scholarly journals For the generation of an intense isolated pulse in hard X-ray region using X-ray free electron laser

2012 ◽  
Vol 30 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Sandeep Kumar ◽  
Heung-Sik Kang ◽  
Dong-Eon Kim
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Electron Bunch ◽  
Attosecond Pulse ◽  
Current Profile ◽  
Distribution Profile ◽  
X Ray ◽  
Isolated Attosecond Pulse ◽  
Pump Probe Experiment ◽  
Pal Xfel

AbstractFor a real, meaningful pump-probe experiment with attosecond temporal resolution, an intense isolated attosecond pulse is in demand. For that purpose we report the generation of an intense isolated attosecond pulse, especially in X-ray region using a current-enhanced self-amplified spontaneous emission in a free electron laser (FEL). We use a few cycle laser pulse to manipulate the electron-bunch inside a two-period planar wiggler. In our study, we employ the electron beam parameters of Pohang Accelerator Laboratory (PAL)-XFEL. The RF phase effect of accelerator columns on the longitudinal energy distribution profile and current profile of electron-bunch is also studied, aiming that these results can be experimentally realized in PAL-XFEL. We show indeed that the manipulation of electron-energy bunch profile may lead to the generation of an isolated attosecond hard X-ray pulse: 150 attosecond radiation pulse at 0.1 nm wavelength can be generated.

scholarly journals Focusing X-ray free-electron laser pulses using Kirkpatrick–Baez mirrors at the NCI hutch of the PAL-XFEL

2018 ◽  
Vol 25 (1) ◽  
pp. 289-292 ◽  
Author(s):  
Jangwoo Kim ◽  
Hyo-Yun Kim ◽  
Jaehyun Park ◽  
Sangsoo Kim ◽  
Sunam Kim ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Laser Pulses ◽  
Mirror System ◽  
X Rays ◽  
X Ray ◽  
Fixed Sample ◽  
Scattering Geometry ◽  
Diffraction Imaging ◽  
Pal Xfel

The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) is a recently commissioned X-ray free-electron laser (XFEL) facility that provides intense ultrashort X-ray pulses based on the self-amplified spontaneous emission process. The nano-crystallography and coherent imaging (NCI) hutch with forward-scattering geometry is located at the hard X-ray beamline of the PAL-XFEL and provides opportunities to perform serial femtosecond crystallography and coherent X-ray diffraction imaging. To produce intense high-density XFEL pulses at the interaction positions between the X-rays and various samples, a microfocusing Kirkpatrick–Baez (KB) mirror system that includes an ultra-precision manipulator has been developed. In this paper, the design of a KB mirror system that focuses the hard XFEL beam onto a fixed sample point of the NCI hutch, which is positioned along the hard XFEL beamline, is described. The focusing system produces a two-dimensional focusing beam at approximately 2 µm scale across the 2–11 keV photon energy range. XFEL pulses of 9.7 keV energy were successfully focused onto an area of size 1.94 µm × 2.08 µm FWHM.

scholarly journals Slice collective dynamics, projected emittance deterioration and free electron laser performances detrimental effects

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
G. Dattoli ◽  
S. Di Mitri ◽  
F. Nguyen ◽  
A. Petralia
Keyword(s):  
Phase Space ◽  
Output Power ◽  
Free Electron ◽  
Free Electron Laser ◽  
Coherence Length ◽  
Electron Bunch ◽  
Laser Intensity ◽  
Beam Transport ◽  
X Ray ◽  
Laser Dynamics

Self-amplified spontaneous emission (SASE) free electron laser (FEL) devices have disclosed an unexpected interplay between the laser intensity growth and regions of the electron bunch of the order of the coherence length. They are usually identified with the bunch slice and contribute to the laser dynamics with their own characteristics. The dynamical effects inducing geometrical and phase space misalignment of bunch slice in X-ray operating FELs can be traced back to a plethora of phenomena, both in the Linac accelerating section or inside the beam transport optic magnet. They are responsible for spoiling of the beam projected qualities and, if not corrected properly, induce an increase of the saturation length and a decreasing of the output power. We discuss the inclusion of these effects in models employing scaling formulae.

