IPAC2015 - Classification: 2: Photon Sources and Electron Accelerators / A08

Paper	Title	Page
MOXGB2	Commissioning and Operation of 12 GeV CEBAF	1
	A. Freyberger JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 The Continuous Electron Beam Accelerator Facility (CEBAF) located at the Thomas Jefferson National Accelerator Laboratory (JLab) has been recently upgraded to deliver continuous electron beams to the experimental users at a maximum energy of 12 GeV, three times the original design energy of 4 GeV. This paper will present an overview of the upgrade, referred to as the 12GeV upgrade, and highlights from recent beam commissioning results.
	Slides MOXGB2 [4.359 MB]
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TUPWA002	Layout Options for the AXXS Injector and XFEL	1394
	M.J. Boland, Y.E. Tan, D. Zhu SLSA, Clayton, Australia
	A new injector is being planned for the Australian Synchrotron that is designed to feed both an upgraded storage ring and an XFEL. The desire to fit the AXXS project on the same site as the existing light source presents several layout difficulties. Several options are studied and simulations are performed to check the impact each choice has on the beam performance.
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TUPWA029	ARES: Accelerator Research Experiment at SINBAD	1469
	B. Marchetti, R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, J. Grebenyuk, M. Hüning, Y.C. Nie, H. Schlarb, J. Zhu DESY, Hamburg, Germany
	ARES is a planned linear accelerator for R&D for production of ultra-short electron bunches. It will be hosted at the SINBAD facility, at DESY in Hamburg. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with high arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The baseline layout of the accelerator foresees an S-band photo-injector which compresses low charge electron bunches via velocity bunching and accelerates them to 100 MeV energy. In the second stage, it is planned to install a third S-band accelerating cavity to reach 200 MeV as well as two X-band cavities: One for the linearization of the longitudinal phase space (subsequently allowing an improved bunch compression) and another one as a transverse deflecting cavity for longitudinal beam diagnostics. Moreover a magnetic bunch compressor is envisaged allowing to cut out the central slice of the beam** or hybrid bunch compression. * R. Assmann et al., TUPME047, Proceedings of IPAC 2014. R. Assmann, J. Grebenyuk, TUOBB01, Proceedings of IPAC 2014. * P. Emma et al., PRL 92 7 (2004).
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TUPWA030	Compression of an Electron-bunch by Means of Velocity Bunching at ARES	1472
	B. Marchetti, R.W. Aßmann, U. Dorda, J. Grebenyuk, J. Zhu DESY, Hamburg, Germany
	ARES is a planned linear accelerator for research and development in the field of production of ultra-short electron bunches. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with improved arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The ARES layout will allow to perform and compare different kind of conventional e-bunch compression techniques, such as pure velocity bunching, hybrid velocity bunching (i.e. velocity bunching plus magnetic compression) and pure magnetic compression with the slit insertion. This flexibility will allow to directly compare the different methods in terms of arrival time stability and local peak current. In this paper we present simulation results for the compression of an electron bunch with 0.5 pC charge. We compare the case of pure velocity bunching compression to the one of a hybrid compression using velocity bunching plus a magnetic compressor. M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010). ** P. Emma et al., PRL 92 7 (2004).
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TUPWA031	Compression of Train of Bunches with Ramped Intensity Profile at SPARC_LAB	1476
	B. Marchetti DESY, Hamburg, Germany A. Bacci Istituto Nazionale di Fisica Nucleare, Milano, Italy E. Chiadroni, M. Ferrario, R. Pompili INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy
	The production and acceleration of train of bunches with variable spacing in the ps/sub-ps range having ramped intensity profile are interesting to drive a plasma wave in the so-called resonant Plasma Wake-Fields Acceleration (r-PWFA). At SPARC_LAB trains having a constant intensity profile have been produced for the first time by using a shaped photo-cathode laser combined with the use of the velocity bunching compression technique,,*. If the sub-bunches have ramped intensity, i.e. they have different charge density, the space charge force affects differently the development of the longitudinal phase space of each one of them during the compression. In this paper we present preliminary simulations for the compression of a ramped train of bunches. The differences between the beam dynamics for a train of bunches having constant intensity profile and the ramped train are underlined. We discuss also the possibility of properly tuning the shaping of the photocathode laser to balance the space charge effect. SLAC-PUB-3528 M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010). * M. Ferrario et al. NIM A 637, S43-S46 (2011). **** E. Chiadroni et al., Rev. Sci. Instrum. 84, 022703
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TUPWA032	Progress in the Injector Upgrade of the LINAC II at DESY	1479
	Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz DESY, Hamburg, Germany
	A new injection system is under development for the LINAC II at DESY to improve the reliability of the machine and mitigate the radiological problem due to electron losses at energy of hundreds of MeV. It consists of a 100 kV triode DC gun, a 2.998 GHz pre-buncher, a novel 2.998 GHz hybrid buncher, and the dedicated beam transport and diagnostic elements. As the key components, the pre-buncher and the hybrid buncher realize a two-stage velocity bunching process including the ballistic bunching and the phase space rotation. Therefore, they produce a certain number of well-bunched 5 MeV micro-bunches from the input 2 ns-50 ns electron pulse for the downstream LINAC II. The overall upgrade plan, developments of the critical components, as well as the latest beam test results will be reported.
