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Toroidal Variable-Line-Space Gratings: The Good, the Bad and The UglyToroidal variable-line-space (VLS) gratings are an important factor in the design of an efficient VUV solar telescope that will measure the CIV (155nm) and MgII (280nm) emissions lines in the Sun's transition region. In 1983 Kita and Harada described spherical VLS gratings but the technology to commercially fabricate these devices is a recent development, especially for toroidal surfaces. This paper will describe why this technology is important in the development of the Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program (the good), the delays due to the conversion between the TVLS grating design and the optical fabrication (the bad), and finally the optical testing, alignment and tolerancing of the gratings (the ugly). The Solar Ultraviolet Magnetograph Investigation, SUMI, has been reported in several papers since this program began in 2000. The emphasis of this paper is to describe SUMI's Toroidal Variable-Line-Space (TVLS) gratings. These gratings help SUMI meet its scientific goals which require both high spectral resolution and high optical efficiency for magnetic field measurements in the vacuum ultraviolet wavelength band of the solar spectrum (the good). Unfortunately, the technology readiness level of these gratings has made their implementation difficult, especially for a sounding rocket payload (the bad). Therefore, this paper emphasizes the problems and solutions that were developed to use these gratings in SUMI (the ugly). Section 2 contains a short review of the scientific goals of SUMI and why this mission is important in the understanding of the 3D structure of the magnetic field on the Sun. The flight hardware that makes up the SUMI payload is described in Section 3 with emphasis on those components that affect the TVLS gratings. Section 4 emphasizes the alignment, testing and optical modeling that were developed to optimize the performance of these gratings.
Document ID
20090034843
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
West, Edward A. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Kobayashi, Ken (Alabama Univ. Huntsville, AL, United States)
Cirtain, Jonathan (NASA Marshall Space Flight Center Huntsville, AL, United States)
Gary, Allen (Alabama Univ. Huntsville, AL, United States)
Davis, John (NASA Marshall Space Flight Center Huntsville, AL, United States)
Reader, Joseph (National Inst. of Standards and Technology Gaithersburg, MD, United States)
Date Acquired
August 24, 2013
Publication Date
August 2, 2009
Subject Category
Solar Physics
Report/Patent Number
M09-0573
M09-0264
Meeting Information
Meeting: SPIE Optics and Photonics: Optical System Alignment, Tolerancing, and Verification III
Location: San Diego, CA
Country: United States
Start Date: August 2, 2009
End Date: August 6, 2009
Sponsors: International Society for Optical Engineering
Distribution Limits
Public
Copyright
Public Use Permitted.

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