Femtosecond electron bunch generation, measurement, and control

利用激光与等离子体相互作用的激光加速电子束具有超短脉冲宽度。预期的脉冲宽度为飞秒量级（1飞秒= 1/（1四次方）秒）。电子束将作为化学反应测量和控制的源，本研究进行了稳定的电子束产生和脉宽测量。由于安全性和容易估计等离子体密度，使用氦气作为靶。通过改变靶为氮气，我们成功地产生了稳定的电子束。此外，我们还成功地测量了电子束的脉宽。电子束在激光场中振荡。从振荡，1.7飞秒的脉冲宽度已被测量。

Laser accelerated electron beam via laser-plasma interaction has an ultra-short pulse width. The expected pulse width is the order of femtosecond (1 femtosecond = 1/(1 quadrillion) second). The electron beam will be a source for measurement of the chemical reaction and the control.In this research, a stable electron beam generation and a pulse width measurement are conducted. As a target, helium gas is used due to the safety and the easy estimation of the plasma density. By changing the target to nitrogen, we have succeeded the stable electron beam generation. Furthermore, we have succeeded to measure the pulse width of the electron beam. The electron beam is oscillated in the laser field. From the oscillation, 1.7 femtosecond of the pulse width has been measured.