User operation of the first undulator on Aladdin

The first undulator on Aladdin recently began operating as a user facility. The device is equipped with a 6-meter toroidal grating monochromator beamline. The undulator and its beamline have several unique characteristics. Furthermore, the adjacent bending magnet beamline is almost a twin of the undulator beamline, with similar grating efficiencies and reflection losses. This makes it easy to directly compare undulator and bending magnet source beamlines in a realistic environment. The results indicate that the undulator beamline produces between 20 and 100 times more flux in the first harmonic than a similar beamline on a bending magnet. The excellent polarization of 99.5% for the first harmonic makes this beamline extremely useful for polarization studies. User programs based on the undulator radiation included angle-resolved photoemission in gas phase and tests of optical components. The beamline is now entirely dedicated to soft X-ray spectromicroscopy (project MAXIMUM).