Cesium Iodide Thallium-doped Incident Energy Spectrometer (CITIES): A Hard X-Ray Detector for CubeSats

Cesium Iodide Thallium-doped Incident Energy Spectrometer (CITIES): A Hard X-Ray Detector for CubeSats

This paper describes the design and operation of the detector known as the Cesium Iodide Thallium-doped Incident Energy Spectrometer (CITIES). The CITIES design implements CsI(Tl) scintillation crystals to detect hard x-rays (HXRs) and gamma rays from the Sun and other astrophysical sources in the range of 10 keV - 400 keV. Laboratory tests to characterize the operation of CITIES are discussed. CITIES is used on two CubeSat missions through the University of Minnesota; Experiment for X-Ray Characterization and Timing (EXACT) and Signal of Opportunity CubeSat Ranging and Timing Experiment System (SOCRATES). EXACT’s objective is to better understand HXR emissions from solar flare activity which have effects on the near-Earth environment. The mechanisms of flare-accelerated electrons are not well understood, but can be explored through the study of the HXR’s they emit, providing a better understanding of the causes of space weather. The mission of SOCRATES is to serve as proof-of-concept for the positioning, navigation and timing (PNT) functionality of CITIES by using astrophysical sources such as pulsars and x-ray binaries for GPS-denied and deep space operations.