IPAC2013 - List of Keywords (laser)

Paper	Title	Other Keywords	Page
MOYBB101	Review of Laser Wakefield Accelerators	electron, plasma, injection, wakefield	11
	V. Malka LOA, Palaiseau, France
	Funding: European Research Council for funding the PARIS ERC project (Contract No. 226424). EC FP7 LASERLABEUROPE/ LAPTECH (Contract No. 228334) EuCARD/ANAC, EC FP7 (Contract No. 227579) This review talk will highlight the tremendous evolution of the research on laser wakefield accelerators* that has, in record time, led to the production of high quality electron beams beyond the GeV level, using compact laser systems. I will describe the path we followed to explore different injection schemes (bubble, colliding laser pulses, injection in gradient, longitudinal and transverse, ionisation injection) and I will present the most significant breakthroughs which allowed to generate stable, high peak current and high quality electron beams, with control of the charge, of the relative energy spread and of the electron energy. Modelling and experimental results will be as well reported with examples of applications*. V. Malka, Physics of Plasmas 19, 055501 (2012) ** V. Malka et al., Nature Physics 4, 447 (2008)
	Slides MOYBB101 [14.550 MB]

MOODB101	Manufacturing of the First of Series SIS100 Dipole Magnet	dipole, synchrotron, instrumentation, magnet-design	31
	St. Sattler, W. Gärtner, Dr. Scheller, R. Schönbein, W. Walter BNG, Würzburg, Germany E.S. Fischer, J.P. Meier, H. Müller, P. Schnizer GSI, Darmstadt, Germany
	Babcock Noell (Würzburg, Germany) manufactures the First of Series (FOS) SIS100 dipole magnet for the FAIR project. This contribution reports on the progress during the design-phase, performed together with GSI, and on the manufacturing- and assembly-processes. Special emphasis will be given on new or special techniques adopted to fulfill the stringent requirements demanded by such a magnet. The new tooling systems and machines which were developed and brought into operation for this FOS magnet will be discussed.

MOPEA014	Temporal and Spectral Observation of Laser-induced THz Radiation at DELTA	electron, radiation, storage-ring, simulation	94
	P. Ungelenk, H. Huck, M. Huck, M. Höner, S. Khan, R. Molo, A. Schick DELTA, Dortmund, Germany N. Hiller, V. Judin KIT, Karlsruhe, Germany
	Funding: Work supported by the DFG, the BMBF, the Federal State NRW, the Initiative and Networking Fund of the Helmholtz Association, and the German Federal Ministry of Education and Research. Coherent THz pulses caused by a laser-induced density modulation of the electron bunches are routinely produced and observed at DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University. New measurements performed with a fast hot-electron bolometer allow insight into the turn-by-turn evolution of these pulses. Furthermore, first results from a Fourier transform infrared spectrometer, which is currently under commissioning, are presented.

MOPEA022	Beam Profile Measurement for High Intensity Electron Beams	electron, scattering, photon, diagnostics	118
	T. Weilbach, K. Aulenbacher, M.W. Bruker HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany
	Recent developments in the field of high intensity electron beams in the regime below 10 MeV, e.g. energy recovery linacs or magnetized high energy electron coolers, have led to special demands on the beam diagnostics. Since commonly used diagnostic tools like synchrotron radiation and scintillation screens are ineffective or not able to withstand the beam power without being damaged, new methods are needed. Hence a beam profile measurement system based on beam induced fluorescence (BIF) was built. This quite simple system images the light generated by the interaction of the beam with the residual gas onto a PMT. A more elaborated system, the Thomson Laser Scanner (TLS) - the non-relativistic version of the Laser Wire Scanner - is proposed as a method for non-invasive measurement of all phase space components, especially in the injector and merger parts of an ERL. Both methods are implemented in a 100 keV photo gun. Beam profile measurements with BIF as well as first results of the TLS will be presented.

MOPFI001	Characterization of a Superconducting Pb Photocathode in a SRF Gun Cavity	cathode, gun, cavity, electron	279
	R. Barday, T. Kamps, O. Kugeler, A. Neumann, M. Schmeißer, J. Völker HZB, Berlin, Germany P. Kneisel JLAB, Newport News, Virginia, USA R. Nietubyć NCBJ, Świerk/Otwock, Poland J.K. Sekutowicz DESY, Hamburg, Germany J. Smedley BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Bundesministerium für Bildung und Forschung and Land Berlin. The Pb deposition activity is supported by EuCARD. Photocathodes are a limiting factor for the next generation of ultra-high brightness photoinjector driven accelerators. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting rf gun cavity related to the quantum efficiency, its spatial distribution and the work function. Cathode surface contaminations can modify the performance of the photocathodes as well as the gun cavity. We discuss the possibilities to remove these contaminations.

MOPFI002	Results from Beam Commissioning of an SRF Plug-gun Cavity Photoinjector	cavity, emittance, cathode, gun	282
	M. Schmeißer, R. Barday, A. Burrill, A. Jankowiak, T. Kamps, J. Knobloch, O. Kugeler, P. Lauinger, A. Neumann, J. Völker HZB, Berlin, Germany P. Kneisel JLAB, Newport News, Virginia, USA R. Nietubyć NCBJ, Świerk/Otwock, Poland J.K. Sekutowicz DESY, Hamburg, Germany I. Will MBI, Berlin, Germany
	Superconducting rf photoelectron injectors (SRF guns) hold the promise to deliver high brightness, high average current electron beam for future lightsources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid Pb coated plug-gun Nb cavity based SRF photoinjector for beam energies up to 3 MeV at Helmholtz-Zentrum Berlin. Emittance measurements and transverse phase space characterization with solenoid-scan and pepperpot methods will be presented.

MOPFI006	A New Load Lock System for the Source of Polarised Electrons at ELSA	electron, polarization, vacuum, ion	294
	D. Heiliger, W. Hillert, B. Neff ELSA, Bonn, Germany
	Funding: supported by DFG (SFB/TR16) The inverted source of polarized electrons at the electron stretcher accelerator ELSA routinely provides a pulsed beam with a current of 100 mA and a polarization degree of about 80%. One micro-second long pulses with 100 nC charge are produced by irradiating a GaAs strained-layer superlattice photocathode (8 mm in diameter) with laser light. Future accelerator operation requires a significantly higher beam intensity, which can be achieved by using photocathodes with sufficiently high quantum efficiency. Therefore, and in order to enhance the reliability and uptime of the source, a new extreme high-vacuum (XHV) load lock system was installed and commissioned. It consists of a loading chamber in which an atomic hydrogen source is used to remove any remaining surface oxidation, an activation chamber for heat cleaning of the photocathodes and activation with cesium and oxygen and a storage chamber in which up to five different types of photocathodes with various diameters of the emitting surface can be stored under XHV conditions. Additionally, tests of the photocathodes' properties can be performed during accelerator operation.

MOPFI013	A Lifetime Study of CsK2Sb Cathode	cathode, electron, vacuum, brightness	309
	M. Kuriki, H. Iijima, K. Miyoshi, N. Norihito HU/AdSM, Higashi-Hiroshima, Japan
	Funding: Cooperative and Supporting Program for Researches and Educations in　Universities by High energy accelerator research organization (KEK) CsK2Sb multi-alkali cathode is one of the candidates of robust and high efficiency cathode for high brightness electron source. CsKSb can be driven by green laser and it is a big advantage comparing to Cs2Te cathode which is widely used as a robust photo-cathode and driven by UV light. In Hiroshima University, a test chamber for CsK2Sb photo-cathode study is developed. In the chamber, CsK2Sb photo-cathode is formed by evaporation on SUS base plate. During the evaporation, amount is monitored by quartz meter. We devised good locations of the evaporation source, base plate, and thickness monitor, so that all evaporation processes for Cs, K, and Sb are under control. The base plate temperature is also controlled during the cathode formation. More than 2.0% quantum efficiency was achieved at the first activation test. The cathode lifetime was more than 200 hours and more than 20C in charge. The latest experimental result will be reported.

MOPFI019	Beam Generation from a 500 kV DC Photoemission Electron Gun	gun, cathode, electron, high-voltage	321
	N. Nishimori, R. Hajima, S.M. Matsuba, R. Nagai JAEA, Ibaraki-ken, Japan Y. Honda, T. Miyajima, M. Yamamoto KEK, Ibaraki, Japan H. Iijima, M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan M. Kuwahara Nagoya University, Nagoya, Japan
	Funding: This work is supported by MEXT Quantum Beam Technology Program and partially supported by JSPS Grants-in-Aid for Scientific Research in Japan (23540353). The next generation light source such as X-ray FEL oscillator requires high brightness electron gun with megahertz repetition rate. We have developed a DC photoemission electron gun at JAEA for the compact energy recovery linac (cERL) light source under construction at KEK. This DC gun employs a segmented insulator with guard rings to protect the insulator from field emission generated from central stem electrode. We have successfully applied 500-kV on the ceramics with a cathode electrode in place and generated beam from the 500kV DC photoemission gun in October 2012. Details of the beam generation test will be presented.

MOPFI023	Development of Better Quantum Efficiency and Long Lifetime Iridium Cerium Photocathode for High Charge electron RF Gun	cathode, electron, gun, linac	327
	D. Satoh TIT, Tokyo, Japan N. Hayashizaki RLNR, Tokyo, Japan M. Yoshida KEK, Ibaraki, Japan
	We developed an Ir5Ce photocathode as a high charge electron source for SuperKEKB electron linac. The required electron beam parameters are 5 nC and 10 mm•mrad from the electron gun of the SuperKEKB electron linac. We plan to generate this electron beam using a laser-driven RF gun installed with a photocathode that has a long lifetime and a high-power laser system through more than a year without replacement. Therefore, we focused on the Ir5Ce compound as a new photocathode which has a high melting point (> 2100 K) and a low work function (2.57 eV). The results of measurements showed that the quantum efficiency of Ir5Ce photocathode was 1.0×10^-4 treated by the laser cleaning using the 4nd harmonic of Nd:YAG laser or the heater treatment. Furthermore, its photoemission properties could be maintained for a long term even if its photocathode was in the low vacuum conditions ( ～10^-6 Pa) since the Ir5Ce compound is far less contaminated than other photocathodes. Finally, We have succeed to generate electron beams of 4.4 nC by the Ir5Ce photocathode installed at the 3-2 sector DAW type RF gun and accelerate it through a linac end in KEK electron linac.

MOPFI024	Ultra-short Electron Bunch Generation by an ECC RF Gun	gun, electron, radiation, cathode	330
	Y. Koshiba, T. Aoki, M. Mizugaki, K. Sakaue, M. Washio Waseda University, Tokyo, Japan T. Takatomi, J. Urakawa KEK, Ibaraki, Japan
	Funding: Work supported by JSPS Grant-in-Aid for Young Scientists (B) 23740203 and Scientific Research (A) 10001690 Energy Chirping Cell attached rf gun (ECC rf gun) is a photocathode rf gun specialized for ultra-short bunch generation. This ECC rf gun has been made with the collaboration of High Energy Accelerator Research Organization (KEK). Although the bunch length could be controlled by the laser pulse width, the bunch length ends up to be more than 1ps due to space charge effect when using a femto-second laser and a normal 1.6 cell cavity. Concerning this phenomenon, ECC is attached right after the 1.6 cell so that the electron bunch would be compressed after the electron bunch is accelerated around 5MeV. The roll of ECC is to chirp the energy with the linear part of the rf electric field. The electron bunch would be compressed by velocity difference as it drifts. Simulation results from PARMELA and GPT show that ECC rf gun can accelerate an 100pC bunch with the bunch length less than 100fs. We already manufactured this ECC rf gun and installed in our system. We demonstrated the ultra-short bunch by measuring the coherent THz light by synchrotron radiation and transition radiation. In this conference, we will report the results of ultra-short bunch generation experiments, and future plans.

MOPFI038	Generation and Measurement of Sub-picosecond Electron Bunch in Photocathode RF Gun	electron, radiation, emittance, acceleration	372
	W.W. Li, Z.G. He, R. Huang, Q.K. Jia, G. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	The generation of subpicosecond electron bunch in the photocathode rf gun was considered and simulated by improving the acceleration gradient of the gun, suitably tuning the charge of the electron bunch and the acceleration phase. To measure the length of the electron bunch, the design of a nondestructive bunch length measurement technology was also presented in this paper.

MOPFI058	Studies of Cs3Sb Cathodes for the CLIC Drive Beam Photoinjector Option	cathode, gun, electron, vacuum	413
	I. Martini, E. Chevallay, S. Döbert, V. Fedosseev, C. Heßler, M. Martyanov CERN, Geneva, Switzerland
	Within the CLIC (Compact Linear Collider) project, feasibility studies of a photoinjector option for the drive beam as an alternative to its baseline design using a thermionic electron gun are on-going. This R&D program covers both the laser and the photocathode side. Whereas the available laser pulse energy in ultra-violet (UV) is currently limited by the optical defects in the 4th harmonics frequency conversion crystal induced by the 0.14 ms long pulse trains, recent measurements of Cs3Sb photocathodes sensitive to green light showed their potential to overcome this limitation. Moreover, using visible laser beams leads to better stability of produced electron bunches and one can take advantages of the availability of higher quality optics. The studied Cs3Sb photocathodes have been produced in the CERN photoemission laboratory using the co-deposition technique and tested in a DC gun set-up. The analysis of data acquired during the cathode production process will be presented in this paper, as well as the results of life-time measurements in the DC gun.

MOPFI062	Optimization Studies for the SwissFEL RF-Gun	gun, cathode, emittance, solenoid	425
	M. Schaer, A. Adelmann, A. Anghel, S. Bettoni, P. Craievich, L. Stingelin, C. Vicario, R. Zennaro PSI, Villigen PSI, Switzerland Z. Zhang TUB, Beijing, People's Republic of China
	The 250 MeV SwissFEL injector test facility is in operation since August 2010. Measurements with the "CTF2 Gun 5" photocathode S-band rf-gun show promising beam parameters and satisfy the requirements of the SwissFEL project. Since the performance of the electron source is fundamental for the stability and brightness of a free electron laser, further gun optimization studies are pursued. Under investigation is currently a 3.6 cell C-band gun. First ASTRA simulations indicate that with this gun the peak-current can be increased, thanks to a shorter laser pulse and a higher initial acceleration, by almost a factor of two, at slightly better emittance values than the S-band "PSI Gun 1". Since the beam-quality depends also on the achieved performance of the cathode, several copper cathodes had been tested in the SwissFEL injector test facility to analyze the observed rapid degradation of quantum efficiency.

MOPFI065	VELA (formerly EBTF) Simulations and First Beam Commissioning	gun, diagnostics, simulation, electron	431
	J.W. McKenzie, D. Angal-Kalinin, J.K. Jones, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	VELA (Versatile Electron Linear Accelerator), formerly known as EBTF (Electron Beam Test Facility), at STFC Daresbury Laboratory, is a photoinjector test facility which will provide beam into two user areas for scientific and industrial applications. It is based on a 2.5 cell S-band RF photoinjector driven by a Ti:Sapphire laser. The design is aimed to deliver short bunches at 10-250 pC charge with low transverse emittance. We present beam dynamics simulations of VELA as well as the results from first beam commissioning.

MOPFI068	High Repetition Rate Highly Stable S-band Photocathode Gun for the CLARA Project	gun, cavity, electron, cathode	437
	B.L. Militsyn, L.S. Cowie, P. Goudket, S.P. Jamison, J.W. McKenzie, K.J. Middleman, R. Valizadeh, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom V.V. Paramonov RAS/INR, Moscow, Russia M.D. Roper STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Compact Linear Accelerator for Research and Applications (CLARA) is a 250 MeV electron facility which is under development at STFC ASTeC. The CLARA photo-injector is based on a RF photocathode gun operating with metal photocathodes and driven by a third harmonic of Ti: Sapphire laser (266 nm). The injector will be operated with laser pulses with an energy of up to 2 mJ, pulse durations down to 180 fs FWHM and a repetition rate of up to 400 Hz. In order to investigate performance of different photocathodes the gun is equipped with a load-lock system which would allow replacement of the photocathodes. Duration and emittance of electron bunches essentially depends on the mode of operation and vary from 0.1 ps at 20 pC to 5 ps at 200 pC and from 0.2 to 2 mm mrad respectively. Requirements for the stability of beam arrival time at the CLARA experimental area are extremely high and vary from hundreds down to tenths femtoseconds. In the presented article we analyse stability of the guns with 1.5 and 2.5 cell and the beam quality delivered by a gun with coaxial and waveguide coupler and analyse possibility of injection time stabilisation with low level RF and optical feedback system.

MOPFI074	Ultracold and High Brightness Electron Source for Next Generation Particle Accelerators	electron, plasma, brightness, emittance	452
	G.X. Xia, R. Appleby, W. Bertsche, M.A. Harvey UMAN, Manchester, United Kingdom S. Chattopadhyay STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom A.J. Murray The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
	The ultra-cold plasma-based electron source has recently been proposed as an alternative to the conventional photoemitters or thermionic electron guns, which are widely used in today’s particle accelerators. The advantages of the ultra-cold plasma-based electron source lie in the fact that the electron beam extracted from the cold plasma (from ionization of cold atoms) has very low electron temperature, e.g. down to 10 K, and has the potential for producing high brightness and ultra-short electron bunches. All these features are crucial for the next generation particle accelerators, e.g. free electron lasers, plasma-based accelerators and the future linear colliders. In this paper, we will introduce our proposed facility on cold electron source based at Photon Science Institute (PSI) in the University of Manchester.

MOPFI076	Electron Emission Studies in the New High-charge Cs2Te Photoinjector at Argonne National Laboratory	gun, cathode, wakefield, factory	455
	E.E. Wisniewski, M.E. Conde, W. Gai, C.-J. Jing, W. Liu, J.G. Power ANL, Argonne, USA L.K. Spentzouris, Z.M. Yusof Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: This work was funded by the U.S. Dept. of Energy Office of Science under contract number DE-AC02-06CH11357. A new L-band 1.3 GHz 1.5 cell gun for the new 75 MeV drive beam is being commissioned and will soon be operating at the Argonne Wakefield Accelerator (AWA) facility as part of the facility upgrade (see M. E. Conde, this proceedings.) The photoinjector is high-field (peak accelerating field > 80MV/m) and has a large \mathrm{Cs}₂\mathrm{Te} photocathode (diameter > 30 mm) fabricated in-house. The photoinjector generates high-charge, short pulse, single bunches (Q > 100 nC) or bunch-trains (Q ≈ 1000 nC) for wakefield experiments. Field emission from the \mathrm{Cs}₂\mathrm{Te} cathode is to be measured during RF conditioning and benchmarked against measurements from a copper cathode. Quantum efficiency (QE) will be measured in single and multi-bunch modes. Preliminary results are presented.

MOPFI078	The Possibility of Generation of High Energy Electron Beam at the SNS Facility	electron, acceleration, linac, solenoid	458
	T.V. Gorlov, A.V. Aleksandrov, V.V. Danilov ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725 The linac of the SNS accelerator facility can be used to produce an electron beam with 300-400 MeV energy. At present there are a few predesigned experiments with electron beam that can be alternatively carried out at the SNS. However, the SNS linac is designed and optimized for acceleration of H⁻ , which brings some problems when considering direct acceleration of electrons. Alternative machine setup for electron acceleration and transport are discussed. Here, we present a study of the optimal electron beam parameters that can be achieved without any significant changes of the SNS accelerator.

MOPFI080	Fabrication, Transport and Characterization of Cesium Potassium Antimonide Cathode in Electron Guns	cathode, gun, vacuum, SRF	461
	T. Rao, S.A. Belomestnykh, I. Ben-Zvi, X. Liang, I. Pinayev, B. Sheehy, J. Skaritka, J. Smedley, E. Wang, T. Xin BNL, Upton, Long Island, New York, USA R.R. Mammei, J.L. McCarter, M. Poelker JLAB, Newport News, Virginia, USA M. Ruiz-Osés Stony Brook University, Stony Brook, USA
	a number of accelerator applications need high current, low emittance and high brightness electron beams. Recent studies have shown cesium potassium antimonide to be a robust photocathode capable of producing high peak and average currents. However, for some applications, the UHV conditions required for producing these cathodes necessitate their fabrication site to be physically removed from the gun location and the cathode to be transferred between the two sites in UHV load-lock chambers. We have fabricated two cathodes at BNL, transported and tested them in DC gun at JLab at 100 kV and 200 kV. These cathodes have delivered up to 8A/cm² without significant degradation. Localized changes in the QE have been attributed to heating due to laser, increasing the QE at lower laser power, but damaging the cathode at higher power. Two more load-lock chambers have been built to transport and insert similar cathodes in SRF guns operating at 700 MHz and 112 MHz for the first time. In this paper, we will describe the design of the load-lock chambers, transfer mechanisms, transport of the cathodes over ~ 1000 km and the cathode performance in gun environment.

MOPME005	Goubau Line and Beam Characterization of TURBO-ICT for SwissFEL	instrumentation, FEL, resonance, electron	476
	S. Artinian, J.F. Bergoz, F. Stulle BERGOZ Instrumentation, Saint Genis Pouilly, France P. Pollet, V. Schlott PSI, Villigen PSI, Switzerland
	SwissFEL will be able to operate with electron bunch doublets 28ns apart. Each of the bunches carries 10pC to 200pC of charge with bunch lengths of a few femto-seconds. For charge calibration of the FEL photon pulses, a measurement accuracy of 1% is desired. The Turbo-ICT accomplishes these requirements with negligible beam position and bunch length dependence. It is insensitive to dark current and features high immunity to background noise. We characterize the Turbo-ICT performance on a Goubau line, also known as single-wire transmission line. The Goubau line utilizes electromagnetic fields with frequencies up to many GHz. It allows accurate bench testing including beam position and bunch length dependence. The results are compared to beam measurements performed at the SwissFEL Injector Test Facility (SITF).

MOPME008	Beam Diagnostics by Using Bunch-by-bunch Feedback Systems at the DELTA Storage Ring	feedback, injection, kicker, electron	485
	M. Höner, H. Huck, M. Huck, S. Khan, R. Molo, A. Schick, P. Ungelenk DELTA, Dortmund, Germany
	Funding: Work supported by BMBF (05K10PEB) At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, longitudinal and transverse bunch-by-bunch feedback systems are in use to detect and suppress multi-bunch instabilities. Besides that, the digital feedback systems are excellent diagnostics tools. As an example, by exciting a certain number of bunches within the bunch train, the coupling to the non-excited bunches can be investigated below and above the instability threshold. Other examples include studies of the injection process and monitoring bunch oscillations during sudden beam loss. First experimental results will be presented in this paper.

MOPME014	Electro-optical Bunch Length Measurements at the ANKA Storage Ring	electron, wakefield, storage-ring, background	500
	N. Hiller, A. Borysenko, E. Hertle, E. Huttel, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, A. Plech, M. Schuh, S.N. Smale KIT, Karlsruhe, Germany P. Peier, V. Schlott PSI, Villigen PSI, Switzerland B. Steffen DESY, Hamburg, Germany
	Funding: Supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320 and by the German Federal Ministry of Education and Research under contract number 05K10VKC A setup for near-field electro-optical bunch length measurements has recently been installed into the UHV system of the ANKA storage ring. For electro-optical bunch length measurements during ANKA's low alpha operation, a laser pulse is used to probe the field induced birefringence in an electro-optical crystal (GaP in our case). The setup allows for both electro-optical sampling (EOS, multi-shot) and spectral decoding (EOSD, single- and multi-shot) measurements. This paper presents first results and discusses challenges of this method employed for the first time at a storage ring.

MOPME015	Numerical Wakefield Calculations for Electro-optical Measurements	simulation, wakefield, storage-ring, impedance	503
	B. Kehrer, A. Borysenko, E. Hertle, N. Hiller, V. Judin, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh KIT, Karlsruhe, Germany
	Funding: This project is funded by the Federal Ministry of Education and Research under the contract number 05K10VKC The technique of electro-optical measurements allows precise and single-shot measurements of the bunch length and shape. The installation of such a near-field setup changes the impedance of the storage ring and the corresponding effects have to be studied carefully. One possibility is to use numerical codes for simulating the wakefields induced by the setup. Such simulations has been done using the wakefield solver implemented in the CST Studio Suite. In this paper we present the simulation results together with first measurements.

MOPME029	Multi-strip Current Monitor for Pulsed Laser Plasma Diagnostics	plasma, ion, rfq, target	538
	Y. Fuwa, Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan M. Okamura BNL, Upton, Long Island, New York, USA
	A compact position-sensitive beam instrumentation devise is under development. The beam detection area of this devise is composed of multi-strip electrodes and scanned by multiplexers, which reduces the number of read-out lines and feed-through connectors. Combined with an electrostatic deflector and ToF information, this monitor can discriminate charge to mass ratios of particles. A prototype of this monitor is fabricated for measurement of ion distribution and charge state in laser induced plasma. This model has fifteen strip electrodes and the multiplexed signal and the clock signal are read out through two coaxial cables. Thus, only three cables are needed including a +5V power supply line. The test result will be presented.

MOPME036	Prototype Experiment Preparation of a 54.167MHz Laser Wire System for FEL-THz Facility at CAEP	electron, photon, FEL, cathode	550
	D. Wu TUB, Beijing, People's Republic of China W. Bai, M. Li, H. Wang, J. Wang, X. Yang CAEP/IAE, Mianyang, Sichuan, People's Republic of China
	In this paper, a prototype experiment preparation of a 54.167 MHz laser wire system is presented, which will be used to measure the beam size of a CW DC gun built as an electron source of FEL-THz facility in China Academmy of Engineering Physics (CAEP). The rms beam size is less than 1 mm and the average current of the electron beam is more than 1 mA. This new-type LW system ultilizes the excess power other the photocathode drive laser and becomes much cheaper and simpler. Plus, it can distinguish beams with different energies which are very close in ERLs. The system layout and the simulation results are also presented.

MOPME060	Introduction to Beam Diagnostics Components for PAL-ITF	electron, diagnostics, gun, radiation	610
	H. J. Choi, M.S. Chae, J.H. Hong, C. Kim, D.T. Kim, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory (PAL) is building the 4th generation X-ray free electron laser (XFEL). The Injection Test Facility (ITF) is a test facility established to improve the functions of the laser gun and pre-injector to be installed in XFEL. To improve the effects of ITF, two factors are required. The first is to be able to generate low-emittance electron beams stably at the laser gun, and the second is to control increasing emittance by space charge effect by accelerating electron beams with high energy at the pre-injector. In this way, high-quality electron beams can be materialized. Various beam diagnostics are installed in the accelerator system for beam diagnostics and measurements. Five kinds of beam diagnostics were installed in the PAL-ITF. These are (1) ICT and (2) Faraday Cup to measure current and electrons charge, (3) Stripline BPM to measure the location of beams, (4) a YAG/OTR Screen Monitor to measure beam energy and transverse profile motion and (5) a Wire Scanner to measure beam size. In this paper, the purposes and properties of each diagnostic unit and measurement results are introduced.

MOPME061	Femtosecond e-bunch Length Measurement at fs-THz Accelerator at PAL	radiation, electron, linac, gun	613
	J.H. Ko, I.S. Ko POSTECH, Pohang, Kyungbuk, Republic of Korea H.-S. Kang PAL, Pohang, Kyungbuk, Republic of Korea
	Longitudinal distribution of femto-second electron beam has been evaluated by the coherent transition radiation Michelson interferometer with the reconstruction procedure from interferograms. We measure the bunch length of the Thz Accelerator using interferogram method in Pohang Accelerator Lab and compare with the energy of transition radiation and bunch length.

MOPME075	Laser Based Stripping System for Measurement of the Transverse Emittance of H⁻ Beams at the CERN LINAC4	electron, linac, background, emittance	652
	T. Hofmann, E. Bravin, U. Raich, F. Roncarolo CERN, Geneva, Switzerland B. Cheymol ESS, Lund, Sweden
	Funding: LA3NET is funded by the European Commission under Grant Agreement Number GA-ITN-2011-289191 The new LINAC4 at CERN will accelerate H⁻ particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H⁻ ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H⁰ atoms from the main H⁻ beam. By imaging these H⁰ atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material intercepting the H⁻ beam allows the measurement of a full power H⁻ beam. This paper will focus on the general design and integration of both the laser and H⁰ detector systems.

MOPME077	Electro-0ptical Bunch Profile Measurement at CTF3	electron, photon, vacuum, polarization	658
	R. Pan, A. Andersson, W. Farabolini, A. Goldblatt, T. Lefèvre, M. Martyanov, S. Mazzoni, S.F. Rey, L. Timeo CERN, Geneva, Switzerland W.A. Gillespie, R. Pan, D.A. Walsh University of Dundee, Nethergate, Dundee, Scotland, United Kingdom S.P. Jamison STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	A new electro-optic bunch profile monitor has recently been installed in CLIC Test Facility 3 at CERN. The monitor is based on an electro-optic spectral decoding scheme which reconstructs the longitudinal profile of the electron bunch by measuring its Coulomb field. The system uses a 780 nm fibre laser system, transported over a 20m long distance to the interaction chamber, where a ZnTe crystal is positioned close to the beam. The assembly also contains a traditional OTR screen, which is coupled to a second optical line and used to adjust the temporal overlap between the laser and the electron pulse. This paper presents the detection system in detail, as well as reporting on the first measurements performed with beam.

MOPWA022	A 500 kV Pulser with Fast Risetime for EMP Simulation	high-voltage, simulation, pulsed-power, impedance	708
	W. Jia, W.Q. Chen, J.N. Li, J.P. Tang, L.S. Xie, Y.Z. Xie, G.W. Zhang NINT, Xi'an, People's Republic of China
	A fast risetime generator with 500kV rated output voltage for the electromagnetic pulse ( EMP ) effects experiment is fabricated. It mainly consists of a low inductance Marx ge nerator, a compact independent-sealed peaking capacitor, an output switch, and a small quantity of gas-sealed insulated containers. Compared with other similar pulsers mentioned in IEC 61000-4-32, the insulated containers of the generator are independent of each other in gas-sealed structure, and its number is les s than that of other pulsers. It can be used to drive a guided wave antenna directly to produce an electromagnetic environment, which conformed with the new standard for high-altitude nuclear explosion electromagnetic pulse (HEMP) developed by IEC. Output voltage produced by the generator in demo-load state can reach to 600kV. And, risetime of the waveform is 1.2ns, pulse width (FWHM) being 32ns. When the generator driving a 10m guided-wave antenna, an output voltage with a risetime of no more than 2.7ns and a FWHM of 30ns is achieved.

MOPWA041	The New SLS Beam Size Monitor, First Results	emittance, polarization, synchrotron, radiation	759
	Á. Saá Hernández, N. Milas, M. Rohrer, V. Schlott, A. Streun PSI, Villigen PSI, Switzerland Å. Andersson, J. Breunlin MAX-lab, Lund, Sweden
	Funding: This research has received funding from the European Commission under the FP7-INFRASTRUCTURES-2010-1/INFRA-2010-2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905. An extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package “SLS Vertical Emittance Tuning” of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.

MOPWA049	Status Report of the FETS Photo Detachment Emittance Instrument at RAL	ion, emittance, diagnostics, dipole	783
	C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson JAI, Egham, Surrey, United Kingdom A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom V.E. Scarpine Fermilab, Batavia, USA
	The Front End Test Stand at the Rutherford Appleton Laboratory (RAL) is being developed to demonstrate a chopped H⁻ beam of 60 mA at 3 MeV with 10% duty cycle. Due to the high beam power it is advisable to use the technique of photo detachment to avoid intrusive methods. It is intended to apply this technique to perform emittance measurements at the output of the RFQ at full power. This requires a dedicated diagnostics dipole with a special-made vacuum chamber giving room for the different beam paths necessary to install a particle detector to measure the produced neutrals. Other aspects are the beam transport and influence of the dipole and its fringe field to the beam transport Other considerations are the installation of the laser, the optics and the particle detector itself.

