FEL2014 - List of Keywords (diagnostics)

Paper	Title	Other Keywords	Page
MOP012	Implementation Phase of the European XFEL Photon Diagnostics	photon, undulator, FEL, electron	41
	J. Grünert, J. Buck, F. Dietrich, W. Freund, A. Koch, M. Planas XFEL. EU, Hamburg, Germany
	The European XFEL facility with 3 undulators and initially 6 experimental end-stations requires an extensive set of photon beam diagnostics for commissioning and user operation, capable of handling the extreme brilliance and its inherent damage potential, and the high intra bunch train repetition rate of 4.5MHz, potentially causing additional damage by high heat loads and making shot-to-shot diagnostics very demanding [1]. After extensive design [2-4] and prototype studies, in 2014 the installation of the photon beam devices starts with the equipment in the first photon tunnel XTD2 which is where the SASE1 hard X-ray undulator is located. This contribution reports on the device construction progress by focusing on the XTD2 tunnel devices and their implementation into the tunnel environment. [1] J.Grünert, Framework for X-Ray Photon Diagnostics at the European XFEL, TR-2012-003, 04/2012 [2] J.Buck, Online Photoemission Time-of-Flight Spectrometer for X-ray Photon Diagnostics, TR-2012-002, 06/2012 [3] C.Ozkan, Conceptual design report for Imaging Stations at the European XFEL, TR-2012-004, 02/2012 [4] W.Freund, The European XFEL Undulator Commissioning Spectrometer, XFEL. EU 05/2011

MOP014	X-ray Photon Temporal Diagnostics for the European XFEL	photon, brilliance, electron, laser	45
	J. Liu, J. Buck, F. Dietrich, W. Freund, J. Grünert, M. Meyer XFEL. EU, Hamburg, Germany
	European XFEL (XFEL. EU) that will commissioning in 2016 shows great features on its extremely high number of light bullets (27000 p/s) and extremely high average brilliance. The FEL pulses in XFEL. EU are produced in a 10 Hz bunch trains that contains 2700 sub-pulses within the 600 μs time intervals, corresponding to a 220 ns sub-pulse separation and 4.5 MHz repetition rate. Characterizing the temporal properties of the high repetition rate FEL pulses that implicitly different from shot to shot is important for “pump and probe” experiments and data interpretation. Here we report the concept and recent progress about temporal diagnostic for XFEL. EU. THz streaking technique and spectral encoding will be implemented considering the high repetition rate and high brilliance of XFEL. EU. Laser based THz generation, optimization and numerical simulation for streaking FEL electrons with different photon energies will be presented. High repetition rate diagnostic requirements and solutions will also be discussed.

MOP020	Compact Spectrometer for Single Shot X-ray Emission and Photon Diagnostics	photon, FEL, target, synchrotron	62
	F. Frassetto, P. Miotti, L. P. Poletto CNR-IFN, Padova, Italy M. Coreno CNR-IMIP, Monterotondo Stazione RM, Italy A. Di Cicco, F. Iesari Università di Camerino, Camerino, Italy P. Finetti, E. Giangrisostomi, R. Mincigrucci, E. Principi Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy C. Grazioli Universita Degli Studi di Trieste, Trieste, Italy A. Kivimaki IOM-CNR, Trieste, Italy S. Stagira CNR-IFN & Dipartimento di Fisica - Politecnico di Milano, Milano, Italy S. Stagira Politecnico/Milano, Milano, Italy
	The design and characterization of a compact spectrometer realized for photon in-photon out experiments (in particular X-Ray Emission Spectroscopy), conceived to be used at the FERMI free-electron-laser (FEL) at ELETTRA (Italy) is here presented. The instrument can be easily installed on different end stations at variable distances from the target area both at synchrotron and FEL beamlines. Different input sections can be accommodated in order to fit the experimental requests. The design is compact in order to realize a portable instrument within an overall size of less than one square meter. The spectrometer covers the 25-800 eV spectral range, with spectral resolution better than 0.2%. The characterization on Gas Phase @ ELETTRA as instrument for XES and some experimental data of the FEL emission acquired at EIS-TIMEX @ FERMI, where the instrument has been used for photon beam diagnostics, are introduced.

