A Low Noise, High QE, Large Format CCD Camera System for the NASA MIGHTI Instrument

Abstract:

The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument is part of the NASA Ionspheric Connection Explorer (ICON) mission designed to uncover the mysteries of the extreme variability of the Earth’s ionosphere. MIGHTI consists of two identical units positioned to observe the Earth’s low latitude thermosphere from perpendicular viewing directions. The MIGHTI instrument is a spatial heterodyne spectrometer and requires a low noise, high QE, large format camera system to detect slight phase changes in the fringe patterns which reveal the neutral wind velocity.

 

The MIGHTI camera system uses a single control electronics box to operate two identical CCD camera heads and communicate with the ICON payload electronics. The control electronics are carefully designed for a low noise implementation of CCD biases, clocking, and CCD output digitization. The camera heads consist of a 2k by 2K, back-illuminated, frame transfer CCD provided by e2v. The CCD’s are both TEC cooled and have butcher-block filters mounted in close proximity of the active area. The CCDs are nominally operated in binned mode, the control electronics register settings provide flexibility for binning and gain control. An engineering model of the camera system has been assembled and tested. The EM camera system characterization meets all performance requirements. Performance highlights include a measured read noise of 5.7 electrons and dark current of 0.01 electronics/pixel/second. The camera system design and characterization results will be presented.