SGM-E and SGM-AH Grating Chambers for Spherical Grating Monochromators

The SGM-E and SGM-AH are the first water-cooled SGMs produced at PSL. These SGMs incorporate precision UHV mechanism design to promote ease of use and accuracy in an economical instrument. The first unit was completed in 1993. The rectangular, open-top chamber is decoupled from the mechanism so that barometric pressure changes do not affect the mechanism's accuracy. Gratings may be scanned under computer control and manually indexed while at any scan angle. Special UHV low-friction bearings, designed for zero radial and thrust play, are used for the scan angle rotation.