The gratings, with 400 lines/mm, are ruled on CaF2 substrate of 4.52 mm thickness. Area of the ruling is  36 mm X 36 mm. The dispersion obtained on the detector plane is 1.2 nm/ arcsec & 0.6 nm/arcsec  in the first and second orders respectively at 136 nm. Aberrations are introduced by the grating and the PSF is ~ 2" FWHM. Grating specifications and the measured transmission curves are listed below.

Substrate CaF2 CaF2 CaF2
Grooves 400 lines/mm 400 lines/mm 400 lines/mm
Diameter 52.00 mm 51.95 mm 51.99 mm
Thickness 4.52 mm 4.52 mm 4.52 mm
Ruled Area 36 x 36 mm 36 x 36 mm 36 x 36 mm
1st Order Peak λ 190 nm 240 nm 210 nm
2nd Order Peak λ 140 nm 156 nm 154 nm
Crossover 150 nm 175 nm 166 nm


Transmission efficiency of FUV Grating-1, measured in Lab
FUV Grating1: Transmittance


Transmission efficiency of FUV Grating-2, measured in Lab
FUV Grating2: Transmittance


Transmission efficiency of NUV Grating, measured in Lab
NUV Grating: Transmittance