Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, Massachusetts 02138

99 -- ECHELLE DIFFRACTION GRATING SOL RFP539-8-96 DUE 100796 POC Contact Point, Peter W. Sozanski, 617/495-7376, Contracting Officer, George D. Dick, 617/495-7401, FAX 617/496-7692 The Smithsonian Astrophysical Observatory (SAO) requires two Plane Echelle Diffraction Gratings with a ruling density of 150 grooves per millimeter and a blaze angle of 63.5 degrees. These gratings will be operated with an opening angle of 13 degrees between the incident and diffracted beams. The gratings will be replicated from a ruled master onto a Zerodur substrate whose dimensions are 320 mm by 420 mm. The minimum allowed dimensions of the ruled clear aperture of each grating are 302 mm (in the direction parallel to the grooves) by 410 mm (in the direction perpendicular to the grooves). These two gratings will be mosaiced (with a 5 mm gap between the substrates) to create a 302 mm by 835 mm grating assembly. Proposals may, in addition to the baseline gratings described here, offer a single, monolithic grating with a 302 mm by 835 mm clear aperture which adheres to all other specifications in the solicitation package. The coated grating shall have an absolute efficiency ( i.e., not relative to the coating reflectivity) of 36% or greater over a wavelength range extending from 3600 angstroms to 1.1 microns in the operating configuration (i.e., with a 13 degree opening angle). The efficiency test and all other verification tests must be performed with an elliptical beam with a 302 mm minor axis and 835 mm major axis so that one edge of the clear aperture is tangent to the ellipse at the major axis and the other clear aperture edge coincides with the minor axis of the illuminating ellipse. Less than 0.01% of the incident flux shall emerge in ghosts of any sort. A goal of better than 0.001% ghost flux is desirable. Assuming a perfect illuminating beam, the wavefront reflected from the grating should contain no more than 0.6 microns of spherical and 0.2 microns of irregular departure from flatness. A goal of 0.15 microns of irregular departure is desirable. This wavefront accuracy should be achieved with the elliptical illumination pattern described above. The completed gratings shall be delivered on or before 1 October 1998. Only written or faxed requests (FAX # 617/496-7692) received directly from the requester are acceptable. All responsible sources may submit an offer. No telephone requests for the solicitation package will be accepted. (0229)

Loren Data Corp. http://www.ld.com (SYN# 0323 19960820\99-0001.SOL)