U125-2_NIM
U125-2_NIM
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.
| 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 |
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.
References
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.