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TUPWA042	Status of the Accelerator Physics Test Facility FLUTE	1506
	M.J. Nasse, A. Bernhard, I. Birkel, A. Borysenko, A. Böhm, S. Hillenbrand, N. Hiller, S. Höninger, S. Marsching, A.-S. Müller, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, B. Smit, S. Walther, M. Weber, P. Wesolowski KIT, Karlsruhe, Germany R.W. Aßmann, M. Felber, K. Flöttmann, C. Gerth, M. Hoffmann, P. Peier, H. Schlarb, B. Steffen DESY, Hamburg, Germany R. Ischebeck, B. Keil, V. Schlott, L. Stingelin PSI, Villigen PSI, Switzerland
	A new compact versatile linear accelerator named FLUTE (Ferninfrarot Linac Und Test Experiment) is currently under construction at the Karlsruhe Institute of Technology (KIT). It will serve as an accelerator test facility and allow conducting a variety of accelerator physics studies. In addition, it will be used to generate intense, ultra-short THz pulses for photon science experiments. FLUTE consists of a ~7 MeV photo-injector gun, a ~41 MeV S-band linac and a D-shaped chicane to compress bunches to a few femtoseconds. This contribution presents an overview of the project status and the accompanying simulation studies.
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TUPWA045	Further Investigations on the MESA injector	1515
	R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander IKP, Mainz, Germany
	Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA" The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster).
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TUPWA057	DAΦNE LINAC: Beam Diagnostics and Outline of the Last Improvements	1549
	B. Buonomo, L.G. Foggetta INFN/LNF, Frascati (Roma), Italy
	The LINAC of the DAΦNE complex is in operation since 1996, both as injector of the e⁺ e⁻ phi-factory, and, since 2003, for the extraction of electron beam to the Beam Test Facility. In the last years, many improvements has been developed in different sub-systems of the LINAC, aiming at a wider, tunable range of beam parameters, in particular the pulse time width and the pulse charge. A long term measurement campaign has been recently started to characterize the LINAC performance after that many sub-systems has been overhauled and improved, starting from RF power (i.e. klystron substitution, modulator re-newing, RF driver layout, SLED tuning) as well as the timing system, magnets, cooling, vacuum, control system and energy/position diagnostics. This work reports the latest results on the optimization of the fully consolidated system.
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TUPWA065	Generation of Multi-bunch Beam with Beam Loading Compensation by Using RF Amplitude Modulation in Laser Undulator Compact X-ray (LUCX)	1576
	M.K. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan K. Sakaue, M. Washio RISE, Tokyo, Japan
	We have developed a compact X-ray source based on inverse Compton scattering between an electron beam and a laser pulse stacked in an optical cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. The accelerator consists of a 3.6 cell photo-cathode rf-gun, a 12cell standing wave accelerating structure and a 4-mirror planar optical cavity. Our aim is to obtain a clear X-ray image in a shorter period of times and the target flux of X-ray is 1.7x10⁷ photons/pulse with 10% bandwidth at present. To achieve this target, it is necessary to increase the intensity of an electron beam to 500nC/pulse with 1000 bunches at 30 MeV. Presently, we have achieved the generation of 24MeV beam with total charge of 600nC in 1000bunches with beam-loading compensation by using the delta T method and the amplitude modulation of RF pulse. The bunch-by-bunch energy difference is within 1.3% peak to peak. We will report the results of the multi-bunch beam generation and acceleration in this accelerator. This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
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TUPJE003	Quasi-Traveling Wave RF Gun and Beam Commissioning for SuperKEKB	1610
	T. Natsui The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	We are developing a new RF gun for SuperKEKB. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun which has two side coupled standing wave field. We call it quasi-traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. This RF gun has been installed in the KEK J-linac. Beam commissioning with the RF gun is in progress.
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TUPJE007	Measurement of Temporal Electric Field of Electron Bunch using Photoconductive Antenna	1623
	K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	A temporal electric field profile, which is a radially polarized terahertz (THz) pulse from an electron bunch, was measured by a large-aperture photoconductive antenna (PCA) with micro-structured concentric electrodes* for the detection of THz pulses. Photo-induced charge carriers were generated by irradiation of femtosecond laser pulses on semiconductor plane of the electrodes on the PCA. Time-domain measurement of coherent transition radiation (CTR) was conducted by the measurement of electric-field-induced current output from the PCA with sweeping the timing of the laser irradiation. The measurements on femtosecond electron bunches of 32 MeV and >80 pC will be reported. * K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).
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TUPJE014	An X-Band Linac with Tunable Beam Energy	1644
	L. Zhang, H.B. Chen, Y.-C. Du, Q.X. Jin, J. Shi, C.-X. Tang, P. Wang, Z. Zhang TUB, Beijing, People's Republic of China
