96 research outputs found
Record high extraction efficiency of free electron laser oscillator
共振器型自由電子レーザの世界最高変換効率を達成 --長波長赤外での強光子場の実現とアト秒X線源の開発に大きく前進--. 京都大学プレスリリース. 2020-10-13.The highest extraction efficiency (9.4%) of a free electron laser (FEL) oscillator has been achieved at the midinfrared FEL facility of Kyoto University. Because of the interaction between the electron beam and FEL electromagnetic field, a maximum electron energy decrease of 16% was observed. The measured energy decrease was consistent with the measured FEL spectrum. An FEL micropulse energy of ~100 μJ with the expected few-cycle pulse duration at a wavelength of 11 μm was observed. This result is an important milestone for the high-extraction-efficiency FEL oscillator and will contribute to the strong-field physics of atoms and molecules
Full characterization of few-cycle superradiant pulses generated from a free-electron laser oscillator
The detailed structure of few-cycle superradiant pulses generated from a
free-electron laser (FEL) oscillator was experimentally revealed for the first
time. As predicted in numerical simulations, the obtained pulse structures have
ringing, i.e., a train of subpulses following the main pulse. Owing to the
phase retrieval with a combination of linear and nonlinear autocorrelation
measurements, the temporal phase was also obtained with the pulse shape, and
-phase jumps between each pulse were confirmed. This particular pulse
shape with -phase jumps is a common feature of Burnham-Chiao ringing or
superradiance ringing. Using unaveraged FEL simulations, the ringing was found
to originate from repeated formation and deformation of microbunches across
successive bunch slices. The simulation results imply that there should be
superluminal propagation of the FEL pulse due to strong gain modulation along
the undulator of the FEL oscillator.Comment: Main: 16 pages, 5 figures, Supplementary material: 10 pages, 10
figures, 1 vide
Generation of primary photons through inverse Compton scattering using a Monte Carlo simulation code
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Overview of the development program
ニュースバル放射光施設において開催される核セキュリティワークショップにおいて、核セキュリティ補助金事業で実施した研究開発プログラムの概要について報告する。Workshop on demonstration of nuclear resonance fluorescence technique for detection of nuclear material hidden in a shiel
Bandwidth of a Compton radiation source with an electron beam of asymmetric emittance
Compton scattered radiation sources have been utilizedin a broad range of experiments from fundamental science to industrialapplications for their unique features,the generation of energy-tunable, nearly mono-energetic polarizedphoton beams. In the Compton radiation sources, the radiation bandwidthcan be controlled by a collimator to restrict the scattering angle,but the bandwidth is also affected by the emittance and energy spreadof the electron beam. In this study, we discuss collimator optimizationto obtain narrow-band radiation from a Compton source withan electron beam having asymmetric emittance in the horizontaland vertical planes. A Monte Carlo simulation code based onGeant4 has been developed and used to compare circular and rectangularcollimators for shaping the radiation spectrum of Compton sources
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