Reflective Optical System for Time-Resolved Electron Bunch Measurements at PITZ

TL;DR

This paper discusses the development of a reflective optical system using mirror telescopes to enhance time-resolved measurements of electron bunches at PITZ, addressing dispersion issues in lens-based systems.

Contribution

It introduces a mirror-based optical system design that improves temporal resolution for electron bunch diagnostics, surpassing traditional lens-based systems.

Findings

Mirror telescopes reduce dispersion effects

Improved temporal resolution demonstrated

Hybrid lens-mirror system as proof of concept

Abstract

The Photo-Injector Test facility at DESY, Zeuthen site (PITZ), produces pulsed electron beams with low transverse emittance and is equipped with diagnostic devices for measuring various electron bunch properties, including the longitudinal and transverse electron phase space distributions. The longitudinal bunch structure is recorded using a streak camera located outside the accelerator tunnel, connected to the diagnostics in the beam-line stations by an optical system of about 30 m length. This system mainly consists of telescopes of achromatic lenses, which transport the light pulses and image them onto the entrance slit of the streak camera. Due to dispersion in the lenses, the temporal resolution degrades during transport. This article presents general considerations for time-resolving optical systems as well as simulations and measurements of specific candidate systems. It then describes the development of an imaging system based on mirror telescopes which will improve the temporal resolution, with an emphasis on off-axis parabolic mirror systems working at unit magnification. A hybrid system of lenses and mirrors will serve as a proof of principle.