Absolute measurement of the spectral and angular properties of undulator radiation with a pinhole transmission grating spectrometer

Abstract

Absolute measurements of undulator radiation in the soft x-ray region from 50 to 500 eV are presented. A dedicated compact pinhole transmission grating spectrometer has been built, which was calibrated with relative uncertainties between 5% (at 100 eV) and 20% (at 500 eV) in the calculable undispersed dipole radiation of the storage ring BESSY. We report measurements of the spectral and angular radiation properties of the 35 period wiggler/undulator installed at BESSY for K parameters of 0.1 and 1.0. Good agreement with theoretical calculations is found.