A twohyphen;crystal double axis xhyphen;ray spectrometer, capable of goniometric accuracy on the order of 0.1Prime;, has been developed. Some of its unique design features are presented. These include (1) a modified commercial thrust bearing which furnishes a precise, full circle Vthgr;:2Vthgr; coupling, (2) a new tangent drive system design in which a considerable reduction of the lead screw effective pitch is achieved, and (3) an automatic step scanning control which eliminates most of the mechanical deficiencies of the tangent drive by directly reading the tangent arm displacement.
展开▼
