McPherson’s (Chelmsford, MA) Model 642-1 calibration light source for extreme ultraviolet (EUV) and soft x-ray (XUV) features a six-position anode carousel to exchange target materials. It permits selecting various emission wavelengths without breaking vacuum. Dual symmetrical output beams provide sample/reference comparison and device calibration in various test set-ups. The Model 642-1 is a Manson type electron impact light source, and uses a hot filament to produce electrons subsequently accelerated towards a solid anode target by high voltage. The EUV and XUV output emission spectrum follows the target anode material valence band structure. Users can readily exchange anodes in the carousel in order to produce desired wavelengths, for example Ti (0.27nm), Si (0.71nm), Mg (0.98nm) and more.