TUB03	FEL Overcompression in the LCLS	electron, simulation, experiment, FEL	337
	J.L. Turner, F.-J. Decker, Y. Ding, Z. Huang, R.H. Iverson, J. Krzywinski, H. Loos, A. Marinelli, T.J. Maxwell, H.-D. Nuhn, D.F. Ratner, T.J. Smith, J.J. Welch, F. Zhou SLAC, Menlo Park, California, USA
	Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515 Overcompression of the Linac Coherent Light Source (LCLS) x-ray Free Electron Laser (FEL) at the SLAC National Accelerator Center is studied. The studies and operational implications are summarized in this talk.
	Slides TUB03 [4.493 MB]

TUP021	Recent Updates to the Optical Propagation Code OPC	FEL, undulator, electron, free-electron-laser	412
	P.J.M. van der Slot, K.J. Boller Mesa+, Enschede, The Netherlands P.J.M. van der Slot CSU, Fort Collins, Colorado, USA
	Funding: This research is supported in part by Office of Naval Research Global, grant number N62909-10-1-7151 In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that (i) improves the speed of the code and (ii) extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation. Finally, work is underway to support HDF5 to remain compatible with the upcoming new release of GENESIS 1.3.

TUP075	Commissioning Status of the ASTA Facility at Fermilab	cryomodule, gun, laser, cavity	537
	A.H. Lumpkin, D.R. Broemmelsiek, D.J. Crawford, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, J.R. Leibfritz, J. Ruan, J.K. Santucci, G. Stancari, D. Sun, J.C.T. Thangaraj, R.M. Thurman-Keup, A. Warner, J. Zhu Fermilab, Batavia, Illinois, USA
	Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy. Early commissioning results and status of the Advanced Superconducting Test Accelerator (ASTA) at Fermilab will be described. The ASTA facility consists of an L-band rf photocathode (PC) gun, two superconducting L-band rf booster cavities, transport lines, and an 8-cavity TESLA style cryomodule. Early results include first photoelectrons from the Cs2Te photocathode and operations at 3-5 MeV from the rf PC gun. The beam line with one 4-dipole chicane, extensive diagnostics, and 50-MeV spectrometer are being installed. The base beam profile imaging stations have been equipped with both YAG:Ce scintillators and optical transition radiation (OTR) screens, optical transport, and with 5 Mpix digital CCD cameras using Gig-E readout. A set of rf BPMs, wall current monitors, and toroids are also being implemented. Transport of OTR to a C5680 Hamamatsu streak camera is also planned for longitudinal profile information at the picosecond level. Downstream of this location is the 8-cavity cryomodule in which most cavities have been operated at the targeted 31.5 MV/m gradient. Initial beam measurements at 20 MeV and updated cryomodule results will be presented as available.

TUP091	Developments in the CLARA FEL Test Facility Accelerator Design and Simulations	FEL, gun, linac, cavity	589
	P.H. Williams, D. Angal-Kalinin, A.D. Brynes, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom
	We present recent developments in the accelerator design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory. These comprise a revised front-end to ensure integration with the existing VELA line, simulations of a magnetically compressed ultra-short mode and a post-FEL diagnostics section. We also present first considerations on the inclusion of final acceleration using X-band structures.

WEB03	European XFEL Construction Status	photon, undulator, electron, laser	623
	W. Decking DESY, Hamburg, Germany F. Le Pimpec XFEL. EU, Hamburg, Germany
	The European XFEL is presently constructed in the Hamburg region, Germany. It aims at producing X-rays in the range from 260 eV up to 24 keV out of three undulators that can be operated simultaneously with up to 27000 pulses/second. The FEL is driven by a 17.5 GeV linear accelerator based on TESLA-type superconducting accelerator modules. This paper presents the status of major components, the present project schedule and a summary of beam parameters that are adapted to the evolving needs of the users.
	Slides WEB03 [12.982 MB]

THB02	Experimental Results of Diagnostics Response for Longitudinal Phase Space	electron, laser, radiation, free-electron-laser	657
	F. Frei, V.R. Arsov, H. Brands, R. Ischebeck, B. Kalantari, R. Kalt, B. Keil, W. Koprek, F. Löhl, G.L. Orlandi, A. Saá Hernández, T. Schilcher, V. Schlott PSI, Villigen PSI, Switzerland
	At SwissFEL, electron bunches will be accelerated, shaped, and longitudinally compressed by different radio frequency (RF) structures (S-, C-, and X-band) in combination with magnetic chicanes. In order to meet the envisaged performance, it is planned to regulate the different RF parameters based on the signals from numerous electron beam diagnostics. Here we will present experimental results of the diagnostics response on RF phase and field amplitude variations that were obtained at the SwissFEL Injector Test Facility.
	Slides THB02 [6.110 MB]

