The High Energy X-ray Probe

The HEX-P payload consists of a suite of three co-aligned X-ray telescopes designed to cover the 0.2 — 80 keV bandpass. The High Energy Telescope (HET) has an effective bandpass of 2-80 keV, and is composed of two High Energy Mirror Assemblies (HEMAs), which utilize thin electroformed Ni shells coated with Pt/C and W/Si multilayer coatings for high energy response. These focus onto two High Energy Detector Assemblies (HEDAs), which are photon counting CdZnTe hybrid detectors based on the NuSTAR design. The Low Energy Telescope (LET) has an effective bandpass of 0.2-20 keV and is composed of a Low Energy Mirror Assembly (LEMA) optimized for improved spatial resolution that capitalizes on Si segmented mirror technology developed at the NASA Goddard Space Flight Center. The LEMA focuses onto the Low Energy Detector Assembly (LEDA), which utilizes a Depleted P-Channel Field Effect Transistor (DEPFET).

The three Wolter type I (Wolter-I) telescope mirror assemblies are mounted to a Northrop Grumman three-axis stabilized spacecraft bus that serves as the base for a three-sided, coilable boom, extended after launch to place the detector bench at a focal length of 20 m. The coilable boom is enclosed in a thermal Kapton sock to suppress stray-light and bremsstrahlung activation of the boom components by solar X-ray flux. The boom deploys with an array of three aperture stops to mitigate stray-light from sources outside the field-of-view and the cosmic X-ray background. 

For more information about the HEX-P instrument and mission profile, see Madsen et al. (FrASS, submitted;arXiv:2312.04678).