0 to relativistic during its path*. The 3-phase method in RF photo-injector has been simulated by ASTRA and PARMELA codes, validating the principle of the method. First measurement has been done on PHIL accelerator at LAL, showing a good agreement with the expected length. I will then show results obtained at PITZ with a standing wave booster and a comparison with those coming from a Cerenkov detector. Finally, measurements at higher energy performed on the SOLEIL LINAC with travelling wave accelerating structures will be exposed.
* : K-J. Kim, “RF and Space Charge Effects in Laser-Driven RF Electron Guns”, Nucl. Instr. Meth., A275, 201 (1989)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME095

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME109

EOS at CW Beam Operation at ELBE

electron, operation, FEL, diagnostics

3492

Ch. Schneider, M. Gensch, M. Kuntzsch, P. Michel, W. Seidel
HZDR, Dresden, Germany
P.E. Evtushenko
JLab, Newport News, Virginia, USA
Ç. Kaya
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
A. Shemmary, N. Stojanovic
DESY, Hamburg, Germany

The ELBE accelerator is a super conduction electron cw machine located at the Helmholtz Center Dresden Rossendorf Germany with 1 mA current, now tested for up to 2 mA. Besides other important diagnostics for setting up the machine for user beam time and further improvement of the machine – a THz source is momentary under commissioning – a EOS measuring station for bunch length measurements is locate right behind the second super conducting Linac. Measuring with a crystal in the vicinity of an up to 2 mA cw beam implies higher beam loss and also higher radiation exposure of the crystal and hence also a safety risk for the UHV conditions of the super conducting cavities in the case of crystal damage. Therefore the EOS measuring principle is adapted to larger measuring distances and also for beam requirements with lower bunch charge at ELBE. A description of the setup, considerations of special boundary conditions and as well results for 13 MHz cw beam operation are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME109

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME112

Design of a Compact Setup to Measure Beam Energy by Detection of Compton Backscattered Photons at ANKA

photon, electron, background, detector

3494

C. Chang, D. Batchelor, E. Hertle, E. Huttel, V. Judin, A.-S. Müller, A.-S. Müller, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
One of the most important parameters of accelerators is their beam energy. So far, the method of resonant depolarization was used to accurately determine the energy at 2.5 GeV of the ANKA electron storage ring, which, however, becomes cumbersome for lower energies. A good alternative is the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam. To achieve compactness and integration into the storage ring, the setup of transverse scattering is proposed instead of conventional head-on collision. The feasibility has been studied by comparison between simulations of Compton backscattered photons by AT and CAIN 2.35 and actual measurement of background radiation with an HPGe (High Purity Germanium) spectrometer. The layout of the setup is also included in the paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME112

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME118

A Freon-filled Bubble Chamber for Gamma-ray Detection in Strong Laser-plasma Interaction

photon, electron, plasma, detector

3512

W.B. Zhao, J.E. Chen, C. Lin, L.H.Y. Lu, X.Q. Yan, Y.Y. Zhao, B.Y. Zou
PKU, Beijing, People's Republic of China

When a laser pulse with focused intensity exceeding 1018W/cm² interacts with a solid target, electrons in the focal spot are accelerated to relativistic velocity and where they generate inner-shell vacancies and hard x-ray(>10 keV) spectral line and Bremsstrahlung radiation. In laser plasma interactions, the resonance between betatron motion of electrons and ultraintense laser pulses is an interesting phenomenon in both electron acceleration and gamma photon production. Even though the gamma-ray synchrotron is micron scale, the energy ranges from ~1 MeV to ~102MeV. To detect the energy of the gamma-ray accurately is particularly significant. Owing to a lot of various energy of gamma-ray are emitted in femtosecond scale, which are impossible distinguished from each other on the time. A small freon-filled bubble chamber is being built to measure the energy spectrum of high-energy photons. After that, we can calculate the electron’s energy and then offer the data for various of electron acceleration theories. It combines a good spatial resolution with a large depth of field, allowing a large number of tracks. This improves the statistical quality of the photon spectrum.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME118

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME123

Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

electron, simulation, linac, gun

3527

A. Borysenko, E. Hertle, N. Hiller, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, P. Wesolowski
KIT, Karlsruhe, Germany
B. Steffen
DESY, Hamburg, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP crystal. Simulations of the electro-optic signal for different operation modes of FLUTE were performed and main challenges are discussed in this talk. This work is funded by the European Union under contract PITN-GA-2011-289191

