Upgrades of beam diagnostics in support of emittance-exchange experiments at the Fermilab A0 photoinjector

TL;DR

This paper discusses recent upgrades to beam diagnostics at Fermilab's A0 photoinjector, enabling precise measurements crucial for emittance exchange experiments and accelerator optimization.

Contribution

It introduces specific diagnostic improvements, including resolution enhancements and optical system adjustments, to support emittance exchange experiments.

Findings

Enhanced screen resolution and depth-of-focus control

Successful measurement of small energy spreads (<10 keV)

Achievement of bunch lengths less than 500 fs

Abstract

The possibility of using electron beam phase space manipulations to support a free-electron laser accelerator design optimization has motivated our research. An on-going program demonstrating the exchange of transverse horizontal and longitudinal emittances at the Fermilab A0 photoinjector has benefited recently from the upgrade of several of the key diagnostics stations. Accurate measurements of these properties upstream and downstream of the exchanger beamline are needed. Improvements in the screen resolution term and reduced impact of the optical system's depth-of-focus by using YAG:Ce single crystals normal to the beam direction will be described. The requirement to measure small energy spreads (<10 keV) in the spectrometer and the exchange process which resulted in bunch lengths less than 500 fs led to other diagnostics performance adjustments and upgrades as well. A longitudinal to transverse exchange example is also reported.