Modified Visible and Infrared Optical Design for the ITER Upper Ports
This document reports the results of a follow-on optical design study of visible-light and infrared optics for the ITER upper ports, performed by LLNL under contract for the US ITER Project Office. The major objectives of this work are to move the viewing aperture closer to the plasma so that the optical path does not cut through any adjacent blanket shield module other than the module designated for the port; move optics forward into the port tube to increase the aperture size and therefore improve the spatial resolution; assess the trade-off between spatial resolution and spatial coverage by reducing the field of view; and create a mechanical model with a neutron labyrinth. Here we show an optical design incorporating all these aspects. The new design fits into a 360 mm ID tube, as did the previous design. The entrance aperture is increased from 10 mm to 21 mm, with a corresponding increase in spatial resolution. The Airy disk diameter for 3.8 {micro}m wavelength IR light is 5.1 mm at the most distant target point in the field of view. The field of view is reduced from 60 toroidal degrees (full toroidal coverage with 6 cameras) to 50 toroidal degrees. The 10 degrees eliminated are those nearest the camera, which have the poorest view of the divertor plate and in fact saw little of the plate. The Cassegrain telescope that was outside the vacuum windows in the previous design is now in vacuum, along with lenses for visible light. The Cassegrain for visible light is eliminated. An additional set of optical relay lenses is added for the visible and for the IR.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 938503
- Report Number(s):
- LLNL-TR-403218; TRN: US0806104
- Country of Publication:
- United States
- Language:
- English
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