MOPWA053	Sub-Micrometre Resolution Laserwire Transverse Beam Size Measurement System	electron, alignment, photon, background	795
	L.J. Nevay, G.A. Blair, S.T. Boogert, V. Karataev, K.O. Kruchinin Royal Holloway, University of London, Surrey, United Kingdom A.S. Aryshev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan L. Corner, R. Walczak Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project Eu-CARD, grant agreement no. 227579 We present the results from the laserwire system at the Accelerator Test Facility 2 (ATF2) during recent operation after relocation to the virtual image point of the ATF2 final focus. The characterisation of the 150 mJ, 77 ps long laser pulses at a scaled virtual interaction point is used to deconvolve the transverse laserwire profile demonstrating a 1.16 ± 0.06 um vertical electron beam profile. Horizontal laserwire scans were used in combination with the vertical scans to measure the electron beam size using a full overlap integral model due to the problems presented by a large aspect ratio electron beam.

MOPWA063	Proposed Coherent Diffraction Radiation Measurements of Bunch Length at ASTA	radiation, electron, cryomodule, gun	822
	A.H. Lumpkin, J. Ruan, R.M. Thurman-Keup Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The feasibility of using the autocorrelation of coherent diffraction radiation (CDR) as a non-intercepting diagnostics technique for bunch length and indirectly rf phase measurements is evaluated and proposed for the Advanced Superconducting Test Accelerator (ASTA) facility under construction at Fermilab. Previous experiments on an rf thermionic cathode gun beam at 50 MeV provide a proof-of-principle reference for the ASTA injector. The ASTA injector is based on an L-band rf photocathode (PC) gun with UV pulse drive laser, two L-band superconducting accelerator structures, a chicane bunch compressor, and an electron spectrometer. The injector energy of 40-50 MeV is expected. The 3-MHz micropulse repetition rate with micropulse charges up to to 3.2 nC and 1-ps bunch lengths should generate sufficient CDR signal for standard pyroelectric detectors to be used. The CDR signals will also be evaluated as a bunch compression signal for beam-based feedback for rf phase. The technique would also be applicable at high energy in straight transport lines after the cryomodules.

MOPWA069	Time-resolved Electron Beam Position Monitor Macropulse Waveform Measurement in MkV Linear Accelerator at University of Hawaii Free Electron Laser Laboratory	electron, FEL, controls, free-electron-laser	837
	P. Niknejadi, M.R. Hadmack, B.T. Jacobson, J. Madey, G.S. Varner University of Hawaii, Honolulu, HI, USA
	Real time waveform measurements of electron beams will provide valuable data and possibility of online bunch diagnostics in linear accelerators. The University of Hawaii Linear Accelerator utilizes a thermionic LaB6 cathode microwave gun injector and a single section of S-band linear accelerator capable of producing a 40MeV, 1-2 ps bunched electron beam with average current of 200mA over the duration of a 4.5 us macropulse. This beam, pulsed at 4 Hz, produces strong RF signal at 2.856 GHz which is coupled out of the beam-pipe by a family of stripline beam position monitors (BPM's) and read out using custom built logarithmic-difference based electronics installed in 2012.* A high speed Analog to Digital Convertor and Field-Programmable Gate Array will be used to digitize the signal and record the waveform. The goal is to make a cost effective oscilloscope on a chip/board with feasible and functional operation to achieve optimal beam configuration. The circuit board design, in-circuit programming, waveform digitization challenges, and preliminary results from the prototype will be presented at the conference. * B. T. Jacobson, M. R. Hadmack, J. M. J. Madey, P. Niknejadi "Modular Logarithmic Amplifier Beam Position Monitor Readout System at University of Hawai’i," IBIC Conf. Proc. (2012)

TUOCB102	SPARC_LAB Recent Results	electron, plasma, photon, FEL	1114
	M. Ferrario, D. Alesini, M.P. Anania, A. Bacci, M. Bellaveglia, M. Castellano, E. Chiadroni, D. Di Giovenale, G. Di Pirro, A. Drago, A. Esposito, A. Gallo, G. Gatti, A. Ghigo, T. Levato, A. Mostacci, L. Palumbo, A.R. Rossi, B. Spataro, C. Vaccarezza, F. Villa INFN/LNF, Frascati (Roma), Italy A. Cianchi INFN-Roma II, Roma, Italy G. Dattoli, E. Di Palma, L. Giannessi, A. Petralia, C. Ronsivalle, V. Surrenti ENEA C.R. Frascati, Frascati (Roma), Italy C. De Martinis INFN/LASA, Segrate (MI), Italy R. Faccini INFN-Roma, Roma, Italy M. Gambaccini INFN-Ferrara, Ferrara, Italy D. Giulietti UNIPI, Pisa, Italy L.A. Gizzi, L. Labate CNR/IPP, Pisa, Italy S. Lupi Università di Roma I La Sapienza, Roma, Italy V. Petrillo, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy J.V. Rau ISM-CNR, Rome, Italy G. Turchetti Bologna University, Bologna, Italy
	A new facility named SPARC_LAB (Sources for Plasma Accelerators and Radiation Compton with Lasers and Beams) has been recently launched at the INFN National Labs in Frascati, merging the potentialities of the an ultra-brilliant electron beam photoinjector and of a high power Ti:Sa laser. The test facility is now completed, hosting a 150 MeV high brightness electron beam injector which feeds a 12 meters long undulator. Observation of FEL radiation in variuous configurations has been performed. In parallel to that a 200 TW laser that is linked to the linac and devoted to explore laser-matter interaction, in particular with regard to laser-plasma acceleration of electrons (and protons) in the self injection and external injection modes. The facility will be also used for particle driven plasma acceleration experiments (the COMB experiment). A Thomson scattering experiment coupling the electron bunch to the high-power laser to generate coherent monochromatic X-ray radiation is also in the commissioning phase. We report in this paper the recent results obtained at the SPARC_LAB facility.
	Slides TUOCB102 [12.874 MB]

TUPEA008	Physics of the AWAKE Project	plasma, wakefield, electron, injection	1179
	P. Muggli, E. Oz, R. Tarkeshian MPI, Muenchen, Germany C. Bracco, E. Gschwendtner, A. Pardons CERN, Geneva, Switzerland A. Caldwell, O. Reimann MPI-P, München, Germany K.V. Lotov BINP SB RAS, Novosibirsk, Russia A.M. Pukhov HHUD, Dusseldorf, Germany J. Vieira IPFN, Lisbon, Portugal M. Wing UCL, London, United Kingdom
	The goal of the AWKAKE collaboration is the study of plasma wakefields driven by proton (p⁺) bunches through experiments, simulations and theory. Proton bunches are interesting wakefield drivers because they can be ultra-relativistic (TeVs/p⁺) and carry large amounts of energy (>kJ). It was demonstrated in simulations* that acceleration of an electron (e-) bunch from 10GeV to >500GeV can be achieved in ~500m of plasma driven by a 1TeV, 100micron-long, bunch with 10¹¹ p+. Such short p⁺ bunches do not exist today. It was suggested** that a p⁺ bunch long compared to the plasma period can transversely self-modulate and resonantly drive wakefields to large amplitudes (~GV/m). Initial experiments based on self-modulation instability (SMI) will use single 12cm-long CERN SPS bunches with 1-3·10¹¹, 450GeV p⁺ to study physics of SMI. With a plasma density of 7·10¹⁴/cc the plasma wave and modulation period is 1.3mm. The SMI saturates after ~3m with amplitude in the GV/m range. Later a low energy (~10MeV) witness e^- bunch will be injected at the SMI saturation point. Energy gain over ~7m of plasma can reach the GeV level. Translation from physics to experimental plan and setup will be presented. * A. Caldwell et al., Nature Physics 5, 363 (2009) ** N. Kumar et al., Phys. Rev. Lett. 104, 255003 (2010)

TUPEA010	FERMI Seeded FEL Progress Report	FEL, electron, undulator, free-electron-laser	1182
	M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, 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, L. Giannessi, M. Kiskinova, G.L. Loda, M. Lonza, B. Mahieu, N. Mahne, C. Masciovecchio, F. Parmigiani, G. Penco, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, L. Sturari, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy P. Craievich PSI, Villigen PSI, Switzerland B. Mahieu CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
	Funding: Work supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3 FERMI, the seeded Free Electron Laser located at the Elettra laboratory in Trieste, Italy, welcomed in December 2012 the first external users on the FEL-1 line. This line is based on a single stage of High Gain Harmonic Generation (HGHG), seeded by a UV laser, and covers wavelengths between 80 and 20 nm. The photon energy reached more than 300 μJ. The second FEL line, FEL-2, covering the lower wavelength range between 20 and 4 nm thanks to a double stage cascaded HGHG scheme, has generated its first coherent photons in October 2012. This is the first experimental demonstration of a seeded free electron laser configured as a two stages cascade operating in the "fresh bunch injection” mode, where the second stage is seeded by the light produced by the first stage. This paper describes the status of the operation and user experiments with FEL-1 and reports about the progress in the commissioning of FEL-2.

TUPEA011	Double Stage Seeded FEL with Fresh Bunch Injection Technique at FERMI@Elettra	FEL, electron, undulator, photon	1185
	S. Di Mitri, E. Allaria, D. Castronovo, P. Cinquegrana, P. Craievich, G. D'Auria, M.B. Danailov, G. De Ninno, A.A. Demidovich, B. Diviacco, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, G. Gaio, L. Giannessi, R. Ivanov, B. Mahieu, N. Mahne, I. Nikolov, F. Parmigiani, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, D. Zangrando, M. Zangrando Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy D. Gauthier University of Nova Gorica, Nova Gorica, Slovenia
	During the month of October 2012 the commissioning of the light source FEL-2 at FERMI was successfully concluded. Fermi FEL-2 is the first seeded FEL operating with a double stage cascade in the "fresh bunch injection" mode. The two stages are two high gain harmonic generation FELs where the first stage is seeded by the 3rd harmonic of a Ti:Sa laser system, which is up converted to the 4th-12th harmonic. The output of the first stage is then used to seed the second stage. A final wavelength of 10.8 nm was obtained as the 24th harmonic of the seed wavelength at the end of the two frequency conversion processes, demonstrating that the FEL is capable of producing single mode narrow bandwidth pulses with an energy of several tens ofμjoules. We report on the experimental characterisation of the FEL performances in this configuration. I. Ben-Zvi, K. M. Yang, L. H. Yu, ”The ”fresh-bunch” technique in FELs”, NIM A 318 (1992), p 726-729

TUPEA016	Relativistic Theory for Laser-ion Acceleration	ion, acceleration, electron, plasma	1193
	Y.S. Huang, Y.J. Shi, X.Z. Tang, N.Y. Wang CIAE, Beijing, People's Republic of China
	Funding: The Key Project of Chinese National Programs for Fundamental Research (973 Program) under contract No. 2011CB808104 and the Chinese National Natural Science Foundation under contract No. 11105233. An analytical relativistic model is proposed to describe the relativistic ion acceleration in the interaction of ultra-intense laser pulses with thin-foil plasmas. It is found that there is a critical value of the ion momentum to make sure that the ions are trapped by the light sail and accelerated in the radiation pressure acceleration (RPA) region. If the initial ion momentum is smaller than the critical value, that is in the classical case of RPA, the potential has a deep well and traps the ions to be accelerated. There is a new ion acceleration region different from RPA, called ultra-relativistic acceleration, if the ion momentum exceeds the critical value. In this case, ions will experience a potential downhill. The dependence of the ion momentum and the self-similar variable at the ion front on the acceleration time has been obtained. The critical conditions of the laser and plasma parameters which identify the two acceleration modes have been achieved. No matter RPA or ultra-relativistic acceleration, the potential difference is a constant, which dedicates the maximum ion energy.

TUPEA017	Monoenergetic Electron Beams with Ultralow Normalized Emittance Generated from Laser-Gas Interaction	electron, plasma, emittance, simulation	1196
	D.Z. Li, J. Gao, K. Huang, J. Jiarui, Y. Ma IHEP, Beijing, People's Republic of China L.M. Chen, W.C. Yan Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
	High quality electron bunches are generated by using 2 TW, 80 fs, high contrast laser pulses interacting with helium gas targets. In optimized condition, we get tens MeV monoenergetic electron beams with small energy spread and the normalized emittance 0.07π mm·mrad. Due to its ultra small emittance and high initial energy, such bunch is very suitable for high current linear accelerators.

TUPEA018	Recent Progress of Laser Plasma Proton Accelerator at Peking University	plasma, proton, target, acceleration	1199
	X.Q. Yan, J.E. Chen, H.Z. Fu, Y.X. Geng, Z.Y. Guo, C. Lin, Y.R. Lu, Y. Shang, Z.X. Yuan, S. Zhao, K. Zhu PKU, Beijing, People's Republic of China
	Funding: National Natural Science Foundation of China (Grant Nos.10935002, 10835003, 11025523) Recent a project called Laser plasma Proton Accelerator (LAPA) is approved by MOST in China. A prototype of laser driven proton accelerator (1~15MeV) based on the PSA mechanism and plasma lens is going to be built at Peking University in the next five years. It can be used for the applications such as cancer therapy, plasma imaging and fast ignition for inertial confine fusion. The recent progress of LAPA is reported here.

TUPEA019	Proton Acceleration driven by High Energy Density Electrons	proton, acceleration, plasma, electron	1202
	S. Zhao, C. Chao, J.E. Chen, H.Z. Fu, Y.X. Geng, C. Lin, B. Liu, H. Wang, X.Q. Yan PKU, Beijing, People's Republic of China
	Resonance Electrons Driving Ion Acceleration S. Zhao, C. Lin, X. Q. Yan Institute of Heavy Ion Physics, Peking University Proton acceleration driven by resonance electrons is proposed. Energetic electron beam generated through direct laser acceleration in the near critical dense plasma is dense and directional. When interacting with a thin foil target, resonance electrons can transmit the target and drive periodical electrostatic field at the back surface, therefore protons are more efficiently accelerated in a much longer distance in propagation direction of resonance electrons, compared to the classical target normal sheath acceleration. For a Gaussian laser pulse with pulse duration of 80fs, peak intensity I=1.38*10⁸W/cm² , the cutoff energy of the output collimated proton beam is 14MeV, enhanced by a factor of 3 or 4. The scaling law predicts hundreds MeV Proton beam can be generated in laser intensity of 10²⁰W/cm².

TUPEA028	Echo-enabled Harmonic Generation based on Hefei Storage Ring	FEL, electron, bunching, storage-ring	1208
	H.T. Li, W.W. Gao, Q.K. Jia, L. Wang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Echo-Enabled Harmonic Generation (EEHG) has been proposed and experimently demonstrated recently. In this paper, we numerically investigate the possibility of operating EEHG based on Hefei storage ring, which has a short circumference and a small momentum compaction factor. The difference to other similar reserch is that we use the whole ring as the first dispersive section and an optical klystron as the second one.

TUPEA029	Theory Calculation of PASER in Gas Mixture Active Medium	electron, resonance, wakefield, plasma	1211
	X.F. Tian, C.-F. Wu USTC/NSRL, Hefei, Anhui, People's Republic of China
	In the PASER (particle acceleration by stimulated emission of radiation), the energy stored in an active medium transferred directly to the electron beam passing through in discrete amounts by emitting a photon when the bounded electron returns from upper to lower energy state. In this paper, the wake-field generated by a bunch of electrons traversing in an active medium has been discussed. The calculations of the development of amplitude for gas mixture active medium about CO2 and ArF were made respectively. The results show that the gradient can reach around 1GeV/m. In addition, the electron energy gain occurring as a train of electron micro-bunches traversing in gas mixture was analyzed by a two dimension model. The train of micro-bunches can obviously gain energy from the active medium and the energy exchange is linearly proportional to the interaction length d. The influence of the bunch figure and other quantities on the energy exchange occurring as a train of electron micro-bunches traversing CO2 gas mixture were investigated when the interaction length is 0.5m. The results illustrate that maximum electron energy gain can be obtained by the train of micro-bunches with optimized parameters.

TUPEA033	Proposals for Chirped Pulse Amplification in HGHG and CHG at SDUV-FEL	FEL, electron, radiation, undulator	1217
	C. Feng, L. Shen, D. Wang, D. Xiang, M. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	In this paper, a proposal to generate intense ultra-short free-electron laser (FEL) pulses at Shanghai deep ultraviolet FEL (SDUV-FEL) by combining the chirped pulse amplification (CPA) technique with the high-gain harmonic generation (HGHG) technique is presented. In this proposal, a frequency chirped seed pulse obtained by stretching an ultra-short laser pulse is first used to create frequency-chirped bunching at the laser harmonics in an electron beam; then the frequency chirped harmonic radiation is amplified by an energy chirped electron beam; finally the output radiation pulse which inherits the properties of the seed pulse is compressed to provide an ultra-intense ultra-short radiation pulse. The feasibility and performance of this CPA-HGHG scheme are studied with start-to-end simulations using the parameters of the SDUV-FEL.

TUPEA038	Pre-chirp Control Broadband Non-collinear Optical Parametric Amplifier for the Future Laser Weak-field Accelerator	controls, electron	1223
	L. Shen, C. Feng, L. Feng, D. Wang, H.F. Yao, W.Y. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Ultra-short pulse has been proved to be a very useful tool for accelerating electron close to GeV now. But limited by gain narrowing effect, conventional CPA technology is quite hard to get less than 30fs at high energy level. Non-collinear optical parametric amplification (NOPA) looks more and more attractive for generating super-broadbandwidth pulses which is possible to be compressed to ultra-short pulses. Previous NOPAs, pumped by 400nm pulses, were using BBO crystals to reach shorter signal pulse durations. But the associated spectral bandwidths are still strongly linked with higher order nonlinear effects. which make it quite difficult to get higher energy with short pulse duration. Here we proposed to use pre-chirped few nm bandwidths around 515nm pumped pulses to amplify ultra-short pulses centered at 800nm. In our setup, we have found just one dramatical geometry configuration which support that we have possibility to get amplification from 720nm to 900nm, which will support to less than 10fs by well re-compression. This design is well adapted for BBO crystals. But the idea could be used also for other crystals.

TUPEA042	Linac Design for Dalian Coherent Light Source	linac, FEL, emittance, simulation	1226
	M. Zhang, H.X. Deng, D. Gu, Q. Gu SINAP, Shanghai, People's Republic of China
	Dalian Coherent Light (DCL) Source is a FEL user facility in which HGHG scheme is adopted. Beam quality requirements for the linear accelerator (linac) are critical, including not only the beam brightness, but also the stability and the reliability. In this paper, optimization study is performed for the linac. Based on beam stability simulation in the longitudinal direction, the tolerant budget is formed for the short period jitter. For the transverse orbit error, beam based alignment (BBA) technique is implemented by beam dynamics simulations and the transverse jitter is also presented accordingly. Measurement method for the beam quality is also described in the paper.

TUPEA051	Beam Transfer Line Design for a Plasma Wakefield Acceleration Experiment (AWAKE) at the CERN SPS	plasma, quadrupole, instrumentation, proton	1247
	C. Bracco, J. Bauche, D. Brethoux, V. Clerc, B. Goddard, E. Gschwendtner, L.K. Jensen, A. Kosmicki, G. Le Godec, M. Meddahi, C. Mutin, J.A. Osborne, K.D. Papastergiou, A. Pardons, F.M. Velotti, H. Vincke CERN, Geneva, Switzerland P. Muggli MPI, Muenchen, Germany
	The world’s first proton driven plasma wakefield acceleration experiment is presently being studied at CERN. The experiment will use a high energy proton beam extracted from the SPS as driver. Two possible locations for installing the AWAKE facility are considered: the West Area and the CNGS long baseline beam-line. The previous transfer line from the SPS to the West Area was completely dismantled in 2000 and it would need to be fully re-designed and re-built. For this option, geometric constraints for radio protection reasons would limit the maximum proton beam energy to 300 GeV. The existing CNGS line could be used by applying only minor changes to the final part of the lattice for the final focusing and the interface between the proton beam and the laser, required for plasma ionisation and bunch-modulation seeding. The beam line design studies performed for the two options are presented.

TUPEA053	Feasibility Study of the AWAKE Facility at CERN	proton, plasma, electron, wakefield	1253
	E. Gschwendtner, C. Bracco, B. Goddard, M. Meddahi, A. Pardons, E.N. Shaposhnikova, H. Timko, F.M. Velotti, H. Vincke CERN, Geneva, Switzerland
	Plasma Wakefield acceleration is a rapidly developing field which appears to be a promising candidate technology for future high-energy accelerators. The Proton Driven Plasma Wakefield Acceleration has been proposed as an approach to eventually accelerate an electron beam to the TeV energy range in a single plasma section. To verify this novel technique, a proof-of-principle demonstration experiment, AWAKE, is proposed using 400 GeV proton bunches from the SPS. Detailed studies on the identification of the best site for the installation of the AWAKE facility resulted in proposing the CNGS facility as best location. Design and integration layouts covering the beam line, the experimental area and all interfaces and services will be shown. Among other issues, radiation protection, safety and civil engineering constraints will be raised.

TUPEA058	The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation	FEL, electron, photon, linac	1265
	J.A. Clarke, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, P.A. Corlett, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, L. Ma, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, R.N.C. Santer, Y.M. Saveliev, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R. Appleby, M. Serluca, G.X. Xia UMAN, Manchester, United Kingdom R.J. Barlow, A.M. Kolano University of Huddersfield, Huddersfield, United Kingdom R. Bartolini, I.P.S. Martin Diamond, Oxfordshire, United Kingdom N. Bliss, R.J. Cash, G. Cox, G.P. Diakun, A. Gallagher, D.M.P. Holland, B.G. Martlew, M.D. Roper STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom S.T. Boogert Royal Holloway, University of London, Surrey, United Kingdom G. Burt Lancaster University, Lancaster, United Kingdom L.T. Campbell, B.W.J. MᶜNeil USTRAT/SUPA, Glasgow, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Lyapin JAI, Egham, Surrey, United Kingdom D. Newton, A. Wolski The University of Liverpool, Liverpool, United Kingdom V.V. Paramonov RAS/INR, Moscow, Russia
	The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.

TUPEA059	CLARA Accelerator Design and Simulations	linac, diagnostics, FEL, emittance	1268
	P.H. Williams, D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Science & Technology Facilities Council We present the accelerator design for CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory. CLARA will be a testbed for novel FEL configurations. The accelerator will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. We describe the transport in detail including dedicated diagnostic sections. Beam dynamics simulations are then used to define a set of operating working points suitable for the different FEL schemes intended to be tested on CLARA.

TUPEA060	Jitter Tolerance for CLARA	linac, electron, cathode, FEL	1271
	B.P.M. Liggins, J.K. Jones, J.W. McKenzie, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Science & Technology Facilities Council CLARA (Compact Linear Accelerator for Research and Applications) at Daresbury Laboratory will be a test-bed for novel FEL configurations. CLARA will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. Ensuring stability of the VUV radiation pulses is a key aim of the project. To this end, we investigate in detail the jitter tolerance of the machine. This will ultimately determine the pulse stability.

TUPEA062	Advanced Gabor Lens Lattice for Medical Applications	ion, proton, space-charge, focusing	1277
	J.K. Pozimski, M. Aslaninejad, P.A. Posocco Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The widespread introduction of Hadron therapy for cancer treatment is inhibited by the large costs for the accelerator and treatment facility and the subsequent maintenance costs which reflects into the cost per treatment. In the long term future (laser) plasma wakefield accelerated hadrons could offer compact treatment devices with significantly reduced treatment costs. In the moment the particle distributions produced by such accelerators do not fulfill the medical requirements. Beside the reliable production of a sufficient number of ions at the required energy the formation of a particle beam suitable for treatment from the burst of ions created in the acceleration process is one of the major challenges. While conventional optical systems will be operating at the technical limits which would be contradictory to the cost argument, space charge lenses of the Gabor type might be a cost effective alternative. An advanced beam line consisting of Gabor lenses, a few cavities and an dipole will be presented together with results from particle transport simulations.

TUPEA065	Design of a Photonic Crystal Accelerator for Basic Radiation Biology	vacuum, acceleration, electron, simulation	1283
	A. Aimidula, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Aimidula, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom K. Koyama, Y. Matsumura University of Tokyo, Tokyo, Japan T. Natsui, M.Y. Yoshida KEK, Ibaraki, Japan M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan G.X. Xia UMAN, Manchester, United Kingdom
	Funding: This work is supported by the EU under Grant Agreement 289485, the STFC Cockcroft Institute Core Grant No. ST/G008248/1 and KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120. The application of photonic crystals to realize an on-chip electron beam source for fundamental radiation biology is highly interesting for a number of applications. The unique combination of nanometer beam size and attosecond-short pulses has a very promising potential for use in microscopic and ultra-fast analyses of damage and repair of radiation-irradiated DNA and chromosomes. Simulations studies indicate an output electron beam energy, beam intensity and device size of the order of MeVs, fCs and a few cm, respectively. In this contribution, first results from numerical studies into the design of such compact accelerator structure are presented. The dimensions of a novel dual grating-based acceleration structure are shown together with the estimated laser parameters. Finally, a system consisting of an electron injector and multi-stage accelerating structures is proposed, which corresponds to a miniaturized optical linear accelerator.

TUPEA071	THz Bench Tests of a Slab-symmetric Dielectric Waveguide	acceleration, simulation, wakefield, emittance	1292
	F. Lemery, H. Panuganti, P. Piot Northern Illinois University, DeKalb, Illinois, USA D. Mihalcea, P. Piot Fermilab, Batavia, USA P. Stoltz Tech-X, Boulder, Colorado, USA
	Funding: This work is supported by DTRA contract HDTRA1-10-1-0051 and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359. Dielectric-lined waveguides (DLW) are becoming more popular for beam driven acceleration applications. An experiment to demonstrate beam-driven acceleration using a slab-symmetric dielectric-lined waveguide driven by a flat beam is in preparation at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In this paper we characterize the structure using a THz pulse obtained from optical rectification using an amplified laser pulse. After propagation through the DLW structure, the THz pulse is analyzed using a Michelson interferometer and single-shot electro-optical imaging. Data for various gap size will be presented.

TUPEA075	Passively Driving X-band Structures to Achieve Higher Beam Energies	electron, linac, impedance, gun	1304
	S. Biedron, S.V. Milton, N. Sipahi, T. Sipahi CSU, Fort Collins, Colorado, USA
	Particle accelerators at X-band frequencies have gradients of around 100 MV/m. This technology permits more compact accelerators. One of our aims at the Colorado State University Accelerator Laboratory is to adapt this technology to our L-band (1.3 GHz) accelerator system to increase our overall beam energy; however, we would like to do this in a passive manner, i.e. one that does not require investment in an expensive, custom, high-power klystron system. In this paper we explore using the beam from our L-band 6 MeV photoinjector to power an x-band structure tuned to the 9th harmonic of our L-band system, 11.7 GHz. Electron bunches will be generated at a repetition rate of 81.25 MHz and passed through a high shunt impedance x-band accelerating structure where they will resonantly excite the fundamental field. We will optimize the system to create the highest accelerating potential within this structure. Once the peak gradient is achieved we will send a single electron bunch through the system at a phase that places it on the crest of the X-band accelerating wave thereby increasing the electron bunch energy by some amount without need for additional external power sources.

TUPEA079	Experimental Search For Acceleration in the Micro-accelerator Platform	electron, acceleration, vacuum, coupling	1307
	J.C. McNeur, K.S. Hazra, B. Matthews, E.B. Sozer, G. Travish UCLA, Los Angeles, USA R.J. England, B. Montazeri, K. Soong, Z. Wu SLAC, Menlo Park, California, USA E.A. Peralta Stanford University, Stanford, California, USA R.B. Yoder Goucher College, Baltimore, USA
	The results of recent experimental efforts to observe acceleration in the Micro-Accelerator Platform (MAP) are detailed. The MAP is a slab-symmetric dielectric laser accelerator that when side illuminated by an optical laser, accelerates electrons via a standing wave resonance. This structure has been placed in the beamline at the NLCTA experimental hall at SLAC. A 60 MeV electron beam traverses the MAP when it is illuminated by a laser and, using a camera placed around a spectrometer bend magnet, signs of acceleration in the energy spectrum of the beam are searched for. The details of this search, as well as simulations that motivate the search, are elaborated on below.

TUPEA080	Numerical Modeling and Experimental Data Analysis for Dielectric Laser Accelerators	electron, acceleration, vacuum, GUI	1310
	E.B. Sozer, K.S. Hazra, J.C. McNeur, G. Travish UCLA, Los Angeles, USA R.J. England, K. Soong SLAC, Menlo Park, California, USA E.A. Peralta Stanford University, Stanford, California, USA R.B. Yoder Goucher College, Baltimore, USA
	Funding: Work supported by a grant for the US Defense Threat Reduction Agency (DTRA). Work on Dielectric Laser Accelerators (DLAs) has been ongoing for the past decade. These devices come in a variety of configurations but share the use of lasers as power sources and dielectrics as the primary building material. While these devices have many of the same characteristics and dynamics as conventional accelerating structures, they operate in a dramatically different regime. One version of these DLAs is the Micro Accelerator Platform (MAP): a slab-symmetric device operated with a standing wave (Pi-mode) and powered by a transversely coupled laser. The coupler is essentially a transmissive diffraction grating and therefore reinforced the desired mode. The remainder of the structure is composed of two Distributed Bragg Reflectors (DBRs) which serve to form a resonant cavity in an evacuated bounded by the reflectors. The MAP has now undergone experimental testing at SLAC’s E-163. As with many advanced accelerators, identifying the best data analysis approach demands extensive numerical modelling of the anticipated beam parameters and development of data visualization tools. We present the latest numerical results and data analysis tools developed for dielectric laser acceleration experiments with MAP.

TUPEA086	Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source	FEL, linac, emittance, electron	1316
	Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou SLAC, Menlo Park, California, USA P. Emma LBNL, Berkeley, California, USA
	Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.

TUPEA089	Modeling and Experimental Update on Quasi-phase Matched Direct Laser Electron Acceleration In Density-modulated Plasma Waveguides	plasma, electron, simulation, target	1325
	M.W. Lin, D.R. Abercrombie, I. Jovanovic, A. Rakhman Penn State University, University Park, Pennsylvania, USA
	Funding: This work has been supported by the Defense Threat Reduction Agency through Contract HDTRA1-11-1-0009. Direct laser acceleration (DLA) of electrons using the axial electric field of a radially polarized, guided intense laser pulse has the potential to lead to compact laser-driven accelerators* for security and medical applications. A density-modulated plasma waveguide could be applied to extend the laser beam propagation distance and to achieve quasi-phase matching (QPM) between laser and electron pulses for efficient DLA. We conduct numerical simulations to design the appropriate plasma structure of the waveguides and investigate the properties of accelerated electron beams. An all-optical method, based on the igniter-heater scheme for plasma waveguide fabrication, is experimentally implemented to machine the density-modulated plasma waveguides with low-Z gas targets. A novel angle-multiplexed diagnostic technique has been developed to extract the polarization state and temporal characteristics of a radially polarized femtosecond laser pulse using spatial-spectral interferometry. The goal of our experiments is to characterize the propagation of femtosecond radially polarized pulses in plasma waveguides. P. Serafim, et al., IEEE Trans. Plasma Sci. 28, 1155 (2000). M. -W. Lin and I. Jovanovic, Phys. Plasmas 19, 113104 (2012). *P. Bowlan, et al., Opt. Exp. 14, 11892 (2006)

TUPFI004	Longitudinal Manipulation to Obtain and Keep the Low Emittance and High Charge Electron Beam for SuperKEKB Injector	emittance, wakefield, alignment, gun	1337
	M. Yoshida, N. Iida, T. Natsui, Y. Ogawa, S. Ohsawa, H. Sugimoto, L. Zang, X. Zhou KEK, Ibaraki, Japan
	The design strategy of SuperKEKB is based on the.nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, we installed new photocathode RF-Gun with the focusing electric field and temporal adjusting laser system. Further the projected emittance dilution in the LINAC is an important issue for the low emittance injection. The longitudinal bunch length and shape is an important key to avoid the space charge effect and emittance dilution. The longitudinal manipulation using the temporal adjusting laser system and the bunch compression will be presented. Further the longitudinal bunch measurement will be also presented.

