FEL2017 - List of Authors (Prat, E.)

Paper	Title	Page
MOP038	Overview of the Soft X-Ray Line Athos at SwissFEL	125
	R. Ganter, S. Bettoni, H.-H. Braun, M. Calvi, P. Craievich, R. Follath, C.H. Gough, F. Löhl, M. Paraliev, L. Patthey, M. Pedrozzi, E. Prat, S. Reiche, T. Schmidt, A.Z. Zandonella PSI, Villigen PSI, Switzerland
	The Athos line will cover the photon energy range from 250 to 1900 eV and will operate parallel to the hard x-ray line Aramis of SwissFEL. Athos consists of fast kicker magnets, a dog-leg transfer line, a small linac and 16 APPLE undulators. The Athos undulators follow a new design: the so-called APPLE X design where the 4 magnet arrays can be moved radially in a symmetric way. Besides mechanical advantages of such a symmetric distribution of forces, this design allows for easy photon energy scans at a constant polarization or for the generation of transverse magnetic gradients. Another particularity of the Athos FEL line is the inclusion of a short magnetic chicane between every undulator segment. These chicanes will allow the FEL to operate in optical klystron mode, high-brightness SASE mode, or superradiance mode. A larger delay chicane will split the Athos line into two sections such that two colors can be produced with adjustable delay. Finally a post undulator transverse deflecting cavity will be the key tool for the commissioning of the FEL modes. The paper will present the current status of this four years project started in 2017.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP038
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TUP053	The ACHIP Experimental Chambers at PSI	336
	E. Ferrari, M. Bednarzik, S. Bettoni, S. Borrelli, H.-H. Braun, M. Calvi, Ch. David, M.M. Dehler, F. Frei, T. Garvey, V. Guzenko, N. Hiller, R. Ischebeck, C. Ozkan Loch, E. Prat, J. Raabe, S. Reiche, L. Rivkin, A. Romann, B. Sarafinov, V. Schlott, S. Susmita PSI, Villigen PSI, Switzerland E. Ferrari, L. Rivkin EPFL, Lausanne, Switzerland P. Hommelhoff University of Erlangen-Nuremberg, Erlangen, Germany J.C. McNeur Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
	Funding: Gordon and Betty Moore Foundation The Accelerator on a Chip International Program (ACHIP) is an international collaboration, funded by the Gordon and Betty Moore Foundation, whose goal is to demonstrate that a laser-driven accelerator on a chip can be integrated to fully build an accelerator based on dielectric structures. PSI will provide access to the high brightness electron beam of SwissFEL to test structures, approaches and methods towards achieving the final goal of the project. In this contribution, we will describe the two interaction chambers installed on SwissFEL to perform the proof-of-principle experiments. In particular, we will present the positioning system for the samples, the magnets needed to focus the beam to sub-micrometer dimensions and the diagnostics to measure beam properties at the interaction point.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP053
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WEB01	Characterization of High-Brightness Electron Beams at the Frontiers of Temporal and Spatial Resolution
	R. Tarkeshian, T. Feurer, M. Hayati, Z. Ollmann Universität Bern, Institute of Applied Physics, Bern, Switzerland T. Garvey, R. Ischebeck, E. Prat, S. Reiche, V. Schlott PSI, Villigen PSI, Switzerland P. Krejcik SLAC, Menlo Park, California, USA W. Leemans, R. Lehé, S. Steinke LBNL, Berkeley, California, USA
	We present two novel diagnostics to characterize high-brightness electron beams. The first technique, based on the tunnel ionization of a neutral gas by the intense (GV/m) self-field of the electron beam, can be used to measure the volumetric charge density of the beam, for example to reconstruct pulse durations shorter than few femtoseconds or to measure transverse beam sizes below the micron level. Experiments with sub-femtosecond unipolar self-field of electron beam, that approach the through-the-barrier tunneling times, could further deepen our understanding of quantum tunneling process. The second method can be used to streak electron beams with single cycle THz radiation concentrated in a micrometer gap of a resonant antenna, creating an enhanced electric near-field distribution. With this diagnostic one can measure with sub-femtosecond resolution the longitudinal duration, the slice emittance and energy spread of beams with energies up to tens of MeV. We show the validity of both methods with analytical calculations and particle-in-cell code simulations. We finally present practical implementation of both diagnostics at LCLS, in the XLEAP* experiment, and BELLA. * X-Ray Laser Enhanced Altosecond Pulse Generation (XLEAP) For LCLS.
