Accurate Electron Beam Size Measurement at the Metrology Light Source

For the operation of the Metrology Light Source MLS , the dedicated electron storage ring of the Physikalisch Technische Bundesanstalt PTB , as the national primary radiation source standard from the near infrared to the vacuum ultraviolet spectral region, all storage ring parameters which are relevant for the calculation of the radiant intensity by the Schwinger equation have to be known absolutely with small uncertainties. For the measurement of the effective vertical electron beam size a Bragg polarimeter, operating at a photon energy of 1103 eV, has been designed and successfully put into operatio