FEL2014 - List of Authors (Marcus, G.)

Paper

Title

Page

Harmonic Lasing Options for LCLS-II

148

G. Marcus, Y. Ding, Z. Huang, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
G. Penn
LBNL, Berkeley, California, USA

Harmonic lasing can be a cheap and relatively efficient way to extend the photon energy range of a particular FEL beamline. Furthermore, in comparison to nonlinear harmonics, harmonic lasing can provide a beam that is more intense, stable, and narrow-band. This paper explores the application of the harmonic lasing concept at LCLS-II using various combinations of phase shifters and attenuators. In addition, a scheme by which individual undulator modules are tuned to amplify either the third or fifth harmonic in different configurations is presented in detail.

MOP075

Laser Seeding Schemes for Soft X-rays at LCLS-II

223

G. Penn
LBNL, Berkeley, California, USA
P. Emma, E. Hemsing, G. Marcus, T.O. Raubenheimer, L. Wang
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract Nos. DE-AC02-05CH11231 and DE-AC02-76SF00515.
The initial design for LCLS-II incorporates both SASE and self-seeded configurations. Increased stability and/or coherence than is possible with either configuration may be provided by seeding with external lasers followed by one or more stages of harmonic generation, especially in the soft x-ray regime. External seeding also allows for increased flexibility, for example the ability to quickly vary the pulse duration. Studies of schemes based on high-gain harmonic generation and echo-enabled harmonic generation are presented, including realistic electron distributions based on tracking through the injector and linac.

MOC02

Correlated Energy Spread Removal with Space Charge for High Gain Harmonic Generation

E. Hemsing, G. Marcus, A. Marinelli
SLAC, Menlo Park, California, USA
D. Xiang
Shanghai Jiao Tong University, Shanghai, People's Republic of China

We study the effect of longitudinal space charge on the correlated energy spread of a relativistic beam that has been microbunched for the emission of coherent, high harmonic radiation. We show that, in the case of microbunching induced by a laser modulator followed by a dispersive chicane, longitudinal space charge forces can act to significantly reduce the induced energy spread of the beam without a reduction in the harmonic bunching content. This effect may be optimized to significantly increase the harmonic number achievable in seeded HGHG free electrons lasers, which are otherwise limited by the induced energy spread from the laser.
The work presented here has been published in Reference [1].
[1] E. Hemsing et al., to appear in Phys. Rev. Lett. (2014)

Slides MOC02 [4.092 MB]

TUP031

FEL Code Comparison for the Production of Harmonics via Harmonic Lasing

451

G. Marcus, W.M. Fawley
SLAC, Menlo Park, California, USA
S. Reiche
PSI, Villigen PSI, Switzerland
E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

Harmonic lasing offers an attractive option to significantly extend the photon energy range of FEL beamlines. Here, the fundamental FEL radiation is suppressed by various combinations of phase shifters, attenuators, and detuned undulators while the radiation at a desired harmonic is allowed to grow linearly. The support of numerical simulations is extensively used in evaluating the performance of this scheme. This paper compares the results of harmonic growth in the harmonic lasing scheme using three FEL codes: FAST, GENESIS, and GINGER.

TUP032

FEL Simulation and Performance Studies for LCLS-II

456

G. Marcus, Y. Ding, P. Emma, Z. Huang, T.O. Raubenheimer, L. Wang, J. Wu
SLAC, Menlo Park, California, USA

The design and performance of the LCLS-II free-electron laser beamlines are presented using start-to-end numerical particle simulations. The particular beamline geometries were chosen to cover a large photon energy tuning range with x-ray pulse length and bandwidth flexibility. Results for self-amplified spontaneous emission and self-seeded operational modes are described in detail for both hard and soft x-ray beamlines in the baseline design.

