Femtosecond Synchroscan Streak Tube

Abstract

A femtosecond synchroscan streak tube has been developed. In order to achieve femtosecond time resolution, the following conditions were adopted in the tube design: high electric field application near the photocathode, high positive voltage application to the focusing electrode to reduce photoelectron transit time spread in the focusing region, and setting the anode electric potential as low as possible to obtain a very high deflection sensitivity for sweep due to low photoelectron drift velocity between the anode and the sweeping screen. The electrode structure and the applied voltages were designed by computer simulation of electron trajectory, and the theoretical time resolution obtained is ∼520 fs. Based on the above design parameters, a prototype tube was fabricated and evaluated. A time resolution of ∼660 fs was experimentally obtained at the synchroscan frequency of ∼80 MHz.