THB04	Electron Beam Diagnostics and Feedback for the LCLS-II	cavity, feedback, controls, undulator	666
	J.C. Frisch, P. Emma, A.S. Fisher, P. Krejcik, H. Loos, T.J. Maxwell, T.O. Raubenheimer, S.R. Smith SLAC, Menlo Park, California, USA
	Funding: work supported by DOE contract DE-AC02-76-SF00515 The LCLS_II is a CW superconducting accelerator driven, hard and soft X-ray Free Electron Laser which is planned to be constructed at SLAC. It will operate with a variety of beam modes from single shot to approximately 1 MHz CW at bunch charges from 10pc to 300pC with average beam powers up to 1.2 MW. A variety of types of beam instrumentation will be used, including stripline and cavity BPMS, fluorescent and OTR based beam profile monitors, fast wire scanners and transverse deflection cavities. The beam diagnostics system is designed to allow tuning and continuous measurement of beam parameters, and to provide signals for fast beam feedbacks.
	Slides THB04 [1.501 MB]

THP082	Measurements of Compressed Bunch Temporal Profile using Electro-Optic Monitor at SITF	laser, electron, vacuum, optics	922
	Ye. Ivanisenko, V. Schlott PSI, Villigen PSI, Switzerland P. Peier DESY, Hamburg, Germany
	Funding: The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n.°290605 (PSI-FELLOW/COFUND) The SwissFEL Injector Test Facility (SITF) is an electron linear accelerator with a single bunch compression stage at Paul Scherrer Institute (PSI) in Switzerland. Electro-optic monitors (EOMs) are available for bunch temporal profile measurements before and after the bunch compressor. The profile reconstruction is based upon spectral decoding technique. This diagnostic method is non-invasive, compact and cost-effective. It does not have high resolution and wide dynamic range of an RF transverse deflecting structure (TDS), but it is free of transverse beam size influence, what makes it a perfect tool for fast compression tuning. We present results of EOM and TDS measurements with down to 150 fs long bunches after the compression stage at SITF.

THP083	Coherent Radiation Diagnostics for Longitudinal Bunch Characterization at European XFEL	radiation, electron, detector, feedback	925
	P. Peier, H. Dinter, C. Gerth DESY, Hamburg, Germany
	European XFEL comprises a 17.5 GeV linear accelerator for the generation of hard X-rays. Electron bunches from 20 pC to 1 nC will be produced with a length of a few ps in the RF gun and compressed by three orders of magnitude in three bunch compressor (BC) stages. European XFEL is designed to operate at 10 Hz delivering bunch trains with up to 2700 bunches separated by 222 ns. The high intra-bunch train repetition rate offers the unique possibility of stabilizing the machine with an intra-bunch train feedback, which puts in turn very high demand on fast longitudinal diagnostics. Two different systems will be installed in several positions of the machine. Five bunch compression monitors (BCM) will monitor the compression factor of each BC stage and used for intra-bunch train feedbacks. A THz spectrometer will be used to measure parasitically the longitudinal bunch profile after the energy collimator at 17.5 GeV beam energy. We will present concepts for fast longitudinal diagnostic for European XFEL based on coherent radiation, newest developments for high repetition rate measurements and simulations for the feedback capability of the system.

THP085	Commissioning and Results from the Bunch Arrival-time Monitor Downstream the Bunch Compressor at the SwissFEL Test Injector	pick-up, cavity, laser, timing	933
	V.R. Arsov, M. Aiba, M.M. Dehler, F. Frei, S. Hunziker, M.G. Kaiser, A. Romann, V. Schlott PSI, Villigen PSI, Switzerland
	A high bandwidth Bunch Arrival-Time Monitor has been commissioned at the Swiss FEL test injector. A new acquisition front end allowing utilization of the ADC full dynamic range has been implemented. The resolution is measured as a function of the charge for different EOM front-ends. Downstream the magnetic chicane the bunch arrival time is sensitive to the amplitude and phases of the RF structures, responsible for creation of an energy chirp, used for bunch compression, as well as the ones of the harmonic cavity, used for phase space linearization. The time of flight as a function of the angle of the magnetic chicane has also been measured.

