Drive laser system for the DC-SRF photoinjector at Peking University

TL;DR

This paper presents the design, construction, and successful application of a new drive laser system for a DC-SRF photoinjector at Peking University, achieving stable UV laser output suitable for high-quality electron beam generation.

Contribution

A novel drive laser system tailored for the Peking University DC-SRF photoinjector, with detailed design and performance analysis, enhancing stability and UV laser quality.

Findings

Stable operation of the photoinjector with the new laser system.

UV laser at 266 nm with ~1W power delivered to photocathode.

Laser instability less than 5% over long-term operation.

Abstract

Photoinjectors are widely used for linear accelerators as electron sources to generate high-brightness electron beam. Drive laser, which determines the timing structure and quality of the electron beam, is a crucial device of photoinjector. A new drive laser system has been designed and constructed for the upgraded 3.5-cell DC-SRF photoinjector at Peking University. The drive laser system consists of a 1064 nm laser oscillator, a four- stage amplifier, the second and fourth harmonic generators, the optical system to transfer the UV pulses to the photocathode, and the synchronization system. The drive laser system has been successfully applied in the stable operation of DC-SRF photoinjector and its performance meets the requirements. 266 nm laser with an average power close to 1W can be delivered to illuminate the Cs2Te photocathode and the instability is less than 5% for long time operation. The design consideration for improving the UV laser quality, a detailed description of laser system, and its performance are presented in this paper.