X-ray diffraction apparatus
View Patent ↗An x-ray diffraction apparatus comprises an x-ray source for generating an x-ray beam, a monochromator for generating a monochromatic x-ray beam from the x-ray beam, and a collimator for collimating the monochromatic x-ray beam and directing it onto a sample, wherein the x-ray source and the monochromator are pre-assembled and fixed with respect to each other in an integrated unit such that in use the path length of the x-ray beam from the source to the monochromator is maintained substantially constant. X-ray flux at the sample is further enhanced by use of a partial monocapillary collimator arranged to direct part of the X-ray beam to the sample by a single grazing reflection.
1. An x-ray diffraction apparatus comprising:
an x-ray source for generating an x-ray beam;
a monochromator arranged to receive the x-ray beam and to generate a monochromatic x-ray beam from said x-ray beam, wherein the monochromator and the x-ray source are pre-assembled and mounted with respect to each other in an integrated unit such that in use the path length of the x-ray beam from the source to a point on the monochromator is maintained substantially constant; and,
a collimator arranged to receive the monochromatic x-ray beam, the collimator having a section towards the end proximate the sample position which includes a monocapillary, wherein an outer diverging region of the monochromatic x-ray beam entering the collimator is reflected only once from an internal surface of the monocapillary so as to be directed to a sample position, and wherein the monocapillary section of the collimator extends over less than half the total length of the collimator.
2. An apparatus according to claim 1 , adapted such that the angle of incidence of the x-ray beam on the monochromator may be varied.
3. An apparatus according to claim 2 , in which the collimator is mounted such that the angle of the longitudinal axis of the collimator is variable with respect to the monochromator.
4. An apparatus according to claim 3 , in which the angle can be varied in two orthogonal planes.
5. An apparatus according to claim 2 , in which the collimator is mounted such that the direction of its longitudinal axis passes substantially through the centre of the monochromator.
6. An apparatus according to claim 5 , in which the collimator is mounted in a socket in a collimator holder.
7. An apparatus according to claim 6 , in which the integrated unit also includes a shutter located between the x-ray source and the monochromator such that the x-ray source can be isolated, and in which the collimator holder is integrated with the unit comprising the source, the monochromator and the shutter.
8. An apparatus according to claim 1 ,in which the monochromator is rotatable on an axis passing through it.
9. An apparatus according to claim 1 , in which the integrated unit also includes a shutter located between the x-ray source and the monochromator such that the x-ray source can be isolated.
10. An apparatus according to claim 1 , in which the collimator is mounted such that the angle of the longitudinal axis of the collimator is variable with respect to the monochromator.
11. An apparatus according to claim 10 , in which the angle can be varied in two orthogonal planes.
12. An apparatus according to claim 1 , in which the collimator is mounted such that the direction of its longitudinal axis passes substantially through the centre of the monochromator.
13. An apparatus according to claim 12 , in which the collimator is mounted in a socket in a collimator holder.
14. An apparatus according to claim 13 , in which the integrated unit also includes a shutter located between the x-ray source and the monochromator such that the x-ray source can be isolated, and in which the collimator holder is integrated with the unit comprising the source, the monochromator and the shutter.
15. An x-ray diffraction apparatus according to claim 1 , wherein the monocapillary is cylindrical.
16. An x-ray diffraction apparatus comprising:
an x-ray source for generating an x-ray beam;
a monochromator arranged to receive the x-ray beam and to generate a monochromatic x-ray beam from said x-ray beam, wherein the monochromator and x-ray source are pre-assembled and mounted with respect to each other in an integrated unit such that in use the path length of the x-ray beam from the source to a point on the monochromator is maintained substantially constant; and
a collimator arranged to receive the monochromator x-ray beam, the collimator comprising a tube having a section towards the end proximate the sample position which includes a non-tapered monocapillary, wherein a first outer diverging region of the monochromatic x-ray beam entering the collimator is not reflected by the monocapillary and a second outer diverging region of the monochromatic x-ray beam entering the collimator is reflected only once from an internal surface of the monocapillary so as to be directed to a simple position, and wherein the monocapillary section of the collimator extends over less than half the total length of the collimator.