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WEP040	Sub-Femtosecond Time-Resolved Measurements Based on a Variable Polarization X-Band Transverse Deflecting Structures for SwissFEL	499
	P. Craievich, M. Bopp, H.-H. Braun, R. Ganter, M. Pedrozzi, E. Prat, S. Reiche, R. Zennaro PSI, Villigen PSI, Switzerland R.W. Aßmann, F. Christie, R.T.P. D'Arcy, B. Marchetti, D. Marx DESY, Hamburg, Germany N. Catalán Lasheras, A. Grudiev, G. McMonagle, W. Wuensch CERN, Geneva, Switzerland
	The SwissFEL project, under commissioning at the Paul Scherrer Institut (PSI), will produce FEL radiation for soft and hard X-rays with pulse durations ranging from a few to several tens of femtoseconds. A collaboration between DESY, PSI and CERN has been established with the aim of developing and building an advanced X-Band transverse deflector structure (TDS) with the new feature of providing variable polarization of the deflecting force. As this innovative CERN design requires very high manufacturing precision to guarantee highest azimuthal symmetry of the structure to avoid the deterioration of the polarization of the streaking field, the high-precision tuning-free assembly procedures developed at PSI for the SwissFEL C-band accelerating structures will be used for the manufacturing. Such a TDS will be installed downstream of the undulators of the soft X-ray beamline of SwissFEL and thanks to the variable polarization of the TDS, it will be possible to perform a complete characterization of the 6D phase-space. We summarize in this work the status of the project and its main technical parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP040
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THB04	Two-Color Beam Generation via Wakefield Excitation
	S. Bettoni, E. Prat, S. Reiche PSI, Villigen PSI, Switzerland
	Several beam manipulation methods have been studied and experimentally tested to generate two-color photon beams in free electron laser facilities to accommodate the user requests. We propose to use the interaction of the beam with an oscillating longitudinal wakefield source to obtain a suitable electron beam structure. The bunch generates two sub-pulses with different energies and delays in time passing through a magnetic chicane after its longitudinal phase space has been modulated by the wakefield source. According to this approach, the power of the emitted radiation is not degraded compared to the monochromatic beam, and the set-up in the machine is quite simple because the bunch is manipulated only in the high energy section where the beam is more rigid. We present the design applied to SwissFEL. We identified the parameters and the corresponding range of tunability of the time and energy separation among the two sub-bunches. Reference: Phys. Rev. Accel. Beams 19, 050702 (2016)
	Slides THB04 [10.429 MB]
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FRA02	Using the Optical-Klystron Effect to Increase and Measure the Intrinsic Beam Energy Spread in Free-Electron Laser Facilities
	E. Prat, S. Reiche, T. Schietinger PSI, Villigen PSI, Switzerland E. Ferrari EPFL, Lausanne, Switzerland
	We present a setup based on the optical klystron concept consisting of two undulator modules separated by a magnetic chicane, that addresses two issues in free-electron laser (FEL) facilities. On the one hand, it allows an increase of the intrinsic energy spread of the beam at the source, which is useful to counteract the harmful microbunching instability. This represents an alternative method to the more conventional laser heater with the main advantage that no laser system is required. On the other hand, the setup can be used to reconstruct the initial beam energy spread, whose typical values in FEL injectors around 1 keV are very difficult to measure with standard procedures.
	Slides FRA02 [2.306 MB]
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Paper

