U.S. Patent 5,274,435
- Self-Focusing Concave Grating
– High Throughput - Grazing Incidence: Soft X-Ray Use
- Stationary Slits
- Fixed Beam Directions
- Fixed Numerical Aperture
- Broadband Tunability
Specifications
- Mounting
- Hettrick, U.S. Patent 5,274,435; Spherical Grating
- Angular Deviation
- 4.5°(Fixed). Nominal graze angle of 2.25°
- Grating Stage Format
- Gold Surface;
Active Circular Aperture 100 mm - Grating Groove Density
- 750 g/mm
- Wavelength Range
- 10~100 Angstroms (m=1); approx. 6~50 Angstroms (m=2), depending on source intensity
- Fractional Dispersive Resolution
- 0.167/mm (at Source and Exit Slit)
- Optical Aberration (image tilt)
- Δλ/λ < 0.010 at 6 mrad Sagittal Aperture, 10~50 Angstroms (m=1)
- Meridonial Aperture
- 12.5 mrad, on Rowland Circle
- Sagittal Aperture
- 0~30 mrad, astigmatic (Φ)
- Exit Slit Width (Vacuum Selectable)
- 200 µm at 0.2°
100 µm at 0.2° (10-13 Å)
100 µm at 0.7° (13-20 Å)
100 µm at 1.2° (20-28 Å)
100 µm at 1.7° (28-37 Å)
100 µm at 2.2° (> 37 Å) - Exit Slit Length
- 20 mm
- External Drive
- Single Micro-Stepped Motor with Compumotor ZETA6104-57-83 Indexer/Drive w/RS232C Interface Port
- Vacuum Chamber
- Weld-Free 6061 Aluminum, Electroless Nickel Plated; TEFLAT/BLACKFLAT Sealed Knife-edge Ports
- Entrance and Exit Ports
- 4.5″ Conflat Flange (ICF114)
- User Ports
- Three Ports Accept 2.75″ Conflat Flange (ICF070)
- Length
- 0.63 meters (Slit-Slit)
- Aperture Center
- Stationary
Construction
Model SNR-SXR-0.6 is a high aperture (Φ = 12.5 mrad), single-element soft x-ray Monochromator. The grating has a 100 mm circular aperture with grooves extending to the edge. The distance from (slitless) source to exit slit is 628 mm. The fixed angular deviation of 4.5 degrees and gold coated grating provide efficient reflection to wavelengths as short as λmin = 10 Angstroms in first order and to approximately 6 Angstroms in second order. The spectral resolution is determined by the sagittal aperture which may be set by knife-edges at the entrance port of exit slit, over the range of approximately 0 to 30 mrad. A typical setting of 3 mrad (illuminating 2 mm at the exit slit) provides a fractional spectral resolution of 1/160 at 23 Å, 1/68 at 50 Å, and 1/33 at 100 Å. However, the long wavelength performance is improved considerably by employing an exit slit mask containing 6 slits (100 µm wide) at different angles, to match the image tilt over different regions in scanned wavelength. Using the appropriate slit, the resolution is approximately 1/100 over 10~50 Å using a 6 mrad sagittal aperture.
An externally mounted micro-stepping motor with Compumotor indexer provides rotational control of the grating scan under vacuum by means of a shaft feedthrough. The slits are also selectable under vacuum using a micrometer shaft feedthrough. Both the grating chamber and the slit chambers are electroless-nickel plated aluminum and are machined square relative to the grating surface and slit mask, enabling alignment by mechanical indication from the chamber exteriors.
The photograph shows a custom system including model SNR-SXR-0.6 and associated optional equipment (not included with base instrument) such as a Manson model 2 soft x-ray source and compact chamber, pumps, gages, mounting table and brackets, CCD, filter assembly, vacuum-selectable aperture and microscope visible alignment system, for calibrating x-ray transmission gratings in the 5-114 Å region.
