Radiation background and dose estimates for future X-ray observations in the Jovian magnetosphere

摘要

The Jovian magnetosphere is the most luminous system at soft X-ray wave lengths in our solar system, and hence X-ray observations can provide significant information on the Jovian magnetospheric dynamics. During X-ray observations in the Jovian magnetosphere, however, penetrating particles can hit the detector, resulting in the background noise and radiation damage. Here we consider an X-ray telescope instrument (0.3-2 keV) on board a future Jovian magnetospheric spacecraft and estimate the count rates and dose rates by the high-energy particles for the design of the instrument. Based on Monte-Carlo simulations with Geant4 codes, we confirmed that good signal-to-noise ratio (0.5-500) and negligible dose rate ( < 0.1 krad/year) can be accomplished during observations in the lobe (i.e., the region where magnetic field lines are open), which would be achieved by the high-inclination orbit of the spacecraft.