Hard X-ray Imager

Astro-H's hard x-ray imager
Photo of a prototype for the Hard X-ray Imager

Astro-H will carry two Hard X-ray Imagers (HXIs). The HXIs are solid state detectors, which means that they use the X-ray’s interactions with a semi-conductor to detect and characterize incoming X-ray photons.

The HXIs will use layers of two different semi-conductor detectors to cover a broad range of X-rays. As X-rays enter the detector, they will first encounter four layers of “double-sided silicon strip detectors,” or DSSD for short. Lower energy X-rays will be absorbed (and detected) in those DSSD layers, while higher energy X-rays will pass through to be detected in a layer of Cadmium-Telluride detectors, called CdTe for short. These two different semi-conductor detectors will allow the HXIs to detect X-rays in range of 5 to 80 keV.