FEL2015 - List of Keywords (operation)

Paper	Title	Other Keywords	Page
MOP014	Status of the Soft X-Ray FEL User Facility FLASH	photon, electron, experiment, FEL	61
	K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt DESY, Hamburg, Germany
	Since 10 years FLASH at DESY (Hamburg, Germany) has provided high brilliance FEL radiation at XUV and soft X-ray wavelengths for user experiments. Recently FLASH has been upgraded with a second undulator beamline, FLASH2, whose commissioning takes place in parallel of the user operation on FLASH1. This paper summarizes the performance of the FLASH facility during the last user period from January 2014 to April 2015.
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MOP016	Status of the Fabrication of PAL-XFEL Magnet Power Supplies	power-supply, dipole, quadrupole, controls	66
	S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	PAL-XFEL has been constructing including a 10 GeV linac, hard X-ray and soft X-ray branches. PAL-XFEL required for about six hundreds of magnet power supply (MPS). The eight different prototypes of MPS are developing to confirm the performance, functions, size, heat load and so on. This paper describes the test results of the prototype MPS in major specifications. All MPSs have to be installed the end of September in 2015. The installation progress of the MPS was also described.
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MOP017	Beam Commissioning Plan for the SwissFEL Hard-X-Ray Facility	linac, undulator, electron, FEL	69
	T. Schietinger PSI, Villigen PSI, Switzerland
	The SwissFEL facility currently being assembled at the Paul Scherrer Institute is designed to provide FEL radiation in the photon wavelength range between 0.1 and 7 nm. The commissioning of the first phase, comprising the electron injector, the main electron linear accelerator and the first undulator line, named Aramis and dedicated to the production of hard X-rays, is planned for the years 2016 and 2017. We present an overview of the beam commissioning plan elaborated in accordance with the installation schedule to bring into operation the various subsystems and establish beam parameters compatible with first pilot user experiments in late 2017.
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MOP043	Influence of Environment Changes on Libera Sync 3 Long-term Stability	controls, detector, timing, monitoring	126
	S. Zorzut, M. Cargnelutti I-Tech, Solkan, Slovenia S. Hunziker PSI, Villigen PSI, Switzerland
	Libera Sync 3 can be used as a reference clock transfer system in the latest fourth generation light sources where the long-term stability is in the range of a few tens of femtoseconds of drift per day. The system has been developed in collaboration with the Paul Scherrer Institute (PSI) and first units are already tested in SwissFEL machine. In this article we present the influence of temperature and humidity changes on the long-term phase stability of the system.
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MOP047	The BINP HLS to Measure Vertical Changes on PAL-XFEL Buildings and Ground	timing, survey, experiment, alignment	133
	H. J. Choi, K.H. Gil, H.-S. Kang, S.H. Kim, K.W. Seo PAL, Pohang, Kyungbuk, Republic of Korea
	PAL-XFEL is being installed and will be completed by December of 2015 so that users can be supported beginning in 2016. PAL-XFEL equipment should continuously maintain the bunch beam parameter. To this end, PAL-XFEL equipment has to be kept precisely aligned. As a part of the process for installing PAL-XFEL, a surface geodetic network and the installation of a tunnel measurement network inside buildings is in preparation; additionally, the fiducialization of major equipment is underway. After PAL-XFEL equipment is optimized and aligned, if the ground and buildings go through vertical changes during operation, misalignment of equipments will cause errors in the electron beam trajectory, which will lead to changes to the beam parameter. For continuous and systemic measurement of vertical changes in buildings and to monitor ground subsidence (sinks) and uplift, the BINP Ultrasonic-type Hydrostatic Levelling System (HLS) is to be installed and operated in all sections of PAL-XFEL for linear accelerator, undulator and beam line. This study will introduce the operation principle, design concept and advantages (self-calibration) of BINP ULS Sensor, and will outline its installation plan and operation plan.
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MOD03	Alkali Cathode Testing for LCLS-II at APEX	cathode, gun, electron, laser	280
	H.J. Qian, J. Feng, D. Filippetto, J.R. Nasiatka, H.A. Padmore, F. Sannibale LBNL, Berkeley, California, USA R.K. Li, J.F. Schmerge, F. Zhou SLAC, Menlo Park, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 Electron sources of high brightness and high bunch charge (~300 pC) with MHz repetition rate are one of the key technologies for next generation X-FEL facilities such as the LCLS-II at SLAC and the Euro XFEL at DESY. The Advanced Photoinjector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is developing such an electron source based on high quantum efficiency (QE) alkali photocathodes and the VHF-Gun, a new scheme normal conducting RF gun developed at LBNL. The VHF-Gun already demonstrated stable CW operation with high gradient (~ 20 MV/m), high gun voltage (~ 750 kV) and low vacuum pressure (~ 3 E-10 torr) laying the foundation for the generation of high brightness electron beams. In this paper, we report the test and characterization of several different alkali cathodes in high average current (several hundreds of pC/bunch with MHz repetition rate) operation at APEX. Measurements include cathode life time, QE map evolution and thermal emittance characterization, to investigate the compatibility of such cathodes with the challenging requirements of LCLS-II.