	The low-energy X-band linac has a wide application in medical imaging. In this paper, an X-band linac is designed to produce beam energy between 0.5MeV and 1.5MeV, and the output beam energy is continuously adjustable within this range. Two sections of linacs are combined and powered by a single microwave source. During the experiment, we can tune the RF phase and amplitude of the second section of the linac, the electron beam can see either acceleration or deceleration, which tunes the output energy. This paper presented the production of the whole linac system, as well as the measurement of the continuously-adjustable beam energy.
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TUPJE080	First Beam and High-Gradient Cryomodule Commissioning Results of the Advanced Superconducting Test Accelerator at Fermilab	1831
	D.J. Crawford, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B.E. Chase, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, C.D. Joe, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P. Piot, P.S. Prieto, J. Reid, J. Ruan, J.K. Santucci, W.M. Soyars, G. Stancari, D. Sun, R.M. Thurman-Keup, A. Valishev, A. Warner, S.J. Wesseln Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The advanced superconducting test accelerator at Fermilab has accelerated electrons to 20 MeV and, separately, the International Linear Collider (ILC) style 8-cavity cryomodule has achieved the ILC performance milestone of 31.5 MV/m per cavity. When fully completed, the accelerator will consist of a photoinjector, one ILC-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We report on the results of first beam, the achievement of our cryomodule to ILC gradient specifications, and near-term future plans for the facility.
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TUPJE081	Model of Dark Current in SRF Linac	1834
	A.I. Sukhanov, A. Saini, N. Solyak, I.S. Tropin Fermilab, Batavia, Illinois, USA
	Currently, few linacs based on 9-cell TESLA-type SRF cavities are being designed or bult, including XEFL, LCLS-II and ILC. Dark current electron generated by field emission in SRF cavities can be captured and accelerated in the linac up to hundreds MeV before they removed by focusing magnets. Lost dark current electrons interact with the materials surrounding SRF cavities and magnets, produce electromagnetic showers and contribute to the radiation in the linac tunnel. In this paper we present a model of dark current in a linac based on TESLA cavities. We show preliminary results of the simulation applied to ILC main linac.
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TUPMA026	Status of the MaRIE X-FEL Accelerator Design	1894
	J.W. Lewellen, K. Bishofberger, B.E. Carlsten, L.D. Duffy, F.L. Krawczyk, Q.R. Marksteiner, D.C. Nguyen, S.J. Russell, R.L. Sheffield, N.A. Yampolsky LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the MaRIE program at Los Alamos National Laboratory, under contract DE-AC52-06NA25396 The Matter-Radiation Interactions in Extremes (MaRIE) facility is intended to probe and control the time-dependent properties of materials under extreme conditions. At its core, the “MaRIE 1.0” X-FEL is being designed to deliver pulse trains of ~10¹⁰ 42 keV photons, with a minimum bunch spacing of 2.4 ns, enabling time-dependent studies particularly of mesoscale phenomena. The X-FEL accelerator is also intended to deliver a series of 2 nC electron bunches to enable electron radiography concurrently with the X-ray pulse train, so as to provide multi-probe capability to MaRIE. In 2014, the reference design for the MaRIE X-FEL 12 GeV driver linac was changed from an S-band normal-conducting to an L-band superconducting linac to accommodate pulse trains up to 100 μs in duration. This paper does not present a complete solution for the MaRIE linac design; rather it describes our current reference design, achieved parameters, areas of concern and paths towards mitigation of identified issues.
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WEYC3	Commissioning and Operation of the ARIEL Electron Linac at TRIUMF	2444
	M. Marchetto, F. Ames, Z.T. Ang, R.A. Baartman, I.V. Bylinskii, Y.-C. Chao, D. Dale, K. Fong, R. Iranmanesh, F.W. Jones, D. Kaltchev, J. Kavarskas, P. Kolb, S.R. Koscielniak, A. Koveshnikov, M.P. Laverty, R.E. Laxdal, L. Merminga, N. Muller, R.R. Nagimov, R.B. Nussbaumer, T. Planche, M. Rowe, S. Saminathan, V.A. Verzilov, Z.Y. Yao, Q. Zheng, V. Zvyagintsev TRIUMF, Vancouver, Canada
	Funding: Funded under a contribution agreement with NRC (National Research Council Canada). Capital funding from CFI (Canada Foundation for Innovation). ARIEL is the new TRIUMF facility for production of radioactive ion beams that will enable the delivery of three simultaneous RIB beams to the ISAC experimental stations. Two additional target stations will produce beams by using either a 50 kW proton or from 500 kW electrons via photo-fission. The electron beam driver is going to be a 50 MeV 10 mA CW superconducting electron linac. The first stage of the e-linac installation is completed and commissioning is underway. The paper will present the e-linac design characteristics, installation, commissioning strategy and current results.
	Slides WEYC3 [13.765 MB]
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WEBD1	12 GeV CEBAF Transverse Emittance Evolution	640
	T. Satogata, Y. Roblin, M.G. Tiefenback, D.L. Turner JLab, Newport News, Virginia, USA
	We present commissioning results of measurements of beam phase space evolution of the newly commissioned 12 GeV CEBAF accelerator. These measurements range over two orders of magnitude in energy for a non-equilibrium beam, from near the photocathode to the diamond bremsstrahlung target for the GlueX experiment. We also compare these measurements to modeled beam evolution, and emittance growth expectations driven by synchrotron radiation.
	Slides WEBD1 [4.297 MB]
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Paper

