Berden G, Gillespie W A, Jamison S P, Knabbe E-A, MacLeod A M, van der Meer A F G, Phillips P J, Schlarb H, Schmidt B, Schmüser P, Steffen B
FOM Institute for Plasma Physics Rijnhuizen, Edisonbaan 14, 3439 MN Nieuwegein, The Netherlands.
Phys Rev Lett. 2007 Oct 19;99(16):164801. doi: 10.1103/PhysRevLett.99.164801. Epub 2007 Oct 17.
The longitudinal profiles of ultrashort relativistic electron bunches at the soft x-ray free-electron laser FLASH have been investigated using two single-shot detection schemes: an electro-optic (EO) detector measuring the Coulomb field of the bunch and a radio-frequency structure transforming the charge distribution into a transverse streak. A comparison permits an absolute calibration of the EO technique. EO signals as short as 60 fs (rms) have been observed, which is a new record in the EO detection of single electron bunches and close to the limit given by the EO material properties.
利用两种单次探测方案，对软X射线自由电子激光FLASH中超短相对论电子束团的纵向分布进行了研究：一种是测量束团库仑场的电光（EO）探测器，另一种是将电荷分布转换为横向条纹的射频结构。通过比较可以对EO技术进行绝对校准。已观测到短至60飞秒（均方根）的EO信号，这是单次电子束团EO探测中的新记录，且接近由EO材料特性所给出的极限。