Title

Page

Overview of the Soft X-Ray Line Athos at SwissFEL

125

R. Ganter, S. Bettoni, H.-H. Braun, M. Calvi, P. Craievich, R. Follath, C.H. Gough, F. Löhl, M. Paraliev, L. Patthey, M. Pedrozzi, E. Prat, S. Reiche, T. Schmidt, A.Z. Zandonella
PSI, Villigen PSI, Switzerland

The Athos line will cover the photon energy range from 250 to 1900 eV and will operate parallel to the hard x-ray line Aramis of SwissFEL. Athos consists of fast kicker magnets, a dog-leg transfer line, a small linac and 16 APPLE undulators. The Athos undulators follow a new design: the so-called APPLE X design where the 4 magnet arrays can be moved radially in a symmetric way. Besides mechanical advantages of such a symmetric distribution of forces, this design allows for easy photon energy scans at a constant polarization or for the generation of transverse magnetic gradients. Another particularity of the Athos FEL line is the inclusion of a short magnetic chicane between every undulator segment. These chicanes will allow the FEL to operate in optical klystron mode, high-brightness SASE mode, or superradiance mode. A larger delay chicane will split the Athos line into two sections such that two colors can be produced with adjustable delay. Finally a post undulator transverse deflecting cavity will be the key tool for the commissioning of the FEL modes. The paper will present the current status of this four years project started in 2017.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-MOP038

Export •

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

TUP053

The ACHIP Experimental Chambers at PSI

336

E. Ferrari, M. Bednarzik, S. Bettoni, S. Borrelli, H.-H. Braun, M. Calvi, Ch. David, M.M. Dehler, F. Frei, T. Garvey, V. Guzenko, N. Hiller, R. Ischebeck, C. Ozkan Loch, E. Prat, J. Raabe, S. Reiche, L. Rivkin, A. Romann, B. Sarafinov, V. Schlott, S. Susmita
PSI, Villigen PSI, Switzerland
E. Ferrari, L. Rivkin
EPFL, Lausanne, Switzerland
P. Hommelhoff
University of Erlangen-Nuremberg, Erlangen, Germany
J.C. McNeur
Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany

Funding: Gordon and Betty Moore Foundation
The Accelerator on a Chip International Program (ACHIP) is an international collaboration, funded by the Gordon and Betty Moore Foundation, whose goal is to demonstrate that a laser-driven accelerator on a chip can be integrated to fully build an accelerator based on dielectric structures. PSI will provide access to the high brightness electron beam of SwissFEL to test structures, approaches and methods towards achieving the final goal of the project. In this contribution, we will describe the two interaction chambers installed on SwissFEL to perform the proof-of-principle experiments. In particular, we will present the positioning system for the samples, the magnets needed to focus the beam to sub-micrometer dimensions and the diagnostics to measure beam properties at the interaction point.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-TUP053

Export •

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

WEB01

Characterization of High-Brightness Electron Beams at the Frontiers of Temporal and Spatial Resolution

R. Tarkeshian, T. Feurer, M. Hayati, Z. Ollmann
Universität Bern, Institute of Applied Physics, Bern, Switzerland
T. Garvey, R. Ischebeck, E. Prat, S. Reiche, V. Schlott
PSI, Villigen PSI, Switzerland
P. Krejcik
SLAC, Menlo Park, California, USA
W. Leemans, R. Lehé, S. Steinke
LBNL, Berkeley, California, USA

We present two novel diagnostics to characterize high-brightness electron beams. The first technique, based on the tunnel ionization of a neutral gas by the intense (GV/m) self-field of the electron beam, can be used to measure the volumetric charge density of the beam, for example to reconstruct pulse durations shorter than few femtoseconds or to measure transverse beam sizes below the micron level. Experiments with sub-femtosecond unipolar self-field of electron beam, that approach the through-the-barrier tunneling times, could further deepen our understanding of quantum tunneling process. The second method can be used to streak electron beams with single cycle THz radiation concentrated in a micrometer gap of a resonant antenna, creating an enhanced electric near-field distribution. With this diagnostic one can measure with sub-femtosecond resolution the longitudinal duration, the slice emittance and energy spread of beams with energies up to tens of MeV. We show the validity of both methods with analytical calculations and particle-in-cell code simulations. We finally present practical implementation of both diagnostics at LCLS, in the XLEAP* experiment, and BELLA.
* X-Ray Laser Enhanced Altosecond Pulse Generation (XLEAP) For LCLS.

