The Solar X-Ray Imager (SXI) is essentially a small telescope that is used to monitor solar conditions and activity. Every minute the SXI captures an image of the sun's atmosphere in X-rays, providing space weather forecasters with the necessary information in order to determine when to issue forecasts and alerts of conditions that may harm space and ground systems.
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SXI Parameter |
Performance |
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Imaging exposure times |
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Solar flare sites |
<10 ms |
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Active regions |
<100 ms |
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Coronal loops |
<1 s |
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Coronal hole boundaries |
<10 s |
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Spacecraft SXI boresight pointing (to the center of the solar disk) |
Within 3 arc-min elevation,
within 3.5 arc-min azimuth |
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Field of view |
42 by 42 arc-min, minimum |
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Pixel size |
5 by 5 arc-sec, squared pixels, maximum |
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Spectral sensitivity
(integration time £100 ms) |
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Spectral Band |
6 to 20 Å |
6 to 60 Å |
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Source |
Al (8.3 Å) |
C (44.7 Å) |
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Minimum detectable photon radiance incident on the telescope entrance
(photon cm-2 arcsec-2 sec-1) |
7 |
132 |
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Dynamic range |
1000 when measured with monochromatic illumination
at 44.7 Å |
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Telemetry amplitude digitization |
10 bits (linear or logarithmic channels) |
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Point response (image on pixel array) Percentage of total
energy incident on detector
falling inside |
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1 by 1 pixel |
25% |
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2 by 2 pixel |
40% |
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HASS resolution |
±5 arc-sec or better |
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SXI on-orbit useful life |
3 years with a goal of 5
years (after 5 years
ground storage) |
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