Development of a photoelectron spectrometer for hard x-ray photon diagnostics

Area of Science:

• * Physics
• * Spectroscopy
• * Photon Diagnostics

Background:

• * Hard X-ray photon diagnostics are crucial for free-electron laser (FEL) research.
• * Existing methods face challenges due to low cross-sections and high photoelectron kinetic energies.
• * Accurate spectral distribution diagnostics are needed for FEL operational control and user data interpretation.

Purpose of the Study:

• * To develop and characterize an angle-resolved photoelectron spectrometer for hard X-ray diagnostics.
• * To provide pulse-resolved, non-invasive spectral distribution measurements.
• * To address the diagnostic challenges in the hard X-ray regime at FEL facilities.

Main Methods:

• * Design and implementation of an angle-resolved photoelectron spectrometer utilizing the electron time-of-flight (eTOF) concept.
• * Characterization of the instrument's performance using hard X-rays at the PETRA III synchrotron.
• * Comparison of experimental results with detailed electron trajectory simulations.

Main Results:

• * Demonstration of a resolving power of 10 eV for incident photon energies up to at least 20 keV.
• * Successful operation and characterization in multibunch mode at a synchrotron facility.
• * Validation of instrument performance through comparison with theoretical simulations.

Conclusions:

• * The developed spectrometer is a viable tool for hard X-ray photon diagnostics at FELs.
• * The instrument provides essential pulse-resolved spectral information, enhancing operational capabilities.
• * The achieved resolving power meets critical requirements for advanced X-ray science applications.