	Slides MOD03 [6.030 MB]
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TUA03	Multi-beamline Operation Test at SACLA	electron, undulator, kicker, laser	293
	T. Hara, T. Inagaki, R. Kinjo, C. Kondo, Y. Otake, H. Takebe, H. Tanaka, K. Togawa RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan K. Fukami JASRI/SPring-8, Hyogo-ken, Japan
	A new undulator beamline (BL2) was installed in September 2014 at SACLA. Following the installation of this second beamline, a DC switching magnet was replaced by a kicker magnet and a DC septum magnet for bunch-to-bunch multi-beamline operation. The commissioning of the new beamline and bunch-to-bunch operation was started early this year. Since SACLA has been operated with much higher peak currents around 10 kA compared to its original design value of 3 kA, the CSR effect in the beam transport line to BL2, where the electron beam is deflected twice by 3 degree, turns out to be non-negligible. BL2 is currently operated with reduced peak currents and the photon pulse energies of 100-150 μJ are obtained with increased undulator K-values around 2.6-2.85. Although the photon pulse energies of BL2 are still smaller than those of the existing beamline (BL3), the expected stability of the electron beam orbit after the bunch-to-bunch BL switching was achieved and simultaneous lasing at the two beamlines was demonstrated with 8 GeV electron beams. We will report the status and operational issues related to the multi-beamline operation at SACLA.
	Slides TUA03 [7.095 MB]
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TUA04	First Simultaneous Operation of Two Sase Beamlines in FLASH	undulator, photon, electron, FEL	297
	M. Scholz, B. Faatz, S. Schreiber, J. Zemella DESY, Hamburg, Germany
	FLASH2, the second undulator beamline of the FLASH FEL user facility at DESY (Hamburg, Germany) is under commissioning. Its first lasing was achieved in August 2014. FLASH is the first soft X-ray FEL operating two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. Fast kickers and a septum are installed to distribute one part of the electron bunch train to FLASH1 and the other part to FLASH2 with full repetition rate. The commissioning of FLASH2 takes place primarily in parallel to FLASH1 user operation. Various beam optics measurements has been carried out in order to ensure the required electron beam quality for efficient SASE generation. This paper reports the status of the FLASH2 commissioning.
	Slides TUA04 [9.655 MB]
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TUP010	Recent Progress in Upgrade of the High-Intensity THz-FEL at Osaka University	FEL, electron, linac, klystron	354
	G. Isoyama, M. Fujimoto, S. Funakoshi, K. Furukawa, A. Irizawa, R. Kato, K. Kawase, A. Tokuchi, R. Tsutsumi, M. Yaguchi ISIR, Osaka, Japan
	We are upgrading the THz-FEL at Osaka University for its applications to high intensity THz sciences, which originally generated the high intensity FEL with the macropulse energy up to 3.7 mJ and the micropulse energy up to ~10 uJ at a wavelength around 70 um. To increase the micropulse energy, charge in electron bunches is increased four time higher and the bunch intervals are expanded four times longer to maintain the average current in the linac unchanged. In the new operation mode, the macropulse energy increases up to 26 mJ and the micropulse energy to ~0.2 mJ, which is 20 times higher than the energy previously obtained in the conventional mode. We have developed a solid-state switch for the klystron modulator to highly stabilize the klystron voltage, so that the output power of the FEL becomes stable. We are conducting basic studies on FEL for further improvement of its performance, including measurement of power evolution from start-up to saturation, time structures of FEL micropulses measured with a Michelson interferometer, and time structures of macropulses measured with a Schottky diode detector. We will report results of these studies on the THz-FEL at Osaka University.
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TUP011	Performance and Tolerance Studies of the X-Ray Production for the X-Band FEL Collaboration	undulator, simulation, electron, FEL	359
	J. Pfingstner, E. Adli University of Oslo, Oslo, Norway
	The X-band FEL collaboration is currently designing an X-ray free-electron laser based on X-band acceleration technology. This paper reports on the recent progress on the design of the undulator part of this machine including simulations of the X-ray production process. The basic parameters have been chosen and a beam transport system has been designed, considering strong and weak focusing of quadrupole and undulator magnets. Simulations of the X-ray production process have been carried out with realistic input beam distributions from particle tracking studies of the linac design team. The expectable X-ray properties for SASE and seeded FEL operation have been investigated and also undulator taper options have been studied.
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TUP015	Status of the ALICE IR-FEL: from ERL Demonstrator to User Facility	FEL, laser, cavity, radiation	379
