John J Hicks

US Patent:

51577020, Oct 20, 1992

Filed:

Dec 14, 1990

Appl. No.:

7/627844

Inventors:

Frederic H. Middleton - Madison WI
John W. Hicks - Madison WI

Assignee:

Wisconsin Alumni Research Foundation - Madison WI

International Classification:

G21K 106

US Classification:

378 85

Abstract:

A double-crystal X-ray monochromator includes entrance and exit crystal assemblies mounted on a support structure to provide full parallelism of the crystals while one crystal is rotated and the other rotated and translated with respect to the first, allowing selection of the wavelength of X-rays to be passed through the monochromator. The monochromator is mounted in an ultra-high vacuum chamber by supports which pass through the vacuum chamber to support the monochromator independently of the vacuum chamber. Bearings supporting the monochromator provide very low friction to linear movement and rotation to allow high precision to be obtained. To compensate for the heating of the entrance crystal due to impingement of high energy X-rays on the crystal, the entrance crystal is cooled using a radiation heat transfer system which provides no physical contact between the radiator connected to the entrance crystal assembly and the heat transfer structure on the vacuum chamber. The exit crystal may be heated so that its temperature can be matched to that of the entrance crystal to allow the precision alignment of the crystals to be maintained.