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Proceedings Paper

Technique for diamond machining large ZnSe grisms for the Rapid Infrared/Imager Spectrograph (RIMAS)
Author(s): Paul J. Kuzmenko; Steve L. Little; Alexander S. Kutyrev; John I. Capone
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Paper Abstract

The Rapid Infrared Imager/Spectrograph (RIMAS) is an instrument designed to observe gamma ray burst afterglows following initial detection by the SWIFT satellite. Operating in the near infrared between 0.9 and 2.4 μm, it has capabilities for both low resolution (R~25) and moderate resolution (R~4000) spectroscopy. Two zinc selenide (ZnSe) grisms provide dispersion in the moderate resolution mode: one covers the Y and J bands and the other covers the H and K. Each has a clear aperture of 44 mm. The YJ grism has a blaze angle of 49.9° with a 40 μm groove spacing. The HK grism is blazed at 43.1° with a 50 μm grooves spacing.

Previous fabrication of ZnSe grisms on the Precision Engineering Research Lathe (PERL II) at LLNL has demonstrated the importance of surface preparation, tool and fixture design, tight thermal control, and backup power sources for the machine. The biggest challenges in machining the RIMAS grisms are the large grooved area, which indicates long machining time, and the relatively steep blaze angle, which means that the grism wavefront error is much more sensitive to lathe metrology errors. Mitigating techniques are described.

Paper Details

Date Published: 22 July 2016
PDF: 12 pages
Proc. SPIE 9912, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II, 99120C (22 July 2016); doi: 10.1117/12.2231834
Show Author Affiliations
Paul J. Kuzmenko, Lawrence Livermore National Lab. (United States)
Steve L. Little, Lawrence Livermore National Lab. (United States)
Alexander S. Kutyrev, NASA Goddard Space Flight Ctr. (United States)
Univ. of Maryland, College Park (United States)
John I. Capone, Univ. of Maryland, College Park (United States)


Published in SPIE Proceedings Vol. 9912:
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation II
Ramón Navarro; James H. Burge, Editor(s)

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