scholarly journals A micro channel-cut crystal X-ray monochromator for a self-seeded hard X-ray free-electron laser

2019 ◽  
Vol 26 (5) ◽  
pp. 1496-1502 ◽  
Author(s):  
Taito Osaka ◽  
Ichiro Inoue ◽  
Ryota Kinjo ◽  
Takashi Hirano ◽  
Yuki Morioka ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Electron Bunch ◽  
Optical Pulse ◽  
Seed Pulse ◽  
Micro Channel ◽  
Free Electron Lasers ◽  
X Ray ◽  
Optical Delay ◽  
Temporal Overlap

A channel-cut Si(111) crystal with a channel width of 90 µm was developed for achieving reflection self-seeding in hard X-ray free-electron lasers (XFELs). With the crystal a monochromatic seed pulse is produced from a broadband XFEL pulse generated in the first undulator section with an optical delay of 119 fs at 10 keV. The small optical delay allows a temporal overlap between the seed optical pulse and the electron bunch by using a small magnetic chicane for the electron beam placed between two undulator sections. Peak reflectivity reached 67%, which is reasonable compared with the theoretical value of 81%. By using this monochromator, a monochromatic seed pulse without broadband background in the spectrum was obtained at SACLA with a conversion efficiency from a broadband XFEL pulse of 2 × 10−2, which is ∼10 times higher than the theoretical efficiency of transmission self-seeding using a thin diamond (400) monochromator.

Recent Progress of the PAL-XFEL after User Service Start

2021 ◽  
Vol 30 (5) ◽  
pp. 15-18
Author(s):  
Changbum KIM ◽  
Chi Hyun SHIM ◽  
Inhyuk NAM ◽  
Haeryong YANG ◽  
Chang-Ki MIN ◽  
...  
Keyword(s):  
Pulse Energy ◽  
Free Electron ◽  
Present Status ◽  
Free Electron Laser ◽  
Recent Progress ◽  
Beam Quality ◽  
X Ray ◽  
The Public ◽  
Pohang Accelerator Laboratory ◽  
Pal Xfel

The X-ray Free Electron Laser of the Pohang Accelerator Laboratory (PAL-XFEL) was open to the public in 2017 and started user service. Even after the user service had started, improvement of beam quality was continuously attempted, and several meaningful results were achieved. In this paper, we present recent progress in the PAL-XFEL, including the present status of its operation. The increase in the FEL pulse energy is explained, and the generation of a self-seeding FEL is described. In addition, the generation of a two-color FEL is mentioned.

scholarly journals Laser systems for time-resolved experiments at the Pohang Accelerator Laboratory X-ray Free-Electron Laser beamlines

2019 ◽  
Vol 26 (3) ◽  
pp. 868-873 ◽  
Author(s):  
Minseok Kim ◽  
Chang-Ki Min ◽  
Intae Eom
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Near Infrared ◽  
Fundamental Wave ◽  
Regenerative Amplifier ◽  
X Ray ◽  
Laser Systems ◽  
Pohang Accelerator Laboratory ◽  
Optical Laser ◽  
Pal Xfel

Optical laser systems for ultrafast X-ray sciences have been established at the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) beamlines. Three Ti:sapphire regenerative amplifier systems are synchronized to the XFEL with femtosecond precision, and the low temporal jitter of the PAL-XFEL results in an experimental time resolution below 150 fs (full width at half-maximum). A fundamental wave and its harmonics are currently provided for all beamlines, and tunable sources from ultraviolet to near-infrared are available for one beamline. The position stability of the optical laser extracted from the intensity-based center of mass at the sample position is less than 3% (r.m.s.) of the spot size.

X-Ray Free Electron Laser Facility for Next Generation of Scientific Exploration and Discovery

2011 ◽  
Vol 131 (2) ◽  
pp. 68-71
Author(s):  
Etsuo FUJIWARA ◽  
Eiichi ANAYAMA ◽  
Yuichiro KATSUTA ◽  
Toshiki IZUTANI ◽  
Daichi OKUHARA ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Next Generation ◽  
X Ray ◽  
Scientific Exploration ◽  
Laser Facility
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