Hard X-ray Imaging Spectrometer: fov 6.4 arcmin, 8 or 32 arcsec res,3.5-30 keV

Description

The objective of the Hard X-ray Imaging Spectrometer (HXRIS) experiment was to measure the position, structure, and thermodynamic properties of hot thermal and nonthermal sources in active regions and in flares. This instrument produced two-dimensional images with 8-arc-s resolution over an approximately square area of side 2 min 40 s, or 32-arc-s resolution over a square of side 6 min 24 s. These images were observed in six selectable energy channels, between 3.5 and 30 keV, with a temporal resolution of 0.5 to 7 s, depending on the mode of operation. By means of a flare flag, the experiment alerted other SMM instruments when a flare began and indicated the position of the brightest pixel of the observation. The instrument consisted of 10 etched grid plates, each divided into 576 sections that formed the collimator, and 900 miniproportional counters that provided a position-sensitive detector system capable of spectral analysis. A dual microcomputer system permitted three modes of operation with commandable parameters that provided for a flexible tradeoff between temporal resolution and spatial coverage during different phases of a solar flare. For more details on this experiment, see H. R. Van Beek et al., Solar Phy., v. 65, p. 39, 1980.