First results from the ground calibration of the NuSTAR flight optics

Abstract

NuSTAR is a hard X-ray satellite experiment to be launched in 2012. Two optics with 10.15 m focal length focus Xrays with energies between 5 and 80 keV onto CdZnTe detectors located at the end of a deployable mast. The FM1 and FM2 flight optics were built at the same time based on the same design and with very similar components, and thus the performance of both is expected to be very similar. We provide an overview of calibration data that is being used to build an optics response model for each optic and describe initial results for energies above 10 keV from the ground calibration of the flight optics. From a preliminary analysis of the data, our current best determination of the overall HPD of both the FM1 and FM2 flight optics is 52'', and nearly independent of energy. The statistical error is negligible, and a preliminary estimate of the systematic error is of order 4''. The as-measured effective area and HPD meet the toplevel NuSTAR mission sensitivity requirements. ? 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).