|
Figure 11
The resolving power (top panel) and the transmission (bottom panel) using the two gratings (280 lines mm−1 and 950 lines mm−1) in first and second orders of diffraction as a function of photon energy. Solid lines correspond to fully open apertures while dashed lines show the results for `optimal illumination', where further reduction of the illumination does not improve energy reslution. This occurs in all configurations for an illumination of around 70–90 mm on the 150 mm long gratings. |