TUPME010	High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB	positron, emittance, linac, electron	1583
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 10³⁵ /s.cm², 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.

TUPME013	Coherent Thomson Scattering using Beam Echo	electron, scattering, undulator, radiation	1592
	K. Ohmi, S. Kamada KEK, Ibaraki, Japan H. Fares Kanazawa University, Kanazawa, Japan
	Longitudinal phase space of the beam is modulated by laser interacting in undulators. The beam can have higher frequency component using the beam echo than than the laser as dicussed by G. Stupakov et al. The modulated beam has a potential to emit coherent radiation with the wave length. We evaluate coherent short wave length (~nm) and/or short pulse (attosec) light source using the beam echo in a low energy accelerator ~100MeV.

TUPME015	Proposal of Polarized Gamma-ray Source for ILC Based on CSR Inverse Compton Scattering	electron, cavity, positron, scattering	1598
	M. Shimada, K. Yokoya KEK, Ibaraki, Japan R. Hajima JAEA, Ibaraki-ken, Japan M. Tecimer University of Hawaii at Manoa, Honolulu, USA
	The positron source of International Linear Collider (ILC) requires a circular polarized gamma-ray with a flux more than 10¹⁶ phs./s and a helical undulator-based gamma-ray source is proposed in the baseline design. Although the undulator scheme is technically feasible, it is not easy for a stand-alone operation because of the required electron energy, ~ 150GeV. In this paper, we propose an alternative method, the inverse Compton scattering with a high-power mid-infrared optical pulse generated from coherent synchrotron radiation (CSR). To achieve the high flux gamma-ray, CSR with a few MHz is stacked in a high-finesse optical cavity made of a photonic crystal. In the proposed scheme, a stand-alone operation is feasible because the electron energy is less than 10GeV.

TUPME027	Advanced Studies on New Generation of Electron-positron Accelerators and Colliders for Fundamental and Applied Researches	electron, FEL, radiation, gun	1631
	A. Dudarev, N. Balalykin, U.A. Budagov, V. Kobets, M.V. Lyablin, B.M. Sabirov, G. Shirkov, E. Syresin, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia
	JINR actively leads the R&D works in particle accelerator physics and engineering, construction of the free electron laser with the aim to prepare proposals for the project of JINR participation in international collaboration on construction of the future Linear Collider (CLIC/ILC). JINR scientists and engineers study in free electron laser physics, development and construction of systems applied for formation and diagnostics of ultra short dense bunches in the linear electron accelerators. JINR physicists also take part in several fields of activity in ILC: works on photo injector prototype, participation in design and construction of cryomodules, laser metrology, and possible ILC location near Dubna.

TUPME031	Considerations for a Higgs Facility Based on Laser Wakefield Acceleration	plasma, luminosity, collider, electron	1643
	S. Hillenbrand, A.-S. Müller KIT, Karlsruhe, Germany R.W. Aßmann, S. Hillenbrand, D. Schulte CERN, Geneva, Switzerland
	Laser Wakefield Accelerators have seen tremendous progress over the last decades. It is hoped that they will allow to significantly reduce the size and cost of a future liner collider. Based on scaling laws, laser-driven plasma accelerators are investigated as drivers for smaller scale facilities capable of producing Z and Higgs bosons.

TUPME062	Simulation and Analysis of Microbunching Instability in a High Repetition rate FEL Beam Delivery System	electron, simulation, linac, FEL	1709
	J. Qiang, J.N. Corlett, P. Emma, C.E. Mitchell, M. Venturini 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. Microbunching instability in the accelerator beam delivery system of an FEL can significantly degrade the electron beam quality and limit performance of the X-ray radiation. In this paper, we present detailed numerical simulation and analytical analysis of the microbunching instability in a high repetition rate X-ray FEL beam delivery system that is being studied at Lawrence Berkeley National Laboratory. Our results suggest that by using a flexible accelerator design and a laser heater, the effects of microbunching instability can be suppressed without significantly sacrificing the final electron beam quality.

TUPME067	Design Concept of a Gamma-gamma Higgs Factory Driven by Thin Laser Targets and Energy Recovery Linacs	photon, electron, target, collider	1721
	Y. Zhang JLAB, Newport News, Virginia, USA
	Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177. A gamma-gamma collider has long been considered an option for a Higgs Factory. Such photon colliders usually rely on Compton back-scattering for generating high energy gamma photons and further Higgs bosons through gamma-gamma collisions. The presently existing proposals or design concepts all have chosen a very thick laser target (i.e., high laser photon intensity) for Compton scatterings. In this paper, we present a new design concept of a gamma-gamma collider utilizing a thin laser target (i.e., relatively low photon density), thus leading to a low electron to gamma photon conversion rate. This new concept eliminates most useless and harmful low energy soft gamma photons from multiple Compton scattering so the detector background is improved. It also greatly relaxes the requirement of the high peak power of the laser, a significant technical challenge. A high luminosity for such a gamma-gamma collider can be achieved through an increase of the bunch repetition rate and current of the driven electron beam. Further, multi-pass recirculating linac could greatly reduce the linac cost and energy recovery is required to reduce the needed RF power.

TUPWA050	Effect of Transverse Coupling on Asymmetric Cooling in Compton Rings	emittance, coupling, electron, betatron	1823
	E.V. Bulyak NSC/KIPT, Kharkov, Ukraine J. Urakawa KEK, Ibaraki, Japan F. Zimmermann CERN, Geneva, Switzerland
	Fast cooling of bunches circulating in a Compton ring is achieved by placing the collision point between electron bunches and laser pulses in a dispersive section and by, in addition, introducing a transverse offset between the laser pulse and the electron-beam closed orbit. Growth of the emittance in the dispersive transversal direction due to the additional excitation of betatron oscillations limits this type of cooling. Here we present the results of further studies on the fast cooling process, looking at the effect of the coupling of the transverse (betatron) oscillations. We first show theoretically that the transverse betatron coupling shortens the cooling time and hence reduces the steady-state energy spread of the electron beam, as well as the quantum losses. The theoretical estimates are then validated by simulations. Finally, a proof-of-principle experiment at the KEK ATF Damping Ring is proposed.

TUPWA058	Experimental Study of Soliton Wave Trains in Intense Electron Beams	electron, space-charge, simulation, induction	1835
	Y. Mo, B.L. Beaudoin, D.W. Feldman, I. Haber, R.A. Kishek, P.G. O'Shea UMD, College Park, Maryland, USA
	Funding: Supported by the US Dept. of Energy, Office of High Energy Physics, and by the US Dept. of Defense, Office of Naval Research and the Joint Technology Office. Longitudinal perturbations in intense beams can lead to instabilities or degradation of beam quality, ultimately affecting the performance of accelerators, especially near the source where space charge is important. In this experimental study, conducted on the University of Maryland Electron Ring (UMER), large-amplitude perturbations are purposefully generated and their propagation observed over a long transport length. It is found that narrow, large-amplitude perturbations on a long-pulse beam develop into Korteweg-deVries (KdV) type soliton wave trains. Each peak in the wave train has a constant width and amplitude over a long propagation distance, with the amplitude inversely proportional to the square of the width. Furthermore, two such pulses are seen to interact with each other and emerge from the collision unchanged. The experimental data is compared with the KdV model and particle-in-cell simulations with good agreement. We induce perturbations using two methods: using photoemission to perturb the density at the cathode, or using an induction cell to directly perturb particle velocities.

TUPWO007	Investigation of the Magnetic Chicane of the New Short-Pulse Facility at the DELTA Storage Ring	undulator, simulation, electron, klystron	1889
	R. Molo, J.A. Grewe, H. Huck, M. Huck, M. Höner, S. Khan, A. Schick, P. Ungelenk DELTA, Dortmund, Germany
	Funding: Supported by DFG, BMBF, and the Federal State NRW. The new short-pulse facility at DELTA (a 1.5-GeV synchrotron light source) based on coherent harmonic generation (CHG) utilizes an electromagnetic undulator which can be configured as optical klystron (undulator – chicane – undulator). To optimize the CHG signal, the energy modulation of the electrons in the first undulator and the dispersion of the magnetic chicane (i.e. the R56 matrix element) have to be optimized. Since the R56 value of the present chicane is not sufficient, it is planned to rewire the magnetic coils to create a more efficient chicane. Simulations of the present chicane will be compared to measurements of the R56 matrix element and a new chicane configuration will be presented which increases the R56 value by a factor of ten.

TUPWO029	Beam Line Design at the CAEP THz Free Electron Laser	electron, cavity, emittance, FEL	1937
	P. Li, W. Bai, H. Wang CAEP/IAE, Mianyang, Sichuan, People's Republic of China X. Li TUB, Beijing, People's Republic of China
	China Academy of Physics (CAEP) is currently building a THz Free Electron Laser (THz-FEL) which serves as a radiation light sourse used for research in a variety of experimental fields. In this paper, we present the design of the beam line, which was accomplished using PARMELA and TRANSPORT code simulations. The accelerator consists of a 350 kV photocathode DC gun in conjunction with one cryomodule containing two 4-cell superconductiong RF cavities. The energy of the elctron beam is 7~8 MeV, and the maximum of the average beam current is 5 mA. A transverse emittance typically below 10 pi mm.mrad can be achieved.

WEZB102	Overview of Seeding Methods for FELs	FEL, electron, radiation, undulator	2063
	S. Reiche PSI, Villigen PSI, Switzerland
	In recent years enormous progress has been achieved in the theoretical understanding and experimental demonstration of FEL seeding. The state of the art for FEL seeding should be reviewed and compared to HHG, HGHG, EEHG techniques. The potential of various seeding methods and their promise to produce radiation pulses that approach the transform limit in a range of experimental configurations at different user facilities should be explored.
	Slides WEZB102 [4.238 MB]

WEODB101	X-ray Spectra and Peak Power Control with iSASE	FEL, undulator, electron, radiation	2068
	J. Wu, F.-J. Decker, Y. Feng, J. Krzywinski, H. Loos, A.A. Lutman, A. Marinelli, H.-D. Nuhn, C. Pellegrini, D.F. Ratner, D.H. Zhang, D. Zhu SLAC, Menlo Park, California, USA
	Funding: Work is supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515. We report the first measurement of spectral line-width reduction in a self-amplified spontaneous emission (SASE) X-ray free-electron laser (FEL) obtained by introducing repeated delays of the electron bunch with respect to the radiation field pulse. The improved longitudinal coherence obtained by this method reduces the intensity spiking effect characteristic of a SASE FEL. The electron-photon delays introduced along the FEL undulator mix the spikes phase and amplitude, increasing the cooperation length and generating a smaller bandwidth than in the conventional SASE mode of operation of an FEL. We call this mode of operation, based on repeated electron-photon delays, ‘‘improved SASE'' (iSASE). We also show with theoretical and simulation analysis that in the iSASE mode it is possible to choose the separation and magnitude of the delays to obtain a nearly transform limited X-ray pulse. This analysis is carried out using a time dependent, one-dimensional model and with GENESIS numerical simulation, including three-dimensional effects.
	Slides WEODB101 [7.647 MB]

WEPWA003	Hall-Probe Bench for Cryogenic in-Vacuum-Undulators	undulator, vacuum, cryogenics, permanent-magnet	2126
	C. Kuhn, H.-J. Bäcker, J. Bahrdt, A. Gaupp, B. Schulz HZB, Berlin, Germany
	The Helmholtz-Zentrum Berlin (HZB) builds a 2m long in-vacuum-hall-probe-bench for the characterization of several cryogenic undulators currently under development. Short period lengths and small gaps require an accurate correlation between Hall probe position / orientation and the 3D-magnetic field. The geometric tolerances of an in-vacuum bench in the presence of strong temperature gradients do not permit a Hall probe movement along a straight line without corrections. The HZB-bench employs a system of laser interferometers and position sensitive detectors, which is used in a feed-back loop for the Hall probe position / orientation. First measurements on the accuracy and reproducibility of the new device are presented.

WEPWA005	Experimental Characterization of the Coherent Harmonic Generation Source at the DELTA Storage Ring	radiation, electron, undulator, synchrotron	2132
	M. Huck, H. Huck, M. Höner, S. Khan, R. Molo, A. Schick, P. Ungelenk DELTA, Dortmund, Germany S. Cramm, L. Plucinski, C.M. Schneider Forschungszentrum Jülich, Peter-Gruenberg-Institut-6, Jülich, Germany S. Döring, L. Plucinski, C.M. Schneider Universität Duisburg-Essen, Duisburg, Germany
	Funding: Work supported by DFG, BMBF, and by the Federal State NRW. The short-pulse facility at the 1.5-GeV synchrotron light source DELTA, operated by the TU Dortmund University, generates coherent VUV and THz radiation by Coherent Harmonic Generation (CHG). Here, a femtosecond laser pulse interacts with an electron bunch in an undulator causing a periodic energy modulation and subsequent micro-bunching, which gives rise to coherent radiation at harmonics of the seed wavelength. Rather than using Ti:Sapphire laser pulses at 795 nm directly, the second harmonic is employed for seeding since 2012. After significant modifications of the seed laser beamline and the dispersive chicane to improve the microbunching, the last commissioning steps include characterization of the CHG radiation and preparing the experimental setup at an existing VUV beamline for time-resolved photoemission spectroscopy. In this paper, the status of the project and recent experimental results are presented.

WEPWA008	Simulating the Bunch Structure in the THz Source FLUTE	simulation, space-charge, linac, dipole	2141
	S. Naknaimueang, E. Huttel, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, M. Schreck, M. Schuh, M. Schwarz, M. Weber, P. Wesolowski KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	FLUTE is a planned THz source at KIT operating at a beam energy of 40 to 50 MeV in a wide bunch charge range. It consists of a laser driven rf-gun, a linac and a magnetic bunch compressor. The high current density combined with relatively low energy of FLUTE leads to complex strong self-field and beam-radiation field interactions, which are the limiting factors for the bunch compression efficiency. The results of numerical studies are presented in this paper.

WEPWA010	FLUTE: A Versatile Linac-based THz Source Generating Ultra-short Pulses	radiation, linac, gun, electron	2147
	M.J. Nasse, E. Huttel, S. Marsching, A.-S. Müller, S. Naknaimueang, R. Rossmanith, R. Ruprecht, M. Schreck, M. Schuh, M. Schwarz, P. Wesolowski KIT, Karlsruhe, Germany R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb DESY, Hamburg, Germany H.-H. Braun, R. Ganter, L. Stingelin PSI, Villigen PSI, Switzerland
	FLUTE is a linac-based accelerator test facility and a THz source currently being constructed at KIT with an electron beam energy of ~41 MeV. It is designed to cover a large charge range from a few pC to ~3 nC. FLUTE is optimized to provide ultra-short electron bunches with an RMS length down to a few fs. In this contribution, we focus on the layout of the machine from the RF gun & gun laser over the linac and the compressor to the THz beamline for the generation of coherent synchrotron, transition and edge radiation (CSR, CTR, CER).
	Poster WEPWA010 [0.802 MB]

WEPWA015	Progress in Construction of the 35 MeV Compact Energy Recovery Linac at KEK	linac, gun, cryomodule, shielding	2159
	S. Sakanaka, 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, 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, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, 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.M. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma JAEA, Ibaraki-ken, Japan H. Takaki ISSP/SRL, Chiba, Japan
	The 35-MeV Compact Energy Recovery Linac (the Compact ERL or cERL) is under construction at the High Energy Accelerator Research Organization (KEK) in Japan. With the Compact ERL, we aim at establishing cutting-edge technologies for the GeV-class ERL-based synchrotron light source. To install the accelerator components of the cERL, we have constructed a shielding room having an area of about 60 m x 20 m. We have then installed a 500-kV DC photocathode gun, a 5-MV superconducting (SC) cryomodule for the injector, a 30-MV SC cryomodule for the main linac, and some of the other components. High-power test on the main SC cryomodule is underway in December, 2012. High-power or high-voltage tests on the injector cryomodule and on the DC gun are planned during January to March, 2013. An injector of the Compact ERL will be commissioned in April, 2013. We report the newest status of its construction.

WEPWA016	Production of Intense High Energy Gamma Beam for LEPS2 Project at SPring-8	injection, storage-ring, electron, scattering	2162
	T. Yorita, T. Hotta, N. Muramatsu, T. Nakano, M. Oka, M. Yosoi RCNP, Osaka, Japan S. Daté, Y. Ohashi, H. Ohkuma, M. Oishi, Y. Okayasu, M. Shoji, S. Suzuki, Y. Taniuchi JASRI/SPring-8, Hyogo-ken, Japan
	Construction of new beam line for LEPS2 Project at SPring-8 has been done and development is now undergoing. LEPS2 is the project for high energy hadron physics using intense high energy gamma beam as probe. The gamma beam is produced by laser backward Compton scattering with injecting high power UV laser into the 8 GeV electron beam on long straight section of SPring-8 storage ring. The target intensities are ~10⁷/s for E_γ=2.4 GeV, ~10⁶/s for E_γ=2.9 GeV.

WEPWA017	Development of Laser-Compton X-ray Source using Optical Storage Cavity	electron, cavity, booster, linac	2165
	K. Sakaue, M. Washio Waseda University, Tokyo, Japan M.K. Fukuda, Y. Honda, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Funding: Work supported by the Quantum Beam Technology Program of MEXT and JSPS Grant-in-Aid for Young Scientists (B) 23740203 We have been developing a pulsed-laser storage technique in a super-cavity for a compact x-ray sources. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. We already obtained a pulse-train x-rays through the laser-Compton scattering between a multi-bunch electron beam and an optical super-cavity. And also, we performed a X-ray imaging via laser-Compton X-ray. On these successful results, we decided to upgrade our system for increasing X-ray flux by 3-order of magnitudes for practical use. For an optical cavity, we designed 4-mirrors bow-tie cavity in order to increase the power. On the other hand, electron accelerator was also upgraded to increase the bunch number in the train. We use 3.6cells rf-gun and 12cell standing wave booster linac. As a result, 2-order increase of X-ray flux was achieved. Design of upgraded our laser-Compton X-ray source, the results of X-ray experiments and future prospective will be presented at the conference.

WEPWA020	Laser Electron Storage Ring for TTX	cavity, electron, storage-ring, quadrupole	2171
	H.S. Xu, W.-H. Huang, C.-X. Tang, L.X. Yan, Y. You TUB, Beijing, People's Republic of China D. Jehanno, Z.F. Zomer LAL, Orsay, France S.-Y. Lee IUCEEM, Bloomington, Indiana, USA
	Tsinghua Thomson scattering X-ray (TTX) source, proposed by Tsinghua University, is a hard x-ray source with multi-application in condensed matter physics, etc. The TTX is composed of an S-band photocathode RF gun and a SLAC type 3m travelling wave Linac, and a femto-second tera-watt laser system drives the photocathode. The TTX source is in operation. To extend the capability of TTX, we plan to design a ring based system to increase the photon flux. In this paper, we report the design of the compact electron storage ring and optical cavity, expected performance, and future prospects.

WEPWA021	X-ray Spectra Reconstruction with HOPG Crystal on TTX	photon, scattering, simulation, electron	2174
	Z. Zhang, Y.-C. Du, J.F. Hua, W.-H. Huang, C.-X. Tang, D. Wang, L.X. Yan TUB, Beijing, People's Republic of China
	Thomson Scattering sources, as the new generation of bright X-ray sources, have great application potential in many respects. Traditional spectra measurement methods, applied to measured the spectra of Thomson Scattering source, are troublesome as the X-ray beam is too intense to cause pile up problems. In this article, we use the HOPG crystal to reconstruct the X-ray spectra of Tsinghua Thomson X-ray source (TTX) through Braggs law. This method can get reasonable results with single or several shots, with high energy resolution. We also compare the experiment results of this method with the reconstructed spectra by analyzing the attenuation data of the X-ray beam in silicon , and these two results agree well with each other.

WEPWA029	Undulator Chamber R&D for SXFEL	undulator, vacuum, controls, free-electron-laser	2193
	X. Hu, L. Yin SINAP, Shanghai, People's Republic of China
	The upcoming construction of Shanghai Soft X-ray Free Electron Laser Facility (SXFEL) will use 18 m small gap undulators. Each undulator is 3 meters long and will work at a minimum gap of 9 mm. This requires a vacuum chamber with an outer height of 8 mm and an elliptic inner aperture. The pressure inside of the chamber shall be less than 10^-5 Pa for the beam operation. An oxygen-free copper vacuum chamber was designed and a prototype was developed. This chamber includes three parts, a copper pipe manufactured by stretching, two flanges made of clad metal and a set of supports. The main fabrication procedure and the test results for the chamber prototype are described in this paper.

WEPWA037	Effect of Ground Vibration on the Out-coupled Power in a Terahertz FEL Oscillator	FEL, cavity, simulation, alignment	2211
	Q. Fu, L.Z. Deng, B. Qin, P. Tan, Y.Q. Xiong, Y.B. Yibin, H. Zeng HUST, Wuhan, People's Republic of China
	To acquire high power out-coupled, we must ensure the co-axis of electron orbit, optical beam and magnetic field. The propagation of ground vibration through the optical platform will lead to misalignment of the optical axis in the FEL optical cavity. Based on measurement results of the ground vibration, simulations of misalignment are studied with GENESIS+OPC. The tolerance of mirror tilt and offset is also discussed.

WEPWA040	Options for PAL-XFEL Injector Operation	emittance, gun, FEL, cathode	2217
	J.H. Han PAL, Pohang, Kyungbuk, Republic of Korea M.S. Chae POSTECH, Pohang, Kyungbuk, Republic of Korea
	Present designs of the PAL-XFEL injector assume a 120 MV/m peak field at the cathode in the gun and a flat-top longitudinal drive-laser profile. As accelerating field in the gun decreases and laser shape becomes imperfect, beam quality degradation takes place. On the other hand, by reducing accelerating field in the gun and by relaxing drive-laser shaping requirement the stability of the injector can be increased. We study various options for operating conditions of the injector with relaxed RF and drive-laser parameters.

WEPWA043	Construction of Injector Test Facility (ITF) for the PAL XFEL	gun, emittance, controls, klystron	2220
	S.J. Park, H. J. Choi, T. Ha, J.H. Han, J.H. Hong, W.H. Hwang, H.-S. Kang, T.-H. Kang, D.T. Kim, J.M. Kim, S.-C. Kim, I.S. Ko, B.H. Lee, H.-S. Lee, W.W. Lee, C.-K. Min, Y.J. Park, Y.G. Son PAL, Pohang, Kyungbuk, Republic of Korea M.S. Chae POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: Work supported by the Ministry of Education, Science and Technology (MEST) in Korea. An injector test facility (ITF) for the PAL-XFEL has been successfully constructed and its commissioning is under way. The facility is to demonstrate beam performances required by the PAL XFEL (beam energy of 139 MeV, projected rms emittance of < 0.5 mm mrad @ 200 pC, and beam repetition rate of 60 Hz) with good enough stabilities. We have constructed a dedicated building for the facility in which a radiation-shielding tunnel (19.2-m long, 3.5-m wide, and 2.4-m high inner space), a klystron-modulator gallery, a laser room, and a control room are installed. The injector consists of an in-house-developed photo-cathode rf gun, a 30-mJ Ti:Sa laser system, two accelerating structures (as well as two sets of klystron-modulator systems), and various diagnostics as well as magnets & instrumentations. The installation of a transverse deflecting cavity (S-band, 10-fs resolution) and a laser heater is scheduled in 2013. In this article we report on the facility construction and some of the early commisisoning results.

WEPWA058	Operation of the NSRRC 2998 MHz Photo-cathode RF Gun	gun, electron, cathode, cavity	2247
	A.P. Lee, M.C. Chou, J.-Y. Hwang, W.K. Lau NSRRC, Hsinchu, Taiwan P. Chiu, N.Y. Huang, P. Wang NTHU, Hsinchu, Taiwan
	We are developing the photoinjector technology for single pass high gain FEL research at NSRRC. A gun test facility(GTF) equipped with a 35 MW, S-band high power pulsed klystron as well as a 300 uJ, UV driver laser has been constructed for testing photo-cathode rf guns. Recently, a 2998 MHz, 1.6-cell photo-cathode rf gun has been fabricated in house and is being tested at the NSRRC GTF. Details of this setup will be described and the operational performance of this electron gun will be reported.

WEPWA059	Operation of the Drive Laser System for the 2998 MHz NSRRC Photoinjector	gun, cathode, electron, target	2250
	M.C. Chou, W.K. Lau, A.P. Lee NSRRC, Hsinchu, Taiwan
	A 266nm UV laser system has been installed as the drive laser of the NSRRC 2998 MHz photo-cathode rf gun. We will report our experiences on using such laser system for rf gun beam test. UV optics for laser beam transport as well as shaping technique we used for emittance preservation will also be presented.

WEPWA061	ALICE ERL Intra-train Variation Investigation using Bunch-by-bunch BPMs	FEL, cathode, linac, gun	2256
	D. Angal-Kalinin, F. Jackson, S.P. Jamison, J.K. Jones, A. Kalinin, T.T. Thakker, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The ALICE ERL is an energy recovery test facility based at Daresbury Laboratory. We present investigations of charge and transverse variations/oscillations in the ALICE trains (up to 1600 bunches, spacing 55.2ns, bunch charge up to 60pC), using turn-by-turn EMMA BPMs adjusted for bunch-by-bunch measurements. A set-up was established which allows use of pickups immediately downstream of the DC Gun as well as in the Arcs. To analyse variations, a DFT was used. It was established that a previously observed prominent (~10%) 300kHz charge envelope variation is a feature of the Photoinjector Laser. A set of transverse variations at 300kHz and below that depended on steering was also observed in the Injection Line. Downstream of the Booster, it was discovered that the transverse spectra are different. Prevailing quite regular variations (in range of 50um) were observed around 100kHz, manifesting themselves in the horizontal plane, present in non-dispersive regions, and dependent on trajectory offset in the Booster. We discuss the results, and also present our plans to apply this technique to a new single bunch injector EBTF now under commissioning in Daresbury Laboratory. A. Kalinin et al, MOPA30, IBIC12, Tsukuba, Japan.

WEPWA073	Compton Scattering Gamma-ray Light Source Modeling and Optimization	electron, radiation, brightness, photon	2283
	F.V. Hartemann, R.A. Marsh, 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 In Compton scattering light sources, a short (ps to ns) laser pulse and a high brightness relativistic electron beam collide to yield tunable, monochromatic, polarized gamma-ray photons. The properties of the gamma-ray phase space is studied, in relation to the full electron bunch and laser pulse phase spaces, along with collimation, nonlinear effects and other sources of spectral broadening. This process has potential high impact applications in homeland security, nuclear waste assay, medical imaging and stockpile surveillance, among other areas of interest. Detailed theoretical modeling is outlined to aid the design of Compton light sources and provide optimization strategies relevant within the context of nuclear photonics applications.

WEPWA080	Development of a Compact Insertion Device for Coherent Sub-mm Generation	radiation, linac, impedance, wakefield	2295
	A.V. Smirnov, R.B. Agustsson, S. Boucher, T.J. Grandsaert, J.J. Hartzell, M. Ruelas, S. Storms RadiaBeam, Santa Monica, USA A. Andrews, B.L. Berls, C.F. Eckman, K. Folkman, A.W. Hunt, Y. Kim, A.E. Knowles-Swingle, C. O'Neill, M. Smith IAC, Pocatello, IDAHO, USA P. Buaphad, Y. Kim ISU, Pocatello, Idaho, USA
	Funding: Department of Energy Contracts DE- SC-FOA-0000760 and DE-FG02-07ER84877 A novel design of resonant Cherenkov wakefield extractor that produced a ~0.9 mm wavelength radiation is presented. The experiment was performed at Idaho Accelerator Center (IAC) using specially upgraded 1.3 GHz 44 MeV linac facility. Specifics of the radiator performance and design are outlined including low-energy beam interaction with non-circular geometry. Some elements of the design may have certain potential for future compact mm-sub-mm-wave sources.

WEPWO017	Efforts on Nondestructive Inspections for SC Cavities	cavity, target, SRF, cryogenics	2352
	Y. Iwashita, Y. Fuwa, M. Hashida, S. Sakabe, S. Tokita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano, K. Watanabe, Y. Yamamoto KEK, Ibaraki, Japan K. Otani INRS-EMT, Varennes (Québec), Canada
	The high resolution camera, so-called Kyoto Camera, inspecting the Sc cavity inner surface showed the importance of nondestructive inspections to improve yield in production of high performance SC Cavities. Further efforts have been continued for the inspection and the high resolution T-map, X-map and eddy current scanner have been developed. A radiography to detect small voids inside the Nb EBW seam with the target resolution of 0.1 mm is under investigation. We have carried out radiography tests with X-rays induced from an ultra short pulse intense laser.

WEPWO061	Readiness for the Cornell ERL	emittance, cathode, cavity, linac	2447
	G.H. Hoffstaetter, A.C. Bartnik, I.V. Bazarov, D.H. Bilderback, M.G. Billing, J.D. Brock, J.A. Crittenden, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, R.D. Ehrlich, M. P. Ehrlichman, R. Eichhorn, K. Finkelstein, E. Fontes, M.J. Forster, S.J. Full, F. Furuta, D. Gonnella, S.W. Gray, S.M. Gruner, C.M. Gulliford, D.L. Hartill, Y. He, R.G. Helmke, K.M.V. Ho, R.P.K. Kaplan, S.S. Karkare, V.O. Kostroun, H. Lee, Y. Li, M. Liepe, X. Liu, J.M. Maxson, C.E. Mayes, A.A. Mikhailichenko, H. Padamsee, J.R. Patterson, S.B. Peck, S. Posen, P. Quigley, P. Revesz, D.H. Rice, D. Sagan, J. Sears, V.D. Shemelin, D.M. Smilgies, E.N. Smith, K.W. Smolenski, A.B. Temnykh, M. Tigner, N.R.A. Valles, V. Veshcherevich, A.R. Woll, Y. Xie, Z. Zhao CLASSE, Ithaca, New York, USA
	Funding: Supported by NSF award DMR-0807731 and NY State Energy-Recovery Linacs (ERLs) are proposed as drivers for hard x-ray sources because of their ability to produce electron bunches with small, flexible cross sections and short lengths at high repetition rates. Cornell University has pioneered the design and hardware for ERL lightsources. This preparatory research for ERL-lightsource construction will be discussed. Important milestones have been achieved in Cornell's prototype ERL injector, including the production of a prototype SRF cavity that exceeds design specifications, the regular production of long-lived and low emittance cathodes, the acceleration of ultra-low emittance bunches, and the world-record of 65 mA current from a photoemission DC gun. We believe that demonstration of the practical feasibility of these technologies have progressed sufficiently to allow the construction of an ERL-based lightsource like that described in [erl.chess.cornell.edu/PDDR].

