Design and manufacture of the integrated field unit for the NIRSpec spectrometer on JWST

Dan Lobb; David Robertson; Martin Closs; Andy Barnes

doi:10.1117/12.797766

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27 September 2008 Design and manufacture of the integrated field unit for the NIRSpec spectrometer on JWST

Dan Lobb, David Robertson, Martin Closs, Andy Barnes

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Proceedings Volume 7100, Optical Design and Engineering III; 710012 (2008) https://doi.org/10.1117/12.797766
Event: Optical Systems Design, 2008, Glasgow, Scotland, United Kingdom

Abstract

The NIRSpec imaging spectrometer, which forms part of the James Webb Space Telescope instrumentation, will include an integrated field unit (IFU). The IFU will be tasked specifically with efficient analysis of extended objects, including galaxies; it will accept a square image area at the spectrometer entrance field, dissect this area into 30 parallel sub-slits, and image the sub-slits end-to-end, forming a single virtual entrance slit. The IFU, uses all-mirror optics to operate over the spectral range 700nm to 5000nm. 95 mirrors and the main support structure are made in a common aluminium alloy, to achieve athermal performance down to an operating temperature of around 30K. Relatively complex mirror surface shapes are produced by diamond machining. The IFU has been designed and constructed by SSTL, with optics produced by CfAI; the unit is currently undergoing performance tests. This paper describes the IFU optical design and performance, and outlines the mirror manufacturing methods and alignment procedures.

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Dan Lobb, David Robertson, Martin Closs, and Andy Barnes "Design and manufacture of the integrated field unit for the NIRSpec spectrometer on JWST", Proc. SPIE 7100, Optical Design and Engineering III, 710012 (27 September 2008); https://doi.org/10.1117/12.797766

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