FEL2012 - List of Authors (Travish, G.)

Paper

Title

Page

Use of Monocapillary X-Ray Optics as a Means to Reduce Linewidth and Fluctuations in SASE FELs

539

A.L. Lin, G. Travish
UCLA, Los Angeles, USA

Funding: UCLA
The Self Amplified Spontaneous Emission (SASE) operation of high-gain Free Electron Lasers (FELs) allows for amplification from "noise" when no suitable seed sources are available. While SASE FELs can achieve high powers and short radiation pulses within the X-ray region, they are hindered by large linewidths and fluctuations in amplitude and temporal profiles. Various approaches have been proposed to "clean up" the spontaneous emission and produce better effective seed signals. This paper presents the use of monocapillary X-ray optics as an alternative to current methods to improve SASE operation. A monocapillary tube placed at the beginning stages of the undulator can reduce the bandwidth and enhance a narrow band of the spontaneous emission amplified by the FEL. Monocapillary tubes guide radiation due to total external reflection, and the critical angle of the guiding is dependent on the frequency of the radiation (and indirectly on the surface profile and materials).

Slides THOB04 [1.013 MB]

THPD43

Progress on a Laser-driven Dielectric Structure for Use as a Short-period Undulator

630

J.M. Allen, G. Travish
UCLA, Los Angeles, California, USA
H. Gong
UESTC, Chengdu, Sichuan, People's Republic of China
R.B. Yoder
Manhattanville College, Purchase, New York, USA

A laser-powered dielectric structure, based on theμAccelerator Platform, has been design and offers undulator periods in the micron to millimeter range. This design was shown previously to potentially support a deflection field strength of several GV/m, equivalent to a magnetic undulator with field strength of about 40 T. In this paper, we address a previous problem in the design involving the junction between half periods of the undulator. Because the structure is resonant, flipping from one deflection direction to the opposite one required controlling the phase of the incident laser and reestablishing a new resonance. One solution to this 'phase flipping' problem involves the use of two lasers at different wavelengths to excite adjacent half-periods. This new approach is explored further here along with simulations of the beam trajectory and resulting undulator radiation. We also consider parameter sets that may be possible for these extremely short period undulators.

Paper	Title	Page
THOB04	Use of Monocapillary X-Ray Optics as a Means to Reduce Linewidth and Fluctuations in SASE FELs	539
	A.L. Lin, G. Travish UCLA, Los Angeles, USA
	Funding: UCLA The Self Amplified Spontaneous Emission (SASE) operation of high-gain Free Electron Lasers (FELs) allows for amplification from "noise" when no suitable seed sources are available. While SASE FELs can achieve high powers and short radiation pulses within the X-ray region, they are hindered by large linewidths and fluctuations in amplitude and temporal profiles. Various approaches have been proposed to "clean up" the spontaneous emission and produce better effective seed signals. This paper presents the use of monocapillary X-ray optics as an alternative to current methods to improve SASE operation. A monocapillary tube placed at the beginning stages of the undulator can reduce the bandwidth and enhance a narrow band of the spontaneous emission amplified by the FEL. Monocapillary tubes guide radiation due to total external reflection, and the critical angle of the guiding is dependent on the frequency of the radiation (and indirectly on the surface profile and materials).
	Slides THOB04 [1.013 MB]

THPD43	Progress on a Laser-driven Dielectric Structure for Use as a Short-period Undulator	630
	J.M. Allen, G. Travish UCLA, Los Angeles, California, USA H. Gong UESTC, Chengdu, Sichuan, People's Republic of China R.B. Yoder Manhattanville College, Purchase, New York, USA
	A laser-powered dielectric structure, based on theμAccelerator Platform, has been design and offers undulator periods in the micron to millimeter range. This design was shown previously to potentially support a deflection field strength of several GV/m, equivalent to a magnetic undulator with field strength of about 40 T. In this paper, we address a previous problem in the design involving the junction between half periods of the undulator. Because the structure is resonant, flipping from one deflection direction to the opposite one required controlling the phase of the incident laser and reestablishing a new resonance. One solution to this 'phase flipping' problem involves the use of two lasers at different wavelengths to excite adjacent half-periods. This new approach is explored further here along with simulations of the beam trajectory and resulting undulator radiation. We also consider parameter sets that may be possible for these extremely short period undulators.