The two normal-incidence monochromator beam lines of PTB at BESSY II

In the present contribution the two normal-incidence monochromator beam lin es of the Physikalisch-Technische Bundesanstalt (PTB) for the calibration o f radiation sources and detectors and the characterisation of optical compo nents are briefly described. After shut down of BESSY I these bending magne t beam lines have been transferred to the radiometry laboratory of PTB at B ESSY II. Emphasis is laid on the technical aspects linked with the change f rom BESSY I to BESSY II such as, e.g., the out-of-plane acceptance of the s ynchrotron radiation to reduce the heat load on the normal-incidence optics caused by the higher characteristic energy of BESSY II bending magnet radi ation compared to BESSY I. (C) 2001 Elsevier Science B.V. All rights reserv ed.