![]() This figure shows the black optical baffle that admits light onto the four detectors while blocking it from hitting any surfaces that might reflect, such as the edges of a detector. Each of the four detectors looks like the one shown in Figure 1. The mid-infrared detectors have about 1 million pixels each.įigure 3: This figure shows four 0.6 - 2.5 μm James Webb Space Telescope NIRCam H2RGs mounted into a focal plan module. Each Webb H2RG detector has about 4 million pixels. The mid-infrared detectors were made by Raytheon Vision Systems, which is also in California. "H2RG" is the name of the Teledyne product line. ![]() ![]() The near-infrared detectors were made by Teledyne Imaging Sensors in California. Webb uses two different types of detectors: mercury-cadmium-telluride (abbreviated HgCdTe) "H2RG" detectors for the 0.6-5 μm "near-infrared" and arsenic doped silicon (abbreviated Si:As) detectors for the 5-28 μm "mid-infrared". Webb has extended the state of the art for infrared detectors by producing arrays that are lower noise, larger format, and longer lasting than their predecessors.ĭifferent Detectors for Near and Mid-Infrared It needs large-area arrays of detectors (Figure. Webb needs extraordinarily sensitive detectors to record the feeble light from far-away galaxies, stars, and planets. The detectors are where photons are absorbed and ultimately converted into the electronic voltages that we measure. ![]() The instruments filter the light, or spectroscopically disperse it, before finally focusing it onto the detectors (Figures 1-2). Webb's mirrors collect light from the sky and direct it to the science instruments. It has a 1024x1024 pixel array of arsenic doped silicon pixels. Figure 2: This MIRI detector (green) is housed in a brick-like unit called a focal plane module. ![]()
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