A quasi periodic elliptical undulator (QP-EPU105) has been recently put in operation at the Electron Spectro Microscopy beamline at NSLS-II. Commissioning results pertaining to its initial characterization are presented. The spectral and angular distributions of the light have been probed and compared with emission calculations based on the measured magnetic field. The light polarization produced in parallel and anti-parallel operation modes is also quantitatively analyzed.
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