	N. Thompson, J.A. Clarke, D.J. Dunning, A.J. Moss, Y.M. Saveliev, M. Surman STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T. Craig, M.R.F. Siggel-King, P. Weightman The University of Liverpool, Liverpool, United Kingdom O.V. Kolosov, P.D. Tovee Lancaster University, Lancaster, United Kingdom M.R.F. Siggel-King Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The ALICE (Accelerators and Lasers In Combined Experiments) accelerator at STFC Daresbury Laboratory in the UK was conceived in 2003 and constructed as a short-term Energy Recovery Linac demonstrator to develop the underpinning technology and expertise required for a proposed 600MeV ERL-based FEL facility. In this paper we present an update on the performance and status of ALICE which now operates as a funded IR-FEL user facility. We discuss the challenges of evolving a short-term demonstrator into a stable, reliable user facility and present a summary of the current scientific programme.
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TUP041	Simultaneous Operation of Three Laser Systems at the FLASH Photoinjector	laser, electron, cathode, free-electron-laser	459
	S. Schreiber, C. Grün, K. Klose, J. Rönsch-Schulenburg, B. Steffen DESY, Hamburg, Germany
	The free-electron laser facility FLASH at DESY (Hamburg, Germany) operates two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of trains of several hundred microsecond spaced bunches with a repetition rate of 10 Hz. A fast kickers-septum system is installed to distribute one part of the electron bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both beamlines. In order to deliver different beam properties to each beamline, the FLASH photoinjector uses two independent laser systems to generate different bunch pattern and bunch charges. One laser serves the FLASH1 beamline, the other the FLASH2 beamline. A third laser with adjus ö laser pulse duration is used to generate ultra-short bunches for single spike lasing.
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TUP042	Lifetime of Cs2Te Cathodes Operated at the FLASH Facility	laser, cathode, gun, electron	464
	S. Schreiber, S. Lederer DESY, Hamburg, Germany
	The injector of the free-electron laser facility FLASH at DESY (Hamburg, Germany) uses Cs2Te photocathodes. We report on the lifetime, quantum efficiency (QE), and darkcurrent of photocathodes operated at FLASH during the last year. Cathode 618.3 has been operated for a record of 439 days with a stable QE in the order of 3%. The fresh cathode 73.3 shows an enhancement of emitted electrons for a few microseconds of a 1 MHz pulse train.
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TUP070	Energy Jitter Minimization at LCLS	linac, timing, experiment, simulation	523
	L. Wang, A.L. Benwell, A. Brachmann, W.S. Colocho, F.-J. Decker, Z. Huang, T.J. Maxwell, T. Tao, J.L. Turner SLAC, Menlo Park, California, USA
	The energy jitters of the electron beam can affects the FEL in self-seeded modes if the jitter is large compared to the FEL parameter. We work in multiple ways to reduce the jitters, including hardware improvement, optimization linac set-up. This paper discusses the optimization of linac set-up. The solutions always suggest that we can largely reduce the energy jitter from a weak compression at BC1 and a stronger compression at BC2. Meanwhile a low beam energy at BC2 also reduce the energy jitter, which is confirmed by the experiment. The results can be explained by a simple model. Experimental results are also presented, demonstrating better than 20% and 40% relative energy jitter reduction for 13.6 and 4 GeV linac operation, respectively.
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TUP080	Terahertz Source Utilizing Resonant Coherent Diffraction Radiation at KEK ERL Test Accelerator	radiation, cavity, photon, extraction	547
	Y. Honda, A. Aryshev, M. Shevelev, M. Shimada KEK, Ibaraki, Japan
	An energy recovery linac test accelerator, cERL, has been developing at KEK. It can produce a high repetition rate short bunched electron beam in a continuous operation mode. We propose to develop a high power THz radiation source at the return loop of the cERL. Coherent diffraction radiation of THz regime is emitted when an electron bunch passes through a conductive mirror with a beam hole at the center. If we form an optical cavity using two mirrors facing each other and the cavity length coincides with the bunch repetition rate, the coherent diffraction radiation of multiple bunches adds up coherently in the cavity. By extracting the power through transmission of one of the mirrors, we can realize a high power and high efficiency THz source. We discuss performance of the source assuming the beam parameters of cERL.
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WEB01	A Two-Color Storage Ring FEL	FEL, undulator, electron, cavity	571
	J. Yan, H. Hao, S.F. Mikhailov, V. Popov, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA S. Huang PKU, Beijing, People's Republic of China J.Y. Li USTC/NSRL, Hefei, Anhui, People's Republic of China N. Vinokurov BINP SB RAS, Novosibirsk, Russia J. Wu SLAC, Menlo Park, California, USA
	Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033. Using different undulator configurations on the Duke storage ring, we have successfully achieved lasing with a novel two-color storage ring FEL. Using a pair of dual-band FEL mirrors, simultaneous lasing was realized in IR (around 720 nm) and in UV (around 360 nm). With this two-color FEL, we have demonstrated independent wavelength tuning of either IR or UV lasing. With careful tuning, we have also realized harmonic lasing with the UV lasing tuned to the second harmonic of the IR lasing. The tuning of harmonic two-color lasing has also been demonstrated with the locked wavelengths. Furthermore, we have demonstrated good control of the FEL power sharing between the two colors. The two-color FEL has created new opportunities to drive a two-color Compton gamma-ray beam at the High Intensity gamma-ray Source at Duke.
