The Solar Maximum Mission was a NASA satellite originally launched on February 14, 1980. It carried the Hard X-ray Imaging Spectrometer (HXIS, van Beek 1980), the first attempt at imaging the sun in hard X-rays. The HXIS used a brute-force method of imaging: an array of collimators each with a narrow field of view, so that each collimator channel functioned as one pixel of an imaging telescope. It achieved a spatial resolution of 8 arcsec over a 2'40'' square field of view and a 32 arcsec resolution over a 6'24'' diameter circle. The detector used was a position-sensitive proportional counter, consisting of two Xe-filled chambers deep, each equipped with 450 anodes. Additional information available at "http://solarwww.mtk.nao.ac.jp/kobayash/thesis/node8.html" [Summary provided by the National Astronomical Observatory of Japan]
HXIS
X-Ray/Gamma Ray Detectors