Performance of the first undulator beamline U49-1-SGM at BESSY II

In July 1998, the first undulator beamline of BESSY II consisting of a sphe rical grating monochromator with variable included angle installed at an 83 period undulator with 49 mm period length was brought into operation. The characterization now has been completed, The energy range extends from abou t 90-1500 eV. An ultimate determination of the energy resolution of the mon ochromator generally fails because of the intrinsic lifetime broadening of the gases investigated. However, comparing the results at the N-2 K-edge of the U125-1-PGM a very high energy resolution of more than 40,000 can be es timated at 200 eV. For high energy resolution a flux of 10(9)-10(12) photon s per second has been recorded. The focus at the sample position has a FWHM size of 14 mum x 37 mum. The synchronous drive of monochromator and undula tor offers improved quality of spectra which have to be recorded over a lar ge photon energy range. (C) 2001 Elsevier Science B.V. All rights reserved.