	Slides WEB01 [18.975 MB]
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WEB04	Saturation Dynamics, Fine Spectrum, and Chirp Control in a CW FEL Oscillator	FEL, laser, electron, coupling	580
	H. S. Marks, A. Gover, H. Kleinman University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel D. Borodin, A. Damti, A. Friedman, Y. Vashdi Ariel University, Ariel, Israel M. Einat, M. Kanter, Y. Lasser, Yu. Lurie, A. Yahalom Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel
	As in conventional laser physics, the saturation dynamics of a long-pulse Electrostatic Accelerator FEL (EA-FEL) oscillator consists of oscillations build-up, resonator modes competition, and establishment of narrow linewidth single mode lasing. In EA-FEL the gain curve drifts to lower frequencies during the long laser pulse due to inevitable droop in the acceleration voltage. This post-saturation drift renders fine chirp of the single mode laser frequency due to the oscillator frequency pulling effect. We have integrated a voltage-ramping element into the electrostatic accelerator terminal that makes it possible to control the acceleration voltage throughout the lasing pulse. This allows us to keep the voltage constant throughout the e-beam pulse, and so increase the single mode lasing time, avoiding mode-hopping during the pulse due to the drift of the gain curve. Furthermore, by adjusting the voltage ramp rate and polarity we obtained controllable positive/negative laser frequency chirp that can be used in a single pulse sweep for fine spectral line (10^-6) gas-spectroscopy. The study was conducted on the Israeli EA-FEL that operates at tunable frequencies between 95-110 GHz.
	Slides WEB04 [2.310 MB]
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WEP022	Photon Energies beyond the Selenium K-Edge at LCLS	FEL, photon, electron, linac	630
	F.-J. Decker, W.S. Colocho, Y. Ding, R.H. Iverson, H. Loos, J. Sheppard, H. Smith, J.L. Turner SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515. The Linac Coherent Light Source (LCLS) was designed for a photon energies of 830 eV to 8.3 keV. This range was widened and up to 11.2 keV photons were already delivered for users. The Selenium K-edge at 12.6578 keV is very interesting since Selenium can replace Sulfur in biological structures and then that structure could be precisely measured. To reach this the electron energy would need to be raised by about 6% which initially didn't seem possible. The trick is to change the final compression scheme from a high correlated energy spread and moderate R56 in the compression chicane to moderate energy spread and high R56. The same bunch length can be achieved and RF energy is freed up, so the overall beam energy can be raised. Photons up to an energy of 12.82 keV (1.3% above the K-edge) with a pulse intensity of 0.93 mJ were achieved. The photon energy spread with this setup is wider at around 40-50 eV FWHM, since less correlated energy spread is left after the compression.
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WEP078	Advances on the LUNEX5 and COXINEL Projects	FEL, laser, electron, plasma	730
	M.-E. Couprie, C. Benabderrahmane, P. Berteaud, C. Bourassin-Bouchet, F. Bouvet, J.D. Bozek, F. Briquez, L. Cassinari, L. Chapuis, J. Da Silva, J. Daillant, D. Dennetière, Y. Dietrich, M. Diop, J.P. Duval, M.E. El Ajjouri, T.K. El Ajjouri, C. Herbeaux, N. Hubert, M. Khojoyan, M. Labat, N. Leclercq, A. Lestrade, A. Loulergue, J. Lüning, P. Marchand, O. Marcouillé, J.L. Marlats, F. Marteau, C. Miron, P. Morin, A. Nadji, R. Nagaoka, F. Polack, F. Ribeiro, J.P. Ricaud, P. Rommeluère, P. Roy, G. Sharma, K.T. Tavakoli, M. Thomasset, M. Tilmont, M.-A. Tordeux, M. Valléau, J. Vétéran, W. Yang, D. Zerbib SOLEIL, Gif-sur-Yvette, France S. Bielawski, M. Le Parquier PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France X. Davoine CEA/DAM/DIF, Arpajon, France N. Delerue, M. El Khaldi, W. Kaabi, F. Wicek LAL, Orsay, France G. Devanz, C. Madec CEA/IRFU, Gif-sur-Yvette, France A. Dubois CCPMR, Paris, France C. Evain, C. Szwaj PhLAM/CERLA, Villeneuve d'Ascq, France D. Garzella CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France G. Lambert, V. Malka, A. Rousse, C. Thaury LOA, Palaiseau, France A. Mosnier CEA/DSM/IRFU, France E. Roussel Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Funding: ERC COXINEL 340015 LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating compact and advanced Free Electron Laser (FEL). It comprises one one hand a 400 MeV superconducting linac for studies of advanced FEL schemes, high repetition rate operation (10 kHz), multi-FEL lines, and one the other hand a Laser Wake Field Accelerator (LWFA) for its qualification by a FEL application, an undulator line enabling advanced seeding and pilot user applications in the 40-4 nm spectral range. Following the CDR completion, different R&D programs were launched, as for instance on FEL pulse duration measurement, high repetition rate electro-optical sampling. The COXINEL ERC Advanced Grant aims at demonstrating LWFA based FEL amplification, thanks to a proper electron beam manipulation, with a test experiment under preparation. As a specific hardware is also under development such as a cryo-ready 3 m long undulator of 15 mm period is under development.
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Paper