TUP033

Broadly Tunable Free-Electron Laser for Four-wave Mixing Experiments with Soft X-ray Pulses

461

G. Marcus
SLAC, Menlo Park, California, USA
G. Penn
LBNL, Berkeley, California, USA
A. Zholents
ANL, Argonne, Illinois, USA

This paper examines a FEL design for the production of three soft x-ray pulses from a single electron beam suitable for four-wave mixing experiments. Independent control of the wavelength, timing and angle of incidence of the three ultra-short, ultra-intense pulses with exquisite synchronization is critical. A process of selective amplification where a chirped electron beam and a tapered undulator are used to isolate the gain region to only a short fraction of the electron beam is explored in detail. Numerical particle simulations are used to demonstrate the essential features of this scheme in the context of the LCLS-II design study.

TUC02

Soft X-ray Self-seeding Setup and Results at LCLS

D.F. Ratner, J.W. Amann, D.K. Bohler, M. Boyes, D. Cocco, F.-J. Decker, Y. Ding, D. Fairley, Y. Feng, J.B. Hastings, P.A. Heimann, Z. Huang, J. Krzywinski, H. Loos, A.A. Lutman, G. Marcus, A. Marinelli, T.J. Maxwell, S.P. Moeller, P.A. Montanez, D.S. Morton, H.-D. Nuhn, D.R. Walz, J.J. Welch, J. Wu
SLAC, Menlo Park, California, USA
K. Chow, L.N. Rodes
LBNL, Berkeley, California, USA
U. Flechsig
PSI, Villigen PSI, Switzerland
S. Serkez
DESY, Hamburg, Germany

The soft X-ray self seeding program was designed to provide near transform-limited pulses in the range of 500 eV to 1000 eV. The project was a three-way collaboration between SLAC, Lawrence Berkeley National Lab, and the Paul Scherrer Institute in Switzerland. Installation finished in the Fall of 2013, and after the early stages of commissioning we have measured up to 0.5mJ pulse energy and resolving powers of up to 5000 across the design wavelength range, representing a several-fold increase in the brightness compared to the normal LCLS operating mode. Future work will aim to increase the total pulse energy and establish self-seeding as a robust user operation mode.

Slides TUC02 [10.464 MB]

Paper	Title	Page
MOP054	Harmonic Lasing Options for LCLS-II	148
	G. Marcus, Y. Ding, Z. Huang, T.O. Raubenheimer SLAC, Menlo Park, California, USA G. Penn LBNL, Berkeley, California, USA
	Harmonic lasing can be a cheap and relatively efficient way to extend the photon energy range of a particular FEL beamline. Furthermore, in comparison to nonlinear harmonics, harmonic lasing can provide a beam that is more intense, stable, and narrow-band. This paper explores the application of the harmonic lasing concept at LCLS-II using various combinations of phase shifters and attenuators. In addition, a scheme by which individual undulator modules are tuned to amplify either the third or fifth harmonic in different configurations is presented in detail.

MOP075	Laser Seeding Schemes for Soft X-rays at LCLS-II	223
	G. Penn LBNL, Berkeley, California, USA P. Emma, E. Hemsing, G. Marcus, T.O. Raubenheimer, L. Wang SLAC, Menlo Park, California, USA
	Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract Nos. DE-AC02-05CH11231 and DE-AC02-76SF00515. The initial design for LCLS-II incorporates both SASE and self-seeded configurations. Increased stability and/or coherence than is possible with either configuration may be provided by seeding with external lasers followed by one or more stages of harmonic generation, especially in the soft x-ray regime. External seeding also allows for increased flexibility, for example the ability to quickly vary the pulse duration. Studies of schemes based on high-gain harmonic generation and echo-enabled harmonic generation are presented, including realistic electron distributions based on tracking through the injector and linac.

