Beamline data
Segment H03
Location (Pillar) 4.2
Source U125-2 (Undulator)
Monochromator 10m-NIM
Energy range 6(4) - 40 eV
Energy resolution E/dE = 85000 @ d = 1200l/mm, 2nd order, 10 µm slits
Flux 1×1e12 @ 21.75 eV [photons/s/0.1A/0.1%BW]
Polarisation horizontal
Divergence horizontal 5.5 mrad
Divergence vertical 12 mrad
Focus size (hor. x vert.) 350 x 200* [v x h]
User endstation possible
Distance Focus/last valve 1190 mm
Height Focus/floor level 1750 (1400 mm with concrete experiment platform) mm
Beam availability 12h/d
Phone --
Applicable station(s)
User station
Small Reflectometer room temperature
nmTransmission NEXAFS room temperature

Normal incidence monochromators (NIM) are typically used in synchrotron beamlines which are dedicated to experiments operating in an energy range of about 4 to 35 eV only. The decisive advantages of this type of monochromator design are that only small aberration errors occur and highest resolution can be easily achieved with it.

The 10m-NIM beamline (Reichardt et al. 2001) was designed for the undulator U125-2 (Bahrdt et al. 2001) and is based on the so called off-Rowland circle mounting design (Samson 1967). This implies that the grating has to be rotated and slightly translated in order to get the highest resolution and a small spot size in the experiment.


Reichardt, G.; Bahrdt, J.; Schmidt, J. S.; Gudat, W.; Ehresmann, A.; Muller-Albrecht, R. et al. (2001): A 10m-normal incidence monochromator at the quasi-periodic undulator U125-2 at BESSY II. In NUCL INSTRUM METH A 467, pp. 462–465.

Bahrdt, J.; Frentrup, W.; Gaupp, A.; Scheer, M.; Gudat, W.; Ingold, G.; Sasaki, S. (2001): A quasi-periodic hybrid undulator at BESSY II. In NUCL INSTRUM METH A 467-468, pp. 130–133.

Samson, James A. (1967): Techniques of Vacuum Ultraviolet Spectroscopy. New York, London, Sydney: John Wiley & Sons, Inc.