Title

Other Keywords

Page

MOP014

Status of the Soft X-Ray FEL User Facility FLASH

photon, electron, experiment, FEL

61

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

Since 10 years FLASH at DESY (Hamburg, Germany) has provided high brilliance FEL radiation at XUV and soft X-ray wavelengths for user experiments. Recently FLASH has been upgraded with a second undulator beamline, FLASH2, whose commissioning takes place in parallel of the user operation on FLASH1. This paper summarizes the performance of the FLASH facility during the last user period from January 2014 to April 2015.

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MOP016

Status of the Fabrication of PAL-XFEL Magnet Power Supplies

power-supply, dipole, quadrupole, controls

66

S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

PAL-XFEL has been constructing including a 10 GeV linac, hard X-ray and soft X-ray branches. PAL-XFEL required for about six hundreds of magnet power supply (MPS). The eight different prototypes of MPS are developing to confirm the performance, functions, size, heat load and so on. This paper describes the test results of the prototype MPS in major specifications. All MPSs have to be installed the end of September in 2015. The installation progress of the MPS was also described.

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MOP017

Beam Commissioning Plan for the SwissFEL Hard-X-Ray Facility

linac, undulator, electron, FEL

69

T. Schietinger
PSI, Villigen PSI, Switzerland

The SwissFEL facility currently being assembled at the Paul Scherrer Institute is designed to provide FEL radiation in the photon wavelength range between 0.1 and 7 nm. The commissioning of the first phase, comprising the electron injector, the main electron linear accelerator and the first undulator line, named Aramis and dedicated to the production of hard X-rays, is planned for the years 2016 and 2017. We present an overview of the beam commissioning plan elaborated in accordance with the installation schedule to bring into operation the various subsystems and establish beam parameters compatible with first pilot user experiments in late 2017.

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MOP043

Influence of Environment Changes on Libera Sync 3 Long-term Stability

controls, detector, timing, monitoring

126

S. Zorzut, M. Cargnelutti
I-Tech, Solkan, Slovenia
S. Hunziker
PSI, Villigen PSI, Switzerland

Libera Sync 3 can be used as a reference clock transfer system in the latest fourth generation light sources where the long-term stability is in the range of a few tens of femtoseconds of drift per day. The system has been developed in collaboration with the Paul Scherrer Institute (PSI) and first units are already tested in SwissFEL machine. In this article we present the influence of temperature and humidity changes on the long-term phase stability of the system.

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MOP047

The BINP HLS to Measure Vertical Changes on PAL-XFEL Buildings and Ground

timing, survey, experiment, alignment

133

H. J. Choi, K.H. Gil, H.-S. Kang, S.H. Kim, K.W. Seo
PAL, Pohang, Kyungbuk, Republic of Korea

PAL-XFEL is being installed and will be completed by December of 2015 so that users can be supported beginning in 2016. PAL-XFEL equipment should continuously maintain the bunch beam parameter. To this end, PAL-XFEL equipment has to be kept precisely aligned. As a part of the process for installing PAL-XFEL, a surface geodetic network and the installation of a tunnel measurement network inside buildings is in preparation; additionally, the fiducialization of major equipment is underway. After PAL-XFEL equipment is optimized and aligned, if the ground and buildings go through vertical changes during operation, misalignment of equipments will cause errors in the electron beam trajectory, which will lead to changes to the beam parameter. For continuous and systemic measurement of vertical changes in buildings and to monitor ground subsidence (sinks) and uplift, the BINP Ultrasonic-type Hydrostatic Levelling System (HLS) is to be installed and operated in all sections of PAL-XFEL for linear accelerator, undulator and beam line. This study will introduce the operation principle, design concept and advantages (self-calibration) of BINP ULS Sensor, and will outline its installation plan and operation plan.

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MOD03

Alkali Cathode Testing for LCLS-II at APEX

cathode, gun, electron, laser

280

H.J. Qian, J. Feng, D. Filippetto, J.R. Nasiatka, H.A. Padmore, F. Sannibale
LBNL, Berkeley, California, USA
R.K. Li, J.F. Schmerge, F. Zhou
SLAC, Menlo Park, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
Electron sources of high brightness and high bunch charge (~300 pC) with MHz repetition rate are one of the key technologies for next generation X-FEL facilities such as the LCLS-II at SLAC and the Euro XFEL at DESY. The Advanced Photoinjector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is developing such an electron source based on high quantum efficiency (QE) alkali photocathodes and the VHF-Gun, a new scheme normal conducting RF gun developed at LBNL. The VHF-Gun already demonstrated stable CW operation with high gradient (~ 20 MV/m), high gun voltage (~ 750 kV) and low vacuum pressure (~ 3 E-10 torr) laying the foundation for the generation of high brightness electron beams. In this paper, we report the test and characterization of several different alkali cathodes in high average current (several hundreds of pC/bunch with MHz repetition rate) operation at APEX. Measurements include cathode life time, QE map evolution and thermal emittance characterization, to investigate the compatibility of such cathodes with the challenging requirements of LCLS-II.

