FEL2013 - List of Authors (Prat, E.)

Paper

Title

Page

Slice Emittance Optimization at the SwissFEL Injector Test Facility

200

E. Prat, M. Aiba, S. Bettoni, B. Beutner, M.W. Guetg, R. Ischebeck, S. Reiche, T. Schietinger
PSI, Villigen PSI, Switzerland

Slice emittance measurements in the SwissFEL injector test facility have demonstrated emittances for the 10pC-200pC bunch charges which are well below the tight requirements of SwissFEL. Results, emittance tuning strategy and measurement methods are reported.

Slides TUOCNO06 [0.537 MB]

TUPSO14

Transverse Deflecting Structures for Bunch Length and Slice Emittance Measurements on SwissFEL

236

P. Craievich, R. Ischebeck, F. Löhl, G.L. Orlandi, E. Prat
PSI, Villigen PSI, Switzerland

The SwissFEL project, under development at the Paul Scherrer Institut, will produce FEL radiation in a wavelength range from 0.1 nm to 7 nm. 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 magnetic chicanes will compress the beam between 2.5 fs rms and 25 fs rms depending on the operation mode. The bunch length and slice parameters will be measured after the first bunch compressor (330 MeV) by using an S-band transverse deflecting structure (TDS). A C-band TDS will be employed to measure the longitudinal parameters of the beam just upstream the undulator beamline (5.8 GeV). With the designed transverse beam optics, an integrated deflecting voltage of 70 MV is required in order to achieve a longitudinal resolution on the femtosecond time scale. In this paper we present the TDS measurement systems to be used at SwissFEL, with a particular emphasis on the new C-band device, including hardware, lattice layout and beam optics.

TUPSO22

Status of SwissFEL Undulator Lines

263

R. Ganter, M. Aiba, H.-H. Braun, M. Calvi, P. Heimgartner, G. Janzi, H. Jöhri, R. Kobler, F. Löhl, M. Negrazus, L. Patthey, E. Prat, S. Reiche, S. Sanfilippo, U. Schaer, T. Schmidt, L. Schulz, V. Vranković, J. Wickstroem
PSI, Villigen PSI, Switzerland

An overview of the Aramis Hard-X ray FEL line of SwissFEL is presented, showing its future integration in the tunnel as well as the space reservation for possible future upgrades: Athos Soft X-ray FEL line, post-undulator deflecting cavities. The design of the FEL components like the energy collimator, the matching sections or the dog leg transfer line linking the linac to the future Athos line are almost completed. The characterization of the in-vacuum undulator prototype is described in a companion paper. The installation of the components will start in spring 2015 while the first photons are planned for December 2016 with the alignment and adjustment of the undulators foreseen for first SASE operation by spring 2017 .

TUPSO24

Dispersion Based Beam Tilt Correction

267

M.W. Guetg, B. Beutner, E. Prat, S. Reiche
PSI, Villigen PSI, Switzerland

In Free Electron Lasers (FEL), a transverse centroid misalignment of longitudinal slices in an electron bunch reduces the effective overlap between radiation field and electron bunch and therefore the FEL performance. The dominant sources of slice misalignments for FELs are the incoherent and coherent synchrotron radiation within bunch compressors as well as transverse wake fields in the accelerating cavities. This is of particular importance for over-compression which is required for one of the key operation modes for the SwissFEL planned at the Paul Scherrer Institute. The centroid shift is corrected using corrector magnets in dispersive sections, e.g. the bunch compressors. First and second order corrections are achieved by pairs of sextupole and quadrupole magnets in the horizontal plane while skew quadrupoles correct to first order in the vertical plane. Simulations and measurements at the SwissFEL Injector Test Facility are done to investigate the proposed correction scheme for SwissFEL. This paper presents the methods and results obtained.

TUPSO86

Photocathode Laser Wavelength-tuning for Thermal Emittance and Quantum Efficiency Studies

434

C. Vicario, S. Bettoni, B. Beutner, M.C. Divall, C.P. Hauri, E. Prat, T. Schietinger, A. Trisorio
PSI, Villigen PSI, Switzerland

SwissFEL compact design is based on extremely low emittance electron beam from an RF photoinjector. Proper temporal and spatial shaping of the photocathode drive laser is employed to reduce the space charge emittance contribution. However, the ultimate limit for the beam emittance is the thermal emittance, which depends on the excess energy of the emitted photoelectrons. By varying the photocathode laser wavelength it is possible to reduce the thermal emittance. For this purpose, we developed a tunable Ti:sapphire laser and an optical parametric amplifier which allow to scan the wavelength between 250 and 305 nm. The system permits to study the thermal emittance and the quantum efficiency evolution as function of the laser wavelength for the copper photocathode in the RF gun of the SwissFEL injector test facility. The results are presented and discussed.

WEPSO51

Self-seeding Design for SwissFEL

618

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

The SwissFEL facility, planned at the Paul Scherrer Institute, will provide SASE and self-seeded FEL radiation at a hard (1-7 Å) and soft (7-70 Å) X-ray FEL beamlines. This paper presents the current status of the self-seeding design for SwissFEL. The layout and full 6D start-to-end simulation results are presented for the hard X-ray beamline. Studies for different charges and optimization of the first and second undulator stages are shown.