Title

Page

Commissioning and Operation of 12 GeV CEBAF

1

A. Freyberger
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The Continuous Electron Beam Accelerator Facility (CEBAF) located at the Thomas Jefferson National Accelerator Laboratory (JLab) has been recently upgraded to deliver continuous electron beams to the experimental users at a maximum energy of 12 GeV, three times the original design energy of 4 GeV. This paper will present an overview of the upgrade, referred to as the 12GeV upgrade, and highlights from recent beam commissioning results.

Slides MOXGB2 [4.359 MB]

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TUPWA002

Layout Options for the AXXS Injector and XFEL

1394

M.J. Boland, Y.E. Tan, D. Zhu
SLSA, Clayton, Australia

A new injector is being planned for the Australian Synchrotron that is designed to feed both an upgraded storage ring and an XFEL. The desire to fit the AXXS project on the same site as the existing light source presents several layout difficulties. Several options are studied and simulations are performed to check the impact each choice has on the beam performance.

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TUPWA029

ARES: Accelerator Research Experiment at SINBAD

1469

B. Marchetti, R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, J. Grebenyuk, M. Hüning, Y.C. Nie, H. Schlarb, J. Zhu
DESY, Hamburg, Germany

ARES is a planned linear accelerator for R&D for production of ultra-short electron bunches. It will be hosted at the SINBAD facility, at DESY in Hamburg*. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with high arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration**. The baseline layout of the accelerator foresees an S-band photo-injector which compresses low charge electron bunches via velocity bunching and accelerates them to 100 MeV energy. In the second stage, it is planned to install a third S-band accelerating cavity to reach 200 MeV as well as two X-band cavities: One for the linearization of the longitudinal phase space (subsequently allowing an improved bunch compression) and another one as a transverse deflecting cavity for longitudinal beam diagnostics. Moreover a magnetic bunch compressor is envisaged allowing to cut out the central slice of the beam*** or hybrid bunch compression.
* R. Assmann et al., TUPME047, Proceedings of IPAC 2014.
** R. Assmann, J. Grebenyuk, TUOBB01, Proceedings of IPAC 2014.
*** P. Emma et al., PRL 92 7 (2004).

