Generation and measurement of sub-picosecond electron bunch in photocathode rf gun

TL;DR

This paper proposes a method to generate sub-picosecond electron bunches using a photocathode RF gun with optimized parameters and laser shaping, and introduces a nondestructive measurement technique based on wakefield radiation spectrum.

Contribution

It introduces a novel scheme for producing ultra-short electron bunches and a nondestructive measurement method using wakefield radiation spectrum analysis.

Findings

Successful generation of sub-picosecond electron bunches.

Effective measurement of bunch length via wakefield radiation spectrum.

Reduction of transverse emittance growth through laser shaping.

Abstract

We consider a scheme to generate sub-picosecond electron bunch in the photocathode rf gun by improving the acceleration gradient in the gun, suitably tuning the bunch charge, the laser spot size and the acceleration phase, and reducing the growth of transverse emittance by laser shaping. A nondestructive technique is also reported to measure the electron bunch length, by measuring the high-frequency spectrum of wakefield radiation which is caused by the passage of a relativistic electron bunch through a channel surrounded by a dielectric.