THP087	Electron Beam Diagnostics for COXINEL	electron, undulator, plasma, FEL	937
	M. Labat, C. Bourassin-Bouchet, L. Cassinari, M.-E. Couprie, M.E. El Ajjouri, N. Hubert, A. Loulergue SOLEIL, Gif-sur-Yvette, France
	On the path towards more compact free electron lasers (FELs), the project COXINEL was recently funded: a transfer line will be installed to adapt a plasma accelerated beam (from LOA) into an in-vacuum undulator built by SOLEIL. This experiment should enable to demonstrate the first FEL based on a plasma accelerator. Because plasma beams are intrinsically very different from RF acceletor beams (much shorter, divergent and smaller with a higher energy spread and energy jitter), their transport and matching in the undulator is critical if willing to obtain a significant amplification. This is why special care has to be taken in the design of the beam diagnostics to be able to measure the transverse beam sizes, energy spread and jitter, emittance and bunch length. For these purposes, several diagnostics will be implemented from the plasma accelerator exit down to the undulator exit. In each station, several screen types will be available and associated to high resolution imaging screens. In this paper, we present the experimental layout and associated simulation of the diagnostics performances.

THP088	Comparison of Quadrupole Scan and Multi-screen Method for the Measurement of Projected and Slice Emittance at the SwissFEL Injector Test Facility	emittance, quadrupole, optics, FEL	941
	M. Yan, B. Beutner, C. Gerth DESY, Hamburg, Germany R. Ischebeck, E. Prat PSI, Villigen PSI, Switzerland
	High-brightness electron bunches with small transverse emittance are required to drive X-ray free-electron lasers (FELs). For the measurement of the transverse emittance, the quadrupole scan and multi-screen methods are the two most common procedures. By employing a transverse deflecting structure, the measurement of the slice emittance becomes feasible. The quadrupole scan is more flexible in freely choosing the data points during the scan, while the multi-screen method allows on-line emittance measurements utilising off-axis screens in combination with fast kicker magnets. The latter is especially the case for high-repetition multi-bunch FELs, such as the European XFEL, which offer the possibility of on-line diagnostics. In this paper, we present comparative measurements of projected and slice emittance applying these two methods at the SwissFEL Injector Test Facility and discuss the implementation of on-line diagnostics at the European XFEL.

THP092	Transition Radiation of an Electron Bunch and Imprint of Lorentz-Covariance and Temporal-Causality	electron, radiation, optics, simulation	952
	G.L. Orlandi PSI, Villigen PSI, Switzerland
	The study of Transition Radiation (TR) of a bunch of N electrons offers a precious insight into the role that Lorentz-covariance and temporal-causality play in an electromagnetic radiative mechanism of a relativistic beam. The contributions of the N single electrons to the radiation field are indeed characterized by emission phases from the metallic surface which are in a causality relation with the temporal sequence of the N particle collisions onto the radiating screen. The Lorentz-covariance characterizing the virtual quanta field of the relativistic charge is also expected to imprint the radiation field and the related energy spectrum. The main aspects of a Lorentz-covariance and temporal-causality consistent formulation of the TR energy spectrum of an electron bunch will be described.

THP097	Longitudinal Response Matrix Simulations for the SwissFEL Injector Test Facility	simulation, electron, laser, free-electron-laser	964
	Á. Saá Hernández, F. Frei, R. Ischebeck PSI, Villigen PSI, Switzerland B. Beutner DESY, Hamburg, Germany
	The Singular Value Decomposition (SVD) method has been applied to the SwissFEL Injector Test Facility to identify and better expose the various relationships among the possible jitter sources affecting the longitudinal phase space distribution and the longitudinal diagnostic elements that measure them. To this end, several longitudinal tracking simulations have been run using the Litrack code. In these simulations the RF and laser jitter sources are varied one-by-one within a range spanning twice their expected stability. The particle distributions have been dumped at the diagnostic locations and the measured quantities analyzed. A matrix has been built by linearly fitting the response of each measured quantity to each jitter source. This response matrix is normalized to the jitter source stability and the instrumentation accuracy, and it is inverted and analyzed using SVD. From the eigenvalues and eigenvectors the sensitivity of the diagnostics to the jitters can be evaluated and their specifications and locations optimized.