WEPWO087	Parameter Optimization for Laser Polishing of Niobium for SRF Applications	niobium, cavity, SRF, target	2498
	L. Zhao, M.J. Kelley The College of William and Mary, Williamsburg, USA M.J. Kelley, J.M. Klopf, C.E. Reece JLAB, Newport News, Virginia, USA
	Surface smoothness is critical to the performance of SRF cavities. As laser technology has been widely applied to metal machining and surface treatment, we are encouraged to use it on niobium as an alternative to the traditional wet polishing process where aggressive chemicals are involved. In this study, we describe progress toward smoothing by optimizing laser parameters on BCP treated niobium surfaces. Results show that microsmoothing of the surface without ablation is achievable.
	Poster WEPWO087 [1.683 MB]

WEPEA012	Study of Laser Wakefield Accelerators as Injectors for Synchrotron Light Sources	synchrotron, lattice, simulation, storage-ring	2519
	S. Hillenbrand, V. Judin, A.-S. Müller KIT, Karlsruhe, Germany R.W. Aßmann, S. Hillenbrand CERN, Geneva, Switzerland O. Jansen, A.M. Pukhov HHUD, Dusseldorf, Germany
	Short bunch lengths, high beam energies, and small facility footprint make Laser Wakefield Accelerators (LWFA) very interesting as injectors for Synchrotron Light Sources. In this paper, we describe exemplary investigations for the ANKA storage ring.

WEPEA033	Optimization of Injector System for Early Commissioning Phase of Compact-ERL.	emittance, space-charge, solenoid, gun	2573
	J.G. Hwang, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea T. Miyajima KEK, Ibaraki, Japan
	Injector system of Compact-Energy Recovery Linear accelerator, which is currently develping in Photon Factory of KEK at Japan, consists of the photo-cathode DC gun, two solenoids, a 1.3 GHz buncher ,three 1.3 GHz 2 cell injector cavities, 5 quadrupole magnet and merger section. Target values of beam produced by the injector system are kinetic energy of 5 MeV, the normalized transverse emittance of under 0.1 mm-mrad and the bunch length of under 3 ps with the 7.7 pC charge per bunch and the repetition rate of 1.3 Ghz. In this low energy region, the effect of the space charge is dominated to cause the emittance growth. The optimization is performed by using MOGA (Multi-Object Genetic Algorithm) with code GPT to consider the effect of space charge under optimization. The code General Particle Tracer (GPT) is a 3D Paricle-In-Cell(PIC) code based on multi-layer object-oriented design. Using this method with code GPT, the target values was achieved at the exit of the merger section such as the normalized emittance of 0.1 mm-mrad with bunch length of 3 ps and kinetic energy of 5 MeV.

WEPFI036	R&D on a Main Accelerating Section of a Compact THz-FEL	electron, FEL, simulation, radiation	2780
	W. Bai, M. Li, X. Shen, H. Wang, X. Yang CAEP/IAE, Mianyang, Sichuan, People's Republic of China
	In order to develop a tera-hertz(THz) radiation source and to make scientific researches on application of THz technology, a study on tera-hertz source is performed. The radiation source is based on technology of free electron laser(FEL). The energy booster section of the injector uses a 9 Cell standing wave accelerator as the main accelerator for the FEL. The accelerator works at S band.(2856 MHz), excited by a microwave power of about 3.5 MW. At the end of the accelerator, the high quality beam energy is of 6.5MeV ~ 7 MeV, and the current about 300 mA. This paper presents the newly prgress of the , as well as the working condition of the main accelerator.

WEPFI037	Recent Status of a C-band 2MeV Accelerator	electron, target, linac, status	2783
	W. Bai CAEP/IAE, Mianyang, Sichuan, People's Republic of China
	In order to carry out engineering research on miniaturization of accelerator, we performs effort to develop C-band 2MeV standing wave accelerator. At present , the important progress has been achieved on the accelerator development. The accelerating tube has been fully sealed, and the hot test platform of the accelerator has been built. In condition of repetition rate of 200Hz, preliminary power test has been got through. Using ionization chamber dose monitor, we tested the dose rate of X-ray at 1m before the target. And by means of steel absorption method, we tested the energy of the electron beam. The preliminary test results are: beam energy about 2.0MeV, dose rate about 2Gy/min•m.

WEPFI065	The Commissioning of the EBTF S-band Photoinjector Gun at Daresbury Laboratory	cavity, klystron, electron, vacuum	2845
	A.E. Wheelhouse, R.K. Buckley, S.R. Buckley, P.A. Corlett, J.W. McKenzie, B.L. Militsyn, A.J. Moss STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The first stage of the installation of the Electron Beam Test Facility (EBTF) at Daresbury Laboratory has been completed and a commissioning phase is presently underway. At the heart of the machine is a photoinjector based on a two and a half cell S-band RF gun incorporating a metallic photocathode, which is capable of delivering 4-6 MeV, low emittance, short electron pulses (10 - 250 pC). The photoinjector is driven by a UV light at 266 nm wavelength delivered by a laser system and is powered by a RF system incorporating a Low Level RF system, a high power RF modulator and a klystron. This paper describes the commissioning and conditioning of the photoinjector.

WEPFI085	Source and Extraction for Simultaneous Four-hall Beam Delivery System at CEBAF	cavity, extraction, cathode, electron	2896
	R. Kazimi, J. Hansknecht, M. Spata, H. Wang JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A new design for simultaneous delivery of the electron beam to all four 12 GeV CEBAF experimental halls* requires a new 750 MHz RF separator system in the 5th pass extraction region, a 250 MHz repetition rate for its beams, and addition of a fourth laser at the photo-cathode gun. The proposed system works in tandem with the existing 500 MHz RF separators and beam repetition rate on the lower passes. The new 5th pass RF separators will have the same basic design but modified to run at 750 MHz. The change to the beam repetition rate will be at the photo-cathode gun through an innovative upgrade of the seed laser driver system using electro-optic modulators. The new laser system also allows addition of the fourth laser. The new RF separators, the new laser system and other hardware changes required to implement the Four-Hall operation delivery system will be discussed in this paper. * Simultaneous Four-Hall Operation for 12 GeV CEBAF, Proceedings of this conference.

WEPME006	Optical Synchronization and Electron Bunch Diagnostic at ELBE	electron, pick-up, feedback, wakefield	2932
	M. Kuntzsch, M. Gensch, U. Lehnert, F. Röser, R. Schurig HZDR, Dresden, Germany M. Bousonville, M.K. Czwalinna, H. Schlarb, S. Schulz, S. Vilcins DESY, Hamburg, Germany
	The continuous wave electron accelerator ELBE is upgraded to generate short and highly charged electron bunches (~200fs duration, up to 1 nC) . In the last years a prototype of an optical synchronization system using a mode locked fiber laser has been build up at ELBE which is now in commissioning phase. The stabilized pulse train can be used for new methods of electron bunch diagnostics like bunch arrival time measurements with the potential of femtosecond resolution. At ELBE a bunch arrival time monitor (BAM) has been designed and tested at the accelerator. The contribution will show the design of the BAM and first measurement results at the ELBE accelerator.

WEPME008	Precision LLRF Controls for the S-Band Accelerator REGAE	gun, LLRF, electron, controls	2938
	M. Hoffmann, H. Kay, U. Mavrič, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany W. Jałmużna, T. Kozak, A. Piotrowski TUL-DMCS, Łódź, Poland
	The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved experiments of material structure in pump-probe configuration. To achieve the desired 10 fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of 0.01% in amplitude and of 0.01deg in phase. To achieve these demanding stability a recently developed LLRF controller based on the Micro-Telecommunications Computing Architecture (MTCA.4) have been installed and commission. In this paper, we report on measurement performance of the LLRF system, the achieved stability and current limitations.

WEPME009	Recent Developments of the European XFEL LLRF System	LLRF, controls, cavity, beam-loading	2941
	Ch. Schmidt, G. Ayvazyan, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, T. Jeżyński, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, H.C. Weddig, B.Y. Yang DESY, Hamburg, Germany P. Barmuta, S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, D. Sikora, L. Zembala, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland W. Cichalewski, K. Gnidzińska, W. Jałmużna, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, A. Piotrowski, T. Pożniak, K.P. Przygoda TUL-DMCS, Łódź, Poland S. Korolczuk, I.M. Kudla, J. Szewiński NCBJ, Świerk/Otwock, Poland K. Oliwa, W. Wierba IFJ-PAN, Kraków, Poland
	The European XFEL is comprised of more than 800 TESLA-type super-conducting accelerator cavities which are driven by 25 high-power multi-beam klystrons. For reliable, reproducible and maintainable operation of linac, the LLRF system will process more than 3000 RF channels. Beside the large number of RF channels to be processed, stable FEL operation demands field stability better than 0.010deg in phase and 0.01% in amplitude. To cope with these challenges the LLRF system is developed on MTCA.4 platform. In this paper, we will give an update of the latest electronics developments, advances in the feedback controller algorithm and measurement results at FLASH.

WEPME016	Recent Progress of a Laser-based Alignment System at the KEKB Injector Linac	alignment, linac, controls, feedback	2959
	T. Suwada, M. Satoh KEK, Ibaraki, Japan K. Minoshima, S. Telada AIST, Tsukuba, Japan
	A new laser-based alignment system is under development in order to precisely align accelerator components with a precision level of ±0.1 mm along an ideal straight line at the KEKB injector linac. The high-precision alignment system is strongly required for the Super B-factory at KEK. The laser-based alignment system comprises a He-Ne laser source and optical components for delivering the laser beam, and silicon photodetectors. The laser-based alignment system aligns a misalignment of a girder unit for accelerating structures while accelerator components on the girder unit are aligned with another laser tracker system with a similar precision level. A new PC-based feedback system for the laser pointing stability has been introduced in order to stabilize the transverse laser positions at the photodetector. The experimental results show that although the laser pointing stability is easily disturbed by environmental factors without the feedback system, it has been successfully applied to control the laser pointing stability within a few ten-micron-meter. In this report, the experimental investigations in the new feedback system are reported.

WEPME018	Ytterbium Laser Development of DAW RF Gun for SuperKEKB	gun, linac, extraction, emittance	2965
	X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida KEK, Ibaraki, Japan
	For obtaining higher luminosity in the SuperKEKB, the photocathode RF electron gun with strong electric focusing field for high-current, low-emittance beams will be employed in the injector linac. 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 by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Furthermore, for reducing the emittance, the laser pulse width should be reshaped from Gaussian to rectangle structure. Therefore, Ytterbium (Yb)-doped laser system that provides broader bandwidth, higher amplify efficiency and higher output power is employed. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator and two steps Yb-fiber amplifier. To obtain the several 10mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPME021	Development of CO2 Laser Optical Enhancement Cavity for a Laser-Compton X-ray Source	cavity, scattering, polarization, photon	2974
	K. Ando, A. Endo, K. Sakaue, T. Takeichi, M. Washio Waseda University, Tokyo, Japan
	Funding: Work supported by NEDO (New Energy and Industrial Technology Development Organization). We have been developing a laser-Compton X-ray source using optical enhancement cavity. We have studied 1um pulse laser storage in optical cavity and use for the experiments. Usage of 10um laser for optical enhancement cavity will increase the X-ray energy region of one laser-Compton X-ray source, so that we decided to develop the optical cavity for CO2 laser. We have designed external optical cavity for CO2 laser commercially available optics and verified the enhancement of CO2 laser in external optical cavity, and measured fundamental parameters such as finesse, matching efficiency, and enhancement factor. We have already achieved 540 of finesse, 43 of enhancement, and tested non-planer cavity, which storages two circular polarization separately. In this conference, we will report the design and experimental results of CO2 laser storage cavity and also some future prospects.

WEPME024	Gaussian Spectrum Fiber Laser Pulses Generated in an All-normal-dispersion Cavity	cavity, controls, background, status	2983
	Y. You, W.-H. Huang, C.-X. Tang, L.X. Yan TUB, Beijing, People's Republic of China H. Shimizu, J. Urakawa KEK, Ibaraki, Japan
	In this paper, we reported generating a broad bandwidth Gaussian shape spectrum fiber laser pulse directly in an all-normal dispersive cavity. Pulse-shaping is based on spectral filtering. The spectrum has a ~20 nm 20-dB spectrum bandwidth and it is different from the typical spectrum, of steep edge and two spikes. The Gaussian spectrum is preferred since it can be dechirped to transform-limited pulsed duration. The pulse duration corresponds to this kind of spectrum is ~315fs, and pulse energy is up to~9nJ, with a repetition rate of 18.9MHz.

WEPME025	The Surveying Data Processing of Control Network based on HLS Upgrade	controls, survey, synchrotron, synchrotron-radiation	2986
	W. Wang, X.Y. He, P. Wang, S.F. Xu, Q.Y. Yao USTC/NSRL, Hefei, Anhui, People's Republic of China
	The paper introduces the data processing procedure of control network based on the HLS upgrade. The Spatial Analyzer developed by New River Kinematics was used to adjust the data of surveying, In order to check the correctness of the adjustment result, The MAA developed by IHEP was also employed to make three-dimensional adjustment as well as plane adjustment done by SURVEY adding elevation adjustment by NASEW2003. Through comparing the results adjusted by different software, the SA is demonstrated reliable. At last, the cause why different software produces different results was analyzed depending on the adjustment principle of different software.

WEPME035	Overview of the RF Synchronization System for the European XFEL	linac, LLRF, booster, undulator	3001
	K. Czuba, D. Sikora, L. Zembala Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland J. Branlard, F. Ludwig, H. Schlarb, H.C. Weddig DESY, Hamburg, Germany
	One of the most important requirements for the European XFEL RF system is to assure a very precise RF field stability within the accelerating cavities. The required amplitude and phase stability equals respectively dA/A <3·10^-5, dphi<0.01 deg @ 1.3GHz in the injector and dA/A<10^-3, dphi <0.1 deg @1.3GHz in the main LINAC section. Fulfilling such requirements for the 3.4 km long facility is a very challenging task. Thousands of electronic and RF devices must be precisely phase synchronized by means of harmonic RF signals. We describe the proposed architecture of the RF Master Oscillator and the Phase Reference Distribution System designed to assure high precision and reliability. A system of RF cable based interferometers supported by femtosecond-stable optical links will be used to distribute RF reference signals with required short and long term phase stability. We also present test results of prototype devices performed to validate our concept.

WEPME045	Development and Validation of a Multipoint Based Laser Alignment System for CLIC	alignment, linac, target, linear-collider	3028
	G. Stern, J. Kemppinen, F. Lackner, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin CERN, Geneva, Switzerland A. Geiger, S. Guillaume ETH, Zurich, Switzerland
	Alignment is one of the major challenges within CLIC study, since all accelerator components have to be aligned with accuracy up to 10 μm over sliding windows of 200 m. So far, the straight line reference concept has been based on stretched wires coupled with Wire Positioning Sensors. This concept should be validated through inter-comparison with an alternative solution. This paper proposes an alternative concept where laser beam acts as straight line reference and optical shutters coupled with cameras visualise the beam. The principle was first validated by a series of tests using low-cost components. Yet, in order to further decrease measurement uncertainty in this validation step, a high-precision automatised micrometric table and reference targets have been added to the setup. The paper presents the results obtained with this new equipment, in terms of measurement precision. In addition, the paper gives an overview of first tests done at long distance (up to 53 m), having emphasis on beam divergence.

WEPME046	Alignment Challenges for a Future Linear Collider	alignment, linac, collider, linear-collider	3031
	H. Mainaud Durand, D.P. Missiaen, G. Stern CERN, Geneva, Switzerland
	The preservation of ultra-low emittances in the main linac and Beam Delivery System area is one of the main challenges for linear colliders. This requires alignment tolerances never achieved before at that scale, down to the micrometre level. As a matter of fact, in the LHC, the goal for the smoothing of the components was to obtain a 1σ deviation with respect to a smooth curve of 0.15 mm in a 150 m long sliding window, while for the CLIC project for example, it corresponds to 10 micrometres over a sliding window of 200m in the Beam Delivery System area. Two complementary strategies are being studied to fulfill these requirements: the development and validation of long range alignment systems to propagate precision and accuracy over a few hundreds of metres and short range alignment systems over a few metres. The studies undertaken, with associated test setups and the latest results will be detailed, as well as their application for the alignment of both CLIC and ILC colliders.

WEPME048	Adjusting and Calibration Method for TPS Laser PSD System	alignment, factory, storage-ring, synchrotron	3037
	M.L. Chen, 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, T.C. Tseng, H.S. Wang, M.H. Wu NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	Laser PSD positioning system is a part of the TPS girder auto-alignment system and is designed for aligning and positioning the straight-section girders of TPS storage ring. Although the components of Laser PSD system are fabricated, assembling and adjusting precisely in advance, the accuracy of Laser PSD system is still influenced by girder fabricating quality, assembling errors and moving errors by transportation. For system correction, Laser beam positions on four sets of PSDs are formulized as an equation and calibrated with Laser tracker ultimately. According to the PSD calibration formula, the two girders of 18m long straight-section can be aligned and positioned within 20um by comparing with Laser tracker. This paper describes the assembly, installation and calibration process of Laser PSD system.

WEPME049	An Application of Laser Position Sensing Detector for Magnet Centralizing System	quadrupole, alignment, dipole, electron	3040
	C.-S. Lin, J.-R. Chen, M.L. Chen, P.S.D. Chuang, H.C. Ho, K.H. Hsu, D.-G. Huang, C.K. Kuan, W.Y. Lai, C.J. Lin, H.C. Lin, H.M. Luo, S.Y. Perng, P.L. Sung, T.C. Tseng, H.S. Wang, M.H. Wu NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) project has been proposed to create a 3GeV synchrotron light source. The designated ultra-low emittance of this new light source requires high precision positioning of storage ring magnets. The alignment of all magnets is very importance since it directly affects the closed orbit of electron beams. Previously, conventional on-site alignment of the magnets was mainly relying on the theodolite performance. The cumulated errors could be in the order of 0.1mm. In this paper, a new alignment scheme is proposed to enhance the on-site alignment of magnets for TPS project. To achieve the high precision requirements, a device possessing the advantages of expansion mandrel in conjunction with Position Sensing Detector (PSD) is proposed. The development of this alignment device is anticipated to provide a better mechanism to properly align the centers of the both quadrupole and sextupole magnets on girder with less than 30μm positioning errors.

WEPME050	Alignment Design and Status of Taiwan Photon Source	survey, alignment, storage-ring, site	3043
	W.Y. Lai, J.-R. Chen, M.L. Chen, P.S.D. Chuang, H.C. Ho, K.H. Hsu, D.-G. Huang, C.K. Kuan, C.-S. Lin, C.J. Lin, H.C. Lin, H.M. Luo, S.Y. Perng, P.L. Sung, T.C. Tseng, H.S. Wang, M.H. Wu NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) is a new 3-GeV ring with characteristics of great brightness and small emittance, at present under construction at National Synchrotron Radiation Research Center (NSRRC) Taiwan. The positioning of the magnets is highly sensitive to alignment errors, and the entire building will be constructed half underground at depth 12 m relative to Taiwan Light Source (TLS) for stability reasons; for these reasons the survey and alignment work is confined and difficult. To position magnets precisely and quickly, a highly accurate auto-tuning girder system combined with a survey network was designed to accomplish the alignment tasks. The survey network includes a preliminary Global Positioning System (GPS) network and a laser tracking network. The position data from the survey network define a basis for the system of motorized girders to auto-tune and to improve the accuracy. The detailed survey and alignment design, installation process is described in this paper.

WEPME057	Commission of the Drive Laser System for Advanced Superconducting Test Accelerator	gun, controls, monitoring, cryomodule	3061
	J. Ruan, M.D. Church, D.R. Edstrom, Jr, T.R. Johnson, J.K. Santucci Fermilab, Batavia, USA
	Currently an advanced superconducting test accelerator (ASTA) is being built at Fermilab. The accelerator will consist of a photo electron gun, injector, ILC-type cryomodules, multiple downstream beam lines for testing cryomodules and carrying advanced accelerator researches. In this paper we will report the commissioning and the drive laser system for this facility. It consists of a fiber laser system properly locked to the master frequency, a regen-amplifier, several power amplifier and final wavelength conversion stage. We will also report the characterization of the whole laser system and the performance of the laser system.

WEPME062	Short-Pulse Ti:Sapphire Laser System for Photocathode Research at SLAC	gun, cavity, cathode, diagnostics	3076
	W.J. Corbett, A. Brachmann, R.N. Coffee, A.R. Fry, S. Gilevich, N. Hartmann, W. Helml, P. Hering, E.N. Jongewaard, D. Kelley, J.R. Lewandowski, W. Polzin, J. Sheppard, P. Stefan, T. Vecchione, S.P. Weathersby, W.E. White, M. Woods, F. Zhou SLAC, Menlo Park, California, USA
	A photo-cathode research laboratory has been constructed at SLAC to test and characterize the spare LCLS electron gun. At the heart of the laboratory is a dual-purpose Ti:Sapphire oscillator/regen laser that can deliver either a 2.5ps, 760nm beam to the photocathode gun or a 35fs, 800nm beam to prototype diagnostics for the LCLS. The objective of the photocathode research is to definitively identify ‘recipes’ for high-reliability cathode processing resulting in high quantum efficiency and low beam emittance. The LCLS diagnostics program is presently aimed at developing spectral-encoding systems for shot-by-shot pulse arrival time measurements at the 10fs level. In this paper we review the Ti:Sapphire laser system and report on status of the photocathode and diagnostics programs.

WEPME063	Progress Report on Development of a 5-μm Drive Laser for Dielectric Laser Acceleration	acceleration, focusing, HOM, alignment	3079
	G. Xu, I. Jovanovic, S.F. Wandel Penn State University, University Park, Pennsylvania, USA E.R. Arab PBPL, Los Angeles, USA P.D. Hoang, P. Musumeci, B.D. O'Shea, J.B. Rosenzweig UCLA, Los Angeles, USA A.Y. Murokh, A.G. Ovodenko RadiaBeam, Santa Monica, USA I. Pogorelsky BNL, Upton, Long Island, New York, USA
	Funding: This work has been sponsored by Defense Advanced Research Project Agency. A simple and robust ultrafast, high-peak-power 5-μm laser source for pumping a dielectric photonic structure for high-gradient electron acceleration has been designed and is being constructed. The use of long wavelength drive lasers can mitigate the problem of dielectric structure breakdown caused by multiphoton ionization. In addition, structure fabrication requirements are relaxed, and greater energy can be stored in the structure. The 5-μm laser source consists of two components: (1) a type-II-beta-barium borate-based 2-μm optical parametric amplifier (OPA) as a pump source, and (2) a type-I-zinc-germaniu-phosphate-based 5-μm OPA to produce mJ-class, <100 fs pulses. Our supercontinuum seeded two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~1.4 mJ with a pulse duration of 42 fs (~6 optical cycles). Carrier-envelope phase (CEP) stabilization is passively established for 2 μm pulses in our OPA design. An modified design of seed pulse generation for the 5-μm OPA based on several cascaded parametric processes can also result in CEP-stable operation for 5-μm amplified pulses.

THOAB101	Laser Wire Based Parallel Profile Scan of H⁻ Beam at the Superconducting Linac of Spallation Neutron Source	ion, neutron, linac, pick-up	3090
	Y. Liu, A.V. Aleksandrov, D.L. Brown, R. Dickson, C. Huang, C.D. Long ORNL, Oak Ridge, Tennessee, USA C.C. Peters ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. We report on the world’s first experiment of a parallel profile scan of the hydrogen ion (H⁻) beam using a laser wire system. The system was developed at the superconducting linac (SCL) of the Spallation Neutron Source (SNS) accelerator complex. The laser wire profile scanner is based on a photo-detachment process and therefore can be conducted on an operational H⁻ beam in a nonintrusive manner. The parallel profile scanning system makes it possible to simultaneously measure profiles of the 1-MW neutron production H⁻ beam at 9 different locations (corresponding to energy levels of 400 – 950 MeV) of the superconducting linac using a single light source. The entire measurement process takes less than 5 minutes to complete. Together with the hardware modification, we have also upgraded our user interface to visualize the 9-pairs of H⁻ beam profiles in a real-time fashion, which presents a highly intuitive and informative picture of the H⁻ beam propagation along the acceleration path. The laser wire based parallel profile scanning system provides a powerful tool for accelerator operators and physicists to study the SCL modelling, monitor and/or tune the beam parameters.
	Slides THOAB101 [2.277 MB]

THOBB103	THz Electron-pulse-train Dynamics in a MeV Photo-injector	electron, acceleration, cathode, bunching	3109
	F.H. Chao, C.H. Chen, Y.-C. Huang NTHU, Hsinchu, Taiwan P.J. Chou NSRRC, Hsinchu, Taiwan
	A conventional free electron laser (FEL) is bulky and expensive. In order to quickly build up the FEL power in a short undulator, a laser technology has been proposed to generate a pre-bunched electron pulse-train with a THz bunching frequency from a photoinjector. The bunching factor* of an accelerated pulse-train beam is influenced by the beam radius, initial bunching frequency, space charge force, acceleration gradient, and acceleration phase in an accelerator. For a given RF accelerator and initial beam parameters, there is a limitation on the maximally attainable bunching factor and bunching frequency for the accelerated pulse-train beam. This paper presents a theoretical analysis for the bunching factor and bunching frequency of an accelerated pulse-train beam subject to nominal initial beam conditions in a photoinjector. The theoretical analysis is compared with the simulation results from the simulation code, PARMELA. To obtain an output bunching factor larger than 0.5%, our simulation study indicates that the maximum bunching frequency at the cathode is 25 THz for a 150 A beam current under a peak acceleration field of 80 MV/m. * Y.C. Huang, C.H. Chen, A.P. Lee, W.K. Lau, S.G. Liu, NIM, A, 637, S1–S6 (2011). ** Y.C Huang, Appl. Phys. Lett., 96, 231503 (2010).
	Slides THOBB103 [3.076 MB]

THPEA007	Upgrade of Safety Interlock System of e⁺/e⁻ Linac for SuperKEKB Project	linac, gun, PLC, status	3161
	A. Shirakawa, H. Honma, Y. Ogawa KEK, Ibaraki, Japan
	The upgrade of e⁺/e⁻ Injector Linac is going on for SuperKEKB project. The personal interlock system of the Linac has been upgrading several times according to the upgrade phase. One of the biggest changes has been made when the Linac was divided into two areas: upstream and downstream linacs, which allows us to work out the upgrade even during injection to Photon Factories at lower energies using the downstream linac. Most of the interlock system devices were duplicated to start the 'half' accelerator operation. Another remarkable update is to adopt an RF-Gun as a new electron source. We programmed a specific strong logic for the RF-Gun operation. These upgrades will be reported with the introduction of the whole interlock system.

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MOYBB101

Review of Laser Wakefield Accelerators

electron, plasma, injection, wakefield

11

V. Malka
LOA, Palaiseau, France

Funding: European Research Council for funding the PARIS ERC project (Contract No. 226424). EC FP7 LASERLABEUROPE/ LAPTECH (Contract No. 228334) EuCARD/ANAC, EC FP7 (Contract No. 227579)
This review talk will highlight the tremendous evolution of the research on laser wakefield accelerators* that has, in record time, led to the production of high quality electron beams beyond the GeV level, using compact laser systems. I will describe the path we followed to explore different injection schemes (bubble, colliding laser pulses, injection in gradient, longitudinal and transverse, ionisation injection) and I will present the most significant breakthroughs which allowed to generate stable, high peak current and high quality electron beams, with control of the charge, of the relative energy spread and of the electron energy. Modelling and experimental results will be as well reported with examples of applications**.
* V. Malka, Physics of Plasmas 19, 055501 (2012)
** V. Malka et al., Nature Physics 4, 447 (2008)

Slides MOYBB101 [14.550 MB]

MOODB101

Manufacturing of the First of Series SIS100 Dipole Magnet

dipole, synchrotron, instrumentation, magnet-design

31

St. Sattler, W. Gärtner, Dr. Scheller, R. Schönbein, W. Walter
BNG, Würzburg, Germany
E.S. Fischer, J.P. Meier, H. Müller, P. Schnizer
GSI, Darmstadt, Germany

Babcock Noell (Würzburg, Germany) manufactures the First of Series (FOS) SIS100 dipole magnet for the FAIR project. This contribution reports on the progress during the design-phase, performed together with GSI, and on the manufacturing- and assembly-processes. Special emphasis will be given on new or special techniques adopted to fulfill the stringent requirements demanded by such a magnet. The new tooling systems and machines which were developed and brought into operation for this FOS magnet will be discussed.

MOPEA014

Temporal and Spectral Observation of Laser-induced THz Radiation at DELTA

electron, radiation, storage-ring, simulation

94

P. Ungelenk, H. Huck, M. Huck, M. Höner, S. Khan, R. Molo, A. Schick
DELTA, Dortmund, Germany
N. Hiller, V. Judin
KIT, Karlsruhe, Germany

Funding: Work supported by the DFG, the BMBF, the Federal State NRW, the Initiative and Networking Fund of the Helmholtz Association, and the German Federal Ministry of Education and Research.
Coherent THz pulses caused by a laser-induced density modulation of the electron bunches are routinely produced and observed at DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University. New measurements performed with a fast hot-electron bolometer allow insight into the turn-by-turn evolution of these pulses. Furthermore, first results from a Fourier transform infrared spectrometer, which is currently under commissioning, are presented.

MOPEA022

Beam Profile Measurement for High Intensity Electron Beams

electron, scattering, photon, diagnostics

118

T. Weilbach, K. Aulenbacher, M.W. Bruker
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany

Recent developments in the field of high intensity electron beams in the regime below 10 MeV, e.g. energy recovery linacs or magnetized high energy electron coolers, have led to special demands on the beam diagnostics. Since commonly used diagnostic tools like synchrotron radiation and scintillation screens are ineffective or not able to withstand the beam power without being damaged, new methods are needed. Hence a beam profile measurement system based on beam induced fluorescence (BIF) was built. This quite simple system images the light generated by the interaction of the beam with the residual gas onto a PMT. A more elaborated system, the Thomson Laser Scanner (TLS) - the non-relativistic version of the Laser Wire Scanner - is proposed as a method for non-invasive measurement of all phase space components, especially in the injector and merger parts of an ERL. Both methods are implemented in a 100 keV photo gun. Beam profile measurements with BIF as well as first results of the TLS will be presented.

MOPFI001

Characterization of a Superconducting Pb Photocathode in a SRF Gun Cavity

cathode, gun, cavity, electron

279

R. Barday, T. Kamps, O. Kugeler, A. Neumann, M. Schmeißer, J. Völker
HZB, Berlin, Germany
P. Kneisel
JLAB, Newport News, Virginia, USA
R. Nietubyć
NCBJ, Świerk/Otwock, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany
J. Smedley
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Bundesministerium für Bildung und Forschung and Land Berlin. The Pb deposition activity is supported by EuCARD.
Photocathodes are a limiting factor for the next generation of ultra-high brightness photoinjector driven accelerators. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting rf gun cavity related to the quantum efficiency, its spatial distribution and the work function. Cathode surface contaminations can modify the performance of the photocathodes as well as the gun cavity. We discuss the possibilities to remove these contaminations.

MOPFI002

Results from Beam Commissioning of an SRF Plug-gun Cavity Photoinjector

cavity, emittance, cathode, gun

282

M. Schmeißer, R. Barday, A. Burrill, A. Jankowiak, T. Kamps, J. Knobloch, O. Kugeler, P. Lauinger, A. Neumann, J. Völker
HZB, Berlin, Germany
P. Kneisel
JLAB, Newport News, Virginia, USA
R. Nietubyć
NCBJ, Świerk/Otwock, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany
I. Will
MBI, Berlin, Germany

Superconducting rf photoelectron injectors (SRF guns) hold the promise to deliver high brightness, high average current electron beam for future lightsources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid Pb coated plug-gun Nb cavity based SRF photoinjector for beam energies up to 3 MeV at Helmholtz-Zentrum Berlin. Emittance measurements and transverse phase space characterization with solenoid-scan and pepperpot methods will be presented.

