A New Grazing Incidence Spectrometric Mounting

A new spectrometric mount particularly applicable to the region 20–500 A has been developed. Working at grazing incidence, the actual angle may be varied from around 80 to 88° to permit optimizing the compromise between the lowest wavelength detectable (which decreases with increasing angle of incidence) and optical abberations (which increase with increasing angle). Whatever angle is set, readout is linear in angstroms and readings appear directly on a mechanical counter. The mount is convertible for spectrographic use and, with some modifications, may be used as a monochromator in which both entrance and exit slits are accessible from outside of the vacuum.