X-ray diffractometer

Abstract

An X-ray diffractometer has an X-ray source ( 10 ), a double pinhole collimator ( 14 ), a sample ( 22 ) mounted on a rotatable sample stage ( 20 ), an analyser crystal ( 30 ) and a detector ( 34 ). The analyser crystal and detector are arranged to rotate together about an axis ( 21 ) that is coaxial with the axis of rotation of the sample stage. Very few scattered X-rays ( 26 ) reach the detector ( 34 ). The diffractometer has particular use for routine quality control measurements.

1 . An X-ray diffractometer, comprising 
 a sample stage for mounting a sample, the sample stage being rotatable about an axis,    a double pinhole collimator for directing X-ray radiation to a sample on the sample stage,    a detector for detecting X-rays diffracted by the sample, and    an analyser crystal arranged between the sample stage and the detector to direct X-rays diffracted by the sample onto the detector,    wherein the analyser crystal and detector are rotatable about an axis that is coaxial with the axis of rotation of the sample stage.    
     
     
         2 . An X-ray diffractometer according to  claim 1  wherein the size of the pinhole of the double pinhole collimator nearest the sample stage is adjustable for providing an X-ray spot on the sample of variable size.  
     
     
         3 . An X-ray diffractometer according to  claim 1  wherein a slit is arranged between the sample stage and the detector.  
     
     
         4 . An X-ray diffractometer according to  claim 3  wherein the slit is arranged in front of the detector.  
     
     
         5 . An X-ray diffractometer according to  claim 1  and further comprising a drive for rotating the sample stage and the detector and analyser crystal with a ratio of rotation angles of substantially 1:2.