MOPFI006

A New Load Lock System for the Source of Polarised Electrons at ELSA

electron, polarization, vacuum, ion

294

D. Heiliger, W. Hillert, B. Neff
ELSA, Bonn, Germany

Funding: supported by DFG (SFB/TR16)
The inverted source of polarized electrons at the electron stretcher accelerator ELSA routinely provides a pulsed beam with a current of 100 mA and a polarization degree of about 80%. One micro-second long pulses with 100 nC charge are produced by irradiating a GaAs strained-layer superlattice photocathode (8 mm in diameter) with laser light. Future accelerator operation requires a significantly higher beam intensity, which can be achieved by using photocathodes with sufficiently high quantum efficiency. Therefore, and in order to enhance the reliability and uptime of the source, a new extreme high-vacuum (XHV) load lock system was installed and commissioned. It consists of a loading chamber in which an atomic hydrogen source is used to remove any remaining surface oxidation, an activation chamber for heat cleaning of the photocathodes and activation with cesium and oxygen and a storage chamber in which up to five different types of photocathodes with various diameters of the emitting surface can be stored under XHV conditions. Additionally, tests of the photocathodes' properties can be performed during accelerator operation.

MOPFI013

A Lifetime Study of CsK2Sb Cathode

cathode, electron, vacuum, brightness

309

M. Kuriki, H. Iijima, K. Miyoshi, N. Norihito
HU/AdSM, Higashi-Hiroshima, Japan

Funding: Cooperative and Supporting Program for Researches and Educations in　Universities by High energy accelerator research organization (KEK)
CsK2Sb multi-alkali cathode is one of the candidates of robust and high efficiency cathode for high brightness electron source. CsKSb can be driven by green laser and it is a big advantage comparing to Cs2Te cathode which is widely used as a robust photo-cathode and driven by UV light. In Hiroshima University, a test chamber for CsK2Sb photo-cathode study is developed. In the chamber, CsK2Sb photo-cathode is formed by evaporation on SUS base plate. During the evaporation, amount is monitored by quartz meter. We devised good locations of the evaporation source, base plate, and thickness monitor, so that all evaporation processes for Cs, K, and Sb are under control. The base plate temperature is also controlled during the cathode formation. More than 2.0% quantum efficiency was achieved at the first activation test. The cathode lifetime was more than 200 hours and more than 20C in charge. The latest experimental result will be reported.

MOPFI019

Beam Generation from a 500 kV DC Photoemission Electron Gun

gun, cathode, electron, high-voltage

321

N. Nishimori, R. Hajima, S.M. Matsuba, R. Nagai
JAEA, Ibaraki-ken, Japan
Y. Honda, T. Miyajima, M. Yamamoto
KEK, Ibaraki, Japan
H. Iijima, M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan
M. Kuwahara
Nagoya University, Nagoya, Japan

Funding: This work is supported by MEXT Quantum Beam Technology Program and partially supported by JSPS Grants-in-Aid for Scientific Research in Japan (23540353).
The next generation light source such as X-ray FEL oscillator requires high brightness electron gun with megahertz repetition rate. We have developed a DC photoemission electron gun at JAEA for the compact energy recovery linac (cERL) light source under construction at KEK. This DC gun employs a segmented insulator with guard rings to protect the insulator from field emission generated from central stem electrode. We have successfully applied 500-kV on the ceramics with a cathode electrode in place and generated beam from the 500kV DC photoemission gun in October 2012. Details of the beam generation test will be presented.

MOPFI023

Development of Better Quantum Efficiency and Long Lifetime Iridium Cerium Photocathode for High Charge electron RF Gun

cathode, electron, gun, linac

327

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

We developed an Ir5Ce photocathode as a high charge electron source for SuperKEKB electron linac. The required electron beam parameters are 5 nC and 10 mm•mrad from the electron gun of the SuperKEKB electron linac. We plan to generate this electron beam using a laser-driven RF gun installed with a photocathode that has a long lifetime and a high-power laser system through more than a year without replacement. Therefore, we focused on the Ir5Ce compound as a new photocathode which has a high melting point (> 2100 K) and a low work function (2.57 eV). The results of measurements showed that the quantum efficiency of Ir5Ce photocathode was 1.0×10^-4 treated by the laser cleaning using the 4nd harmonic of Nd:YAG laser or the heater treatment. Furthermore, its photoemission properties could be maintained for a long term even if its photocathode was in the low vacuum conditions ( ～10^-6 Pa) since the Ir5Ce compound is far less contaminated than other photocathodes. Finally, We have succeed to generate electron beams of 4.4 nC by the Ir5Ce photocathode installed at the 3-2 sector DAW type RF gun and accelerate it through a linac end in KEK electron linac.

MOPFI024

Ultra-short Electron Bunch Generation by an ECC RF Gun

gun, electron, radiation, cathode

330

Y. Koshiba, T. Aoki, M. Mizugaki, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by JSPS Grant-in-Aid for Young Scientists (B) 23740203 and Scientific Research (A) 10001690
Energy Chirping Cell attached rf gun (ECC rf gun) is a photocathode rf gun specialized for ultra-short bunch generation. This ECC rf gun has been made with the collaboration of High Energy Accelerator Research Organization (KEK). Although the bunch length could be controlled by the laser pulse width, the bunch length ends up to be more than 1ps due to space charge effect when using a femto-second laser and a normal 1.6 cell cavity. Concerning this phenomenon, ECC is attached right after the 1.6 cell so that the electron bunch would be compressed after the electron bunch is accelerated around 5MeV. The roll of ECC is to chirp the energy with the linear part of the rf electric field. The electron bunch would be compressed by velocity difference as it drifts. Simulation results from PARMELA and GPT show that ECC rf gun can accelerate an 100pC bunch with the bunch length less than 100fs. We already manufactured this ECC rf gun and installed in our system. We demonstrated the ultra-short bunch by measuring the coherent THz light by synchrotron radiation and transition radiation. In this conference, we will report the results of ultra-short bunch generation experiments, and future plans.

MOPFI038

Generation and Measurement of Sub-picosecond Electron Bunch in Photocathode RF Gun

electron, radiation, emittance, acceleration

372

W.W. Li, Z.G. He, R. Huang, Q.K. Jia, G. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

The generation of subpicosecond electron bunch in the photocathode rf gun was considered and simulated by improving the acceleration gradient of the gun, suitably tuning the charge of the electron bunch and the acceleration phase. To measure the length of the electron bunch, the design of a nondestructive bunch length measurement technology was also presented in this paper.

MOPFI058

Studies of Cs3Sb Cathodes for the CLIC Drive Beam Photoinjector Option

cathode, gun, electron, vacuum

413

I. Martini, E. Chevallay, S. Döbert, V. Fedosseev, C. Heßler, M. Martyanov
CERN, Geneva, Switzerland

Within the CLIC (Compact Linear Collider) project, feasibility studies of a photoinjector option for the drive beam as an alternative to its baseline design using a thermionic electron gun are on-going. This R&D program covers both the laser and the photocathode side. Whereas the available laser pulse energy in ultra-violet (UV) is currently limited by the optical defects in the 4th harmonics frequency conversion crystal induced by the 0.14 ms long pulse trains, recent measurements of Cs3Sb photocathodes sensitive to green light showed their potential to overcome this limitation. Moreover, using visible laser beams leads to better stability of produced electron bunches and one can take advantages of the availability of higher quality optics. The studied Cs3Sb photocathodes have been produced in the CERN photoemission laboratory using the co-deposition technique and tested in a DC gun set-up. The analysis of data acquired during the cathode production process will be presented in this paper, as well as the results of life-time measurements in the DC gun.

MOPFI062

Optimization Studies for the SwissFEL RF-Gun

gun, cathode, emittance, solenoid

425

M. Schaer, A. Adelmann, A. Anghel, S. Bettoni, P. Craievich, L. Stingelin, C. Vicario, R. Zennaro
PSI, Villigen PSI, Switzerland
Z. Zhang
TUB, Beijing, People's Republic of China

The 250 MeV SwissFEL injector test facility is in operation since August 2010. Measurements with the "CTF2 Gun 5" photocathode S-band rf-gun show promising beam parameters and satisfy the requirements of the SwissFEL project. Since the performance of the electron source is fundamental for the stability and brightness of a free electron laser, further gun optimization studies are pursued. Under investigation is currently a 3.6 cell C-band gun. First ASTRA simulations indicate that with this gun the peak-current can be increased, thanks to a shorter laser pulse and a higher initial acceleration, by almost a factor of two, at slightly better emittance values than the S-band "PSI Gun 1". Since the beam-quality depends also on the achieved performance of the cathode, several copper cathodes had been tested in the SwissFEL injector test facility to analyze the observed rapid degradation of quantum efficiency.

MOPFI065

VELA (formerly EBTF) Simulations and First Beam Commissioning

gun, diagnostics, simulation, electron

431

J.W. McKenzie, D. Angal-Kalinin, J.K. Jones, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

VELA (Versatile Electron Linear Accelerator), formerly known as EBTF (Electron Beam Test Facility), at STFC Daresbury Laboratory, is a photoinjector test facility which will provide beam into two user areas for scientific and industrial applications. It is based on a 2.5 cell S-band RF photoinjector driven by a Ti:Sapphire laser. The design is aimed to deliver short bunches at 10-250 pC charge with low transverse emittance. We present beam dynamics simulations of VELA as well as the results from first beam commissioning.

MOPFI068

High Repetition Rate Highly Stable S-band Photocathode Gun for the CLARA Project

gun, cavity, electron, cathode

437

B.L. Militsyn, L.S. Cowie, P. Goudket, S.P. Jamison, J.W. McKenzie, K.J. Middleman, R. Valizadeh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
V.V. Paramonov
RAS/INR, Moscow, Russia
M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Compact Linear Accelerator for Research and Applications (CLARA) is a 250 MeV electron facility which is under development at STFC ASTeC. The CLARA photo-injector is based on a RF photocathode gun operating with metal photocathodes and driven by a third harmonic of Ti: Sapphire laser (266 nm). The injector will be operated with laser pulses with an energy of up to 2 mJ, pulse durations down to 180 fs FWHM and a repetition rate of up to 400 Hz. In order to investigate performance of different photocathodes the gun is equipped with a load-lock system which would allow replacement of the photocathodes. Duration and emittance of electron bunches essentially depends on the mode of operation and vary from 0.1 ps at 20 pC to 5 ps at 200 pC and from 0.2 to 2 mm mrad respectively. Requirements for the stability of beam arrival time at the CLARA experimental area are extremely high and vary from hundreds down to tenths femtoseconds. In the presented article we analyse stability of the guns with 1.5 and 2.5 cell and the beam quality delivered by a gun with coaxial and waveguide coupler and analyse possibility of injection time stabilisation with low level RF and optical feedback system.

MOPFI074

Ultracold and High Brightness Electron Source for Next Generation Particle Accelerators

electron, plasma, brightness, emittance

452

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

The ultra-cold plasma-based electron source has recently been proposed as an alternative to the conventional photoemitters or thermionic electron guns, which are widely used in today’s particle accelerators. The advantages of the ultra-cold plasma-based electron source lie in the fact that the electron beam extracted from the cold plasma (from ionization of cold atoms) has very low electron temperature, e.g. down to 10 K, and has the potential for producing high brightness and ultra-short electron bunches. All these features are crucial for the next generation particle accelerators, e.g. free electron lasers, plasma-based accelerators and the future linear colliders. In this paper, we will introduce our proposed facility on cold electron source based at Photon Science Institute (PSI) in the University of Manchester.

MOPFI076

Electron Emission Studies in the New High-charge Cs2Te Photoinjector at Argonne National Laboratory

gun, cathode, wakefield, factory

455

E.E. Wisniewski, M.E. Conde, W. Gai, C.-J. Jing, W. Liu, J.G. Power
ANL, Argonne, USA
L.K. Spentzouris, Z.M. Yusof
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: This work was funded by the U.S. Dept. of Energy Office of Science under contract number DE-AC02-06CH11357.
A new L-band 1.3 GHz 1.5 cell gun for the new 75 MeV drive beam is being commissioned and will soon be operating at the Argonne Wakefield Accelerator (AWA) facility as part of the facility upgrade (see M. E. Conde, this proceedings.) The photoinjector is high-field (peak accelerating field > 80MV/m) and has a large \mathrm{Cs}₂\mathrm{Te} photocathode (diameter > 30 mm) fabricated in-house. The photoinjector generates high-charge, short pulse, single bunches (Q > 100 nC) or bunch-trains (Q ≈ 1000 nC) for wakefield experiments. Field emission from the \mathrm{Cs}₂\mathrm{Te} cathode is to be measured during RF conditioning and benchmarked against measurements from a copper cathode. Quantum efficiency (QE) will be measured in single and multi-bunch modes. Preliminary results are presented.

MOPFI078

The Possibility of Generation of High Energy Electron Beam at the SNS Facility

electron, acceleration, linac, solenoid

458

T.V. Gorlov, A.V. Aleksandrov, V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725
The linac of the SNS accelerator facility can be used to produce an electron beam with 300-400 MeV energy. At present there are a few predesigned experiments with electron beam that can be alternatively carried out at the SNS. However, the SNS linac is designed and optimized for acceleration of H⁻ , which brings some problems when considering direct acceleration of electrons. Alternative machine setup for electron acceleration and transport are discussed. Here, we present a study of the optimal electron beam parameters that can be achieved without any significant changes of the SNS accelerator.

MOPFI080

Fabrication, Transport and Characterization of Cesium Potassium Antimonide Cathode in Electron Guns

cathode, gun, vacuum, SRF

461

T. Rao, S.A. Belomestnykh, I. Ben-Zvi, X. Liang, I. Pinayev, B. Sheehy, J. Skaritka, J. Smedley, E. Wang, T. Xin
BNL, Upton, Long Island, New York, USA
R.R. Mammei, J.L. McCarter, M. Poelker
JLAB, Newport News, Virginia, USA
M. Ruiz-Osés
Stony Brook University, Stony Brook, USA

a number of accelerator applications need high current, low emittance and high brightness electron beams. Recent studies have shown cesium potassium antimonide to be a robust photocathode capable of producing high peak and average currents. However, for some applications, the UHV conditions required for producing these cathodes necessitate their fabrication site to be physically removed from the gun location and the cathode to be transferred between the two sites in UHV load-lock chambers. We have fabricated two cathodes at BNL, transported and tested them in DC gun at JLab at 100 kV and 200 kV. These cathodes have delivered up to 8A/cm² without significant degradation. Localized changes in the QE have been attributed to heating due to laser, increasing the QE at lower laser power, but damaging the cathode at higher power. Two more load-lock chambers have been built to transport and insert similar cathodes in SRF guns operating at 700 MHz and 112 MHz for the first time. In this paper, we will describe the design of the load-lock chambers, transfer mechanisms, transport of the cathodes over ~ 1000 km and the cathode performance in gun environment.

MOPME005

Goubau Line and Beam Characterization of TURBO-ICT for SwissFEL

instrumentation, FEL, resonance, electron

476

S. Artinian, J.F. Bergoz, F. Stulle
BERGOZ Instrumentation, Saint Genis Pouilly, France
P. Pollet, V. Schlott
PSI, Villigen PSI, Switzerland

SwissFEL will be able to operate with electron bunch doublets 28ns apart. Each of the bunches carries 10pC to 200pC of charge with bunch lengths of a few femto-seconds. For charge calibration of the FEL photon pulses, a measurement accuracy of 1% is desired. The Turbo-ICT accomplishes these requirements with negligible beam position and bunch length dependence. It is insensitive to dark current and features high immunity to background noise. We characterize the Turbo-ICT performance on a Goubau line, also known as single-wire transmission line. The Goubau line utilizes electromagnetic fields with frequencies up to many GHz. It allows accurate bench testing including beam position and bunch length dependence. The results are compared to beam measurements performed at the SwissFEL Injector Test Facility (SITF).

MOPME008

Beam Diagnostics by Using Bunch-by-bunch Feedback Systems at the DELTA Storage Ring

feedback, injection, kicker, electron

485

M. Höner, H. Huck, M. Huck, S. Khan, R. Molo, A. Schick, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Work supported by BMBF (05K10PEB)
At DELTA, a 1.5-GeV electron storage ring operated by the TU Dortmund University, longitudinal and transverse bunch-by-bunch feedback systems are in use to detect and suppress multi-bunch instabilities. Besides that, the digital feedback systems are excellent diagnostics tools. As an example, by exciting a certain number of bunches within the bunch train, the coupling to the non-excited bunches can be investigated below and above the instability threshold. Other examples include studies of the injection process and monitoring bunch oscillations during sudden beam loss. First experimental results will be presented in this paper.

MOPME014

Electro-optical Bunch Length Measurements at the ANKA Storage Ring

electron, wakefield, storage-ring, background

500

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

Funding: Supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320 and by the German Federal Ministry of Education and Research under contract number 05K10VKC
A setup for near-field electro-optical bunch length measurements has recently been installed into the UHV system of the ANKA storage ring. For electro-optical bunch length measurements during ANKA's low alpha operation, a laser pulse is used to probe the field induced birefringence in an electro-optical crystal (GaP in our case). The setup allows for both electro-optical sampling (EOS, multi-shot) and spectral decoding (EOSD, single- and multi-shot) measurements. This paper presents first results and discusses challenges of this method employed for the first time at a storage ring.

MOPME015

Numerical Wakefield Calculations for Electro-optical Measurements

simulation, wakefield, storage-ring, impedance

503

B. Kehrer, A. Borysenko, E. Hertle, N. Hiller, V. Judin, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh
KIT, Karlsruhe, Germany

Funding: This project is funded by the Federal Ministry of Education and Research under the contract number 05K10VKC
The technique of electro-optical measurements allows precise and single-shot measurements of the bunch length and shape. The installation of such a near-field setup changes the impedance of the storage ring and the corresponding effects have to be studied carefully. One possibility is to use numerical codes for simulating the wakefields induced by the setup. Such simulations has been done using the wakefield solver implemented in the CST Studio Suite. In this paper we present the simulation results together with first measurements.

MOPME029

Multi-strip Current Monitor for Pulsed Laser Plasma Diagnostics

plasma, ion, rfq, target

538

Y. Fuwa, Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
M. Okamura
BNL, Upton, Long Island, New York, USA

A compact position-sensitive beam instrumentation devise is under development. The beam detection area of this devise is composed of multi-strip electrodes and scanned by multiplexers, which reduces the number of read-out lines and feed-through connectors. Combined with an electrostatic deflector and ToF information, this monitor can discriminate charge to mass ratios of particles. A prototype of this monitor is fabricated for measurement of ion distribution and charge state in laser induced plasma. This model has fifteen strip electrodes and the multiplexed signal and the clock signal are read out through two coaxial cables. Thus, only three cables are needed including a +5V power supply line. The test result will be presented.

MOPME036

Prototype Experiment Preparation of a 54.167MHz Laser Wire System for FEL-THz Facility at CAEP

electron, photon, FEL, cathode

550

D. Wu
TUB, Beijing, People's Republic of China
W. Bai, M. Li, H. Wang, J. Wang, X. Yang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

In this paper, a prototype experiment preparation of a 54.167 MHz laser wire system is presented, which will be used to measure the beam size of a CW DC gun built as an electron source of FEL-THz facility in China Academmy of Engineering Physics (CAEP). The rms beam size is less than 1 mm and the average current of the electron beam is more than 1 mA. This new-type LW system ultilizes the excess power other the photocathode drive laser and becomes much cheaper and simpler. Plus, it can distinguish beams with different energies which are very close in ERLs. The system layout and the simulation results are also presented.

MOPME060

Introduction to Beam Diagnostics Components for PAL-ITF

electron, diagnostics, gun, radiation

610

H. J. Choi, M.S. Chae, J.H. Hong, C. Kim, D.T. Kim, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) is building the 4th generation X-ray free electron laser (XFEL). The Injection Test Facility (ITF) is a test facility established to improve the functions of the laser gun and pre-injector to be installed in XFEL. To improve the effects of ITF, two factors are required. The first is to be able to generate low-emittance electron beams stably at the laser gun, and the second is to control increasing emittance by space charge effect by accelerating electron beams with high energy at the pre-injector. In this way, high-quality electron beams can be materialized. Various beam diagnostics are installed in the accelerator system for beam diagnostics and measurements. Five kinds of beam diagnostics were installed in the PAL-ITF. These are (1) ICT and (2) Faraday Cup to measure current and electrons charge, (3) Stripline BPM to measure the location of beams, (4) a YAG/OTR Screen Monitor to measure beam energy and transverse profile motion and (5) a Wire Scanner to measure beam size. In this paper, the purposes and properties of each diagnostic unit and measurement results are introduced.

MOPME061

Femtosecond e-bunch Length Measurement at fs-THz Accelerator at PAL

radiation, electron, linac, gun

613

J.H. Ko, I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea

Longitudinal distribution of femto-second electron beam has been evaluated by the coherent transition radiation Michelson interferometer with the reconstruction procedure from interferograms. We measure the bunch length of the Thz Accelerator using interferogram method in Pohang Accelerator Lab and compare with the energy of transition radiation and bunch length.

MOPME075

Laser Based Stripping System for Measurement of the Transverse Emittance of H⁻ Beams at the CERN LINAC4

electron, linac, background, emittance

652

T. Hofmann, E. Bravin, U. Raich, F. Roncarolo
CERN, Geneva, Switzerland
B. Cheymol
ESS, Lund, Sweden

Funding: LA3NET is funded by the European Commission under Grant Agreement Number GA-ITN-2011-289191
The new LINAC4 at CERN will accelerate H⁻ particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H⁻ ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H⁰ atoms from the main H⁻ beam. By imaging these H⁰ atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material intercepting the H⁻ beam allows the measurement of a full power H⁻ beam. This paper will focus on the general design and integration of both the laser and H⁰ detector systems.

MOPME077

Electro-0ptical Bunch Profile Measurement at CTF3

electron, photon, vacuum, polarization

658

R. Pan, A. Andersson, W. Farabolini, A. Goldblatt, T. Lefèvre, M. Martyanov, S. Mazzoni, S.F. Rey, L. Timeo
CERN, Geneva, Switzerland
W.A. Gillespie, R. Pan, D.A. Walsh
University of Dundee, Nethergate, Dundee, Scotland, United Kingdom
S.P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

A new electro-optic bunch profile monitor has recently been installed in CLIC Test Facility 3 at CERN. The monitor is based on an electro-optic spectral decoding scheme which reconstructs the longitudinal profile of the electron bunch by measuring its Coulomb field. The system uses a 780 nm fibre laser system, transported over a 20m long distance to the interaction chamber, where a ZnTe crystal is positioned close to the beam. The assembly also contains a traditional OTR screen, which is coupled to a second optical line and used to adjust the temporal overlap between the laser and the electron pulse. This paper presents the detection system in detail, as well as reporting on the first measurements performed with beam.

MOPWA022

A 500 kV Pulser with Fast Risetime for EMP Simulation

high-voltage, simulation, pulsed-power, impedance

708

W. Jia, W.Q. Chen, J.N. Li, J.P. Tang, L.S. Xie, Y.Z. Xie, G.W. Zhang
NINT, Xi'an, People's Republic of China

A fast risetime generator with 500kV rated output voltage for the electromagnetic pulse ( EMP ) effects experiment is fabricated. It mainly consists of a low inductance Marx ge nerator, a compact independent-sealed peaking capacitor, an output switch, and a small quantity of gas-sealed insulated containers. Compared with other similar pulsers mentioned in IEC 61000-4-32, the insulated containers of the generator are independent of each other in gas-sealed structure, and its number is les s than that of other pulsers. It can be used to drive a guided wave antenna directly to produce an electromagnetic environment, which conformed with the new standard for high-altitude nuclear explosion electromagnetic pulse (HEMP) developed by IEC. Output voltage produced by the generator in demo-load state can reach to 600kV. And, risetime of the waveform is 1.2ns, pulse width (FWHM) being 32ns. When the generator driving a 10m guided-wave antenna, an output voltage with a risetime of no more than 2.7ns and a FWHM of 30ns is achieved.

MOPWA041

The New SLS Beam Size Monitor, First Results

emittance, polarization, synchrotron, radiation

759

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

Funding: This research has received funding from the European Commission under the FP7-INFRASTRUCTURES-2010-1/INFRA-2010-2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905.
An extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package “SLS Vertical Emittance Tuning” of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.

MOPWA049

Status Report of the FETS Photo Detachment Emittance Instrument at RAL

ion, emittance, diagnostics, dipole

783

C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
V.E. Scarpine
Fermilab, Batavia, USA

The Front End Test Stand at the Rutherford Appleton Laboratory (RAL) is being developed to demonstrate a chopped H⁻ beam of 60 mA at 3 MeV with 10% duty cycle. Due to the high beam power it is advisable to use the technique of photo detachment to avoid intrusive methods. It is intended to apply this technique to perform emittance measurements at the output of the RFQ at full power. This requires a dedicated diagnostics dipole with a special-made vacuum chamber giving room for the different beam paths necessary to install a particle detector to measure the produced neutrals. Other aspects are the beam transport and influence of the dipole and its fringe field to the beam transport Other considerations are the installation of the laser, the optics and the particle detector itself.

MOPWA053

Sub-Micrometre Resolution Laserwire Transverse Beam Size Measurement System

electron, alignment, photon, background

795

L.J. Nevay, G.A. Blair, S.T. Boogert, V. Karataev, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom
A.S. Aryshev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
L. Corner, R. Walczak
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project Eu-CARD, grant agreement no. 227579
We present the results from the laserwire system at the Accelerator Test Facility 2 (ATF2) during recent operation after relocation to the virtual image point of the ATF2 final focus. The characterisation of the 150 mJ, 77 ps long laser pulses at a scaled virtual interaction point is used to deconvolve the transverse laserwire profile demonstrating a 1.16 ± 0.06 um vertical electron beam profile. Horizontal laserwire scans were used in combination with the vertical scans to measure the electron beam size using a full overlap integral model due to the problems presented by a large aspect ratio electron beam.

MOPWA063

Proposed Coherent Diffraction Radiation Measurements of Bunch Length at ASTA

radiation, electron, cryomodule, gun

822

A.H. Lumpkin, J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The feasibility of using the autocorrelation of coherent diffraction radiation (CDR) as a non-intercepting diagnostics technique for bunch length and indirectly rf phase measurements is evaluated and proposed for the Advanced Superconducting Test Accelerator (ASTA) facility under construction at Fermilab. Previous experiments on an rf thermionic cathode gun beam at 50 MeV provide a proof-of-principle reference for the ASTA injector. The ASTA injector is based on an L-band rf photocathode (PC) gun with UV pulse drive laser, two L-band superconducting accelerator structures, a chicane bunch compressor, and an electron spectrometer. The injector energy of 40-50 MeV is expected. The 3-MHz micropulse repetition rate with micropulse charges up to to 3.2 nC and 1-ps bunch lengths should generate sufficient CDR signal for standard pyroelectric detectors to be used. The CDR signals will also be evaluated as a bunch compression signal for beam-based feedback for rf phase. The technique would also be applicable at high energy in straight transport lines after the cryomodules.

MOPWA069

Time-resolved Electron Beam Position Monitor Macropulse Waveform Measurement in MkV Linear Accelerator at University of Hawaii Free Electron Laser Laboratory

electron, FEL, controls, free-electron-laser

837

P. Niknejadi, M.R. Hadmack, B.T. Jacobson, J. Madey, G.S. Varner
University of Hawaii, Honolulu, HI, USA

Real time waveform measurements of electron beams will provide valuable data and possibility of online bunch diagnostics in linear accelerators. The University of Hawaii Linear Accelerator utilizes a thermionic LaB6 cathode microwave gun injector and a single section of S-band linear accelerator capable of producing a 40MeV, 1-2 ps bunched electron beam with average current of 200mA over the duration of a 4.5 us macropulse. This beam, pulsed at 4 Hz, produces strong RF signal at 2.856 GHz which is coupled out of the beam-pipe by a family of stripline beam position monitors (BPM's) and read out using custom built logarithmic-difference based electronics installed in 2012.* A high speed Analog to Digital Convertor and Field-Programmable Gate Array will be used to digitize the signal and record the waveform. The goal is to make a cost effective oscilloscope on a chip/board with feasible and functional operation to achieve optimal beam configuration. The circuit board design, in-circuit programming, waveform digitization challenges, and preliminary results from the prototype will be presented at the conference.
* B. T. Jacobson, M. R. Hadmack, J. M. J. Madey, P. Niknejadi "Modular Logarithmic Amplifier Beam Position Monitor Readout System at University of Hawai’i," IBIC Conf. Proc. (2012)

TUOCB102

SPARC_LAB Recent Results

electron, plasma, photon, FEL

1114

M. Ferrario, D. Alesini, M.P. Anania, A. Bacci, M. Bellaveglia, M. Castellano, E. Chiadroni, D. Di Giovenale, G. Di Pirro, A. Drago, A. Esposito, A. Gallo, G. Gatti, A. Ghigo, T. Levato, A. Mostacci, L. Palumbo, A.R. Rossi, B. Spataro, C. Vaccarezza, F. Villa
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
INFN-Roma II, Roma, Italy
G. Dattoli, E. Di Palma, L. Giannessi, A. Petralia, C. Ronsivalle, V. Surrenti
ENEA C.R. Frascati, Frascati (Roma), Italy
C. De Martinis
INFN/LASA, Segrate (MI), Italy
R. Faccini
INFN-Roma, Roma, Italy
M. Gambaccini
INFN-Ferrara, Ferrara, Italy
D. Giulietti
UNIPI, Pisa, Italy
L.A. Gizzi, L. Labate
CNR/IPP, Pisa, Italy
S. Lupi
Università di Roma I La Sapienza, Roma, Italy
V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
J.V. Rau
ISM-CNR, Rome, Italy
G. Turchetti
Bologna University, Bologna, Italy

A new facility named SPARC_LAB (Sources for Plasma Accelerators and Radiation Compton with Lasers and Beams) has been recently launched at the INFN National Labs in Frascati, merging the potentialities of the an ultra-brilliant electron beam photoinjector and of a high power Ti:Sa laser. The test facility is now completed, hosting a 150 MeV high brightness electron beam injector which feeds a 12 meters long undulator. Observation of FEL radiation in variuous configurations has been performed. In parallel to that a 200 TW laser that is linked to the linac and devoted to explore laser-matter interaction, in particular with regard to laser-plasma acceleration of electrons (and protons) in the self injection and external injection modes. The facility will be also used for particle driven plasma acceleration experiments (the COMB experiment). A Thomson scattering experiment coupling the electron bunch to the high-power laser to generate coherent monochromatic X-ray radiation is also in the commissioning phase. We report in this paper the recent results obtained at the SPARC_LAB facility.

