Induced X-ray fluorescence background for high-voltage space based detectors

A sounding rocket utilizing Gaseous Electron Multiplier detectors experienced a strong source of unexpected signal during flight which prevented the acquisition of usable science data. We find that the flight data is well-matched with a simple fluorescence model corresponding to K- and L-emission lines of the materials present inside the payload. Illuminating the payload with a laboratory electron source produces a similar spectrum. The signal appears to be caused by the presence of ionospheric electrons inside the payload being accelerated by our high-voltage X-ray detectors to energies that can cause fluorescence of the payload interior. Future space based missions utilizing high-voltage detectors should consider the dangers of high-altitude electrons as a potential source of background signal. Missions utilizing Gaseous Electron Multiplier detectors may be at particular risk.