Paper

Title

Other Keywords

Page

MOP012

Implementation Phase of the European XFEL Photon Diagnostics

photon, undulator, FEL, electron

41

J. Grünert, J. Buck, F. Dietrich, W. Freund, A. Koch, M. Planas
XFEL. EU, Hamburg, Germany

The European XFEL facility with 3 undulators and initially 6 experimental end-stations requires an extensive set of photon beam diagnostics for commissioning and user operation, capable of handling the extreme brilliance and its inherent damage potential, and the high intra bunch train repetition rate of 4.5MHz, potentially causing additional damage by high heat loads and making shot-to-shot diagnostics very demanding [1]. After extensive design [2-4] and prototype studies, in 2014 the installation of the photon beam devices starts with the equipment in the first photon tunnel XTD2 which is where the SASE1 hard X-ray undulator is located. This contribution reports on the device construction progress by focusing on the XTD2 tunnel devices and their implementation into the tunnel environment. [1] J.Grünert, Framework for X-Ray Photon Diagnostics at the European XFEL, TR-2012-003, 04/2012 [2] J.Buck, Online Photoemission Time-of-Flight Spectrometer for X-ray Photon Diagnostics, TR-2012-002, 06/2012 [3] C.Ozkan, Conceptual design report for Imaging Stations at the European XFEL, TR-2012-004, 02/2012 [4] W.Freund, The European XFEL Undulator Commissioning Spectrometer, XFEL. EU 05/2011

MOP014

X-ray Photon Temporal Diagnostics for the European XFEL

photon, brilliance, electron, laser

45

J. Liu, J. Buck, F. Dietrich, W. Freund, J. Grünert, M. Meyer
XFEL. EU, Hamburg, Germany

European XFEL (XFEL. EU) that will commissioning in 2016 shows great features on its extremely high number of light bullets (27000 p/s) and extremely high average brilliance. The FEL pulses in XFEL. EU are produced in a 10 Hz bunch trains that contains 2700 sub-pulses within the 600 μs time intervals, corresponding to a 220 ns sub-pulse separation and 4.5 MHz repetition rate. Characterizing the temporal properties of the high repetition rate FEL pulses that implicitly different from shot to shot is important for “pump and probe” experiments and data interpretation. Here we report the concept and recent progress about temporal diagnostic for XFEL. EU. THz streaking technique and spectral encoding will be implemented considering the high repetition rate and high brilliance of XFEL. EU. Laser based THz generation, optimization and numerical simulation for streaking FEL electrons with different photon energies will be presented. High repetition rate diagnostic requirements and solutions will also be discussed.

MOP020

Compact Spectrometer for Single Shot X-ray Emission and Photon Diagnostics

photon, FEL, target, synchrotron

62

F. Frassetto, P. Miotti, L. P. Poletto
CNR-IFN, Padova, Italy
M. Coreno
CNR-IMIP, Monterotondo Stazione RM, Italy
A. Di Cicco, F. Iesari
Università di Camerino, Camerino, Italy
P. Finetti, E. Giangrisostomi, R. Mincigrucci, E. Principi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
C. Grazioli
Universita Degli Studi di Trieste, Trieste, Italy
A. Kivimaki
IOM-CNR, Trieste, Italy
S. Stagira
CNR-IFN & Dipartimento di Fisica - Politecnico di Milano, Milano, Italy
S. Stagira
Politecnico/Milano, Milano, Italy

The design and characterization of a compact spectrometer realized for photon in-photon out experiments (in particular X-Ray Emission Spectroscopy), conceived to be used at the FERMI free-electron-laser (FEL) at ELETTRA (Italy) is here presented. The instrument can be easily installed on different end stations at variable distances from the target area both at synchrotron and FEL beamlines. Different input sections can be accommodated in order to fit the experimental requests. The design is compact in order to realize a portable instrument within an overall size of less than one square meter. The spectrometer covers the 25-800 eV spectral range, with spectral resolution better than 0.2%. The characterization on Gas Phase @ ELETTRA as instrument for XES and some experimental data of the FEL emission acquired at EIS-TIMEX @ FERMI, where the instrument has been used for photon beam diagnostics, are introduced.