MOC02	Correlated Energy Spread Removal with Space Charge for High Gain Harmonic Generation
	E. Hemsing, G. Marcus, A. Marinelli SLAC, Menlo Park, California, USA D. Xiang Shanghai Jiao Tong University, Shanghai, People's Republic of China
	We study the effect of longitudinal space charge on the correlated energy spread of a relativistic beam that has been microbunched for the emission of coherent, high harmonic radiation. We show that, in the case of microbunching induced by a laser modulator followed by a dispersive chicane, longitudinal space charge forces can act to significantly reduce the induced energy spread of the beam without a reduction in the harmonic bunching content. This effect may be optimized to significantly increase the harmonic number achievable in seeded HGHG free electrons lasers, which are otherwise limited by the induced energy spread from the laser. The work presented here has been published in Reference [1]. [1] E. Hemsing et al., to appear in Phys. Rev. Lett. (2014)
	Slides MOC02 [4.092 MB]

TUP031	FEL Code Comparison for the Production of Harmonics via Harmonic Lasing	451
	G. Marcus, W.M. Fawley SLAC, Menlo Park, California, USA S. Reiche PSI, Villigen PSI, Switzerland E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	Harmonic lasing offers an attractive option to significantly extend the photon energy range of FEL beamlines. Here, the fundamental FEL radiation is suppressed by various combinations of phase shifters, attenuators, and detuned undulators while the radiation at a desired harmonic is allowed to grow linearly. The support of numerical simulations is extensively used in evaluating the performance of this scheme. This paper compares the results of harmonic growth in the harmonic lasing scheme using three FEL codes: FAST, GENESIS, and GINGER.

TUP032	FEL Simulation and Performance Studies for LCLS-II	456
	G. Marcus, Y. Ding, P. Emma, Z. Huang, T.O. Raubenheimer, L. Wang, J. Wu SLAC, Menlo Park, California, USA
	The design and performance of the LCLS-II free-electron laser beamlines are presented using start-to-end numerical particle simulations. The particular beamline geometries were chosen to cover a large photon energy tuning range with x-ray pulse length and bandwidth flexibility. Results for self-amplified spontaneous emission and self-seeded operational modes are described in detail for both hard and soft x-ray beamlines in the baseline design.

TUP033	Broadly Tunable Free-Electron Laser for Four-wave Mixing Experiments with Soft X-ray Pulses	461
	G. Marcus SLAC, Menlo Park, California, USA G. Penn LBNL, Berkeley, California, USA A. Zholents ANL, Argonne, Illinois, USA
	This paper examines a FEL design for the production of three soft x-ray pulses from a single electron beam suitable for four-wave mixing experiments. Independent control of the wavelength, timing and angle of incidence of the three ultra-short, ultra-intense pulses with exquisite synchronization is critical. A process of selective amplification where a chirped electron beam and a tapered undulator are used to isolate the gain region to only a short fraction of the electron beam is explored in detail. Numerical particle simulations are used to demonstrate the essential features of this scheme in the context of the LCLS-II design study.

TUC02	Soft X-ray Self-seeding Setup and Results at LCLS
	D.F. Ratner, J.W. Amann, D.K. Bohler, M. Boyes, D. Cocco, F.-J. Decker, Y. Ding, D. Fairley, Y. Feng, J.B. Hastings, P.A. Heimann, Z. Huang, J. Krzywinski, H. Loos, A.A. Lutman, G. Marcus, A. Marinelli, T.J. Maxwell, S.P. Moeller, P.A. Montanez, D.S. Morton, H.-D. Nuhn, D.R. Walz, J.J. Welch, J. Wu SLAC, Menlo Park, California, USA K. Chow, L.N. Rodes LBNL, Berkeley, California, USA U. Flechsig PSI, Villigen PSI, Switzerland S. Serkez DESY, Hamburg, Germany
	The soft X-ray self seeding program was designed to provide near transform-limited pulses in the range of 500 eV to 1000 eV. The project was a three-way collaboration between SLAC, Lawrence Berkeley National Lab, and the Paul Scherrer Institute in Switzerland. Installation finished in the Fall of 2013, and after the early stages of commissioning we have measured up to 0.5mJ pulse energy and resolving powers of up to 5000 across the design wavelength range, representing a several-fold increase in the brightness compared to the normal LCLS operating mode. Future work will aim to increase the total pulse energy and establish self-seeding as a robust user operation mode.
	Slides TUC02 [10.464 MB]