Slides TUOCB102 [12.874 MB]

TUPEA008

Physics of the AWAKE Project

plasma, wakefield, electron, injection

1179

P. Muggli, E. Oz, R. Tarkeshian
MPI, Muenchen, Germany
C. Bracco, E. Gschwendtner, A. Pardons
CERN, Geneva, Switzerland
A. Caldwell, O. Reimann
MPI-P, München, Germany
K.V. Lotov
BINP SB RAS, Novosibirsk, Russia
A.M. Pukhov
HHUD, Dusseldorf, Germany
J. Vieira
IPFN, Lisbon, Portugal
M. Wing
UCL, London, United Kingdom

The goal of the AWKAKE collaboration is the study of plasma wakefields driven by proton (p⁺) bunches through experiments, simulations and theory. Proton bunches are interesting wakefield drivers because they can be ultra-relativistic (TeVs/p⁺) and carry large amounts of energy (>kJ). It was demonstrated in simulations* that acceleration of an electron (e-) bunch from 10GeV to >500GeV can be achieved in ~500m of plasma driven by a 1TeV, 100micron-long, bunch with 10¹¹ p+. Such short p⁺ bunches do not exist today. It was suggested** that a p⁺ bunch long compared to the plasma period can transversely self-modulate and resonantly drive wakefields to large amplitudes (~GV/m). Initial experiments based on self-modulation instability (SMI) will use single 12cm-long CERN SPS bunches with 1-3·10¹¹, 450GeV p⁺ to study physics of SMI. With a plasma density of 7·10¹⁴/cc the plasma wave and modulation period is 1.3mm. The SMI saturates after ~3m with amplitude in the GV/m range. Later a low energy (~10MeV) witness e^- bunch will be injected at the SMI saturation point. Energy gain over ~7m of plasma can reach the GeV level. Translation from physics to experimental plan and setup will be presented.
* A. Caldwell et al., Nature Physics 5, 363 (2009)
** N. Kumar et al., Phys. Rev. Lett. 104, 255003 (2010)

TUPEA010

FERMI Seeded FEL Progress Report

FEL, electron, undulator, free-electron-laser

1182

M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, 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, L. Giannessi, M. Kiskinova, G.L. Loda, M. Lonza, B. Mahieu, N. Mahne, C. Masciovecchio, F. Parmigiani, G. Penco, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, L. Sturari, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
P. Craievich
PSI, Villigen PSI, Switzerland
B. Mahieu
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France

Funding: Work supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
FERMI, the seeded Free Electron Laser located at the Elettra laboratory in Trieste, Italy, welcomed in December 2012 the first external users on the FEL-1 line. This line is based on a single stage of High Gain Harmonic Generation (HGHG), seeded by a UV laser, and covers wavelengths between 80 and 20 nm. The photon energy reached more than 300 μJ. The second FEL line, FEL-2, covering the lower wavelength range between 20 and 4 nm thanks to a double stage cascaded HGHG scheme, has generated its first coherent photons in October 2012. This is the first experimental demonstration of a seeded free electron laser configured as a two stages cascade operating in the "fresh bunch injection” mode, where the second stage is seeded by the light produced by the first stage. This paper describes the status of the operation and user experiments with FEL-1 and reports about the progress in the commissioning of FEL-2.

TUPEA011

Double Stage Seeded FEL with Fresh Bunch Injection Technique at FERMI@Elettra

FEL, electron, undulator, photon

1185

S. Di Mitri, E. Allaria, D. Castronovo, P. Cinquegrana, P. Craievich, G. D'Auria, M.B. Danailov, G. De Ninno, A.A. Demidovich, B. Diviacco, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, G. Gaio, L. Giannessi, R. Ivanov, B. Mahieu, N. Mahne, I. Nikolov, F. Parmigiani, G. Penco, L. Raimondi, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, M. Svandrlik, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
D. Gauthier
University of Nova Gorica, Nova Gorica, Slovenia

During the month of October 2012 the commissioning of the light source FEL-2 at FERMI was successfully concluded. Fermi FEL-2 is the first seeded FEL operating with a double stage cascade in the "fresh bunch injection" mode*. The two stages are two high gain harmonic generation FELs where the first stage is seeded by the 3rd harmonic of a Ti:Sa laser system, which is up converted to the 4th-12th harmonic. The output of the first stage is then used to seed the second stage. A final wavelength of 10.8 nm was obtained as the 24th harmonic of the seed wavelength at the end of the two frequency conversion processes, demonstrating that the FEL is capable of producing single mode narrow bandwidth pulses with an energy of several tens ofμjoules. We report on the experimental characterisation of the FEL performances in this configuration.
* I. Ben-Zvi, K. M. Yang, L. H. Yu, ”The ”fresh-bunch” technique in FELs”, NIM A 318 (1992), p 726-729

TUPEA016

Relativistic Theory for Laser-ion Acceleration

ion, acceleration, electron, plasma

1193

Y.S. Huang, Y.J. Shi, X.Z. Tang, N.Y. Wang
CIAE, Beijing, People's Republic of China

Funding: The Key Project of Chinese National Programs for Fundamental Research (973 Program) under contract No. 2011CB808104 and the Chinese National Natural Science Foundation under contract No. 11105233.
An analytical relativistic model is proposed to describe the relativistic ion acceleration in the interaction of ultra-intense laser pulses with thin-foil plasmas. It is found that there is a critical value of the ion momentum to make sure that the ions are trapped by the light sail and accelerated in the radiation pressure acceleration (RPA) region. If the initial ion momentum is smaller than the critical value, that is in the classical case of RPA, the potential has a deep well and traps the ions to be accelerated. There is a new ion acceleration region different from RPA, called ultra-relativistic acceleration, if the ion momentum exceeds the critical value. In this case, ions will experience a potential downhill. The dependence of the ion momentum and the self-similar variable at the ion front on the acceleration time has been obtained. The critical conditions of the laser and plasma parameters which identify the two acceleration modes have been achieved. No matter RPA or ultra-relativistic acceleration, the potential difference is a constant, which dedicates the maximum ion energy.

TUPEA017

Monoenergetic Electron Beams with Ultralow Normalized Emittance Generated from Laser-Gas Interaction

electron, plasma, emittance, simulation

1196

D.Z. Li, J. Gao, K. Huang, J. Jiarui, Y. Ma
IHEP, Beijing, People's Republic of China
L.M. Chen, W.C. Yan
Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China

High quality electron bunches are generated by using 2 TW, 80 fs, high contrast laser pulses interacting with helium gas targets. In optimized condition, we get tens MeV monoenergetic electron beams with small energy spread and the normalized emittance 0.07π mm·mrad. Due to its ultra small emittance and high initial energy, such bunch is very suitable for high current linear accelerators.

TUPEA018

Recent Progress of Laser Plasma Proton Accelerator at Peking University

plasma, proton, target, acceleration

1199

X.Q. Yan, J.E. Chen, H.Z. Fu, Y.X. Geng, Z.Y. Guo, C. Lin, Y.R. Lu, Y. Shang, Z.X. Yuan, S. Zhao, K. Zhu
PKU, Beijing, People's Republic of China

Funding: National Natural Science Foundation of China (Grant Nos.10935002, 10835003, 11025523)
Recent a project called Laser plasma Proton Accelerator (LAPA) is approved by MOST in China. A prototype of laser driven proton accelerator (1~15MeV) based on the PSA mechanism and plasma lens is going to be built at Peking University in the next five years. It can be used for the applications such as cancer therapy, plasma imaging and fast ignition for inertial confine fusion. The recent progress of LAPA is reported here.

TUPEA019

Proton Acceleration driven by High Energy Density Electrons

proton, acceleration, plasma, electron

1202

S. Zhao, C. Chao, J.E. Chen, H.Z. Fu, Y.X. Geng, C. Lin, B. Liu, H. Wang, X.Q. Yan
PKU, Beijing, People's Republic of China

Resonance Electrons Driving Ion Acceleration S. Zhao, C. Lin, X. Q. Yan Institute of Heavy Ion Physics, Peking University Proton acceleration driven by resonance electrons is proposed. Energetic electron beam generated through direct laser acceleration in the near critical dense plasma is dense and directional. When interacting with a thin foil target, resonance electrons can transmit the target and drive periodical electrostatic field at the back surface, therefore protons are more efficiently accelerated in a much longer distance in propagation direction of resonance electrons, compared to the classical target normal sheath acceleration. For a Gaussian laser pulse with pulse duration of 80fs, peak intensity I=1.38*10⁸W/cm² , the cutoff energy of the output collimated proton beam is 14MeV, enhanced by a factor of 3 or 4. The scaling law predicts hundreds MeV Proton beam can be generated in laser intensity of 10²⁰W/cm².

TUPEA028

Echo-enabled Harmonic Generation based on Hefei Storage Ring

FEL, electron, bunching, storage-ring

1208

H.T. Li, W.W. Gao, Q.K. Jia, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Echo-Enabled Harmonic Generation (EEHG) has been proposed and experimently demonstrated recently. In this paper, we numerically investigate the possibility of operating EEHG based on Hefei storage ring, which has a short circumference and a small momentum compaction factor. The difference to other similar reserch is that we use the whole ring as the first dispersive section and an optical klystron as the second one.

TUPEA029

Theory Calculation of PASER in Gas Mixture Active Medium

electron, resonance, wakefield, plasma

1211

X.F. Tian, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

In the PASER (particle acceleration by stimulated emission of radiation), the energy stored in an active medium transferred directly to the electron beam passing through in discrete amounts by emitting a photon when the bounded electron returns from upper to lower energy state. In this paper, the wake-field generated by a bunch of electrons traversing in an active medium has been discussed. The calculations of the development of amplitude for gas mixture active medium about CO2 and ArF were made respectively. The results show that the gradient can reach around 1GeV/m. In addition, the electron energy gain occurring as a train of electron micro-bunches traversing in gas mixture was analyzed by a two dimension model. The train of micro-bunches can obviously gain energy from the active medium and the energy exchange is linearly proportional to the interaction length d. The influence of the bunch figure and other quantities on the energy exchange occurring as a train of electron micro-bunches traversing CO2 gas mixture were investigated when the interaction length is 0.5m. The results illustrate that maximum electron energy gain can be obtained by the train of micro-bunches with optimized parameters.

TUPEA033

Proposals for Chirped Pulse Amplification in HGHG and CHG at SDUV-FEL

FEL, electron, radiation, undulator

1217

C. Feng, L. Shen, D. Wang, D. Xiang, M. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

In this paper, a proposal to generate intense ultra-short free-electron laser (FEL) pulses at Shanghai deep ultraviolet FEL (SDUV-FEL) by combining the chirped pulse amplification (CPA) technique with the high-gain harmonic generation (HGHG) technique is presented. In this proposal, a frequency chirped seed pulse obtained by stretching an ultra-short laser pulse is first used to create frequency-chirped bunching at the laser harmonics in an electron beam; then the frequency chirped harmonic radiation is amplified by an energy chirped electron beam; finally the output radiation pulse which inherits the properties of the seed pulse is compressed to provide an ultra-intense ultra-short radiation pulse. The feasibility and performance of this CPA-HGHG scheme are studied with start-to-end simulations using the parameters of the SDUV-FEL.

TUPEA038

Pre-chirp Control Broadband Non-collinear Optical Parametric Amplifier for the Future Laser Weak-field Accelerator

controls, electron

1223

L. Shen, C. Feng, L. Feng, D. Wang, H.F. Yao, W.Y. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Ultra-short pulse has been proved to be a very useful tool for accelerating electron close to GeV now. But limited by gain narrowing effect, conventional CPA technology is quite hard to get less than 30fs at high energy level. Non-collinear optical parametric amplification (NOPA) looks more and more attractive for generating super-broadbandwidth pulses which is possible to be compressed to ultra-short pulses. Previous NOPAs, pumped by 400nm pulses, were using BBO crystals to reach shorter signal pulse durations. But the associated spectral bandwidths are still strongly linked with higher order nonlinear effects. which make it quite difficult to get higher energy with short pulse duration. Here we proposed to use pre-chirped few nm bandwidths around 515nm pumped pulses to amplify ultra-short pulses centered at 800nm. In our setup, we have found just one dramatical geometry configuration which support that we have possibility to get amplification from 720nm to 900nm, which will support to less than 10fs by well re-compression. This design is well adapted for BBO crystals. But the idea could be used also for other crystals.

TUPEA042

Linac Design for Dalian Coherent Light Source

linac, FEL, emittance, simulation

1226

M. Zhang, H.X. Deng, D. Gu, Q. Gu
SINAP, Shanghai, People's Republic of China

Dalian Coherent Light (DCL) Source is a FEL user facility in which HGHG scheme is adopted. Beam quality requirements for the linear accelerator (linac) are critical, including not only the beam brightness, but also the stability and the reliability. In this paper, optimization study is performed for the linac. Based on beam stability simulation in the longitudinal direction, the tolerant budget is formed for the short period jitter. For the transverse orbit error, beam based alignment (BBA) technique is implemented by beam dynamics simulations and the transverse jitter is also presented accordingly. Measurement method for the beam quality is also described in the paper.

TUPEA051

Beam Transfer Line Design for a Plasma Wakefield Acceleration Experiment (AWAKE) at the CERN SPS

plasma, quadrupole, instrumentation, proton

1247

C. Bracco, J. Bauche, D. Brethoux, V. Clerc, B. Goddard, E. Gschwendtner, L.K. Jensen, A. Kosmicki, G. Le Godec, M. Meddahi, C. Mutin, J.A. Osborne, K.D. Papastergiou, A. Pardons, F.M. Velotti, H. Vincke
CERN, Geneva, Switzerland
P. Muggli
MPI, Muenchen, Germany

The world’s first proton driven plasma wakefield acceleration experiment is presently being studied at CERN. The experiment will use a high energy proton beam extracted from the SPS as driver. Two possible locations for installing the AWAKE facility are considered: the West Area and the CNGS long baseline beam-line. The previous transfer line from the SPS to the West Area was completely dismantled in 2000 and it would need to be fully re-designed and re-built. For this option, geometric constraints for radio protection reasons would limit the maximum proton beam energy to 300 GeV. The existing CNGS line could be used by applying only minor changes to the final part of the lattice for the final focusing and the interface between the proton beam and the laser, required for plasma ionisation and bunch-modulation seeding. The beam line design studies performed for the two options are presented.

TUPEA053

Feasibility Study of the AWAKE Facility at CERN

proton, plasma, electron, wakefield

1253

E. Gschwendtner, C. Bracco, B. Goddard, M. Meddahi, A. Pardons, E.N. Shaposhnikova, H. Timko, F.M. Velotti, H. Vincke
CERN, Geneva, Switzerland

Plasma Wakefield acceleration is a rapidly developing field which appears to be a promising candidate technology for future high-energy accelerators. The Proton Driven Plasma Wakefield Acceleration has been proposed as an approach to eventually accelerate an electron beam to the TeV energy range in a single plasma section. To verify this novel technique, a proof-of-principle demonstration experiment, AWAKE, is proposed using 400 GeV proton bunches from the SPS. Detailed studies on the identification of the best site for the installation of the AWAKE facility resulted in proposing the CNGS facility as best location. Design and integration layouts covering the beam line, the experimental area and all interfaces and services will be shown. Among other issues, radiation protection, safety and civil engineering constraints will be raised.

TUPEA058

The Conceptual Design of CLARA, A Novel FEL Test Facility for Ultrashort Pulse Generation

FEL, electron, photon, linac

1265

J.A. Clarke, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, P.A. Corlett, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, L. Ma, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, H.L. Owen, R.N.C. Santer, Y.M. Saveliev, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Appleby, M. Serluca, G.X. Xia
UMAN, Manchester, United Kingdom
R.J. Barlow, A.M. Kolano
University of Huddersfield, Huddersfield, United Kingdom
R. Bartolini, I.P.S. Martin
Diamond, Oxfordshire, United Kingdom
N. Bliss, R.J. Cash, G. Cox, G.P. Diakun, A. Gallagher, D.M.P. Holland, B.G. Martlew, M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
S.T. Boogert
Royal Holloway, University of London, Surrey, United Kingdom
G. Burt
Lancaster University, Lancaster, United Kingdom
L.T. Campbell, B.W.J. MᶜNeil
USTRAT/SUPA, Glasgow, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Lyapin
JAI, Egham, Surrey, United Kingdom
D. Newton, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
V.V. Paramonov
RAS/INR, Moscow, Russia

The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.

TUPEA059

CLARA Accelerator Design and Simulations

linac, diagnostics, FEL, emittance

1268

P.H. Williams, D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Science & Technology Facilities Council
We present the accelerator design for CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory. CLARA will be a testbed for novel FEL configurations. The accelerator will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. We describe the transport in detail including dedicated diagnostic sections. Beam dynamics simulations are then used to define a set of operating working points suitable for the different FEL schemes intended to be tested on CLARA.

TUPEA060

Jitter Tolerance for CLARA

linac, electron, cathode, FEL

1271

B.P.M. Liggins, J.K. Jones, J.W. McKenzie, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Science & Technology Facilities Council
CLARA (Compact Linear Accelerator for Research and Applications) at Daresbury Laboratory will be a test-bed for novel FEL configurations. CLARA will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. Ensuring stability of the VUV radiation pulses is a key aim of the project. To this end, we investigate in detail the jitter tolerance of the machine. This will ultimately determine the pulse stability.

TUPEA062

Advanced Gabor Lens Lattice for Medical Applications

ion, proton, space-charge, focusing

1277

J.K. Pozimski, M. Aslaninejad, P.A. Posocco
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The widespread introduction of Hadron therapy for cancer treatment is inhibited by the large costs for the accelerator and treatment facility and the subsequent maintenance costs which reflects into the cost per treatment. In the long term future (laser) plasma wakefield accelerated hadrons could offer compact treatment devices with significantly reduced treatment costs. In the moment the particle distributions produced by such accelerators do not fulfill the medical requirements. Beside the reliable production of a sufficient number of ions at the required energy the formation of a particle beam suitable for treatment from the burst of ions created in the acceleration process is one of the major challenges. While conventional optical systems will be operating at the technical limits which would be contradictory to the cost argument, space charge lenses of the Gabor type might be a cost effective alternative. An advanced beam line consisting of Gabor lenses, a few cavities and an dipole will be presented together with results from particle transport simulations.

TUPEA065

Design of a Photonic Crystal Accelerator for Basic Radiation Biology

vacuum, acceleration, electron, simulation

1283

A. Aimidula, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Aimidula, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
K. Koyama, Y. Matsumura
University of Tokyo, Tokyo, Japan
T. Natsui, M.Y. Yoshida
KEK, Ibaraki, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: This work is supported by the EU under Grant Agreement 289485, the STFC Cockcroft Institute Core Grant No. ST/G008248/1 and KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
The application of photonic crystals to realize an on-chip electron beam source for fundamental radiation biology is highly interesting for a number of applications. The unique combination of nanometer beam size and attosecond-short pulses has a very promising potential for use in microscopic and ultra-fast analyses of damage and repair of radiation-irradiated DNA and chromosomes. Simulations studies indicate an output electron beam energy, beam intensity and device size of the order of MeVs, fCs and a few cm, respectively. In this contribution, first results from numerical studies into the design of such compact accelerator structure are presented. The dimensions of a novel dual grating-based acceleration structure are shown together with the estimated laser parameters. Finally, a system consisting of an electron injector and multi-stage accelerating structures is proposed, which corresponds to a miniaturized optical linear accelerator.

TUPEA071

THz Bench Tests of a Slab-symmetric Dielectric Waveguide

acceleration, simulation, wakefield, emittance

1292

F. Lemery, H. Panuganti, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D. Mihalcea, P. Piot
Fermilab, Batavia, USA
P. Stoltz
Tech-X, Boulder, Colorado, USA

Funding: This work is supported by DTRA contract HDTRA1-10-1-0051 and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359.
Dielectric-lined waveguides (DLW) are becoming more popular for beam driven acceleration applications. An experiment to demonstrate beam-driven acceleration using a slab-symmetric dielectric-lined waveguide driven by a flat beam is in preparation at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In this paper we characterize the structure using a THz pulse obtained from optical rectification using an amplified laser pulse. After propagation through the DLW structure, the THz pulse is analyzed using a Michelson interferometer and single-shot electro-optical imaging. Data for various gap size will be presented.

TUPEA075

Passively Driving X-band Structures to Achieve Higher Beam Energies

electron, linac, impedance, gun

1304

S. Biedron, S.V. Milton, N. Sipahi, T. Sipahi
CSU, Fort Collins, Colorado, USA

Particle accelerators at X-band frequencies have gradients of around 100 MV/m. This technology permits more compact accelerators. One of our aims at the Colorado State University Accelerator Laboratory is to adapt this technology to our L-band (1.3 GHz) accelerator system to increase our overall beam energy; however, we would like to do this in a passive manner, i.e. one that does not require investment in an expensive, custom, high-power klystron system. In this paper we explore using the beam from our L-band 6 MeV photoinjector to power an x-band structure tuned to the 9th harmonic of our L-band system, 11.7 GHz. Electron bunches will be generated at a repetition rate of 81.25 MHz and passed through a high shunt impedance x-band accelerating structure where they will resonantly excite the fundamental field. We will optimize the system to create the highest accelerating potential within this structure. Once the peak gradient is achieved we will send a single electron bunch through the system at a phase that places it on the crest of the X-band accelerating wave thereby increasing the electron bunch energy by some amount without need for additional external power sources.

TUPEA079

Experimental Search For Acceleration in the Micro-accelerator Platform

electron, acceleration, vacuum, coupling

1307

J.C. McNeur, K.S. Hazra, B. Matthews, E.B. Sozer, G. Travish
UCLA, Los Angeles, USA
R.J. England, B. Montazeri, K. Soong, Z. Wu
SLAC, Menlo Park, California, USA
E.A. Peralta
Stanford University, Stanford, California, USA
R.B. Yoder
Goucher College, Baltimore, USA

The results of recent experimental efforts to observe acceleration in the Micro-Accelerator Platform (MAP) are detailed. The MAP is a slab-symmetric dielectric laser accelerator that when side illuminated by an optical laser, accelerates electrons via a standing wave resonance. This structure has been placed in the beamline at the NLCTA experimental hall at SLAC. A 60 MeV electron beam traverses the MAP when it is illuminated by a laser and, using a camera placed around a spectrometer bend magnet, signs of acceleration in the energy spectrum of the beam are searched for. The details of this search, as well as simulations that motivate the search, are elaborated on below.

TUPEA080

Numerical Modeling and Experimental Data Analysis for Dielectric Laser Accelerators

electron, acceleration, vacuum, GUI

1310

E.B. Sozer, K.S. Hazra, J.C. McNeur, G. Travish
UCLA, Los Angeles, USA
R.J. England, K. Soong
SLAC, Menlo Park, California, USA
E.A. Peralta
Stanford University, Stanford, California, USA
R.B. Yoder
Goucher College, Baltimore, USA

Funding: Work supported by a grant for the US Defense Threat Reduction Agency (DTRA).
Work on Dielectric Laser Accelerators (DLAs) has been ongoing for the past decade. These devices come in a variety of configurations but share the use of lasers as power sources and dielectrics as the primary building material. While these devices have many of the same characteristics and dynamics as conventional accelerating structures, they operate in a dramatically different regime. One version of these DLAs is the Micro Accelerator Platform (MAP): a slab-symmetric device operated with a standing wave (Pi-mode) and powered by a transversely coupled laser. The coupler is essentially a transmissive diffraction grating and therefore reinforced the desired mode. The remainder of the structure is composed of two Distributed Bragg Reflectors (DBRs) which serve to form a resonant cavity in an evacuated bounded by the reflectors. The MAP has now undergone experimental testing at SLAC’s E-163. As with many advanced accelerators, identifying the best data analysis approach demands extensive numerical modelling of the anticipated beam parameters and development of data visualization tools. We present the latest numerical results and data analysis tools developed for dielectric laser acceleration experiments with MAP.

TUPEA086

Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source

FEL, linac, emittance, electron

1316

Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou
SLAC, Menlo Park, California, USA
P. Emma
LBNL, Berkeley, California, USA

Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.

TUPEA089

Modeling and Experimental Update on Quasi-phase Matched Direct Laser Electron Acceleration In Density-modulated Plasma Waveguides

plasma, electron, simulation, target

1325

M.W. Lin, D.R. Abercrombie, I. Jovanovic, A. Rakhman
Penn State University, University Park, Pennsylvania, USA

Funding: This work has been supported by the Defense Threat Reduction Agency through Contract HDTRA1-11-1-0009.
Direct laser acceleration (DLA) of electrons using the axial electric field of a radially polarized, guided intense laser pulse has the potential to lead to compact laser-driven accelerators* for security and medical applications. A density-modulated plasma waveguide could be applied to extend the laser beam propagation distance and to achieve quasi-phase matching (QPM) between laser and electron pulses for efficient DLA**. We conduct numerical simulations to design the appropriate plasma structure of the waveguides and investigate the properties of accelerated electron beams. An all-optical method, based on the igniter-heater scheme for plasma waveguide fabrication, is experimentally implemented to machine the density-modulated plasma waveguides with low-Z gas targets. A novel angle-multiplexed diagnostic technique has been developed to extract the polarization state and temporal characteristics of a radially polarized femtosecond laser pulse using spatial-spectral interferometry***. The goal of our experiments is to characterize the propagation of femtosecond radially polarized pulses in plasma waveguides.
* P. Serafim, et al., IEEE Trans. Plasma Sci. 28, 1155 (2000).
** M. -W. Lin and I. Jovanovic, Phys. Plasmas 19, 113104 (2012).
***P. Bowlan, et al., Opt. Exp. 14, 11892 (2006)

TUPFI004

Longitudinal Manipulation to Obtain and Keep the Low Emittance and High Charge Electron Beam for SuperKEKB Injector

emittance, wakefield, alignment, gun

1337

M. Yoshida, N. Iida, T. Natsui, Y. Ogawa, S. Ohsawa, H. Sugimoto, L. Zang, X. Zhou
KEK, Ibaraki, Japan

The design strategy of SuperKEKB is based on the.nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, we installed new photocathode RF-Gun with the focusing electric field and temporal adjusting laser system. Further the projected emittance dilution in the LINAC is an important issue for the low emittance injection. The longitudinal bunch length and shape is an important key to avoid the space charge effect and emittance dilution. The longitudinal manipulation using the temporal adjusting laser system and the bunch compression will be presented. Further the longitudinal bunch measurement will be also presented.

TUPME010

High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB

positron, emittance, linac, electron

1583

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 10³⁵ /s.cm², 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.

TUPME013

Coherent Thomson Scattering using Beam Echo

electron, scattering, undulator, radiation

1592

K. Ohmi, S. Kamada
KEK, Ibaraki, Japan
H. Fares
Kanazawa University, Kanazawa, Japan

Longitudinal phase space of the beam is modulated by laser interacting in undulators. The beam can have higher frequency component using the beam echo than than the laser as dicussed by G. Stupakov et al. The modulated beam has a potential to emit coherent radiation with the wave length. We evaluate coherent short wave length (~nm) and/or short pulse (attosec) light source using the beam echo in a low energy accelerator ~100MeV.

TUPME015

Proposal of Polarized Gamma-ray Source for ILC Based on CSR Inverse Compton Scattering

electron, cavity, positron, scattering

1598

M. Shimada, K. Yokoya
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan
M. Tecimer
University of Hawaii at Manoa, Honolulu, USA

The positron source of International Linear Collider (ILC) requires a circular polarized gamma-ray with a flux more than 10¹⁶ phs./s and a helical undulator-based gamma-ray source is proposed in the baseline design. Although the undulator scheme is technically feasible, it is not easy for a stand-alone operation because of the required electron energy, ~ 150GeV. In this paper, we propose an alternative method, the inverse Compton scattering with a high-power mid-infrared optical pulse generated from coherent synchrotron radiation (CSR). To achieve the high flux gamma-ray, CSR with a few MHz is stacked in a high-finesse optical cavity made of a photonic crystal. In the proposed scheme, a stand-alone operation is feasible because the electron energy is less than 10GeV.

TUPME027

Advanced Studies on New Generation of Electron-positron Accelerators and Colliders for Fundamental and Applied Researches

electron, FEL, radiation, gun

1631

A. Dudarev, N. Balalykin, U.A. Budagov, V. Kobets, M.V. Lyablin, B.M. Sabirov, G. Shirkov, E. Syresin, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia

JINR actively leads the R&D works in particle accelerator physics and engineering, construction of the free electron laser with the aim to prepare proposals for the project of JINR participation in international collaboration on construction of the future Linear Collider (CLIC/ILC). JINR scientists and engineers study in free electron laser physics, development and construction of systems applied for formation and diagnostics of ultra short dense bunches in the linear electron accelerators. JINR physicists also take part in several fields of activity in ILC: works on photo injector prototype, participation in design and construction of cryomodules, laser metrology, and possible ILC location near Dubna.

TUPME031

Considerations for a Higgs Facility Based on Laser Wakefield Acceleration

plasma, luminosity, collider, electron

1643

S. Hillenbrand, A.-S. Müller
KIT, Karlsruhe, Germany
R.W. Aßmann, S. Hillenbrand, D. Schulte
CERN, Geneva, Switzerland

Laser Wakefield Accelerators have seen tremendous progress over the last decades. It is hoped that they will allow to significantly reduce the size and cost of a future liner collider. Based on scaling laws, laser-driven plasma accelerators are investigated as drivers for smaller scale facilities capable of producing Z and Higgs bosons.

TUPME062

Simulation and Analysis of Microbunching Instability in a High Repetition rate FEL Beam Delivery System

electron, simulation, linac, FEL

1709

J. Qiang, J.N. Corlett, P. Emma, C.E. Mitchell, M. Venturini
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.
Microbunching instability in the accelerator beam delivery system of an FEL can significantly degrade the electron beam quality and limit performance of the X-ray radiation. In this paper, we present detailed numerical simulation and analytical analysis of the microbunching instability in a high repetition rate X-ray FEL beam delivery system that is being studied at Lawrence Berkeley National Laboratory. Our results suggest that by using a flexible accelerator design and a laser heater, the effects of microbunching instability can be suppressed without significantly sacrificing the final electron beam quality.

TUPME067

Design Concept of a Gamma-gamma Higgs Factory Driven by Thin Laser Targets and Energy Recovery Linacs

photon, electron, target, collider

1721

Y. Zhang
JLAB, Newport News, Virginia, USA

Funding: Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177.
A gamma-gamma collider has long been considered an option for a Higgs Factory. Such photon colliders usually rely on Compton back-scattering for generating high energy gamma photons and further Higgs bosons through gamma-gamma collisions. The presently existing proposals or design concepts all have chosen a very thick laser target (i.e., high laser photon intensity) for Compton scatterings. In this paper, we present a new design concept of a gamma-gamma collider utilizing a thin laser target (i.e., relatively low photon density), thus leading to a low electron to gamma photon conversion rate. This new concept eliminates most useless and harmful low energy soft gamma photons from multiple Compton scattering so the detector background is improved. It also greatly relaxes the requirement of the high peak power of the laser, a significant technical challenge. A high luminosity for such a gamma-gamma collider can be achieved through an increase of the bunch repetition rate and current of the driven electron beam. Further, multi-pass recirculating linac could greatly reduce the linac cost and energy recovery is required to reduce the needed RF power.

TUPWA050

Effect of Transverse Coupling on Asymmetric Cooling in Compton Rings

emittance, coupling, electron, betatron

1823

E.V. Bulyak
NSC/KIPT, Kharkov, Ukraine
J. Urakawa
KEK, Ibaraki, Japan
F. Zimmermann
CERN, Geneva, Switzerland

Fast cooling of bunches circulating in a Compton ring is achieved by placing the collision point between electron bunches and laser pulses in a dispersive section and by, in addition, introducing a transverse offset between the laser pulse and the electron-beam closed orbit. Growth of the emittance in the dispersive transversal direction due to the additional excitation of betatron oscillations limits this type of cooling. Here we present the results of further studies on the fast cooling process, looking at the effect of the coupling of the transverse (betatron) oscillations. We first show theoretically that the transverse betatron coupling shortens the cooling time and hence reduces the steady-state energy spread of the electron beam, as well as the quantum losses. The theoretical estimates are then validated by simulations. Finally, a proof-of-principle experiment at the KEK ATF Damping Ring is proposed.