Slides MOD03 [6.030 MB]

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TUA03

Multi-beamline Operation Test at SACLA

electron, undulator, kicker, laser

293

T. Hara, T. Inagaki, R. Kinjo, C. Kondo, Y. Otake, H. Takebe, H. Tanaka, K. Togawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
K. Fukami
JASRI/SPring-8, Hyogo-ken, Japan

A new undulator beamline (BL2) was installed in September 2014 at SACLA. Following the installation of this second beamline, a DC switching magnet was replaced by a kicker magnet and a DC septum magnet for bunch-to-bunch multi-beamline operation. The commissioning of the new beamline and bunch-to-bunch operation was started early this year. Since SACLA has been operated with much higher peak currents around 10 kA compared to its original design value of 3 kA, the CSR effect in the beam transport line to BL2, where the electron beam is deflected twice by 3 degree, turns out to be non-negligible. BL2 is currently operated with reduced peak currents and the photon pulse energies of 100-150 μJ are obtained with increased undulator K-values around 2.6-2.85. Although the photon pulse energies of BL2 are still smaller than those of the existing beamline (BL3), the expected stability of the electron beam orbit after the bunch-to-bunch BL switching was achieved and simultaneous lasing at the two beamlines was demonstrated with 8 GeV electron beams. We will report the status and operational issues related to the multi-beamline operation at SACLA.

Slides TUA03 [7.095 MB]

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TUA04

First Simultaneous Operation of Two Sase Beamlines in FLASH

undulator, photon, electron, FEL

297

M. Scholz, B. Faatz, S. Schreiber, J. Zemella
DESY, Hamburg, Germany

FLASH2, the second undulator beamline of the FLASH FEL user facility at DESY (Hamburg, Germany) is under commissioning. Its first lasing was achieved in August 2014. FLASH is the first soft X-ray FEL operating two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. Fast kickers and a septum are installed to distribute one part of the electron bunch train to FLASH1 and the other part to FLASH2 with full repetition rate. The commissioning of FLASH2 takes place primarily in parallel to FLASH1 user operation. Various beam optics measurements has been carried out in order to ensure the required electron beam quality for efficient SASE generation. This paper reports the status of the FLASH2 commissioning.

Slides TUA04 [9.655 MB]

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TUP010

Recent Progress in Upgrade of the High-Intensity THz-FEL at Osaka University

FEL, electron, linac, klystron

354

G. Isoyama, M. Fujimoto, S. Funakoshi, K. Furukawa, A. Irizawa, R. Kato, K. Kawase, A. Tokuchi, R. Tsutsumi, M. Yaguchi
ISIR, Osaka, Japan

We are upgrading the THz-FEL at Osaka University for its applications to high intensity THz sciences, which originally generated the high intensity FEL with the macropulse energy up to 3.7 mJ and the micropulse energy up to ~10 uJ at a wavelength around 70 um. To increase the micropulse energy, charge in electron bunches is increased four time higher and the bunch intervals are expanded four times longer to maintain the average current in the linac unchanged. In the new operation mode, the macropulse energy increases up to 26 mJ and the micropulse energy to ~0.2 mJ, which is 20 times higher than the energy previously obtained in the conventional mode. We have developed a solid-state switch for the klystron modulator to highly stabilize the klystron voltage, so that the output power of the FEL becomes stable. We are conducting basic studies on FEL for further improvement of its performance, including measurement of power evolution from start-up to saturation, time structures of FEL micropulses measured with a Michelson interferometer, and time structures of macropulses measured with a Schottky diode detector. We will report results of these studies on the THz-FEL at Osaka University.

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TUP011

Performance and Tolerance Studies of the X-Ray Production for the X-Band FEL Collaboration

undulator, simulation, electron, FEL

359

J. Pfingstner, E. Adli
University of Oslo, Oslo, Norway

The X-band FEL collaboration is currently designing an X-ray free-electron laser based on X-band acceleration technology. This paper reports on the recent progress on the design of the undulator part of this machine including simulations of the X-ray production process. The basic parameters have been chosen and a beam transport system has been designed, considering strong and weak focusing of quadrupole and undulator magnets. Simulations of the X-ray production process have been carried out with realistic input beam distributions from particle tracking studies of the linac design team. The expectable X-ray properties for SASE and seeded FEL operation have been investigated and also undulator taper options have been studied.

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TUP015

Status of the ALICE IR-FEL: from ERL Demonstrator to User Facility

FEL, laser, cavity, radiation

379

N. Thompson, J.A. Clarke, D.J. Dunning, A.J. Moss, Y.M. Saveliev, M. Surman
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T. Craig, M.R.F. Siggel-King, P. Weightman
The University of Liverpool, Liverpool, United Kingdom
O.V. Kolosov, P.D. Tovee
Lancaster University, Lancaster, United Kingdom
M.R.F. Siggel-King
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The ALICE (Accelerators and Lasers In Combined Experiments) accelerator at STFC Daresbury Laboratory in the UK was conceived in 2003 and constructed as a short-term Energy Recovery Linac demonstrator to develop the underpinning technology and expertise required for a proposed 600MeV ERL-based FEL facility. In this paper we present an update on the performance and status of ALICE which now operates as a funded IR-FEL user facility. We discuss the challenges of evolving a short-term demonstrator into a stable, reliable user facility and present a summary of the current scientific programme.

