High
Resolution Imager (HRI)
Focusing
X-Rays with Cylinders and Straws
X-rays either pass through or are absorbed by most substances,
and they can't be focused with lenses or ordinary mirrors.
But they will glance off a solid surface if they strike
at a very shallow angle.
The orbiting x-ray telescope ROSAT used sets of wide metallic
cylinders to "scoop up" incoming x-rays and focus
them onto a detector called a High-Resolution Imager, or
HRI. The x-rays ricocheted down the cylinders and into a
bundle of microscopic metallic straws in the HRI. The x-rays
knocked electrons off the sides of the straws, which channeled
the electrons onto a fine wire mesh screen. The resulting
electrical impulses were used to create an image showing
the intensity and distribution of the x-ray energy.
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High
Resolution Imagers
The high-resolution imager (pictured, top right) and microchannel
plate (top left) are identical to the one on the Chandra
x-ray satellite. At
bottom is a handmade prototype for a high-resolution x-ray
imager.
Courtesy of Steve Murray, Smithsonian Astrophysical Observatory
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Other Featured
Artifacts in this section of the exhibit:
Hubble Space Telescope Wide-Field/Planetary
Camera & CCD
Hubble Space Telescope Backup Mirror
Penzias and Wilson Pigeon Trap
Return
to: Exploring The Universe in the Digital
Age
Next: Exploring Today
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