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME123

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME132

Generation and Diagnosis of Ultrashort Electron Bunches from a Photocathode RF Gun Linac

electron, detector, linac, gun

3553

I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
H. Kobayashi
KEK, Ibaraki, Japan

Ultrashort electron bunches are essential for time-resolved measurement methods such as pulse radiolysis* from the viewpoint of time resolutions. On the other hand, generation of electro-magnetic wave in the THz range using short electron bunches has been investigated**. Frequency spectra of coherent transition radiation (CTR) emitted by an electron bunch depend on bunch form factor (BFF), which is expressed by Fourier coefficients of longitudinal distribution in the electron bunch. In this study, the bunch length measurement was demonstrated by analyzing THz-waves generated by CTR. Femtosecond electron bunches were generated by a laser photocathode RF gun linac and magnetic bunch compressor. THz-waves generated by CTR, which was emitted on an interface of an aluminum mirror along the beam trajectory, were transported to a Michelson interferometer. The bunch length was measured by analyzing interferogram, which was an infrared detector output as a function of a moving mirror position. Finally, the bunch length was measured according to fitting curves for the interferogram near the centerburst***. Minimum bunch length of 1.3 fs was obtained at a bunch charge of ~1 pC.
*J. Yang et al., Nucl. Instrum. Meth. A 556, 52 (2006).
**K. Kan et al., Appl. Phys. Lett. 99, 231503 (2011).
***A. Murokh et al., Nucl. Instrum. Meth. A 410 (1998).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME132

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME169

Status of the New Beam Size Monitor at SLS

alignment, emittance, optics, radiation

3662

J. Breunlin, Å. Andersson
MAX-lab, Lund, Sweden
N. Milas
LNLS, Campinas, Brazil
M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun
PSI, Villigen PSI, Switzerland

The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required a beam size monitor with the ability to verify a sub-pmrad vertical emittance. This corresponds to a beam height of less than 4 μm. Within the TIARA Work Package ‘SLS Vertical Emittance Tuning’ a new beam size monitor was designed and built. The monitor is based on the imaging of the pi-polarized synchrotron radiation (SR) in the visible and UV spectral ranges. Besides imaging the monitor provides interferometric methods using vertically or horizontally polarized SR. With these complementary methods the consistency of beam size measurements is verified. An intermediate configuration of the monitor beamline using a lens as the focusing element has been commissioned in 2013. With this setup a vertical beam size of 4.8±0.5 μm, corresponding to a vertical emittance of 1.7±0.4 pmrad has been measured. During 2014 the monitor was commissioned in its final configuration with a toroidal mirror. The use of reflective optics allows wider bandwidth imaging and thus higher intensity. We report on challenges during commissioning and present first images of SR taken with the toroidal mirror.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME169

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME190

A Fibre Coupled, Low Power Laserwire Emittance Scanner at CERN LINAC4

emittance, linac, detector, background

3725

S.M. Gibson, G.E. Boorman, A. Bosco, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann, F. Roncarolo
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The new LINAC4 will accelerate H⁻ ions to 160 MeV and ultimately replace the existing 50 MeV LINAC2 in the injector chain for the LHC upgrade. During commissioning in 2013, a laserwire scanner and diamond strip detector were installed for non-invasive emittance measurements of the 3 MeV H⁻ beam. Synergy with the 3 MeV H⁻ Front End Test Stand at RAL, has stimulated collaborative development of a novel laserwire system. A low peak power (8kW) pulsed laser is fibre-coupled for remote installation and alignment free operation. Motorized focusing optics enable remote control of the thickness and position of the laserwire delivered to the vacuum chamber, in which the laser light neutralises a small fraction of H⁻ ions. Undeflected by a dipole magnet, these H atoms drift downstream, where their spatial profile is recorded by a highly sensitive diamond strip detector with ns-time resolution. We present first tests of the laserwire emittance scanner, including measurements of the photo detachment signal with respect to the background from residual gas interactions. The first laserwire transverse beam profile and emittance measurements are compared with conventional slit-grid diagnostics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME190

