Author: Reiche, S.
Paper Title Page
MOOBI1
 Numerical Methods for FEL Simulations  
 
  • S. Reiche
    Paul Scherrer Institut, Villigen, Switzerland
  
  The coupled system of radiation interacting with a co-propagating electron beam within an undulator of an FEL exhibits many degrees of freedom. Only in an idealized and simplified model the FEL equations can be solved analytically and a more complete description requires numerical methods. This presentation gives an overview about the basic algorithms, used in most FEL codes, to model a particle beam with up to 1 billion particles and a co-propagating radiation field with an Angstrom resolution in a Free-electron Laser up to several hundreds of meter long.  
slides icon Slides MOOBI1 [2.425 MB]  
 
TUOA4 Toward TW-level, Hard X-ray Pulses at LCLS 160
 
  • W.M. Fawley, J.C. Frisch, Z. Huang, Y. Jiao, H.-D. Nuhn, C. Pellegrini, J. Wu
    SLAC, Menlo Park, California, USA
  • S. Reiche
    Paul Scherrer Institut, Villigen, Switzerland
  
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
Coherent diffraction imaging of complex molecules, like proteins, requires a large number of hard X-ray photons, ~10+13/pulse, within a time ~10 fs or less. This is equivalent to a peak power of about one TW, much larger than that currently generated by LCLS or other proposed X-ray FELs. We study the feasibility of producing such pulses from LCLS and the proposed LCLS-II, employing a configuration beginning with a SASE amplifier, followed by a "self-seeding" crystal monochromator [1], and finishing with a long tapered undulator. Results suggest that TW-level output power at 8 keV is possible, with a total undulator length below 200 m. We use a 40 pC electron bunch charge, normalized transverse emittance of 0.2-mm-mrad, peak current of 4 kA, and electron energy about 14 GeV. We present a tapering strategy that extends the original "resonant particle" formalism by optimizing the transport lattice to maximize optical guiding and enhance net energy extraction. We also discuss the transverse and longitudinal coherence properties of the output radiation pulse. Fluctuation of such a tapered FEL is studied with realistic jitter measured at LCLS and with start-to-end simulation. 		 
slides icon Slides TUOA4 [9.357 MB]  
 
TUPA15 Status of the SwissFEL Facility at the Paul Scherrer Institute 223
 
  • S. Reiche
    Paul Scherrer Institut, Villigen, Switzerland
  
  SwissFEL is a X-ray Free-electron Laser facility with a soft and hard X-ray beamline, planned to be built at the Paul Scherrer Institute and to be finished in 2016. It covers the wavelength range from 1 Angstrom to 7 nm. In addition to the SASE operation at the entire wavelength, seeding is foreseen down to a wavelength of 1 nm. We report in this presentation the status of the SwissFEL facility, including the layout, the timeline of the project, the different operation modes and the expected performance of the FEL beamlines.  
 
TUPA19 Operation Modes and Longitudinal Layout for the SwissFEL Hard X-Ray Facility 235
 
  • B. Beutner, S. Reiche
    Paul Scherrer Institut, Villigen, Switzerland
  
  The SwissFEL facility will produce coherent, ultrabright, and ultra-short photon pulses covering a wavelength range from 0.1 nm to 7 nm, requiring an emittance between 0.18 to 0.43 mm mrad at bunch charges between 10pC and 200pC. In nominal operation continous changes between these two bunch charges will be offered to the users in order to allow them an individual tradeoff between photon power and pulse length depending on thier requirements. The facility consists of an S-band rf-gun and booster and a C-band main linac, which accelerates the beam up to 5.8 GeV. Two compression chicanes will provide a nominal peak current of about 1-3 kA depending on the charge. In addition special operation setups for ultra short single mode photon pulses and large bandwidth will be availiable to users. In this paper different operation modes including nominal operation as well as special modes are presented and discussed in terms of photon performance and machine stability requiremnts.  
 
TUPA25 EEHG Seeding Design for SwissFEL 251
 
  • E. Prat, S. Reiche
    Paul Scherrer Institut, Villigen, Switzerland
  
  The SwissFEL facility, planned at the Paul Scherrer Institute, is based on the SASE operation of a hard (1-7 Å) and a soft (7-70 Å) X-ray FEL beamline. In addition, seeding is foreseen for the soft X-ray beamline, down to a wavelength of 1 nm. The Echo-Enabled Harmonic Generation (EEHG) scheme, which utilizes a rather complex manipulation of the longitudinal phase space distribution of the electron beam to generate high harmonic density modulation, is presently considered the first choice for seeding at SwissFEL. However, EEHG is highly demanding and complex at 1 nm, therefore other strategies like High-Harmonic Generation (HHG) and self-seeding are also evaluated. This paper presents the current status of the seeding design for SwissFEL based on EEHG.  
 
FROA4 Response Matrix of Longitudinal Instrumentation in SwissFEL 652
 
  • R. Ischebeck, B. Beutner, R. Kalt, P. Peier, S. Reiche, T. Schilcher, V. Schlott
    Paul Scherrer Institut, Villigen, Switzerland
  
  Several sources of jitter and drift affect the longitudinal phase space dynamics of SwissFEL. To evaluate how drifts can be identified and corrected through appropriate diagnostics and beam-based feedbacks, the response matrix of possible longitudinal diagnostics on laser and RF stability is modeled. To this intent, photocathode laser intensity, laser arrival time, RF phases and RF amplitudes are individually varied in an ELEGANT model, and the expected response of on-line diagnostics on the simulated bunches is evaluated. By comparing the slope of the response to the expected resolution of the instrumentation, suitable monitors can be selected for a feedback.  
slides icon Slides FROA4 [2.837 MB]  
 
THPB30 SwissFEL Injector Test Facility – Test and Plans 625
 
  • M. Pedrozzi, M. Aiba, S. Bettoni, B. Beutner, A. Falone, R. Ganter, R. Ischebeck, F. Le Pimpec, G.L. Orlandi, E. Prat, S. Reiche, T. Schietinger, A. Trisorio, C. Vicario
    Paul Scherrer Institut, Villigen, Switzerland
  
  In August 2010 the Paul Scherrer Institute inaugurated the SwissFEL Injector test facility as a first step toward the Swiss hard X-ray FEL planned at PSI. The main purpose of the facility is to demonstrate and consolidate the generation of high-brightness beam as required to drive the 6 GeV SwissFEL accelerator. Additionally the injector serves as a platform supporting development and test of accelerator components/systems and optimization procedures foreseen for SwissFEL. In this paper we report on the present status of the commissioning with some emphasis on emittance measurements and component performances. The scientific program and long-term plans will be discussed as well.