TUB03

FEL Overcompression in the LCLS

electron, simulation, experiment, FEL

337

J.L. Turner, F.-J. Decker, Y. Ding, Z. Huang, R.H. Iverson, J. Krzywinski, H. Loos, A. Marinelli, T.J. Maxwell, H.-D. Nuhn, D.F. Ratner, T.J. Smith, J.J. Welch, F. Zhou
SLAC, Menlo Park, California, USA

Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515
Overcompression of the Linac Coherent Light Source (LCLS) x-ray Free Electron Laser (FEL) at the SLAC National Accelerator Center is studied. The studies and operational implications are summarized in this talk.

Slides TUB03 [4.493 MB]

TUP021

Recent Updates to the Optical Propagation Code OPC

FEL, undulator, electron, free-electron-laser

412

P.J.M. van der Slot, K.J. Boller
Mesa+, Enschede, The Netherlands
P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA

Funding: This research is supported in part by Office of Naval Research Global, grant number N62909-10-1-7151
In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that (i) improves the speed of the code and (ii) extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation. Finally, work is underway to support HDF5 to remain compatible with the upcoming new release of GENESIS 1.3.

TUP075

Commissioning Status of the ASTA Facility at Fermilab

cryomodule, gun, laser, cavity

537

A.H. Lumpkin, D.R. Broemmelsiek, D.J. Crawford, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, J.R. Leibfritz, J. Ruan, J.K. Santucci, G. Stancari, D. Sun, J.C.T. Thangaraj, R.M. Thurman-Keup, A. Warner, J. Zhu
Fermilab, Batavia, Illinois, USA

Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy.
Early commissioning results and status of the Advanced Superconducting Test Accelerator (ASTA) at Fermilab will be described. The ASTA facility consists of an L-band rf photocathode (PC) gun, two superconducting L-band rf booster cavities, transport lines, and an 8-cavity TESLA style cryomodule. Early results include first photoelectrons from the Cs2Te photocathode and operations at 3-5 MeV from the rf PC gun. The beam line with one 4-dipole chicane, extensive diagnostics, and 50-MeV spectrometer are being installed. The base beam profile imaging stations have been equipped with both YAG:Ce scintillators and optical transition radiation (OTR) screens, optical transport, and with 5 Mpix digital CCD cameras using Gig-E readout. A set of rf BPMs, wall current monitors, and toroids are also being implemented. Transport of OTR to a C5680 Hamamatsu streak camera is also planned for longitudinal profile information at the picosecond level. Downstream of this location is the 8-cavity cryomodule in which most cavities have been operated at the targeted 31.5 MV/m gradient. Initial beam measurements at 20 MeV and updated cryomodule results will be presented as available.

TUP091

Developments in the CLARA FEL Test Facility Accelerator Design and Simulations

FEL, gun, linac, cavity

589

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

We present recent developments in the accelerator design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory. These comprise a revised front-end to ensure integration with the existing VELA line, simulations of a magnetically compressed ultra-short mode and a post-FEL diagnostics section. We also present first considerations on the inclusion of final acceleration using X-band structures.

WEB03

European XFEL Construction Status

photon, undulator, electron, laser

623

W. Decking
DESY, Hamburg, Germany
F. Le Pimpec
XFEL. EU, Hamburg, Germany

The European XFEL is presently constructed in the Hamburg region, Germany. It aims at producing X-rays in the range from 260 eV up to 24 keV out of three undulators that can be operated simultaneously with up to 27000 pulses/second. The FEL is driven by a 17.5 GeV linear accelerator based on TESLA-type superconducting accelerator modules. This paper presents the status of major components, the present project schedule and a summary of beam parameters that are adapted to the evolving needs of the users.

Slides WEB03 [12.982 MB]

THB02

Experimental Results of Diagnostics Response for Longitudinal Phase Space

electron, laser, radiation, free-electron-laser

657

F. Frei, V.R. Arsov, H. Brands, R. Ischebeck, B. Kalantari, R. Kalt, B. Keil, W. Koprek, F. Löhl, G.L. Orlandi, A. Saá Hernández, T. Schilcher, V. Schlott
PSI, Villigen PSI, Switzerland

At SwissFEL, electron bunches will be accelerated, shaped, and longitudinally compressed by different radio frequency (RF) structures (S-, C-, and X-band) in combination with magnetic chicanes. In order to meet the envisaged performance, it is planned to regulate the different RF parameters based on the signals from numerous electron beam diagnostics. Here we will present experimental results of the diagnostics response on RF phase and field amplitude variations that were obtained at the SwissFEL Injector Test Facility.

