By Staff Writer - July 22, 2022

Bringing local IR technology to the universe!

There are four science instruments on board the Webb Space Telescope.  Amazingly, all of the infrared detectors inside all four instruments were made within a 50 mile radius of the UCSB campus!  

The HgCdTe (Mercury-Cadmium-Telluride) detectors and focal planes were manufactured by Teledyne Imaging Sensors (TIS) in Camarillo while the Si:As (Arsenic-doped Silicon) detectors and focal planes were manufactured by Raytheon Vision Systems (RVS) in Goleta.  All the pictures you see from the Webb Space Telescope were made possible by these exquisitely-sensitive detectors converting faint infrared light into electrical signals.
Three instruments on Webb use HgCdTe detectors from TIS and have the detectors configured as 2x2 mosaics of sensor chips.  Each sensor chip has 2048 x 2048 pixels each, for a total of 4096 x 4096 pixels in each focal plane.  For NIRCam (Near-Infrared Camera), the two focal planes have, respectively, 0.6-2.3 um and 2.4-5.0 um channels.  For NIRSpec (Near-Infrared Spectrograph), the infrared bandpass is 0.6-5.3 um.  For NIRISS (Near-Infrared Imager and Slitless Spectrograph), the bandpass is 0.6-5.0 um.  (The infrared response bandwidth of HgCdTe is varied by changing the ratio of Hg and Cd when the detector material is grown.  Furthermore, the response of the detectors can be extended into visible wavelengths (0.4 to 0.8 um) by removing the substrate on which the HgCdTe is grown.)
The fourth Webb science instrument, MIRI (Mid-Infrared Instrument), is unique in that it senses infrared radiation at much longer wavelengths than any of the other three Webb instruments: 4.9 to 28.8 um.  That astronomy can be done at these longer wavelengths is possible only because of the cold temperatures on Webb (around -390 degrees Fahrenheit for the optics and -450 degrees F for the detectors) plus the innovative, massive sunshade and the remote orbit of Webb.  The RVS Si:As a focal plane has one million of these long-wavelength pixels in a 1024 x 1024 configuration.

Learn more about Modern Infrared Detectors & Systems Applications
There are four science instruments on board the Webb Space Telescope. Photo credit:

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