The Space Weather X-Ray spectrometer for the Helianthus sub-L1 mission with solar photonic propulsion

Helianthus is a phase A study of a space weather station with solar photonic propulsion. The scientific payload will be made of: an X-ray spectrometer to detect solar flares; SailCor, a coronagraph with a wide field of view; a plasma analyzer; a magnetometer. The maximum allowed mass for the entire scientific payload shall not exceed 5 kg. The two imaging devices (coronagraph and X-ray spectrometer) are of fundamental importance for the sake of remotely and timely mapping the status of the Sun and provide Earth stations with early warning of potentially disruptive events. An extensive research on available X-Ray detectors was performed and the Amptek FAST-SDD spectrometer was selected. It is a very light, compact and vacuum compatible instrument. In order to prove the device readiness for flight, a measurement campaign was organized to investigate its performance in terms of spectral range, spectral resolution, dynamic range and response speed. The campaign was run at the INAF XACT facility in Palermo (Italy). This paper describes the facility, the measurement campaign and the results.