Effect of high slice energy spread of an electron beam on the generation of isolated, terawatt, attosecond X-ray free-electron laser pulse.

摘要: Attosecond (asec) X-ray free-electron laser (XFEL) has attracted considerable interest over the past years. Nowadays typical XFEL application experiments demand 1010–1011 photons per pulse, which corresponds to a peak power of terawatts (TW) in case asec hard pulse. To realization such TW asec-XFEL however, unavoidable increase slice energy spread (SES) due heater, is commonly used mitigate micro-bunching instability (MBI), would be major obstacle. deal with this problem, effect SES investigated work. The results reveal that (1) current spike linearly proportional an electron beam, (2) surprisingly, linearity independent wavelength modulation driving make and (3) gain length undulator sensitive initial SES, so there optimal for successful FEL lasing process. Utilizing these characteristics, series simulations parameters Pohang Accelerator Laboratory Free Electron Laser was carried out demonstrate isolated, pulse can generated even when increased usage heater prevent MBI XFEL. We show isolated >1 duration 73 as (~3 × 1010 photons/pulse at 12.4 keV or 0.1 nm) by using ten spikes current. It becomes clear first time disadvantage from indeed overcome.