Slides THB02 [6.110 MB]

THB04

Electron Beam Diagnostics and Feedback for the LCLS-II

cavity, feedback, controls, undulator

666

J.C. Frisch, P. Emma, A.S. Fisher, P. Krejcik, H. Loos, T.J. Maxwell, T.O. Raubenheimer, S.R. Smith
SLAC, Menlo Park, California, USA

Funding: work supported by DOE contract DE-AC02-76-SF00515
The LCLS_II is a CW superconducting accelerator driven, hard and soft X-ray Free Electron Laser which is planned to be constructed at SLAC. It will operate with a variety of beam modes from single shot to approximately 1 MHz CW at bunch charges from 10pc to 300pC with average beam powers up to 1.2 MW. A variety of types of beam instrumentation will be used, including stripline and cavity BPMS, fluorescent and OTR based beam profile monitors, fast wire scanners and transverse deflection cavities. The beam diagnostics system is designed to allow tuning and continuous measurement of beam parameters, and to provide signals for fast beam feedbacks.

Slides THB04 [1.501 MB]

THP082

Measurements of Compressed Bunch Temporal Profile using Electro-Optic Monitor at SITF

laser, electron, vacuum, optics

922

Ye. Ivanisenko, V. Schlott
PSI, Villigen PSI, Switzerland
P. Peier
DESY, Hamburg, Germany

Funding: The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n.°290605 (PSI-FELLOW/COFUND)
The SwissFEL Injector Test Facility (SITF) is an electron linear accelerator with a single bunch compression stage at Paul Scherrer Institute (PSI) in Switzerland. Electro-optic monitors (EOMs) are available for bunch temporal profile measurements before and after the bunch compressor. The profile reconstruction is based upon spectral decoding technique. This diagnostic method is non-invasive, compact and cost-effective. It does not have high resolution and wide dynamic range of an RF transverse deflecting structure (TDS), but it is free of transverse beam size influence, what makes it a perfect tool for fast compression tuning. We present results of EOM and TDS measurements with down to 150 fs long bunches after the compression stage at SITF.

THP083

Coherent Radiation Diagnostics for Longitudinal Bunch Characterization at European XFEL

radiation, electron, detector, feedback

925

P. Peier, H. Dinter, C. Gerth
DESY, Hamburg, Germany

European XFEL comprises a 17.5 GeV linear accelerator for the generation of hard X-rays. Electron bunches from 20 pC to 1 nC will be produced with a length of a few ps in the RF gun and compressed by three orders of magnitude in three bunch compressor (BC) stages. European XFEL is designed to operate at 10 Hz delivering bunch trains with up to 2700 bunches separated by 222 ns. The high intra-bunch train repetition rate offers the unique possibility of stabilizing the machine with an intra-bunch train feedback, which puts in turn very high demand on fast longitudinal diagnostics. Two different systems will be installed in several positions of the machine. Five bunch compression monitors (BCM) will monitor the compression factor of each BC stage and used for intra-bunch train feedbacks. A THz spectrometer will be used to measure parasitically the longitudinal bunch profile after the energy collimator at 17.5 GeV beam energy. We will present concepts for fast longitudinal diagnostic for European XFEL based on coherent radiation, newest developments for high repetition rate measurements and simulations for the feedback capability of the system.

THP085

Commissioning and Results from the Bunch Arrival-time Monitor Downstream the Bunch Compressor at the SwissFEL Test Injector

pick-up, cavity, laser, timing

933

V.R. Arsov, M. Aiba, M.M. Dehler, F. Frei, S. Hunziker, M.G. Kaiser, A. Romann, V. Schlott
PSI, Villigen PSI, Switzerland

A high bandwidth Bunch Arrival-Time Monitor has been commissioned at the Swiss FEL test injector. A new acquisition front end allowing utilization of the ADC full dynamic range has been implemented. The resolution is measured as a function of the charge for different EOM front-ends. Downstream the magnetic chicane the bunch arrival time is sensitive to the amplitude and phases of the RF structures, responsible for creation of an energy chirp, used for bunch compression, as well as the ones of the harmonic cavity, used for phase space linearization. The time of flight as a function of the angle of the magnetic chicane has also been measured.

