The NASA Solar Dynamics Observatory (SDO), scheduled for launch in 2008, incorporates a suite of instruments including the EUV Variability Experiment (EVE). The EVE instrument package contains grating spectrographs used to measure the solar extreme ultraviolet (EUV) irradiance from 0.1 to 105 nm. The Multiple EUV Grating Spectrograph (MEGS) channels use concave reflection gratings to image solar spectra onto CCDs that are operated at -100 C. MEGS provides 0.1nm spectral resolution between 5-105nm every 10 seconds with an absolute accuracy of better than 25% over the SDO 5-year mission1. Characterizations and selection testing of the CCDs and the thin foil filters for SDO EVE have been performed with both in-band and visible illumination. CCD selection was based on results from testing in LASP facility CTE3 as well as results from MIT testing. All CCDs meet the requirements for electronics gain, flat field, QE, dark current, reverse clock, CTE, bad pixels and the -120 C survival test. The thin foil filters selection was based on tests performed at LASP facilities and NIST. All filters provide >106 attenuation of visible light with the proper transmission needed for order sorting capabilities and are free of critical pinholes.
Citation: SPIE Proceedings--The International Society for Optical Engineering
Pub Type: Journals
CCD, EUV, EVE, MEGS, SDO, thin foil filter