Design of magnetic focusing femtosecond streak tube with prepositive traveling wave deflector

A 265 mm long magnetic focusing femtosecond streak tube with a prepositive traveling wave deflector was theoretically designed. The initial parameters of the electrons emitted both from an ideal point and a slit on the surface of the photoelectric cathode were sampled with Monte Carlo method. The trajectory of the electrons were followed in the CST particle studio, after which the distribution of the electrons on the best image plane and the transit time of the electrons were statistically analyzed. To evaluate the characteristics of the streak tube, this paper also calculated the modulation transform function. The results show that the diameter of the effective area on the photoelectric cathode reaches up to 6 mm, while the amplification rate turns to be 2.4~2.5. By conservative estimates, the time resolution is expected to reach 245 fs.