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TUPWA030

Compression of an Electron-bunch by Means of Velocity Bunching at ARES

1472

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

ARES is a planned linear accelerator for research and development in the field of production of ultra-short electron bunches. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with improved arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The ARES layout will allow to perform and compare different kind of conventional e-bunch compression techniques, such as pure velocity bunching*, hybrid velocity bunching (i.e. velocity bunching plus magnetic compression) and pure magnetic compression with the slit insertion**. This flexibility will allow to directly compare the different methods in terms of arrival time stability and local peak current. In this paper we present simulation results for the compression of an electron bunch with 0.5 pC charge. We compare the case of pure velocity bunching compression to the one of a hybrid compression using velocity bunching plus a magnetic compressor.
* M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010).
** P. Emma et al., PRL 92 7 (2004).

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TUPWA031

Compression of Train of Bunches with Ramped Intensity Profile at SPARC_LAB

1476

B. Marchetti
DESY, Hamburg, Germany
A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
E. Chiadroni, M. Ferrario, R. Pompili
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy

The production and acceleration of train of bunches with variable spacing in the ps/sub-ps range having ramped intensity profile are interesting to drive a plasma wave in the so-called resonant Plasma Wake-Fields Acceleration (r-PWFA)*. At SPARC_LAB trains having a constant intensity profile have been produced for the first time by using a shaped photo-cathode laser combined with the use of the velocity bunching compression technique**,***,****. If the sub-bunches have ramped intensity, i.e. they have different charge density, the space charge force affects differently the development of the longitudinal phase space of each one of them during the compression. In this paper we present preliminary simulations for the compression of a ramped train of bunches. The differences between the beam dynamics for a train of bunches having constant intensity profile and the ramped train are underlined. We discuss also the possibility of properly tuning the shaping of the photocathode laser to balance the space charge effect.
* SLAC-PUB-3528
** M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010).
*** M. Ferrario et al. NIM A 637, S43-S46 (2011).
**** E. Chiadroni et al., Rev. Sci. Instrum. 84, 022703

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TUPWA032

Progress in the Injector Upgrade of the LINAC II at DESY

1479

Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz
DESY, Hamburg, Germany

A new injection system is under development for the LINAC II at DESY to improve the reliability of the machine and mitigate the radiological problem due to electron losses at energy of hundreds of MeV. It consists of a 100 kV triode DC gun, a 2.998 GHz pre-buncher, a novel 2.998 GHz hybrid buncher, and the dedicated beam transport and diagnostic elements. As the key components, the pre-buncher and the hybrid buncher realize a two-stage velocity bunching process including the ballistic bunching and the phase space rotation. Therefore, they produce a certain number of well-bunched 5 MeV micro-bunches from the input 2 ns-50 ns electron pulse for the downstream LINAC II. The overall upgrade plan, developments of the critical components, as well as the latest beam test results will be reported.

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TUPWA042

Status of the Accelerator Physics Test Facility FLUTE

1506

M.J. Nasse, A. Bernhard, I. Birkel, A. Borysenko, A. Böhm, S. Hillenbrand, N. Hiller, S. Höninger, S. Marsching, A.-S. Müller, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, B. Smit, S. Walther, M. Weber, P. Wesolowski
KIT, Karlsruhe, Germany
R.W. Aßmann, M. Felber, K. Flöttmann, C. Gerth, M. Hoffmann, P. Peier, H. Schlarb, B. Steffen
DESY, Hamburg, Germany
R. Ischebeck, B. Keil, V. Schlott, L. Stingelin
PSI, Villigen PSI, Switzerland

A new compact versatile linear accelerator named FLUTE (Ferninfrarot Linac Und Test Experiment) is currently under construction at the Karlsruhe Institute of Technology (KIT). It will serve as an accelerator test facility and allow conducting a variety of accelerator physics studies. In addition, it will be used to generate intense, ultra-short THz pulses for photon science experiments. FLUTE consists of a ~7 MeV photo-injector gun, a ~41 MeV S-band linac and a D-shaped chicane to compress bunches to a few femtoseconds. This contribution presents an overview of the project status and the accompanying simulation studies.

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TUPWA045

Further Investigations on the MESA injector

1515

R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander
IKP, Mainz, Germany

Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA"
The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster).

