Optical alignment and diagnostics for the ATF microundulator FEL oscillator

Abstract Alignment of the BNL-MIT microundulator FEL components, including transverse alignment of the FEL cavity, coalignment of the cavity with the undulator and with the electron beam are described. Cavity length measurements are made by coupling an external laser into the FEL oscillator. Diagnostics for the optical beam, including energy, pointing stability, and spectra are presented. Electron beam diagnostics for charge, position, and energy spread are also described.