Development of a Silicon Drift Detector Array: An X-Ray Fluorescence Spectrometer for Remote Surface Mapping

Over the past three years NASA Marshall Space Flight Center has been collaborating with Brookhaven National Laboratory to develop a modular Silicon Drift Detector (SDD) X-Ray Spectrometer (XRS) intended for fine surface mapping of the light elements of the moon. The value of fluorescence spectrometry for surface element mapping is underlined by the fact that the technique has recently been employed by three lunar orbiter missions; Kaguya, Chandrayaan-1, and Chang e. The SDD-XRS instrument we have been developing can operate at a low energy threshold (i.e. is capable of detecting Carbon), comparable energy resolution to Kaguya (<150 eV at 5.9 keV) and an order of magnitude lower power requirement, making much higher sensitivities possible. Furthermore, the intrinsic radiation resistance of the SDD makes it useful even in radiation-harsh environments such as that of Jupiter and its surrounding moons.