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TUPWA057

DAΦNE LINAC: Beam Diagnostics and Outline of the Last Improvements

1549

B. Buonomo, L.G. Foggetta
INFN/LNF, Frascati (Roma), Italy

The LINAC of the DAΦNE complex is in operation since 1996, both as injector of the e⁺ e⁻ phi-factory, and, since 2003, for the extraction of electron beam to the Beam Test Facility. In the last years, many improvements has been developed in different sub-systems of the LINAC, aiming at a wider, tunable range of beam parameters, in particular the pulse time width and the pulse charge. A long term measurement campaign has been recently started to characterize the LINAC performance after that many sub-systems has been overhauled and improved, starting from RF power (i.e. klystron substitution, modulator re-newing, RF driver layout, SLED tuning) as well as the timing system, magnets, cooling, vacuum, control system and energy/position diagnostics. This work reports the latest results on the optimization of the fully consolidated system.

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TUPWA065

Generation of Multi-bunch Beam with Beam Loading Compensation by Using RF Amplitude Modulation in Laser Undulator Compact X-ray (LUCX)

1576

M.K. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
K. Sakaue, M. Washio
RISE, Tokyo, Japan

We have developed a compact X-ray source based on inverse Compton scattering between an electron beam and a laser pulse stacked in an optical cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. The accelerator consists of a 3.6 cell photo-cathode rf-gun, a 12cell standing wave accelerating structure and a 4-mirror planar optical cavity. Our aim is to obtain a clear X-ray image in a shorter period of times and the target flux of X-ray is 1.7x10⁷ photons/pulse with 10% bandwidth at present. To achieve this target, it is necessary to increase the intensity of an electron beam to 500nC/pulse with 1000 bunches at 30 MeV. Presently, we have achieved the generation of 24MeV beam with total charge of 600nC in 1000bunches with beam-loading compensation by using the delta T method and the amplitude modulation of RF pulse. The bunch-by-bunch energy difference is within 1.3% peak to peak. We will report the results of the multi-bunch beam generation and acceleration in this accelerator.
This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.

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TUPJE003

Quasi-Traveling Wave RF Gun and Beam Commissioning for SuperKEKB

1610

T. Natsui
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
Y. Ogawa, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan

We are developing a new RF gun for SuperKEKB. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun which has two side coupled standing wave field. We call it quasi-traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. This RF gun has been installed in the KEK J-linac. Beam commissioning with the RF gun is in progress.

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TUPJE007

Measurement of Temporal Electric Field of Electron Bunch using Photoconductive Antenna

1623

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

A temporal electric field profile, which is a radially polarized terahertz (THz) pulse from an electron bunch, was measured by a large-aperture photoconductive antenna (PCA) with micro-structured concentric electrodes* for the detection of THz pulses. Photo-induced charge carriers were generated by irradiation of femtosecond laser pulses on semiconductor plane of the electrodes on the PCA. Time-domain measurement of coherent transition radiation (CTR) was conducted by the measurement of electric-field-induced current output from the PCA with sweeping the timing of the laser irradiation. The measurements on femtosecond electron bunches of 32 MeV and >80 pC will be reported.
* K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).

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TUPJE014

An X-Band Linac with Tunable Beam Energy

1644

L. Zhang, H.B. Chen, Y.-C. Du, Q.X. Jin, J. Shi, C.-X. Tang, P. Wang, Z. Zhang
TUB, Beijing, People's Republic of China

The low-energy X-band linac has a wide application in medical imaging. In this paper, an X-band linac is designed to produce beam energy between 0.5MeV and 1.5MeV, and the output beam energy is continuously adjustable within this range. Two sections of linacs are combined and powered by a single microwave source. During the experiment, we can tune the RF phase and amplitude of the second section of the linac, the electron beam can see either acceleration or deceleration, which tunes the output energy. This paper presented the production of the whole linac system, as well as the measurement of the continuously-adjustable beam energy.

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TUPJE080

First Beam and High-Gradient Cryomodule Commissioning Results of the Advanced Superconducting Test Accelerator at Fermilab

1831

D.J. Crawford, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B.E. Chase, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, C.D. Joe, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P. Piot, P.S. Prieto, J. Reid, J. Ruan, J.K. Santucci, W.M. Soyars, G. Stancari, D. Sun, R.M. Thurman-Keup, A. Valishev, A. Warner, S.J. Wesseln
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The advanced superconducting test accelerator at Fermilab has accelerated electrons to 20 MeV and, separately, the International Linear Collider (ILC) style 8-cavity cryomodule has achieved the ILC performance milestone of 31.5 MV/m per cavity. When fully completed, the accelerator will consist of a photoinjector, one ILC-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We report on the results of first beam, the achievement of our cryomodule to ILC gradient specifications, and near-term future plans for the facility.