THP087

Electron Beam Diagnostics for COXINEL

electron, undulator, plasma, FEL

937

M. Labat, C. Bourassin-Bouchet, L. Cassinari, M.-E. Couprie, M.E. El Ajjouri, N. Hubert, A. Loulergue
SOLEIL, Gif-sur-Yvette, France

On the path towards more compact free electron lasers (FELs), the project COXINEL was recently funded: a transfer line will be installed to adapt a plasma accelerated beam (from LOA) into an in-vacuum undulator built by SOLEIL. This experiment should enable to demonstrate the first FEL based on a plasma accelerator. Because plasma beams are intrinsically very different from RF acceletor beams (much shorter, divergent and smaller with a higher energy spread and energy jitter), their transport and matching in the undulator is critical if willing to obtain a significant amplification. This is why special care has to be taken in the design of the beam diagnostics to be able to measure the transverse beam sizes, energy spread and jitter, emittance and bunch length. For these purposes, several diagnostics will be implemented from the plasma accelerator exit down to the undulator exit. In each station, several screen types will be available and associated to high resolution imaging screens. In this paper, we present the experimental layout and associated simulation of the diagnostics performances.

THP088

Comparison of Quadrupole Scan and Multi-screen Method for the Measurement of Projected and Slice Emittance at the SwissFEL Injector Test Facility

emittance, quadrupole, optics, FEL

941

M. Yan, B. Beutner, C. Gerth
DESY, Hamburg, Germany
R. Ischebeck, E. Prat
PSI, Villigen PSI, Switzerland

High-brightness electron bunches with small transverse emittance are required to drive X-ray free-electron lasers (FELs). For the measurement of the transverse emittance, the quadrupole scan and multi-screen methods are the two most common procedures. By employing a transverse deflecting structure, the measurement of the slice emittance becomes feasible. The quadrupole scan is more flexible in freely choosing the data points during the scan, while the multi-screen method allows on-line emittance measurements utilising off-axis screens in combination with fast kicker magnets. The latter is especially the case for high-repetition multi-bunch FELs, such as the European XFEL, which offer the possibility of on-line diagnostics. In this paper, we present comparative measurements of projected and slice emittance applying these two methods at the SwissFEL Injector Test Facility and discuss the implementation of on-line diagnostics at the European XFEL.

THP092

Transition Radiation of an Electron Bunch and Imprint of Lorentz-Covariance and Temporal-Causality

electron, radiation, optics, simulation

952

G.L. Orlandi
PSI, Villigen PSI, Switzerland

The study of Transition Radiation (TR) of a bunch of N electrons offers a precious insight into the role that Lorentz-covariance and temporal-causality play in an electromagnetic radiative mechanism of a relativistic beam. The contributions of the N single electrons to the radiation field are indeed characterized by emission phases from the metallic surface which are in a causality relation with the temporal sequence of the N particle collisions onto the radiating screen. The Lorentz-covariance characterizing the virtual quanta field of the relativistic charge is also expected to imprint the radiation field and the related energy spectrum. The main aspects of a Lorentz-covariance and temporal-causality consistent formulation of the TR energy spectrum of an electron bunch will be described.

THP097

Longitudinal Response Matrix Simulations for the SwissFEL Injector Test Facility

simulation, electron, laser, free-electron-laser

964

Á. Saá Hernández, F. Frei, R. Ischebeck
PSI, Villigen PSI, Switzerland
B. Beutner
DESY, Hamburg, Germany

The Singular Value Decomposition (SVD) method has been applied to the SwissFEL Injector Test Facility to identify and better expose the various relationships among the possible jitter sources affecting the longitudinal phase space distribution and the longitudinal diagnostic elements that measure them. To this end, several longitudinal tracking simulations have been run using the Litrack code. In these simulations the RF and laser jitter sources are varied one-by-one within a range spanning twice their expected stability. The particle distributions have been dumped at the diagnostic locations and the measured quantities analyzed. A matrix has been built by linearly fitting the response of each measured quantity to each jitter source. This response matrix is normalized to the jitter source stability and the instrumentation accuracy, and it is inverted and analyzed using SVD. From the eigenvalues and eigenvectors the sensitivity of the diagnostics to the jitters can be evaluated and their specifications and locations optimized.