TUPWA058

Experimental Study of Soliton Wave Trains in Intense Electron Beams

electron, space-charge, simulation, induction

1835

Y. Mo, B.L. Beaudoin, D.W. Feldman, I. Haber, R.A. Kishek, P.G. O'Shea
UMD, College Park, Maryland, USA

Funding: Supported by the US Dept. of Energy, Office of High Energy Physics, and by the US Dept. of Defense, Office of Naval Research and the Joint Technology Office.
Longitudinal perturbations in intense beams can lead to instabilities or degradation of beam quality, ultimately affecting the performance of accelerators, especially near the source where space charge is important. In this experimental study, conducted on the University of Maryland Electron Ring (UMER), large-amplitude perturbations are purposefully generated and their propagation observed over a long transport length. It is found that narrow, large-amplitude perturbations on a long-pulse beam develop into Korteweg-deVries (KdV) type soliton wave trains. Each peak in the wave train has a constant width and amplitude over a long propagation distance, with the amplitude inversely proportional to the square of the width. Furthermore, two such pulses are seen to interact with each other and emerge from the collision unchanged. The experimental data is compared with the KdV model and particle-in-cell simulations with good agreement. We induce perturbations using two methods: using photoemission to perturb the density at the cathode, or using an induction cell to directly perturb particle velocities.

TUPWO007

Investigation of the Magnetic Chicane of the New Short-Pulse Facility at the DELTA Storage Ring

undulator, simulation, electron, klystron

1889

R. Molo, J.A. Grewe, H. Huck, M. Huck, M. Höner, S. Khan, A. Schick, P. Ungelenk
DELTA, Dortmund, Germany

Funding: Supported by DFG, BMBF, and the Federal State NRW.
The new short-pulse facility at DELTA (a 1.5-GeV synchrotron light source) based on coherent harmonic generation (CHG) utilizes an electromagnetic undulator which can be configured as optical klystron (undulator – chicane – undulator). To optimize the CHG signal, the energy modulation of the electrons in the first undulator and the dispersion of the magnetic chicane (i.e. the R56 matrix element) have to be optimized. Since the R56 value of the present chicane is not sufficient, it is planned to rewire the magnetic coils to create a more efficient chicane. Simulations of the present chicane will be compared to measurements of the R56 matrix element and a new chicane configuration will be presented which increases the R56 value by a factor of ten.

TUPWO029

Beam Line Design at the CAEP THz Free Electron Laser

electron, cavity, emittance, FEL

1937

P. Li, W. Bai, H. Wang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China
X. Li
TUB, Beijing, People's Republic of China

China Academy of Physics (CAEP) is currently building a THz Free Electron Laser (THz-FEL) which serves as a radiation light sourse used for research in a variety of experimental fields. In this paper, we present the design of the beam line, which was accomplished using PARMELA and TRANSPORT code simulations. The accelerator consists of a 350 kV photocathode DC gun in conjunction with one cryomodule containing two 4-cell superconductiong RF cavities. The energy of the elctron beam is 7~8 MeV, and the maximum of the average beam current is 5 mA. A transverse emittance typically below 10 pi mm.mrad can be achieved.

WEZB102

Overview of Seeding Methods for FELs

FEL, electron, radiation, undulator

2063

S. Reiche
PSI, Villigen PSI, Switzerland

In recent years enormous progress has been achieved in the theoretical understanding and experimental demonstration of FEL seeding. The state of the art for FEL seeding should be reviewed and compared to HHG, HGHG, EEHG techniques. The potential of various seeding methods and their promise to produce radiation pulses that approach the transform limit in a range of experimental configurations at different user facilities should be explored.

Slides WEZB102 [4.238 MB]

WEODB101

X-ray Spectra and Peak Power Control with iSASE

FEL, undulator, electron, radiation

2068

J. Wu, F.-J. Decker, Y. Feng, J. Krzywinski, H. Loos, A.A. Lutman, A. Marinelli, H.-D. Nuhn, C. Pellegrini, D.F. Ratner, D.H. Zhang, D. Zhu
SLAC, Menlo Park, California, USA

Funding: Work is supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
We report the first measurement of spectral line-width reduction in a self-amplified spontaneous emission (SASE) X-ray free-electron laser (FEL) obtained by introducing repeated delays of the electron bunch with respect to the radiation field pulse. The improved longitudinal coherence obtained by this method reduces the intensity spiking effect characteristic of a SASE FEL. The electron-photon delays introduced along the FEL undulator mix the spikes phase and amplitude, increasing the cooperation length and generating a smaller bandwidth than in the conventional SASE mode of operation of an FEL. We call this mode of operation, based on repeated electron-photon delays, ‘‘improved SASE'' (iSASE). We also show with theoretical and simulation analysis that in the iSASE mode it is possible to choose the separation and magnitude of the delays to obtain a nearly transform limited X-ray pulse. This analysis is carried out using a time dependent, one-dimensional model and with GENESIS numerical simulation, including three-dimensional effects.

Slides WEODB101 [7.647 MB]

WEPWA003

Hall-Probe Bench for Cryogenic in-Vacuum-Undulators

undulator, vacuum, cryogenics, permanent-magnet

2126

C. Kuhn, H.-J. Bäcker, J. Bahrdt, A. Gaupp, B. Schulz
HZB, Berlin, Germany

The Helmholtz-Zentrum Berlin (HZB) builds a 2m long in-vacuum-hall-probe-bench for the characterization of several cryogenic undulators currently under development. Short period lengths and small gaps require an accurate correlation between Hall probe position / orientation and the 3D-magnetic field. The geometric tolerances of an in-vacuum bench in the presence of strong temperature gradients do not permit a Hall probe movement along a straight line without corrections. The HZB-bench employs a system of laser interferometers and position sensitive detectors, which is used in a feed-back loop for the Hall probe position / orientation. First measurements on the accuracy and reproducibility of the new device are presented.

WEPWA005

Experimental Characterization of the Coherent Harmonic Generation Source at the DELTA Storage Ring

radiation, electron, undulator, synchrotron

2132

M. Huck, H. Huck, M. Höner, S. Khan, R. Molo, A. Schick, P. Ungelenk
DELTA, Dortmund, Germany
S. Cramm, L. Plucinski, C.M. Schneider
Forschungszentrum Jülich, Peter-Gruenberg-Institut-6, Jülich, Germany
S. Döring, L. Plucinski, C.M. Schneider
Universität Duisburg-Essen, Duisburg, Germany

Funding: Work supported by DFG, BMBF, and by the Federal State NRW.
The short-pulse facility at the 1.5-GeV synchrotron light source DELTA, operated by the TU Dortmund University, generates coherent VUV and THz radiation by Coherent Harmonic Generation (CHG). Here, a femtosecond laser pulse interacts with an electron bunch in an undulator causing a periodic energy modulation and subsequent micro-bunching, which gives rise to coherent radiation at harmonics of the seed wavelength. Rather than using Ti:Sapphire laser pulses at 795 nm directly, the second harmonic is employed for seeding since 2012. After significant modifications of the seed laser beamline and the dispersive chicane to improve the microbunching, the last commissioning steps include characterization of the CHG radiation and preparing the experimental setup at an existing VUV beamline for time-resolved photoemission spectroscopy. In this paper, the status of the project and recent experimental results are presented.

WEPWA008

Simulating the Bunch Structure in the THz Source FLUTE

simulation, space-charge, linac, dipole

2141

S. Naknaimueang, E. Huttel, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, M. Schreck, M. Schuh, M. Schwarz, M. Weber, P. Wesolowski
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

FLUTE is a planned THz source at KIT operating at a beam energy of 40 to 50 MeV in a wide bunch charge range. It consists of a laser driven rf-gun, a linac and a magnetic bunch compressor. The high current density combined with relatively low energy of FLUTE leads to complex strong self-field and beam-radiation field interactions, which are the limiting factors for the bunch compression efficiency. The results of numerical studies are presented in this paper.

WEPWA010

FLUTE: A Versatile Linac-based THz Source Generating Ultra-short Pulses

radiation, linac, gun, electron

2147

M.J. Nasse, E. Huttel, S. Marsching, A.-S. Müller, S. Naknaimueang, R. Rossmanith, R. Ruprecht, M. Schreck, M. Schuh, M. Schwarz, P. Wesolowski
KIT, Karlsruhe, Germany
R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
H.-H. Braun, R. Ganter, L. Stingelin
PSI, Villigen PSI, Switzerland

FLUTE is a linac-based accelerator test facility and a THz source currently being constructed at KIT with an electron beam energy of ~41 MeV. It is designed to cover a large charge range from a few pC to ~3 nC. FLUTE is optimized to provide ultra-short electron bunches with an RMS length down to a few fs. In this contribution, we focus on the layout of the machine from the RF gun & gun laser over the linac and the compressor to the THz beamline for the generation of coherent synchrotron, transition and edge radiation (CSR, CTR, CER).

Poster WEPWA010 [0.802 MB]

WEPWA015

Progress in Construction of the 35 MeV Compact Energy Recovery Linac at KEK

linac, gun, cryomodule, shielding

2159

S. Sakanaka, 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, 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, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, 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.M. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
JAEA, Ibaraki-ken, Japan
H. Takaki
ISSP/SRL, Chiba, Japan

The 35-MeV Compact Energy Recovery Linac (the Compact ERL or cERL) is under construction at the High Energy Accelerator Research Organization (KEK) in Japan. With the Compact ERL, we aim at establishing cutting-edge technologies for the GeV-class ERL-based synchrotron light source. To install the accelerator components of the cERL, we have constructed a shielding room having an area of about 60 m x 20 m. We have then installed a 500-kV DC photocathode gun, a 5-MV superconducting (SC) cryomodule for the injector, a 30-MV SC cryomodule for the main linac, and some of the other components. High-power test on the main SC cryomodule is underway in December, 2012. High-power or high-voltage tests on the injector cryomodule and on the DC gun are planned during January to March, 2013. An injector of the Compact ERL will be commissioned in April, 2013. We report the newest status of its construction.

WEPWA016

Production of Intense High Energy Gamma Beam for LEPS2 Project at SPring-8

injection, storage-ring, electron, scattering

2162

T. Yorita, T. Hotta, N. Muramatsu, T. Nakano, M. Oka, M. Yosoi
RCNP, Osaka, Japan
S. Daté, Y. Ohashi, H. Ohkuma, M. Oishi, Y. Okayasu, M. Shoji, S. Suzuki, Y. Taniuchi
JASRI/SPring-8, Hyogo-ken, Japan

Construction of new beam line for LEPS2 Project at SPring-8 has been done and development is now undergoing. LEPS2 is the project for high energy hadron physics using intense high energy gamma beam as probe. The gamma beam is produced by laser backward Compton scattering with injecting high power UV laser into the 8 GeV electron beam on long straight section of SPring-8 storage ring. The target intensities are ~10⁷/s for E_γ=2.4 GeV, ~10⁶/s for E_γ=2.9 GeV.

WEPWA017

Development of Laser-Compton X-ray Source using Optical Storage Cavity

electron, cavity, booster, linac

2165

K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
M.K. Fukuda, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by the Quantum Beam Technology Program of MEXT and JSPS Grant-in-Aid for Young Scientists (B) 23740203
We have been developing a pulsed-laser storage technique in a super-cavity for a compact x-ray sources. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. We already obtained a pulse-train x-rays through the laser-Compton scattering between a multi-bunch electron beam and an optical super-cavity. And also, we performed a X-ray imaging via laser-Compton X-ray. On these successful results, we decided to upgrade our system for increasing X-ray flux by 3-order of magnitudes for practical use. For an optical cavity, we designed 4-mirrors bow-tie cavity in order to increase the power. On the other hand, electron accelerator was also upgraded to increase the bunch number in the train. We use 3.6cells rf-gun and 12cell standing wave booster linac. As a result, 2-order increase of X-ray flux was achieved. Design of upgraded our laser-Compton X-ray source, the results of X-ray experiments and future prospective will be presented at the conference.

WEPWA020

Laser Electron Storage Ring for TTX

cavity, electron, storage-ring, quadrupole

2171

H.S. Xu, W.-H. Huang, C.-X. Tang, L.X. Yan, Y. You
TUB, Beijing, People's Republic of China
D. Jehanno, Z.F. Zomer
LAL, Orsay, France
S.-Y. Lee
IUCEEM, Bloomington, Indiana, USA

Tsinghua Thomson scattering X-ray (TTX) source, proposed by Tsinghua University, is a hard x-ray source with multi-application in condensed matter physics, etc. The TTX is composed of an S-band photocathode RF gun and a SLAC type 3m travelling wave Linac, and a femto-second tera-watt laser system drives the photocathode. The TTX source is in operation. To extend the capability of TTX, we plan to design a ring based system to increase the photon flux. In this paper, we report the design of the compact electron storage ring and optical cavity, expected performance, and future prospects.

WEPWA021

X-ray Spectra Reconstruction with HOPG Crystal on TTX

photon, scattering, simulation, electron

2174

Z. Zhang, Y.-C. Du, J.F. Hua, W.-H. Huang, C.-X. Tang, D. Wang, L.X. Yan
TUB, Beijing, People's Republic of China

Thomson Scattering sources, as the new generation of bright X-ray sources, have great application potential in many respects. Traditional spectra measurement methods, applied to measured the spectra of Thomson Scattering source, are troublesome as the X-ray beam is too intense to cause pile up problems. In this article, we use the HOPG crystal to reconstruct the X-ray spectra of Tsinghua Thomson X-ray source (TTX) through Braggs law. This method can get reasonable results with single or several shots, with high energy resolution. We also compare the experiment results of this method with the reconstructed spectra by analyzing the attenuation data of the X-ray beam in silicon , and these two results agree well with each other.

WEPWA029

Undulator Chamber R&D for SXFEL

undulator, vacuum, controls, free-electron-laser

2193

X. Hu, L. Yin
SINAP, Shanghai, People's Republic of China

The upcoming construction of Shanghai Soft X-ray Free Electron Laser Facility (SXFEL) will use 18 m small gap undulators. Each undulator is 3 meters long and will work at a minimum gap of 9 mm. This requires a vacuum chamber with an outer height of 8 mm and an elliptic inner aperture. The pressure inside of the chamber shall be less than 10^-5 Pa for the beam operation. An oxygen-free copper vacuum chamber was designed and a prototype was developed. This chamber includes three parts, a copper pipe manufactured by stretching, two flanges made of clad metal and a set of supports. The main fabrication procedure and the test results for the chamber prototype are described in this paper.

WEPWA037

Effect of Ground Vibration on the Out-coupled Power in a Terahertz FEL Oscillator

FEL, cavity, simulation, alignment

2211

Q. Fu, L.Z. Deng, B. Qin, P. Tan, Y.Q. Xiong, Y.B. Yibin, H. Zeng
HUST, Wuhan, People's Republic of China

To acquire high power out-coupled, we must ensure the co-axis of electron orbit, optical beam and magnetic field. The propagation of ground vibration through the optical platform will lead to misalignment of the optical axis in the FEL optical cavity. Based on measurement results of the ground vibration, simulations of misalignment are studied with GENESIS+OPC. The tolerance of mirror tilt and offset is also discussed.

WEPWA040

Options for PAL-XFEL Injector Operation

emittance, gun, FEL, cathode

2217

J.H. Han
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Chae
POSTECH, Pohang, Kyungbuk, Republic of Korea

Present designs of the PAL-XFEL injector assume a 120 MV/m peak field at the cathode in the gun and a flat-top longitudinal drive-laser profile. As accelerating field in the gun decreases and laser shape becomes imperfect, beam quality degradation takes place. On the other hand, by reducing accelerating field in the gun and by relaxing drive-laser shaping requirement the stability of the injector can be increased. We study various options for operating conditions of the injector with relaxed RF and drive-laser parameters.

WEPWA043

Construction of Injector Test Facility (ITF) for the PAL XFEL

gun, emittance, controls, klystron

2220

S.J. Park, H. J. Choi, T. Ha, J.H. Han, J.H. Hong, W.H. Hwang, H.-S. Kang, T.-H. Kang, D.T. Kim, J.M. Kim, S.-C. Kim, I.S. Ko, B.H. Lee, H.-S. Lee, W.W. Lee, C.-K. Min, Y.J. Park, Y.G. Son
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Chae
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: Work supported by the Ministry of Education, Science and Technology (MEST) in Korea.
An injector test facility (ITF) for the PAL-XFEL has been successfully constructed and its commissioning is under way. The facility is to demonstrate beam performances required by the PAL XFEL (beam energy of 139 MeV, projected rms emittance of < 0.5 mm mrad @ 200 pC, and beam repetition rate of 60 Hz) with good enough stabilities. We have constructed a dedicated building for the facility in which a radiation-shielding tunnel (19.2-m long, 3.5-m wide, and 2.4-m high inner space), a klystron-modulator gallery, a laser room, and a control room are installed. The injector consists of an in-house-developed photo-cathode rf gun, a 30-mJ Ti:Sa laser system, two accelerating structures (as well as two sets of klystron-modulator systems), and various diagnostics as well as magnets & instrumentations. The installation of a transverse deflecting cavity (S-band, 10-fs resolution) and a laser heater is scheduled in 2013. In this article we report on the facility construction and some of the early commisisoning results.

WEPWA058

Operation of the NSRRC 2998 MHz Photo-cathode RF Gun

gun, electron, cathode, cavity

2247

A.P. Lee, M.C. Chou, J.-Y. Hwang, W.K. Lau
NSRRC, Hsinchu, Taiwan
P. Chiu, N.Y. Huang, P. Wang
NTHU, Hsinchu, Taiwan

We are developing the photoinjector technology for single pass high gain FEL research at NSRRC. A gun test facility(GTF) equipped with a 35 MW, S-band high power pulsed klystron as well as a 300 uJ, UV driver laser has been constructed for testing photo-cathode rf guns. Recently, a 2998 MHz, 1.6-cell photo-cathode rf gun has been fabricated in house and is being tested at the NSRRC GTF. Details of this setup will be described and the operational performance of this electron gun will be reported.

WEPWA059

Operation of the Drive Laser System for the 2998 MHz NSRRC Photoinjector

gun, cathode, electron, target

2250

M.C. Chou, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan

A 266nm UV laser system has been installed as the drive laser of the NSRRC 2998 MHz photo-cathode rf gun. We will report our experiences on using such laser system for rf gun beam test. UV optics for laser beam transport as well as shaping technique we used for emittance preservation will also be presented.

WEPWA061

ALICE ERL Intra-train Variation Investigation using Bunch-by-bunch BPMs

FEL, cathode, linac, gun

2256

D. Angal-Kalinin, F. Jackson, S.P. Jamison, J.K. Jones, A. Kalinin, T.T. Thakker, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The ALICE ERL is an energy recovery test facility based at Daresbury Laboratory. We present investigations of charge and transverse variations/oscillations in the ALICE trains (up to 1600 bunches, spacing 55.2ns, bunch charge up to 60pC), using turn-by-turn EMMA BPMs adjusted for bunch-by-bunch measurements*. A set-up was established which allows use of pickups immediately downstream of the DC Gun as well as in the Arcs. To analyse variations, a DFT was used. It was established that a previously observed prominent (~10%) 300kHz charge envelope variation is a feature of the Photoinjector Laser. A set of transverse variations at 300kHz and below that depended on steering was also observed in the Injection Line. Downstream of the Booster, it was discovered that the transverse spectra are different. Prevailing quite regular variations (in range of 50um) were observed around 100kHz, manifesting themselves in the horizontal plane, present in non-dispersive regions, and dependent on trajectory offset in the Booster. We discuss the results, and also present our plans to apply this technique to a new single bunch injector EBTF now under commissioning in Daresbury Laboratory.
* A. Kalinin et al, MOPA30, IBIC12, Tsukuba, Japan.

WEPWA073

Compton Scattering Gamma-ray Light Source Modeling and Optimization

electron, radiation, brightness, photon

2283

F.V. Hartemann, R.A. Marsh, 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
In Compton scattering light sources, a short (ps to ns) laser pulse and a high brightness relativistic electron beam collide to yield tunable, monochromatic, polarized gamma-ray photons. The properties of the gamma-ray phase space is studied, in relation to the full electron bunch and laser pulse phase spaces, along with collimation, nonlinear effects and other sources of spectral broadening. This process has potential high impact applications in homeland security, nuclear waste assay, medical imaging and stockpile surveillance, among other areas of interest. Detailed theoretical modeling is outlined to aid the design of Compton light sources and provide optimization strategies relevant within the context of nuclear photonics applications.

WEPWA080

Development of a Compact Insertion Device for Coherent Sub-mm Generation

radiation, linac, impedance, wakefield

2295

A.V. Smirnov, R.B. Agustsson, S. Boucher, T.J. Grandsaert, J.J. Hartzell, M. Ruelas, S. Storms
RadiaBeam, Santa Monica, USA
A. Andrews, B.L. Berls, C.F. Eckman, K. Folkman, A.W. Hunt, Y. Kim, A.E. Knowles-Swingle, C. O'Neill, M. Smith
IAC, Pocatello, IDAHO, USA
P. Buaphad, Y. Kim
ISU, Pocatello, Idaho, USA

Funding: Department of Energy Contracts DE- SC-FOA-0000760 and DE-FG02-07ER84877
A novel design of resonant Cherenkov wakefield extractor that produced a ~0.9 mm wavelength radiation is presented. The experiment was performed at Idaho Accelerator Center (IAC) using specially upgraded 1.3 GHz 44 MeV linac facility. Specifics of the radiator performance and design are outlined including low-energy beam interaction with non-circular geometry. Some elements of the design may have certain potential for future compact mm-sub-mm-wave sources.

WEPWO017

Efforts on Nondestructive Inspections for SC Cavities

cavity, target, SRF, cryogenics

2352

Y. Iwashita, Y. Fuwa, M. Hashida, S. Sakabe, S. Tokita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano, K. Watanabe, Y. Yamamoto
KEK, Ibaraki, Japan
K. Otani
INRS-EMT, Varennes (Québec), Canada

The high resolution camera, so-called Kyoto Camera, inspecting the Sc cavity inner surface showed the importance of nondestructive inspections to improve yield in production of high performance SC Cavities. Further efforts have been continued for the inspection and the high resolution T-map, X-map and eddy current scanner have been developed. A radiography to detect small voids inside the Nb EBW seam with the target resolution of 0.1 mm is under investigation. We have carried out radiography tests with X-rays induced from an ultra short pulse intense laser.

WEPWO061

Readiness for the Cornell ERL

emittance, cathode, cavity, linac

2447

G.H. Hoffstaetter, A.C. Bartnik, I.V. Bazarov, D.H. Bilderback, M.G. Billing, J.D. Brock, J.A. Crittenden, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, R.D. Ehrlich, M. P. Ehrlichman, R. Eichhorn, K. Finkelstein, E. Fontes, M.J. Forster, S.J. Full, F. Furuta, D. Gonnella, S.W. Gray, S.M. Gruner, C.M. Gulliford, D.L. Hartill, Y. He, R.G. Helmke, K.M.V. Ho, R.P.K. Kaplan, S.S. Karkare, V.O. Kostroun, H. Lee, Y. Li, M. Liepe, X. Liu, J.M. Maxson, C.E. Mayes, A.A. Mikhailichenko, H. Padamsee, J.R. Patterson, S.B. Peck, S. Posen, P. Quigley, P. Revesz, D.H. Rice, D. Sagan, J. Sears, V.D. Shemelin, D.M. Smilgies, E.N. Smith, K.W. Smolenski, A.B. Temnykh, M. Tigner, N.R.A. Valles, V. Veshcherevich, A.R. Woll, Y. Xie, Z. Zhao
CLASSE, Ithaca, New York, USA

Funding: Supported by NSF award DMR-0807731 and NY State
Energy-Recovery Linacs (ERLs) are proposed as drivers for hard x-ray sources because of their ability to produce electron bunches with small, flexible cross sections and short lengths at high repetition rates. Cornell University has pioneered the design and hardware for ERL lightsources. This preparatory research for ERL-lightsource construction will be discussed. Important milestones have been achieved in Cornell's prototype ERL injector, including the production of a prototype SRF cavity that exceeds design specifications, the regular production of long-lived and low emittance cathodes, the acceleration of ultra-low emittance bunches, and the world-record of 65 mA current from a photoemission DC gun. We believe that demonstration of the practical feasibility of these technologies have progressed sufficiently to allow the construction of an ERL-based lightsource like that described in [erl.chess.cornell.edu/PDDR].

WEPWO087

Parameter Optimization for Laser Polishing of Niobium for SRF Applications

niobium, cavity, SRF, target

2498

L. Zhao, M.J. Kelley
The College of William and Mary, Williamsburg, USA
M.J. Kelley, J.M. Klopf, C.E. Reece
JLAB, Newport News, Virginia, USA

Surface smoothness is critical to the performance of SRF cavities. As laser technology has been widely applied to metal machining and surface treatment, we are encouraged to use it on niobium as an alternative to the traditional wet polishing process where aggressive chemicals are involved. In this study, we describe progress toward smoothing by optimizing laser parameters on BCP treated niobium surfaces. Results show that microsmoothing of the surface without ablation is achievable.

Poster WEPWO087 [1.683 MB]

WEPEA012

Study of Laser Wakefield Accelerators as Injectors for Synchrotron Light Sources

synchrotron, lattice, simulation, storage-ring

2519

S. Hillenbrand, V. Judin, A.-S. Müller
KIT, Karlsruhe, Germany
R.W. Aßmann, S. Hillenbrand
CERN, Geneva, Switzerland
O. Jansen, A.M. Pukhov
HHUD, Dusseldorf, Germany

Short bunch lengths, high beam energies, and small facility footprint make Laser Wakefield Accelerators (LWFA) very interesting as injectors for Synchrotron Light Sources. In this paper, we describe exemplary investigations for the ANKA storage ring.

WEPEA033

Optimization of Injector System for Early Commissioning Phase of Compact-ERL.

emittance, space-charge, solenoid, gun

2573

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

Injector system of Compact-Energy Recovery Linear accelerator, which is currently develping in Photon Factory of KEK at Japan, consists of the photo-cathode DC gun, two solenoids, a 1.3 GHz buncher ,three 1.3 GHz 2 cell injector cavities, 5 quadrupole magnet and merger section. Target values of beam produced by the injector system are kinetic energy of 5 MeV, the normalized transverse emittance of under 0.1 mm-mrad and the bunch length of under 3 ps with the 7.7 pC charge per bunch and the repetition rate of 1.3 Ghz. In this low energy region, the effect of the space charge is dominated to cause the emittance growth. The optimization is performed by using MOGA (Multi-Object Genetic Algorithm) with code GPT to consider the effect of space charge under optimization. The code General Particle Tracer (GPT) is a 3D Paricle-In-Cell(PIC) code based on multi-layer object-oriented design. Using this method with code GPT, the target values was achieved at the exit of the merger section such as the normalized emittance of 0.1 mm-mrad with bunch length of 3 ps and kinetic energy of 5 MeV.

WEPFI036

R&D on a Main Accelerating Section of a Compact THz-FEL

electron, FEL, simulation, radiation

2780

W. Bai, M. Li, X. Shen, H. Wang, X. Yang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

In order to develop a tera-hertz(THz) radiation source and to make scientific researches on application of THz technology, a study on tera-hertz source is performed. The radiation source is based on technology of free electron laser(FEL). The energy booster section of the injector uses a 9 Cell standing wave accelerator as the main accelerator for the FEL. The accelerator works at S band.(2856 MHz), excited by a microwave power of about 3.5 MW. At the end of the accelerator, the high quality beam energy is of 6.5MeV ~ 7 MeV, and the current about 300 mA. This paper presents the newly prgress of the , as well as the working condition of the main accelerator.

WEPFI037

Recent Status of a C-band 2MeV Accelerator

electron, target, linac, status

2783

W. Bai
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

In order to carry out engineering research on miniaturization of accelerator, we performs effort to develop C-band 2MeV standing wave accelerator. At present , the important progress has been achieved on the accelerator development. The accelerating tube has been fully sealed, and the hot test platform of the accelerator has been built. In condition of repetition rate of 200Hz, preliminary power test has been got through. Using ionization chamber dose monitor, we tested the dose rate of X-ray at 1m before the target. And by means of steel absorption method, we tested the energy of the electron beam. The preliminary test results are: beam energy about 2.0MeV, dose rate about 2Gy/min•m.

WEPFI065

The Commissioning of the EBTF S-band Photoinjector Gun at Daresbury Laboratory

cavity, klystron, electron, vacuum

2845

A.E. Wheelhouse, R.K. Buckley, S.R. Buckley, P.A. Corlett, J.W. McKenzie, B.L. Militsyn, A.J. Moss
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The first stage of the installation of the Electron Beam Test Facility (EBTF) at Daresbury Laboratory has been completed and a commissioning phase is presently underway. At the heart of the machine is a photoinjector based on a two and a half cell S-band RF gun incorporating a metallic photocathode, which is capable of delivering 4-6 MeV, low emittance, short electron pulses (10 - 250 pC). The photoinjector is driven by a UV light at 266 nm wavelength delivered by a laser system and is powered by a RF system incorporating a Low Level RF system, a high power RF modulator and a klystron. This paper describes the commissioning and conditioning of the photoinjector.

WEPFI085

Source and Extraction for Simultaneous Four-hall Beam Delivery System at CEBAF

cavity, extraction, cathode, electron

2896

R. Kazimi, J. Hansknecht, M. Spata, H. Wang
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new design for simultaneous delivery of the electron beam to all four 12 GeV CEBAF experimental halls* requires a new 750 MHz RF separator system in the 5th pass extraction region, a 250 MHz repetition rate for its beams, and addition of a fourth laser at the photo-cathode gun. The proposed system works in tandem with the existing 500 MHz RF separators and beam repetition rate on the lower passes. The new 5th pass RF separators will have the same basic design but modified to run at 750 MHz. The change to the beam repetition rate will be at the photo-cathode gun through an innovative upgrade of the seed laser driver system using electro-optic modulators. The new laser system also allows addition of the fourth laser. The new RF separators, the new laser system and other hardware changes required to implement the Four-Hall operation delivery system will be discussed in this paper.
* Simultaneous Four-Hall Operation for 12 GeV CEBAF, Proceedings of this conference.

WEPME006

Optical Synchronization and Electron Bunch Diagnostic at ELBE

electron, pick-up, feedback, wakefield

2932

M. Kuntzsch, M. Gensch, U. Lehnert, F. Röser, R. Schurig
HZDR, Dresden, Germany
M. Bousonville, M.K. Czwalinna, H. Schlarb, S. Schulz, S. Vilcins
DESY, Hamburg, Germany

The continuous wave electron accelerator ELBE is upgraded to generate short and highly charged electron bunches (~200fs duration, up to 1 nC) . In the last years a prototype of an optical synchronization system using a mode locked fiber laser has been build up at ELBE which is now in commissioning phase. The stabilized pulse train can be used for new methods of electron bunch diagnostics like bunch arrival time measurements with the potential of femtosecond resolution. At ELBE a bunch arrival time monitor (BAM) has been designed and tested at the accelerator. The contribution will show the design of the BAM and first measurement results at the ELBE accelerator.

WEPME008

Precision LLRF Controls for the S-Band Accelerator REGAE

gun, LLRF, electron, controls

2938

M. Hoffmann, H. Kay, U. Mavrič, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
W. Jałmużna, T. Kozak, A. Piotrowski
TUL-DMCS, Łódź, Poland

The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved experiments of material structure in pump-probe configuration. To achieve the desired 10 fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of 0.01% in amplitude and of 0.01deg in phase. To achieve these demanding stability a recently developed LLRF controller based on the Micro-Telecommunications Computing Architecture (MTCA.4) have been installed and commission. In this paper, we report on measurement performance of the LLRF system, the achieved stability and current limitations.