Paper	Title	Page
TUOCNO06	Slice Emittance Optimization at the SwissFEL Injector Test Facility	200
	E. Prat, M. Aiba, S. Bettoni, B. Beutner, M.W. Guetg, R. Ischebeck, S. Reiche, T. Schietinger PSI, Villigen PSI, Switzerland
	Slice emittance measurements in the SwissFEL injector test facility have demonstrated emittances for the 10pC-200pC bunch charges which are well below the tight requirements of SwissFEL. Results, emittance tuning strategy and measurement methods are reported.
	Slides TUOCNO06 [0.537 MB]

TUPSO14	Transverse Deflecting Structures for Bunch Length and Slice Emittance Measurements on SwissFEL	236
	P. Craievich, R. Ischebeck, F. Löhl, G.L. Orlandi, E. Prat PSI, Villigen PSI, Switzerland
	The SwissFEL project, under development at the Paul Scherrer Institut, will produce FEL radiation in a wavelength range from 0.1 nm to 7 nm. 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 magnetic chicanes will compress the beam between 2.5 fs rms and 25 fs rms depending on the operation mode. The bunch length and slice parameters will be measured after the first bunch compressor (330 MeV) by using an S-band transverse deflecting structure (TDS). A C-band TDS will be employed to measure the longitudinal parameters of the beam just upstream the undulator beamline (5.8 GeV). With the designed transverse beam optics, an integrated deflecting voltage of 70 MV is required in order to achieve a longitudinal resolution on the femtosecond time scale. In this paper we present the TDS measurement systems to be used at SwissFEL, with a particular emphasis on the new C-band device, including hardware, lattice layout and beam optics.

TUPSO22	Status of SwissFEL Undulator Lines	263
	R. Ganter, M. Aiba, H.-H. Braun, M. Calvi, P. Heimgartner, G. Janzi, H. Jöhri, R. Kobler, F. Löhl, M. Negrazus, L. Patthey, E. Prat, S. Reiche, S. Sanfilippo, U. Schaer, T. Schmidt, L. Schulz, V. Vranković, J. Wickstroem PSI, Villigen PSI, Switzerland
	An overview of the Aramis Hard-X ray FEL line of SwissFEL is presented, showing its future integration in the tunnel as well as the space reservation for possible future upgrades: Athos Soft X-ray FEL line, post-undulator deflecting cavities. The design of the FEL components like the energy collimator, the matching sections or the dog leg transfer line linking the linac to the future Athos line are almost completed. The characterization of the in-vacuum undulator prototype is described in a companion paper. The installation of the components will start in spring 2015 while the first photons are planned for December 2016 with the alignment and adjustment of the undulators foreseen for first SASE operation by spring 2017 .

TUPSO24	Dispersion Based Beam Tilt Correction	267
	M.W. Guetg, B. Beutner, E. Prat, S. Reiche PSI, Villigen PSI, Switzerland
	In Free Electron Lasers (FEL), a transverse centroid misalignment of longitudinal slices in an electron bunch reduces the effective overlap between radiation field and electron bunch and therefore the FEL performance. The dominant sources of slice misalignments for FELs are the incoherent and coherent synchrotron radiation within bunch compressors as well as transverse wake fields in the accelerating cavities. This is of particular importance for over-compression which is required for one of the key operation modes for the SwissFEL planned at the Paul Scherrer Institute. The centroid shift is corrected using corrector magnets in dispersive sections, e.g. the bunch compressors. First and second order corrections are achieved by pairs of sextupole and quadrupole magnets in the horizontal plane while skew quadrupoles correct to first order in the vertical plane. Simulations and measurements at the SwissFEL Injector Test Facility are done to investigate the proposed correction scheme for SwissFEL. This paper presents the methods and results obtained.

TUPSO86	Photocathode Laser Wavelength-tuning for Thermal Emittance and Quantum Efficiency Studies	434
	C. Vicario, S. Bettoni, B. Beutner, M.C. Divall, C.P. Hauri, E. Prat, T. Schietinger, A. Trisorio PSI, Villigen PSI, Switzerland
	SwissFEL compact design is based on extremely low emittance electron beam from an RF photoinjector. Proper temporal and spatial shaping of the photocathode drive laser is employed to reduce the space charge emittance contribution. However, the ultimate limit for the beam emittance is the thermal emittance, which depends on the excess energy of the emitted photoelectrons. By varying the photocathode laser wavelength it is possible to reduce the thermal emittance. For this purpose, we developed a tunable Ti:sapphire laser and an optical parametric amplifier which allow to scan the wavelength between 250 and 305 nm. The system permits to study the thermal emittance and the quantum efficiency evolution as function of the laser wavelength for the copper photocathode in the RF gun of the SwissFEL injector test facility. The results are presented and discussed.

WEPSO51	Self-seeding Design for SwissFEL	618
	E. Prat, S. Reiche PSI, Villigen PSI, Switzerland
	The SwissFEL facility, planned at the Paul Scherrer Institute, will provide SASE and self-seeded FEL radiation at a hard (1-7 Å) and soft (7-70 Å) X-ray FEL beamlines. This paper presents the current status of the self-seeding design for SwissFEL. The layout and full 6D start-to-end simulation results are presented for the hard X-ray beamline. Studies for different charges and optimization of the first and second undulator stages are shown.