Image Number 3 for United States Patent #5878106.
In an x-ray diffractometer having (i) first and second motors 10, 17 for respectively rotating a sample 4 and an x-ray detector 13 around a rotational axis 7 and (ii) .theta.-2.theta. interlock control means 22 for supplying drive signals to the motors 10, 17, such that a .theta.-2.theta. relationship is always maintained between the angles of the sample 4 and the x-ray detector 13 with respect to irradiated x-rays 2, there is disposed a rotational vibration control unit 23 for supplying, to the first motor for rotating the sample holding member 6, a drive signal for rotationally vibrating the sample, in addition to the drive signal for .theta.-2.theta. interlock. Eliminating an individual drive mechanism for rotationally vibrating the sample 4, this arrangement makes it possible that, with a simple and economical structure, diffracted x-rays are efficiently detected even for a sample having an uneven surface, thereby to obtain an accurate measurement result.