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Absolute Radiometric Calibration of EUNIS-06The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.
Document ID
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Thomas, R. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Rabin, D. M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kent, B. J.
(Rutherford Appleton Lab. United Kingdom)
Paustian, W.
(Physikalisch-Technische Bundesanstalt Germany)
Date Acquired
August 23, 2013
Publication Date
May 27, 2007
Subject Category
Solar Physics
Meeting Information
Meeting: American Astronomical Society 210th Meeting
Location: Honolulu, HI
Country: United States
Start Date: May 27, 2007
End Date: May 31, 2007
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