by Staff Writers
Chelmsford, UK (SPX) May 12, 2009
On May 11, 2009 e2v Charge Coupled Device (CCD) imaging sensors were launched into space by NASA, on board the space shuttle Atlantis, as part of a mission to upgrade and repair the Hubble Space Telescope.
e2v CCD imaging sensors will equip Wide Field Camera 3 (WFC3), a new instrument that will be installed on Hubble to take large-scale, extremely clear and detailed pictures of the universe over a very wide range of colours. e2v's CCDs will make the Hubble telescope more powerful than it's ever been.
The Hubble Space Telescope first went into orbit in April 1990, and uses it position above the Earth's atmosphere (which distorts and blocks light reaching our planet), to give a view of the universe that can surpass that of ground-based telescopes. Hubble has beamed thousands of images back to Earth and uncovered many mysteries of the universe.
NASA is now undertaking a final mission to repair and upgrade the telescope. The mission, designated STS-125, will equip the telescope to explore our universe in greater detail than ever before, by replacing equipment and installing new instruments with e2v's CCDs.
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 10 times 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 technology involved in developing the CCD gives the imaging sensor a superior performance specification:
+ Large area, with around 4k(H) by 2k(V) 15 micron pixels
+ Full frame imaging CCD designed to operate in Inverted Mode for low dark signal.
+ Features enhanced Ultra-Violet quantum efficiency and back-illumination to give a very broad waveband response. The typical quantum efficiency is 50% at 250nm and 65% at 500nm.
+ Designed and packaged for assembly in close-butted pairs, typically 250 m (with a specification at 340 m) per chip, i.e.~500 m if butted, thus creating a ~4k square image area.
+ The two high responsivity and very low noise output amplifiers, typically ~2.5 e-rms at 50kHz, 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.
Brian McAllister, General Manager of Space and Scientific Imaging at e2v, said "This is a prime example of how our e2v sensors are being used to accelerate discovery, by upgrading the performance of the Hubble Space Telescope's vision to reach previously unexplored territory."
Dr Randy Kimble, WFC3 Instrument Scientist at NASA's Goddard Space Flight Center said "We have been very pleased to work with the exceptionally talented folks at e2v to bring this technology to the Hubble Space Telescope. It will enable significant advances in large-format ultraviolet and visible observations to provide new discoveries about the nature of our universe."
Space Telescope News and Technology at Skynightly.com
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