IPAC2013 - List of Authors (Huang, Z.)

Paper

Title

Page

Brightness and Coherence of Synchrotron Radiation and FELs

16

Z. Huang
SLAC, Menlo Park, California, USA

Essential properties of radiation from storage rings and FELs include spatial- and temporal beam brightness and coherence. Starting from a fundamental representation of the electron beam as a radiating source the electromagnetic power can be represented as modes in phase-space to characterize beam quality. For storage rings, conditions for transverse coherence are possible which can lead to high-resolution imaging under a variety of polarization conditions. For FELs the radiation brightness is over 10 orders of magnitude higher with finite temporal coherence times and much of the total FEL power contained in the dominant mode. This presentation should provide an overview of the above.

Slides MOYCB101 [9.731 MB]

TUPEA086

Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source

1316

Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou
SLAC, Menlo Park, California, USA
P. Emma
LBNL, Berkeley, California, USA

Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.

WEOBB201

Commissioning of the X-band Transverse Deflector for Femtosecond Electron/X-Ray pulse Length Measurements at LCLS

2091

Y.T. Ding, C. Behrens, J.C. Frisch, Z. Huang, P. Krejcik, J.R. Lewandowski, H. Loos, J.W. Wang, M.-H. Wang, J.J. Welch
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany

X-ray free-electron lasers provide ultrashort x-ray pulses from several to a few hundred femtoseconds for multidisciplinary users. However, tremendous challenges remain in the measurement and control of these ultrashort pulses with femtosecond precision, for both the electron beam and the x-ray pulses. A new diagnostic scheme adding a transverse radio-frequency deflector at the end of the linac coherent light source (LCLS) undulator beamline has been proposed*. Two 1-m long deflecting structures have been installed at LCLS during the summer of 2012. Installation of the high power RF components including the klystron, waveguide, RF controls etc. is proceeding and commissioning is scheduled for March 2013. We report the latest progress of the commissioning of the deflector at LCLS.
* Y. Ding et al., Phys. Rev. ST Accel. Beams 14, 120701 (2011)

Slides WEOBB201 [4.199 MB]

WEPWA075

High-gain X-ray FELs using a Transverse Gradient Undulator in an Ultimate Storage Ring

2286

Y.T. Ding, P. Baxevanis, Y. Cai, Z. Huang, R.D. Ruth
SLAC, Menlo Park, California, USA

An “ultimate” storage ring based on PEP tunnel has been designed to achieve diffraction limited emittance (at 1.5 Angstrom)[*]. With sufficient peak current, the beam brightness of such an “ultimate” storage ring may be sufficient to drive a short-wavelength, high-gain FEL. However, the large energy spread intrinsic to storage rings hinders the FEL applications for x-ray wavelengths. To overcome this problem, we adopt the transverse-gradient undulator concept[**][***] to study a high-gain FEL in an ultimate storage ring. Using PEP-X as an example, we showed from simulations that a high-gain FEL at the photon energy 1keV with a peak power of a few hundred megawatts can be achieved within a saturation length of 100 meters.
* Y. Cai et al., Phys. Rev. ST Accel. Beams 15, 054002 (2012).
** T. Smith et al., J. Appl. Phys. 50, 4580 (1979)
*** Z. Huang, Y. Ding and C. B. Schroeder, Phys. Rev. Lett 109, 204801 (2012).

Paper	Title	Page
MOYCB101	Brightness and Coherence of Synchrotron Radiation and FELs	16
	Z. Huang SLAC, Menlo Park, California, USA
	Essential properties of radiation from storage rings and FELs include spatial- and temporal beam brightness and coherence. Starting from a fundamental representation of the electron beam as a radiating source the electromagnetic power can be represented as modes in phase-space to characterize beam quality. For storage rings, conditions for transverse coherence are possible which can lead to high-resolution imaging under a variety of polarization conditions. For FELs the radiation brightness is over 10 orders of magnitude higher with finite temporal coherence times and much of the total FEL power contained in the dominant mode. This presentation should provide an overview of the above.
	Slides MOYCB101 [9.731 MB]

TUPEA086	Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source	1316
	Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou SLAC, Menlo Park, California, USA P. Emma LBNL, Berkeley, California, USA
	Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.

WEOBB201	Commissioning of the X-band Transverse Deflector for Femtosecond Electron/X-Ray pulse Length Measurements at LCLS	2091
	Y.T. Ding, C. Behrens, J.C. Frisch, Z. Huang, P. Krejcik, J.R. Lewandowski, H. Loos, J.W. Wang, M.-H. Wang, J.J. Welch SLAC, Menlo Park, California, USA C. Behrens DESY, Hamburg, Germany
	X-ray free-electron lasers provide ultrashort x-ray pulses from several to a few hundred femtoseconds for multidisciplinary users. However, tremendous challenges remain in the measurement and control of these ultrashort pulses with femtosecond precision, for both the electron beam and the x-ray pulses. A new diagnostic scheme adding a transverse radio-frequency deflector at the end of the linac coherent light source (LCLS) undulator beamline has been proposed. Two 1-m long deflecting structures have been installed at LCLS during the summer of 2012. Installation of the high power RF components including the klystron, waveguide, RF controls etc. is proceeding and commissioning is scheduled for March 2013. We report the latest progress of the commissioning of the deflector at LCLS. Y. Ding et al., Phys. Rev. ST Accel. Beams 14, 120701 (2011)
	Slides WEOBB201 [4.199 MB]

WEPWA075	High-gain X-ray FELs using a Transverse Gradient Undulator in an Ultimate Storage Ring	2286
	Y.T. Ding, P. Baxevanis, Y. Cai, Z. Huang, R.D. Ruth SLAC, Menlo Park, California, USA
	An “ultimate” storage ring based on PEP tunnel has been designed to achieve diffraction limited emittance (at 1.5 Angstrom)[]. With sufficient peak current, the beam brightness of such an “ultimate” storage ring may be sufficient to drive a short-wavelength, high-gain FEL. However, the large energy spread intrinsic to storage rings hinders the FEL applications for x-ray wavelengths. To overcome this problem, we adopt the transverse-gradient undulator concept[][*] to study a high-gain FEL in an ultimate storage ring. Using PEP-X as an example, we showed from simulations that a high-gain FEL at the photon energy 1keV with a peak power of a few hundred megawatts can be achieved within a saturation length of 100 meters. Y. Cai et al., Phys. Rev. ST Accel. Beams 15, 054002 (2012). T. Smith et al., J. Appl. Phys. 50, 4580 (1979) * Z. Huang, Y. Ding and C. B. Schroeder, Phys. Rev. Lett 109, 204801 (2012).