Imaging Proportional X-Ray Counter for HEAO

The HEAO-B Imaging Proportional Counter (IPC)1 is an X-ray imaging instrument designed for use in the High Energy Astronomy Observatory - Mission B (HEAO-B)c X-Ray Telescope. It measures the spatial location of individual X-ray photons by the risetime method and energy of photons by pulse height analysis. The IPC can locate photons in the energy range 0.2 to 4 keV to within 1 mm and provides 5 bits of energy level information. Each measured X-ray event is also time tagged with 7 bits of temporal data. The IPC also includes an in-flight-calibration source and uses a gas control system that maintains the counter gas density constant to an accuracy of 0.25 percent.