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME191

Simulation Results of the FETS Laserwire Emittance Scanner

ion, detector, emittance, simulation

3729

K.O. Kruchinin, A. Bosco, S.M. Gibson, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
D.C. Faircloth
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) has been developed to demonstrate a high current (60 mA) H⁻ beam with the energy of 3 MeV that will be required for future proton drivers. At such high power beam machine a non-invasive diagnostics is required. To measure the emittance of the ion beam a laserwire scanner is being developed. A high power laser will scan across the H⁻ ion beam. The H⁻ particles will be neutralized via a photo-detachment process producing a stream of fast neutral hydrogen atoms bearing information about the phase space distribution of the initial H⁻ beam. To design an effective detection system and optimize its parameters a simulation of the processes at the interaction point is required. We present recent simulation results of theц FETS laserwire system. Simulations were performed using measured data of the laser propagation and ion beam distribution, obtained with General Particle Tracer code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME191

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME192

Assembly and Installation of Beam Instrumentation for the ASTA Front-end Diagnostic Table

diagnostics, target, gun, electron

3732

D.J. Crawford, R. Andrews, B.J. Fellenz, D. Franck, T.W. Hamerla, J. Ruan, D. Snee
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Early stages of commissioning the Advanced Superconducting Test Accelerator (ASTA) at Fermilab have begun. The Front-end consists of a 1.5 cell normal conducting RF gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a Diagnostic Table upon which instrumentation is mounted for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience with the Diagnostic Table.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME192

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME193

GUI Development for the Drive Laser at Fermilab's ASTA Facility

controls, gun, status, interface

3735

D.R. Edstrom, E.R. Harms, T.R. Johnson, A.H. Lumpkin, J. Ruan, J.K. Santucci
Fermilab, Batavia, Illinois, USA

A comprehensive set of graphical user interfaces is being developed for the drive laser of the Advanced Superconducting Test Accelerator (ASTA) facility at Fermilab. These interfaces have been designed in Synoptic, a Java-based GUI development platform with credential-dependent access to the Fermilab accelerator controls network. Such implementation facilitates the user's ability to monitor and control many aspects of the drive laser system in an intuitive environment, as well as timely updates on the part of the developers made necessary by the evolving drive laser system. Furthermore, the current interface hierarchy readily allows integration into the larger pool of Synoptic applications being developed for other subsystems at ASTA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME193

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI074

Colorado State University (CSU) Accelerator and FEL Facility

electron, controls, linac, undulator

3937

S. Biedron, C. Carrico, A. D'Audney, J.P. Edelen, J. Einstein, C.C. Hall, J.R. Harris, K. Horovitz, J. Martinez, S.V. Milton, A.L. Morin, N. Sipahi, T. Sipahi, J.E. Williams, P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA
P.J.M. van der Slot
Mesa+, Enschede, The Netherlands
P.J.M. van der Slot
Twente University, Laser Physics and Non-Linear Optics Group, Enschede, The Netherlands

The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI074

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI076

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

gun, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI076

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI091

Machine Protection Considerations for BERLinPro

electron, linac, vacuum, diagnostics

3985

S. Wesch, M. Abo-Bakr, M. Dirsat, G. Klemz, P. Kuske, A. Neumann, J. Rahn, T. Schneegans
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
The Berlin energy-recovery-linac project BERLinPro at the HZB is a 50 MeV ERL test facility, which addresses physical and technological questions for future superconducting rf based high brightness, high current electron beam sources. The combination of a 100 mA cw beam, electron bunches with normalized emittances lower than 1 mm mrad and the magnet optics of BERLinPro leads to power densities capable to harm the accelerator components within microseconds if total beam loss occurs. Furthermore, continuous beam loss on the level of 10^-5 has to be controlled to avoid activation and to protect the SRF, beam diagnostics and other infrastructure components. In this paper, we present the evaluation of the required key parameters of the BERLinPro machine protection system and present its first conceptual design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI091

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI109

Auto-alignment Status of the Taiwan Photon Source

alignment, controls, experiment, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI109

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRYBA01

Long-term Accelerator R&D as an Independent Research Field

electron, plasma, SRF, acceleration

4073

R. Brinkmann
DESY, Hamburg, Germany

High energy physics projects have been important drivers of accelerator R&D for several decades. The resulting accelerator technology was used to construct frontier accelerators for HEP but was also very successfully applied in accelerators for other science fields, in particular photon science, nuclear physics, medical applications, … Fewer HEP projects and at the same time a growing number of projects in other areas require a modified approach to accelerator R&D. Efforts and progress to perform accelerator R&D as an independent research program with its own, independent funding are described for the example of the Helmholtz ARD program in Germany. Links to efforts in other countries are discussed and an outlook to future accelerator research is given.

Slides FRYBA01 [3.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-FRYBA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)