Performance Characterization Of The Reflection Grating Arrays (Rga) For The Rgs Experiment Aboard Xmm.

The Reflection Grating Spectrometer (RGS) aboard XMM is a large collecting area(A(eff) > 160 cm(2) @15 Angstrom), dispersive soft X-Ray spectrometer providing high resolution (lambda/Delta lambda(HEW) > 300 @15 Angstrom) and a bandpass of 5-35 Angstrom (for first order). We have built and characterized the two, nearly identical, flight model reflection grating arrays (RGA) for the RGS instrument. Precision alignment and assembly of 182 grating elements into each array array was performed at Columbia Astrophysics/Nevis Laboratory, and end-to-end X-Ray calibration and testing were performed at the MPE-Panter facility. Preliminary results from the calibration are summarized, and reconciliation of those results with baseline optical design, simulations and error budgets are discussed.