WEPME009

Recent Developments of the European XFEL LLRF System

LLRF, controls, cavity, beam-loading

2941

Ch. Schmidt, G. Ayvazyan, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, T. Jeżyński, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
P. Barmuta, S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, D. Sikora, L. Zembala, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
W. Cichalewski, K. Gnidzińska, W. Jałmużna, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, A. Piotrowski, T. Pożniak, K.P. Przygoda
TUL-DMCS, Łódź, Poland
S. Korolczuk, I.M. Kudla, J. Szewiński
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The European XFEL is comprised of more than 800 TESLA-type super-conducting accelerator cavities which are driven by 25 high-power multi-beam klystrons. For reliable, reproducible and maintainable operation of linac, the LLRF system will process more than 3000 RF channels. Beside the large number of RF channels to be processed, stable FEL operation demands field stability better than 0.010deg in phase and 0.01% in amplitude. To cope with these challenges the LLRF system is developed on MTCA.4 platform. In this paper, we will give an update of the latest electronics developments, advances in the feedback controller algorithm and measurement results at FLASH.

WEPME016

Recent Progress of a Laser-based Alignment System at the KEKB Injector Linac

alignment, linac, controls, feedback

2959

T. Suwada, M. Satoh
KEK, Ibaraki, Japan
K. Minoshima, S. Telada
AIST, Tsukuba, Japan

A new laser-based alignment system is under development in order to precisely align accelerator components with a precision level of ±0.1 mm along an ideal straight line at the KEKB injector linac. The high-precision alignment system is strongly required for the Super B-factory at KEK. The laser-based alignment system comprises a He-Ne laser source and optical components for delivering the laser beam, and silicon photodetectors. The laser-based alignment system aligns a misalignment of a girder unit for accelerating structures while accelerator components on the girder unit are aligned with another laser tracker system with a similar precision level. A new PC-based feedback system for the laser pointing stability has been introduced in order to stabilize the transverse laser positions at the photodetector. The experimental results show that although the laser pointing stability is easily disturbed by environmental factors without the feedback system, it has been successfully applied to control the laser pointing stability within a few ten-micron-meter. In this report, the experimental investigations in the new feedback system are reported.

WEPME018

Ytterbium Laser Development of DAW RF Gun for SuperKEKB

gun, linac, extraction, emittance

2965

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

For obtaining higher luminosity in the SuperKEKB, the photocathode RF electron gun with strong electric focusing field for high-current, low-emittance beams will be employed in the injector linac. 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 by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Furthermore, for reducing the emittance, the laser pulse width should be reshaped from Gaussian to rectangle structure. Therefore, Ytterbium (Yb)-doped laser system that provides broader bandwidth, higher amplify efficiency and higher output power is employed. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator and two steps Yb-fiber amplifier. To obtain the several 10mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPME021

Development of CO2 Laser Optical Enhancement Cavity for a Laser-Compton X-ray Source

cavity, scattering, polarization, photon

2974

K. Ando, A. Endo, K. Sakaue, T. Takeichi, M. Washio
Waseda University, Tokyo, Japan

Funding: Work supported by NEDO (New Energy and Industrial Technology Development Organization).
We have been developing a laser-Compton X-ray source using optical enhancement cavity. We have studied 1um pulse laser storage in optical cavity and use for the experiments. Usage of 10um laser for optical enhancement cavity will increase the X-ray energy region of one laser-Compton X-ray source, so that we decided to develop the optical cavity for CO2 laser. We have designed external optical cavity for CO2 laser commercially available optics and verified the enhancement of CO2 laser in external optical cavity, and measured fundamental parameters such as finesse, matching efficiency, and enhancement factor. We have already achieved 540 of finesse, 43 of enhancement, and tested non-planer cavity, which storages two circular polarization separately. In this conference, we will report the design and experimental results of CO2 laser storage cavity and also some future prospects.

WEPME024

Gaussian Spectrum Fiber Laser Pulses Generated in an All-normal-dispersion Cavity

cavity, controls, background, status

2983

Y. You, W.-H. Huang, C.-X. Tang, L.X. Yan
TUB, Beijing, People's Republic of China
H. Shimizu, J. Urakawa
KEK, Ibaraki, Japan

In this paper, we reported generating a broad bandwidth Gaussian shape spectrum fiber laser pulse directly in an all-normal dispersive cavity. Pulse-shaping is based on spectral filtering. The spectrum has a ~20 nm 20-dB spectrum bandwidth and it is different from the typical spectrum, of steep edge and two spikes. The Gaussian spectrum is preferred since it can be dechirped to transform-limited pulsed duration. The pulse duration corresponds to this kind of spectrum is ~315fs, and pulse energy is up to~9nJ, with a repetition rate of 18.9MHz.

WEPME025

The Surveying Data Processing of Control Network based on HLS Upgrade

controls, survey, synchrotron, synchrotron-radiation

2986

W. Wang, X.Y. He, P. Wang, S.F. Xu, Q.Y. Yao
USTC/NSRL, Hefei, Anhui, People's Republic of China

The paper introduces the data processing procedure of control network based on the HLS upgrade. The Spatial Analyzer developed by New River Kinematics was used to adjust the data of surveying, In order to check the correctness of the adjustment result, The MAA developed by IHEP was also employed to make three-dimensional adjustment as well as plane adjustment done by SURVEY adding elevation adjustment by NASEW2003. Through comparing the results adjusted by different software, the SA is demonstrated reliable. At last, the cause why different software produces different results was analyzed depending on the adjustment principle of different software.

WEPME035

Overview of the RF Synchronization System for the European XFEL

linac, LLRF, booster, undulator

3001

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

One of the most important requirements for the European XFEL RF system is to assure a very precise RF field stability within the accelerating cavities. The required amplitude and phase stability equals respectively dA/A <3·10^-5, dphi<0.01 deg @ 1.3GHz in the injector and dA/A<10^-3, dphi <0.1 deg @1.3GHz in the main LINAC section. Fulfilling such requirements for the 3.4 km long facility is a very challenging task. Thousands of electronic and RF devices must be precisely phase synchronized by means of harmonic RF signals. We describe the proposed architecture of the RF Master Oscillator and the Phase Reference Distribution System designed to assure high precision and reliability. A system of RF cable based interferometers supported by femtosecond-stable optical links will be used to distribute RF reference signals with required short and long term phase stability. We also present test results of prototype devices performed to validate our concept.

WEPME045

Development and Validation of a Multipoint Based Laser Alignment System for CLIC

alignment, linac, target, linear-collider

3028

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

Alignment is one of the major challenges within CLIC study, since all accelerator components have to be aligned with accuracy up to 10 μm over sliding windows of 200 m. So far, the straight line reference concept has been based on stretched wires coupled with Wire Positioning Sensors. This concept should be validated through inter-comparison with an alternative solution. This paper proposes an alternative concept where laser beam acts as straight line reference and optical shutters coupled with cameras visualise the beam. The principle was first validated by a series of tests using low-cost components. Yet, in order to further decrease measurement uncertainty in this validation step, a high-precision automatised micrometric table and reference targets have been added to the setup. The paper presents the results obtained with this new equipment, in terms of measurement precision. In addition, the paper gives an overview of first tests done at long distance (up to 53 m), having emphasis on beam divergence.

WEPME046

Alignment Challenges for a Future Linear Collider

alignment, linac, collider, linear-collider

3031

H. Mainaud Durand, D.P. Missiaen, G. Stern
CERN, Geneva, Switzerland

The preservation of ultra-low emittances in the main linac and Beam Delivery System area is one of the main challenges for linear colliders. This requires alignment tolerances never achieved before at that scale, down to the micrometre level. As a matter of fact, in the LHC, the goal for the smoothing of the components was to obtain a 1σ deviation with respect to a smooth curve of 0.15 mm in a 150 m long sliding window, while for the CLIC project for example, it corresponds to 10 micrometres over a sliding window of 200m in the Beam Delivery System area. Two complementary strategies are being studied to fulfill these requirements: the development and validation of long range alignment systems to propagate precision and accuracy over a few hundreds of metres and short range alignment systems over a few metres. The studies undertaken, with associated test setups and the latest results will be detailed, as well as their application for the alignment of both CLIC and ILC colliders.

WEPME048

Adjusting and Calibration Method for TPS Laser PSD System

alignment, factory, storage-ring, synchrotron

3037

M.L. Chen, 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, T.C. Tseng, H.S. Wang, M.H. Wu
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

Laser PSD positioning system is a part of the TPS girder auto-alignment system and is designed for aligning and positioning the straight-section girders of TPS storage ring. Although the components of Laser PSD system are fabricated, assembling and adjusting precisely in advance, the accuracy of Laser PSD system is still influenced by girder fabricating quality, assembling errors and moving errors by transportation. For system correction, Laser beam positions on four sets of PSDs are formulized as an equation and calibrated with Laser tracker ultimately. According to the PSD calibration formula, the two girders of 18m long straight-section can be aligned and positioned within 20um by comparing with Laser tracker. This paper describes the assembly, installation and calibration process of Laser PSD system.

WEPME049

An Application of Laser Position Sensing Detector for Magnet Centralizing System

quadrupole, alignment, dipole, electron

3040

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

Taiwan Photon Source (TPS) project has been proposed to create a 3GeV synchrotron light source. The designated ultra-low emittance of this new light source requires high precision positioning of storage ring magnets. The alignment of all magnets is very importance since it directly affects the closed orbit of electron beams. Previously, conventional on-site alignment of the magnets was mainly relying on the theodolite performance. The cumulated errors could be in the order of 0.1mm. In this paper, a new alignment scheme is proposed to enhance the on-site alignment of magnets for TPS project. To achieve the high precision requirements, a device possessing the advantages of expansion mandrel in conjunction with Position Sensing Detector (PSD) is proposed. The development of this alignment device is anticipated to provide a better mechanism to properly align the centers of the both quadrupole and sextupole magnets on girder with less than 30μm positioning errors.

WEPME050

Alignment Design and Status of Taiwan Photon Source

survey, alignment, storage-ring, site

3043

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

Taiwan Photon Source (TPS) is a new 3-GeV ring with characteristics of great brightness and small emittance, at present under construction at National Synchrotron Radiation Research Center (NSRRC) Taiwan. The positioning of the magnets is highly sensitive to alignment errors, and the entire building will be constructed half underground at depth 12 m relative to Taiwan Light Source (TLS) for stability reasons; for these reasons the survey and alignment work is confined and difficult. To position magnets precisely and quickly, a highly accurate auto-tuning girder system combined with a survey network was designed to accomplish the alignment tasks. The survey network includes a preliminary Global Positioning System (GPS) network and a laser tracking network. The position data from the survey network define a basis for the system of motorized girders to auto-tune and to improve the accuracy. The detailed survey and alignment design, installation process is described in this paper.

WEPME057

Commission of the Drive Laser System for Advanced Superconducting Test Accelerator

gun, controls, monitoring, cryomodule

3061

J. Ruan, M.D. Church, D.R. Edstrom, Jr, T.R. Johnson, J.K. Santucci
Fermilab, Batavia, USA

Currently an advanced superconducting test accelerator (ASTA) is being built at Fermilab. The accelerator will consist of a photo electron gun, injector, ILC-type cryomodules, multiple downstream beam lines for testing cryomodules and carrying advanced accelerator researches. In this paper we will report the commissioning and the drive laser system for this facility. It consists of a fiber laser system properly locked to the master frequency, a regen-amplifier, several power amplifier and final wavelength conversion stage. We will also report the characterization of the whole laser system and the performance of the laser system.

WEPME062

Short-Pulse Ti:Sapphire Laser System for Photocathode Research at SLAC

gun, cavity, cathode, diagnostics

3076

W.J. Corbett, A. Brachmann, R.N. Coffee, A.R. Fry, S. Gilevich, N. Hartmann, W. Helml, P. Hering, E.N. Jongewaard, D. Kelley, J.R. Lewandowski, W. Polzin, J. Sheppard, P. Stefan, T. Vecchione, S.P. Weathersby, W.E. White, M. Woods, F. Zhou
SLAC, Menlo Park, California, USA

A photo-cathode research laboratory has been constructed at SLAC to test and characterize the spare LCLS electron gun. At the heart of the laboratory is a dual-purpose Ti:Sapphire oscillator/regen laser that can deliver either a 2.5ps, 760nm beam to the photocathode gun or a 35fs, 800nm beam to prototype diagnostics for the LCLS. The objective of the photocathode research is to definitively identify ‘recipes’ for high-reliability cathode processing resulting in high quantum efficiency and low beam emittance. The LCLS diagnostics program is presently aimed at developing spectral-encoding systems for shot-by-shot pulse arrival time measurements at the 10fs level. In this paper we review the Ti:Sapphire laser system and report on status of the photocathode and diagnostics programs.

WEPME063

Progress Report on Development of a 5-μm Drive Laser for Dielectric Laser Acceleration

acceleration, focusing, HOM, alignment

3079

G. Xu, I. Jovanovic, S.F. Wandel
Penn State University, University Park, Pennsylvania, USA
E.R. Arab
PBPL, Los Angeles, USA
P.D. Hoang, P. Musumeci, B.D. O'Shea, J.B. Rosenzweig
UCLA, Los Angeles, USA
A.Y. Murokh, A.G. Ovodenko
RadiaBeam, Santa Monica, USA
I. Pogorelsky
BNL, Upton, Long Island, New York, USA

Funding: This work has been sponsored by Defense Advanced Research Project Agency.
A simple and robust ultrafast, high-peak-power 5-μm laser source for pumping a dielectric photonic structure for high-gradient electron acceleration has been designed and is being constructed. The use of long wavelength drive lasers can mitigate the problem of dielectric structure breakdown caused by multiphoton ionization. In addition, structure fabrication requirements are relaxed, and greater energy can be stored in the structure. The 5-μm laser source consists of two components: (1) a type-II-beta-barium borate-based 2-μm optical parametric amplifier (OPA) as a pump source, and (2) a type-I-zinc-germaniu-phosphate-based 5-μm OPA to produce mJ-class, <100 fs pulses. Our supercontinuum seeded two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~1.4 mJ with a pulse duration of 42 fs (~6 optical cycles). Carrier-envelope phase (CEP) stabilization is passively established for 2 μm pulses in our OPA design. An modified design of seed pulse generation for the 5-μm OPA based on several cascaded parametric processes can also result in CEP-stable operation for 5-μm amplified pulses.

THOAB101

Laser Wire Based Parallel Profile Scan of H⁻ Beam at the Superconducting Linac of Spallation Neutron Source

ion, neutron, linac, pick-up

3090

Y. Liu, A.V. Aleksandrov, D.L. Brown, R. Dickson, C. Huang, C.D. Long
ORNL, Oak Ridge, Tennessee, USA
C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
We report on the world’s first experiment of a parallel profile scan of the hydrogen ion (H⁻) beam using a laser wire system. The system was developed at the superconducting linac (SCL) of the Spallation Neutron Source (SNS) accelerator complex. The laser wire profile scanner is based on a photo-detachment process and therefore can be conducted on an operational H⁻ beam in a nonintrusive manner. The parallel profile scanning system makes it possible to simultaneously measure profiles of the 1-MW neutron production H⁻ beam at 9 different locations (corresponding to energy levels of 400 – 950 MeV) of the superconducting linac using a single light source. The entire measurement process takes less than 5 minutes to complete. Together with the hardware modification, we have also upgraded our user interface to visualize the 9-pairs of H⁻ beam profiles in a real-time fashion, which presents a highly intuitive and informative picture of the H⁻ beam propagation along the acceleration path. The laser wire based parallel profile scanning system provides a powerful tool for accelerator operators and physicists to study the SCL modelling, monitor and/or tune the beam parameters.

Slides THOAB101 [2.277 MB]

THOBB103

THz Electron-pulse-train Dynamics in a MeV Photo-injector

electron, acceleration, cathode, bunching

3109

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

A conventional free electron laser (FEL) is bulky and expensive. In order to quickly build up the FEL power in a short undulator, a laser technology has been proposed to generate a pre-bunched electron pulse-train with a THz bunching frequency from a photoinjector*. The bunching factor** of an accelerated pulse-train beam is influenced by the beam radius, initial bunching frequency, space charge force, acceleration gradient, and acceleration phase in an accelerator. For a given RF accelerator and initial beam parameters, there is a limitation on the maximally attainable bunching factor and bunching frequency for the accelerated pulse-train beam. This paper presents a theoretical analysis for the bunching factor and bunching frequency of an accelerated pulse-train beam subject to nominal initial beam conditions in a photoinjector. The theoretical analysis is compared with the simulation results from the simulation code, PARMELA. To obtain an output bunching factor larger than 0.5%, our simulation study indicates that the maximum bunching frequency at the cathode is 25 THz for a 150 A beam current under a peak acceleration field of 80 MV/m.
* Y.C. Huang, C.H. Chen, A.P. Lee, W.K. Lau, S.G. Liu, NIM, A, 637, S1–S6 (2011).
** Y.C Huang, Appl. Phys. Lett., 96, 231503 (2010).

Slides THOBB103 [3.076 MB]

THPEA007

Upgrade of Safety Interlock System of e⁺/e⁻ Linac for SuperKEKB Project

linac, gun, PLC, status

3161

A. Shirakawa, H. Honma, Y. Ogawa
KEK, Ibaraki, Japan

The upgrade of e⁺/e⁻ Injector Linac is going on for SuperKEKB project. The personal interlock system of the Linac has been upgrading several times according to the upgrade phase. One of the biggest changes has been made when the Linac was divided into two areas: upstream and downstream linacs, which allows us to work out the upgrade even during injection to Photon Factories at lower energies using the downstream linac. Most of the interlock system devices were duplicated to start the 'half' accelerator operation. Another remarkable update is to adopt an RF-Gun as a new electron source. We programmed a specific strong logic for the RF-Gun operation. These upgrades will be reported with the introduction of the whole interlock system.

THPEA031

REGAE LLRF Control System Overview

controls, electron, LLRF, feedback

3210

I. Rutkowski, L. Butkowski
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
M. Hoffmann, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved investigation of material structures in pump-probe configuration. To achieve sub-10fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of .005% in amplitude and of .005deg in phase. To achieve these demands, the recently developed LLRF control modules based on the Micro-Telecommunications Computing Architecture (MTCA.4) platform are used. For precise field detection and control a rear transition module (DRTM-DWC8VM1) housing 8 down-converters and 1 vector-modulator has been developed. The down-converted signals are transmitted to low-noise ADCs on an advanced mezzanine card (SIS8300L) with two high speed DACs driving the vector-modulator. The on board FPGA device runs the advanced control algorithms with minimum latency. Shot-to-shot learning feed forward and ultra-fast analog and digital feedbacks are applied. In this paper, the first results of the new RTM-AMC module pairs are presented together with the achievements and limitations on the RF field stability.

THPFI046

First Results of an Experiment on Advanced Collimator Materials at CERN HiRadMat Facility

simulation, proton, vacuum, instrumentation

3391

A. Bertarelli, O. Aberle, R.W. Aßmann, E. Berthomé, V. Boccone, M. Calderón Cueva, F. Carra, F. Cerutti, N. Charitonidis, C. Charrondière, A. Dallocchio, M. Donzé, P. Francon, M. Garlaschè, L. Gentini, M. Guinchard, N. Mariani, A. Masi, P. Moyret, S. Redaelli, A. Rossi, S.D.M. dos Santos
CERN, Geneva, Switzerland
M. Calderón Cueva
Universidad San Francisco de Quito, Cumbayá, Colombia
N. Charitonidis
EPFL, Lausanne, Switzerland
L. Peroni, M. Scapin
Politecnico di Torino, Torino, Italy

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD, grant agreement no. 227579
A comprehensive, first-of-its-kind experiment (HRMT-14) has been recently carried out at CERN HiRadMat facility on six different materials of interest for Beam Intercepting Devices (collimators, targets, dumps). Both traditional materials (Mo, W and Cu alloys) as well as advanced metal/diamond and metal/graphite composites were tested under extreme conditions as to pressure, density and temperature, leading to the development of highly dynamic phenomena as shock-waves, spallation, explosions. Experimental data were acquired, mostly in real time, relying on extensive embarked instrumentation (strain gauges, temperature and vacuum sensors) and on remote acquisition devices (laser Doppler vibrometer and high speed camera). The experiment was a success under all points of view in spite of the technological challenges and harsh environment. First measurements are in good agreement with results of complex simulations, confirming the effectiveness of the acquisition system and the reliability of advanced numerical methods when material constitutive models are completely available. Interesting information has been collected as to thermal shock robustness of tested materials.

THPFI053

A Feasibility Experiment of a W-powder Target in the HiRadMat Facility of CERN

target, proton, instrumentation, factory

3409

N. Charitonidis, I. Efthymiopoulos, A. Fabich
CERN, Geneva, Switzerland
O. Caretta, T.R. Davenne, C.J. Densham, M.D. Fitton, P. Loveridge
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
L. Rivkin
EPFL, Lausanne, Switzerland

Granular solid targets made of fluidized tungsten powder or static pebble bed of tungsten spheres, have been long proposed and are being studied as an alternative configurations towards high-power (>1MW of beam power) target systems, suitable for a future Super Beam or Neutrino Factory. Serving the lack of experimental data on this field, a feasibility experiment was performed in HiRadMat facility of CERN/SPS that tried in a pulse-by-pulse basis to address the effect of the impact of the SPS beam (440GeV/c) on a static tungsten powder target. Online instrumentation such as high-speed photography and Laser - Doppler Vibrometry was employed. Preliminary results show a powder disruption speed of less than 0.5 m/s while the disruption height appears to be scaling proportionally with the beam intensity. Other analysis results will be discussed.

THPFI055

First Year of Operations in the HiRadMat Irradiation Facility at CERN

proton, target, radiation, instrumentation

3415

A. Fabich, N. Charitonidis, N. Conan, K. Cornelis, D. DePaoli, I. Efthymiopoulos, S. Evrard, H. Gaillard, J.L. Grenard, M. Lazzaroni, A. Pardons, Y.D.R. Seraphin, C. Theis, K. Weiss
CERN, Geneva, Switzerland
N. Charitonidis
EPFL, Lausanne, Switzerland

HiRadMat (High Irradiation to Materials) is a new facility at CERN constructed in 2011, designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies can be tested. The facility uses a 440 GeV proton beam extracted from the CERN SPS with a pulse length of 7.2 μs, to maximum pulse energy of 3.4MJ. For 2012, the first year of operations of the facility, nine experiments were scheduled and completed data-taking successfully. The experience gained in operating this unique facility, along with highlights of the experiments and the instrumentation developed for online measurements are reported.

THPFI078

Design and Experiment on Auto-alignment Control System of Taiwan Photon Source

alignment, controls, storage-ring, feedback

3475

M.H. Wu, J.-R. Chen, M.L. 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, T.C. Tseng, H.S. Wang
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

TPS (Taiwan Photon Source) is a new 3-GeV synchrotron ring to be constructed at the NSRRC (National Synchrotron Radiation Research Center), Taiwan. There were hundreds of magnets that must be aligned on the absolute position to keep the electronic beam in the desire path while orbiting. Due to the problems of manpower, set up time, accuracy of adjustment, deformation of the floor, limited workspace and frequent earthquakes in Taiwan, an auto-alignment girder control system was designed to meet this requirement. The design and experiment of the auto-alignment system were tested successfully in the laboratory at NSRRC. The experiment of the auto-alignment control system would be implemented with half of the ring girders in the TPS. The detailed alignment design and status will be discussed in this paper.

THPFI091

Simultaneous Four-hall Operation for 12 GeV CEBAF

linac, extraction, recirculation, electron

3502

R. Kazimi
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The CEBAF accelerator at Jefferson lab will have a new experimental hall, Hall D, added to its existing three halls as a part of the ongoing 12 GeV upgrade. Under the present CEBAF design, there is no option for sending beam to all four halls simultaneously. At least one hall has to stay down during the machine operation. A new pattern for interleaving the beam bunches is introduced that allows simultaneous operation of all four halls and provide opportunity for additional future experimental beams. The new configuration presents only a minimal change to the existing CEBAF extraction system. In fact all the lower pass extractions will stay as they are and only the frequency of 5th-pass horizontal RF separator will change. In order to make room for the new Hall D beam among the existing three beams, the beam repetition rate is reduced only for the halls taking beam at the highest pass. This and other details of the new configuration and beam pattern will be presented and discussed. A separate paper in this conference will cover the implementation choices including changes to the beam source and extraction region.*
* "Source and Extraction for simultaneous Four-Hall beam delivery system at CEBAF", proceedings of this conference.

THPWA009

Generation of Laser Compton Scattered Gamma-rays from a 150-MeV Microtron

microtron, neutron, scattering, photon

3645

R. Hajima, C.T. Angell, I. Daito, T. Hayakawa, M. Kando, T. Shizuma
JAEA, Ibaraki-ken, Japan
H. Ohgaki
Kyoto University, Institute for Advanced Energy, Kyoto, Japan

Funding: This work was supported in part by special coordination funds for promoting science and technology in Japan (Grant No. 066).
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. We have employed laser pulse compression by stimulated Brillouin scattering to obtain high-flux gamma-rays, > 10⁵ ph/s. The gamma-ray source is a prototype of commercial machine for nuclear security applications, non-destructive detection of nuclear material hidden in a ship cargo. Design and performance of the gamma-ray source are presented.

THPWA013

Direct Diagnostic Technique of High-intensity Laser Profile based on Laser-Compton Scattering

solenoid, electron, gun, cathode

3657

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

Funding: Work supported by NEDO (New Energy and Industrial Technology Development Organization).
A high-intensity laser is essential for the LPP (Laser Produced Plasma) EUV generation, which is studied as the next generation light source of ultra-fine semiconductor lithography. Nevertheless, there is no way to directly measure the profile of high-intensity laser. Therefore, we have been developing a method for measuring high-intensity laser profile based on the laser-Compton scattering using a Cs-Te photo cathode RF-Gun at Waseda University. In this diagnostic technique, laser profile is obtained by scanning the extremely-focused electron beam, which is about 10μm by solenoid lens. We have obtained the 10μm beam size by solenoid lens using tracking code GPT (General Particle Tracer) by optimizing the beam parameter and lens shape. Recently, we have installed solenoid lens and generated focused beam. The focused beam size was evaluated by using radiochromic film called GAFCHROMIC dosimetry film type HD-810. In this conference, we will report the results of GPT simulations, beam size measurements and future prospects.

THPWA014

Development of Photon-induced Positron Annihilation Lifetime Spectroscopy using an S-band Compact Electron Linac

positron, photon, electron, linac

3660

Y. Taira, R. Kuroda, B.E. O'Rourke, N. Oshima, R. Suzuki, M. Tanaka, H. Toyokawa
AIST, Tsukuba, Ibaraki, Japan
K. Watanabe
Nagoya University, Nagoya, Japan
T. Yanagida
Kyushu Institute of Technology, Fukuoka, Japan

Funding: This work was supported by Grants-in-Aid for Scientific Research (22360297)
Positron annihilation lifetime spectroscopy (PALS) is a very sensitive tool to characterize materials and study defects at the nanometer scale. However, the application of PALS has been restricted to thin samples because of the limited range of positrons in materials. PALS for thick samples is possible by using high energy photons to create positrons inside the sample via pair production. This technique is called photon-induced positron annihilation lifetime spectroscopy (PiPALS). We have developed a novel PiPALS system using ultra-short photon pulses based on bremsstrahlung radiation to carry out in-situ measurement of structural materials under special conditions (piping for supercritical water and nuclear reactor materials). Intense, ultra-short photon pulses with energies up to 40 MeV can be generated by using an electron linear accelerator with photocathode rf gun system at AIST. In this conference, we will present the experimental result of the positron annihilation lifetime spectrum of a metal target by using ultra-short photon pulses*.
*Y. Taira et al., Rad. Phys. and Chem., accepted for publication 2012.

THPWA027

Evaluation of Zero-failure Data in Transient Ionizing Radiation Based on Ordering Method in the Sample Space

radiation, target, simulation, electron

3681

X.Y. Bai, X.M. Jin, R.B. Li, Y. Liu, Q. Ma, Ch. Qi
NINT, Xi'an, People's Republic of China

The conventional method for the evaluation of data in lot acceptance testing (LAT) of transient ionizing radiation is non-parametric method. But the evaluation results are very conservative. After the discovery of data in transient ionizing radiation belonging to one universal data model “case 1 interval censored data”, ordering method in the sample space was introduced and applied to evaluate zero-failure data and was compared with non-parametric method both theoretically and via a practical LAT on QG-Ⅰ. Through the comparisons, it is concluded that ordering method can expand the scope of dose rate corresponding to the same lower confidence limit. It improves data utilization and this improvement could have practical significance in LAT. It can reduce requirements for the radiation source and can also reduce the number of trials.

THPWA036

Implementation and Commissioning of the New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System

gun, electron, diagnostics, cathode

3708

P.A. McIntosh, D. Angal-Kalinin, R.K. Buckley, S.R. Buckley, J.A. Clarke, B.D. Fell, A.R. Goulden, C. Hill, F. Jackson, S.P. Jamison, J.K. Jones, A. Kalinin, B.P.M. Liggins, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.C.Q. Noakes, Y.M. Saveliev, B.J.A. Shepherd, S.L. Smith, T.T. Thakker, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Bliss, G. Cox, G.P. Diakun, A. Gleeson, L. Ma, B.G. Martlew, A.J. Moss, K. Robertson, M.D. Roper, R.J. Smith
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The EBTF facility will provide enabling infrastructures targeted at the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications in medicine, health, security, energy and industrial processing. The facility has now been implemented at Daresbury Laboratory and the commissioning of the critical accelerator systems has been performed. The facility is now preparing for first exploitation with partnering industries that will be able to utilise the electron beam parameters available on EBTF to either demonstrate new techniques and/or processes or otherwise develop new technologies for future commercial realisation.

THPWA044

R&D into Laser Applications for Accelerators

electron, cathode, acceleration, vacuum

3729

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

Funding: Work supported by the EU under Grant Agreement 289191.
Lasers can be used for the generation of high brightness electron and exotic ion beams, the acceleration of particles with the highest accelerating gradients, as well as for the characterization of many complex particle beams by means of laser-based beam diagnostics methods. In addition, (free electron) lasers can be used for achieving the highest time resolution and strongest fields for experiments in atomic physics, chemistry and biology, i.e. for studies into the dynamics of some of the most fundamental processes in nature. Without constant progress in laser technology and close collaboration between laser experts and accelerator scientists, many of today's most advanced experiments would simply be impossible. The LA3NET consortium combines developments into laser technology and sensors with their application at advanced accelerator facilities, providing complex beams ranging from highest brightness electron beams to high intensity proton beams. This contribution presents the consortium's broad, yet closely interconnected experimental program.

THPWA050

Beam Conditioning System for Laser-driven Hadron Therapy

proton, ion, acceleration, target

3743

K.E. Woods, S. Boucher, F.H. O'Shea
RadiaBeam, Santa Monica, USA
B.M. Hegelich
The University of Texas at Austin, Austin, Texas, USA

While the superior therapeutic efficacy of hadron therapy has been clearly demonstrated, its availability to cancer patients is limited by the cost and size of current systems. RadiaBeam Technologies, in collaboration with the UCLA Department of Radiation Oncology and the University of Texas at Austin, is proposing the utilization of innovative laser-driven ion acceleration (LDIA) technology for the development of a compact, inexpensive proton therapy system that can ultimately be adapted for the acceleration of carbon ions. At less than a third the price of the average proton therapy unit, the realization of this system would make hadron therapy a much more realistic option for hospitals and clinics worldwide. However, LDIA produces a beam with large divergence, wide energy spread with multiple ion species, and a significant background of electrons and X-rays. Thus, a major challenge for clinical implementation of LDIA is the development of a post-target beam conditioning system for collimation, focusing, energy selection, background shielding, and scanning. This paper will discuss the progress of our design of such a system and plans for future testing.