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FLASH is a SASE FEL user facility at DESY (Hamburg) operating with photon wavelengths in the range from vacuum ultraviolet to soft x-rays. Although the slice emittance is a more appropriate parameter to characterize the SASE process, the projected emittance provides a useful measure of the electron beam quality. At FLASH the projected emittance is measured at three location along the linac: in the injector (130 MeV), after the collimator (full electron beam energy), and in the undulator section. The transverse beam shape is measured with OTR monitors and wire scanners. The multi-monitor method is used to determine the emittance. In this paper we describe the measurement set-up and procedure and report recent results and planned upgrades.
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