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TUPJE081

Model of Dark Current in SRF Linac

1834

A.I. Sukhanov, A. Saini, N. Solyak, I.S. Tropin
Fermilab, Batavia, Illinois, USA

Currently, few linacs based on 9-cell TESLA-type SRF cavities are being designed or bult, including XEFL, LCLS-II and ILC. Dark current electron generated by field emission in SRF cavities can be captured and accelerated in the linac up to hundreds MeV before they removed by focusing magnets. Lost dark current electrons interact with the materials surrounding SRF cavities and magnets, produce electromagnetic showers and contribute to the radiation in the linac tunnel. In this paper we present a model of dark current in a linac based on TESLA cavities. We show preliminary results of the simulation applied to ILC main linac.

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TUPMA026

Status of the MaRIE X-FEL Accelerator Design

1894

J.W. Lewellen, K. Bishofberger, B.E. Carlsten, L.D. Duffy, F.L. Krawczyk, Q.R. Marksteiner, D.C. Nguyen, S.J. Russell, R.L. Sheffield, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the MaRIE program at Los Alamos National Laboratory, under contract DE-AC52-06NA25396
The Matter-Radiation Interactions in Extremes (MaRIE) facility is intended to probe and control the time-dependent properties of materials under extreme conditions. At its core, the “MaRIE 1.0” X-FEL is being designed to deliver pulse trains of ~10¹⁰ 42 keV photons, with a minimum bunch spacing of 2.4 ns, enabling time-dependent studies particularly of mesoscale phenomena. The X-FEL accelerator is also intended to deliver a series of 2 nC electron bunches to enable electron radiography concurrently with the X-ray pulse train, so as to provide multi-probe capability to MaRIE. In 2014, the reference design for the MaRIE X-FEL 12 GeV driver linac was changed from an S-band normal-conducting to an L-band superconducting linac to accommodate pulse trains up to 100 μs in duration. This paper does not present a complete solution for the MaRIE linac design; rather it describes our current reference design, achieved parameters, areas of concern and paths towards mitigation of identified issues.

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WEYC3

Commissioning and Operation of the ARIEL Electron Linac at TRIUMF

2444

M. Marchetto, F. Ames, Z.T. Ang, R.A. Baartman, I.V. Bylinskii, Y.-C. Chao, D. Dale, K. Fong, R. Iranmanesh, F.W. Jones, D. Kaltchev, J. Kavarskas, P. Kolb, S.R. Koscielniak, A. Koveshnikov, M.P. Laverty, R.E. Laxdal, L. Merminga, N. Muller, R.R. Nagimov, R.B. Nussbaumer, T. Planche, M. Rowe, S. Saminathan, V.A. Verzilov, Z.Y. Yao, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

Funding: Funded under a contribution agreement with NRC (National Research Council Canada). Capital funding from CFI (Canada Foundation for Innovation).
ARIEL is the new TRIUMF facility for production of radioactive ion beams that will enable the delivery of three simultaneous RIB beams to the ISAC experimental stations. Two additional target stations will produce beams by using either a 50 kW proton or from 500 kW electrons via photo-fission. The electron beam driver is going to be a 50 MeV 10 mA CW superconducting electron linac. The first stage of the e-linac installation is completed and commissioning is underway. The paper will present the e-linac design characteristics, installation, commissioning strategy and current results.

Slides WEYC3 [13.765 MB]

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WEBD1

12 GeV CEBAF Transverse Emittance Evolution

640

T. Satogata, Y. Roblin, M.G. Tiefenback, D.L. Turner
JLab, Newport News, Virginia, USA

We present commissioning results of measurements of beam phase space evolution of the newly commissioned 12 GeV CEBAF accelerator. These measurements range over two orders of magnitude in energy for a non-equilibrium beam, from near the photocathode to the diamond bremsstrahlung target for the GlueX experiment. We also compare these measurements to modeled beam evolution, and emittance growth expectations driven by synchrotron radiation.

Slides WEBD1 [4.297 MB]

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