Export •

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

WEP040

Sub-Femtosecond Time-Resolved Measurements Based on a Variable Polarization X-Band Transverse Deflecting Structures for SwissFEL

499

P. Craievich, M. Bopp, H.-H. Braun, R. Ganter, M. Pedrozzi, E. Prat, S. Reiche, R. Zennaro
PSI, Villigen PSI, Switzerland
R.W. Aßmann, F. Christie, R.T.P. D'Arcy, B. Marchetti, D. Marx
DESY, Hamburg, Germany
N. Catalán Lasheras, A. Grudiev, G. McMonagle, W. Wuensch
CERN, Geneva, Switzerland

The SwissFEL project, under commissioning at the Paul Scherrer Institut (PSI), will produce FEL radiation for soft and hard X-rays with pulse durations ranging from a few to several tens of femtoseconds. A collaboration between DESY, PSI and CERN has been established with the aim of developing and building an advanced X-Band transverse deflector structure (TDS) with the new feature of providing variable polarization of the deflecting force. As this innovative CERN design requires very high manufacturing precision to guarantee highest azimuthal symmetry of the structure to avoid the deterioration of the polarization of the streaking field, the high-precision tuning-free assembly procedures developed at PSI for the SwissFEL C-band accelerating structures will be used for the manufacturing. Such a TDS will be installed downstream of the undulators of the soft X-ray beamline of SwissFEL and thanks to the variable polarization of the TDS, it will be possible to perform a complete characterization of the 6D phase-space. We summarize in this work the status of the project and its main technical parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2017-WEP040

Export •

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

THB04

Two-Color Beam Generation via Wakefield Excitation

S. Bettoni, E. Prat, S. Reiche
PSI, Villigen PSI, Switzerland

Several beam manipulation methods have been studied and experimentally tested to generate two-color photon beams in free electron laser facilities to accommodate the user requests. We propose to use the interaction of the beam with an oscillating longitudinal wakefield source to obtain a suitable electron beam structure. The bunch generates two sub-pulses with different energies and delays in time passing through a magnetic chicane after its longitudinal phase space has been modulated by the wakefield source. According to this approach, the power of the emitted radiation is not degraded compared to the monochromatic beam, and the set-up in the machine is quite simple because the bunch is manipulated only in the high energy section where the beam is more rigid. We present the design applied to SwissFEL. We identified the parameters and the corresponding range of tunability of the time and energy separation among the two sub-bunches.
Reference: Phys. Rev. Accel. Beams 19, 050702 (2016)

Slides THB04 [10.429 MB]

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FRA02

Using the Optical-Klystron Effect to Increase and Measure the Intrinsic Beam Energy Spread in Free-Electron Laser Facilities

E. Prat, S. Reiche, T. Schietinger
PSI, Villigen PSI, Switzerland
E. Ferrari
EPFL, Lausanne, Switzerland

We present a setup based on the optical klystron concept consisting of two undulator modules separated by a magnetic chicane, that addresses two issues in free-electron laser (FEL) facilities. On the one hand, it allows an increase of the intrinsic energy spread of the beam at the source, which is useful to counteract the harmful microbunching instability. This represents an alternative method to the more conventional laser heater with the main advantage that no laser system is required. On the other hand, the setup can be used to reconstruct the initial beam energy spread, whose typical values in FEL injectors around 1 keV are very difficult to measure with standard procedures.

Slides FRA02 [2.306 MB]

Export •

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