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TUP041

Simultaneous Operation of Three Laser Systems at the FLASH Photoinjector

laser, electron, cathode, free-electron-laser

459

S. Schreiber, C. Grün, K. Klose, J. Rönsch-Schulenburg, B. Steffen
DESY, Hamburg, Germany

The free-electron laser facility FLASH at DESY (Hamburg, Germany) operates two undulator beamlines simultaneously. Both undulator beamlines are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of trains of several hundred microsecond spaced bunches with a repetition rate of 10 Hz. A fast kickers-septum system is installed to distribute one part of the electron bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both beamlines. In order to deliver different beam properties to each beamline, the FLASH photoinjector uses two independent laser systems to generate different bunch pattern and bunch charges. One laser serves the FLASH1 beamline, the other the FLASH2 beamline. A third laser with adjus ö laser pulse duration is used to generate ultra-short bunches for single spike lasing.

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TUP042

Lifetime of Cs2Te Cathodes Operated at the FLASH Facility

laser, cathode, gun, electron

464

S. Schreiber, S. Lederer
DESY, Hamburg, Germany

The injector of the free-electron laser facility FLASH at DESY (Hamburg, Germany) uses Cs2Te photocathodes. We report on the lifetime, quantum efficiency (QE), and darkcurrent of photocathodes operated at FLASH during the last year. Cathode 618.3 has been operated for a record of 439 days with a stable QE in the order of 3%. The fresh cathode 73.3 shows an enhancement of emitted electrons for a few microseconds of a 1 MHz pulse train.

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TUP070

Energy Jitter Minimization at LCLS

linac, timing, experiment, simulation

523

L. Wang, A.L. Benwell, A. Brachmann, W.S. Colocho, F.-J. Decker, Z. Huang, T.J. Maxwell, T. Tao, J.L. Turner
SLAC, Menlo Park, California, USA

The energy jitters of the electron beam can affects the FEL in self-seeded modes if the jitter is large compared to the FEL parameter. We work in multiple ways to reduce the jitters, including hardware improvement, optimization linac set-up. This paper discusses the optimization of linac set-up. The solutions always suggest that we can largely reduce the energy jitter from a weak compression at BC1 and a stronger compression at BC2. Meanwhile a low beam energy at BC2 also reduce the energy jitter, which is confirmed by the experiment. The results can be explained by a simple model. Experimental results are also presented, demonstrating better than 20% and 40% relative energy jitter reduction for 13.6 and 4 GeV linac operation, respectively.

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TUP080

Terahertz Source Utilizing Resonant Coherent Diffraction Radiation at KEK ERL Test Accelerator

radiation, cavity, photon, extraction

547

Y. Honda, A. Aryshev, M. Shevelev, M. Shimada
KEK, Ibaraki, Japan

An energy recovery linac test accelerator, cERL, has been developing at KEK. It can produce a high repetition rate short bunched electron beam in a continuous operation mode. We propose to develop a high power THz radiation source at the return loop of the cERL. Coherent diffraction radiation of THz regime is emitted when an electron bunch passes through a conductive mirror with a beam hole at the center. If we form an optical cavity using two mirrors facing each other and the cavity length coincides with the bunch repetition rate, the coherent diffraction radiation of multiple bunches adds up coherently in the cavity. By extracting the power through transmission of one of the mirrors, we can realize a high power and high efficiency THz source. We discuss performance of the source assuming the beam parameters of cERL.

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WEB01

A Two-Color Storage Ring FEL

FEL, undulator, electron, cavity

571

J. Yan, H. Hao, S.F. Mikhailov, V. Popov, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA
S. Huang
PKU, Beijing, People's Republic of China
J.Y. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
N. Vinokurov
BINP SB RAS, Novosibirsk, Russia
J. Wu
SLAC, Menlo Park, California, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
Using different undulator configurations on the Duke storage ring, we have successfully achieved lasing with a novel two-color storage ring FEL. Using a pair of dual-band FEL mirrors, simultaneous lasing was realized in IR (around 720 nm) and in UV (around 360 nm). With this two-color FEL, we have demonstrated independent wavelength tuning of either IR or UV lasing. With careful tuning, we have also realized harmonic lasing with the UV lasing tuned to the second harmonic of the IR lasing. The tuning of harmonic two-color lasing has also been demonstrated with the locked wavelengths. Furthermore, we have demonstrated good control of the FEL power sharing between the two colors. The two-color FEL has created new opportunities to drive a two-color Compton gamma-ray beam at the High Intensity gamma-ray Source at Duke.

