Observation of picometer vertical emittance with a vertical undulator

Area of Science:

• Physics
• Accelerator Physics
• Synchrotron Radiation

Background:

• Electron beam emittance is a critical parameter for synchrotron light source performance.
• Measuring vertical electron beam emittance accurately is challenging.

Purpose of the Study:

• To develop and validate a novel diagnostic for measuring picometer vertical electron beam emittances.
• To assess the applicability of this diagnostic to existing storage rings.

Main Methods:

• Utilized an APPLE-II type undulator phased for a horizontal magnetic field.
• Observed synchrotron radiation sensitive to vertical electron beam emittance.
• Analyzed undulator spectral peak height ratios against simulations.

Main Results:

• Achieved picometer vertical electron beam emittances at the Australian Synchrotron storage ring.
• Demonstrated the sensitivity of the undulator-based method to vertical emittance.

Conclusions:

• The developed undulator-based apparatus is an appropriate and novel diagnostic for vertical emittance.
• This method is readily deployable at most existing electron and positron storage rings.