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Marcus, Gabriel

Publications and source records attributed to Marcus, Gabriel.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Low-loss stable storage of 1.2 Å X-ray pulses in a 14 m Bragg cavity

Here, we present an experimental demonstration of a stable, low-loss, large X-ray cavity operating at 1.2 Å wavelength. The cavity consists of four separate high-reflectivity single crystal diamond Bragg mirrors arranged in a rectangular configuration with a round-trip distance of 14.2 m. Femtosecond X-ray pulses from an X-ray free-electron laser were coupled into the cavity via a transmission phase grating. We show that a stable mode can be maintained with the introduction of cavity focusing and measure round-trip efficiencies approaching 88%, or >96% when excluding grating and lens losses, close to the Bragg mirror theoretical performance limit. The direct observation of sustained stable X-ray circulation provides the most direct evidence to date that cavity-based X-ray free-electron lasers and other cavity-based hard X-ray systems are feasible.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Experimental setup for high-resolution characterization of crystal optics for coherent X-ray beam applications

Stanford Synchrotron Radiation Lightsource serves a wide scientific community with its variety of X-ray capabilities. Recently, a wiggler X-ray source located at beamline 10-2 has been employed to perform high-resolution rocking curve imaging (RCI) of diamond and silicon crystals. X-ray RCI is invaluable for the development of upcoming cavity-based X-ray sources at SLAC, including the cavity-based X-ray free-electron laser and X-ray laser oscillator. In this paper, the RCI apparatus is described and experimental results are provided to validate its design. Future improvements of the setup are also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Refractive Guide Switching a Regenerative Amplifier Free-Electron Laser for High Peak and Average Power Hard X Rays

In this work, we present an x-ray regenerative amplifier free-electron laser design capable of producing fully coherent hard x-ray pulses across a broad tuning range at a high steady state repetition rate. The scheme leverages a strong undulator taper and an apertured diamond output-coupling cavity crystal to produce both high peak and average spectral brightness radiation that is 2 to 3 orders of magnitude greater than conventional single-pass self-amplified spontaneous emission free-electron laser amplifiers. Refractive guiding in the postsaturation regime is found to play a key role in passively controlling the stored cavity power. The scheme is explored both analytically and numerically in the context of the Linac Coherent Light Source II High Energy upgrade.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

X-ray free-electron laser wavefront sensing using the fractional Talbot effect

Wavefront sensing at X-ray free-electron lasers is important for quantitatively understanding the fundamental properties of the laser, for aligning X-ray instruments and for conducting scientific experimental analysis. A fractional Talbot wavefront sensor has been developed. This wavefront sensor enables measurements over a wide range of energies, as is common on X-ray instruments, with simplified mechanical requirements and is compatible with the high average power pulses expected in upcoming X-ray free-electron laser upgrades. Single-shot measurements were performed at 500 eV, 1000 eV and 1500 eV at the Linac Coherent Light Source. These measurements were applied to study both mirror alignment and the effects of undulator tapering schemes on source properties. The beamline focal plane position was tracked to an uncertainty of 0.12 mm, and the source location for various undulator tapering schemes to an uncertainty of 1m, demonstrating excellent sensitivity. These findings pave the way to use the fractional Talbot wavefront sensor as a routine, robust and sensitive tool at X-ray free-electron lasers as well as other high-brightness X-ray sources.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