Slides WEB01 [18.975 MB]

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WEB04

Saturation Dynamics, Fine Spectrum, and Chirp Control in a CW FEL Oscillator

FEL, laser, electron, coupling

580

H. S. Marks, A. Gover, H. Kleinman
University of Tel-Aviv, Faculty of Engineering, Tel-Aviv, Israel
D. Borodin, A. Damti, A. Friedman, Y. Vashdi
Ariel University, Ariel, Israel
M. Einat, M. Kanter, Y. Lasser, Yu. Lurie, A. Yahalom
Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel

As in conventional laser physics, the saturation dynamics of a long-pulse Electrostatic Accelerator FEL (EA-FEL) oscillator consists of oscillations build-up, resonator modes competition, and establishment of narrow linewidth single mode lasing. In EA-FEL the gain curve drifts to lower frequencies during the long laser pulse due to inevitable droop in the acceleration voltage. This post-saturation drift renders fine chirp of the single mode laser frequency due to the oscillator frequency pulling effect. We have integrated a voltage-ramping element into the electrostatic accelerator terminal that makes it possible to control the acceleration voltage throughout the lasing pulse. This allows us to keep the voltage constant throughout the e-beam pulse, and so increase the single mode lasing time, avoiding mode-hopping during the pulse due to the drift of the gain curve. Furthermore, by adjusting the voltage ramp rate and polarity we obtained controllable positive/negative laser frequency chirp that can be used in a single pulse sweep for fine spectral line (10^-6) gas-spectroscopy. The study was conducted on the Israeli EA-FEL that operates at tunable frequencies between 95-110 GHz.

Slides WEB04 [2.310 MB]

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WEP022

Photon Energies beyond the Selenium K-Edge at LCLS

FEL, photon, electron, linac

630

F.-J. Decker, W.S. Colocho, Y. Ding, R.H. Iverson, H. Loos, J. Sheppard, H. Smith, J.L. Turner
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. Department of Energy, Contract DE-AC02-76SF00515.
The Linac Coherent Light Source (LCLS) was designed for a photon energies of 830 eV to 8.3 keV. This range was widened and up to 11.2 keV photons were already delivered for users. The Selenium K-edge at 12.6578 keV is very interesting since Selenium can replace Sulfur in biological structures and then that structure could be precisely measured. To reach this the electron energy would need to be raised by about 6% which initially didn't seem possible. The trick is to change the final compression scheme from a high correlated energy spread and moderate R56 in the compression chicane to moderate energy spread and high R56. The same bunch length can be achieved and RF energy is freed up, so the overall beam energy can be raised. Photons up to an energy of 12.82 keV (1.3% above the K-edge) with a pulse intensity of 0.93 mJ were achieved. The photon energy spread with this setup is wider at around 40-50 eV FWHM, since less correlated energy spread is left after the compression.

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WEP078

Advances on the LUNEX5 and COXINEL Projects

FEL, laser, electron, plasma

730

M.-E. Couprie, C. Benabderrahmane, P. Berteaud, C. Bourassin-Bouchet, F. Bouvet, J.D. Bozek, F. Briquez, L. Cassinari, L. Chapuis, J. Da Silva, J. Daillant, D. Dennetière, Y. Dietrich, M. Diop, J.P. Duval, M.E. El Ajjouri, T.K. El Ajjouri, C. Herbeaux, N. Hubert, M. Khojoyan, M. Labat, N. Leclercq, A. Lestrade, A. Loulergue, J. Lüning, P. Marchand, O. Marcouillé, J.L. Marlats, F. Marteau, C. Miron, P. Morin, A. Nadji, R. Nagaoka, F. Polack, F. Ribeiro, J.P. Ricaud, P. Rommeluère, P. Roy, G. Sharma, K.T. Tavakoli, M. Thomasset, M. Tilmont, M.-A. Tordeux, M. Valléau, J. Vétéran, W. Yang, D. Zerbib
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, M. Le Parquier
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
X. Davoine
CEA/DAM/DIF, Arpajon, France
N. Delerue, M. El Khaldi, W. Kaabi, F. Wicek
LAL, Orsay, France
G. Devanz, C. Madec
CEA/IRFU, Gif-sur-Yvette, France
A. Dubois
CCPMR, Paris, France
C. Evain, C. Szwaj
PhLAM/CERLA, Villeneuve d'Ascq, France
D. Garzella
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
G. Lambert, V. Malka, A. Rousse, C. Thaury
LOA, Palaiseau, France
A. Mosnier
CEA/DSM/IRFU, France
E. Roussel
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Funding: ERC COXINEL 340015
LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating compact and advanced Free Electron Laser (FEL). It comprises one one hand a 400 MeV superconducting linac for studies of advanced FEL schemes, high repetition rate operation (10 kHz), multi-FEL lines, and one the other hand a Laser Wake Field Accelerator (LWFA) for its qualification by a FEL application, an undulator line enabling advanced seeding and pilot user applications in the 40-4 nm spectral range. Following the CDR completion, different R&D programs were launched, as for instance on FEL pulse duration measurement, high repetition rate electro-optical sampling. The COXINEL ERC Advanced Grant aims at demonstrating LWFA based FEL amplification, thanks to a proper electron beam manipulation, with a test experiment under preparation. As a specific hardware is also under development such as a cryo-ready 3 m long undulator of 15 mm period is under development.

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