Knowledge Bank

The possibility of constructing a high resolution monochromator for the vacuum ultraviolet is examined; the off-plane Eagle mounting is chosen as the most suitable one. Considering all optical restrictions arising from an off-plane setting, the resolving power of the grating in the off-plane Eagle mounting is calculated numerically for the following conditions; 3-meter concave grating $(5\times 3\prime$ ruled area) with 30,000 lines/inch or 15,000 lines/inch, 0 to 5800 \AA in the first order, and distance of the entrance slit from the Rowland plane 6 cm. In order to have compactness, a link mechanism introduced by Bair et al. is chosen in the scanning system and a tentative design of a 3-meter vacuum monochromator Will be shown schematically. Therefore, it is recommended to use the off-plane Eagle mounting in constructing a high resolution monochromator for the vacuum ultraviolet.