Charge coupled device (CCD) imaging sensors
Chelmsford, UK
44 (0)1245 493493

e2v CCD imaging sensors were launched recently on the Space Shuttle Atlantis as part of a mission to upgrade and repair the Hubble Space Telescope. The imaging sensors equip the Wide Field Camera 3 (WFC3), a new instrument installed on Hubble to take largescale, extremely clear and detailed pictures of the universe over a very wide range of colors. The mission equipped the telescope to explore the universe in greater detail by replacing equipment and installing new instruments.

WFC3 will replace the existing Wide Field Planetary Camera 2 (WFPC2). Its key feature is the ability to span the electromagnetic spectrum from the ultraviolet (UV), through visible/optical light, and into the near infrared (NIR). It is this wide-field panchromatic ability that is so unique and gives WFC3 the ability to observe young, hot stars (glowing mainly in UV) and older, cooler stars (glowing mainly in red and NIR) in the same galaxy, and more than a 10X improvement over WFPC2 in discovery efficiency at UV wavelengths.

WFC3 is able to do this through its dual-channel design using two sensor technologies. Incoming light is beamed from the telescope to either the Ultraviolet-Visible (UVIS) channel or the Near-Infrared (NIR) channel. The UVIS channel of the instrument is equipped with e2v’s large CCD-43 imaging sensor.

The sensors provide full-frame imaging to operate in Inverted Mode for low dark signal, enhanced ultraviolet quantum efficiency and back-illumination, and two high-responsivity and very-low-noise-output amplifiers on each sensor, enable imaging of feint objects. A parallel charge injection structure permits mitigation against radiation effects of the space environment and a supplementary “notch” or mini-channel is included to further reduce the impact of irradiation when imaging at small signal levels. The readout register has a gate controlled dump drain to allow fast dumping of unwanted data.

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NASA Tech Briefs Magazine

This article first appeared in the August, 2009 issue of NASA Tech Briefs Magazine.

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