Externe Kristalljustierung für die Lang-Topographie

In dependence on crystal altitude, Bragg angle and distance focus-crystal the necessary accuracy of crystal adjustment is calculated on condition that with illumination of the full crystal height the Kα-doublet is separable. In this connection a critical crystal altitude for the Lang-topography is stated, which requires a faultless adjustment of the net plane. For the real altitude of crystal resp. film adequate demands for adjustment are derived. A simple diffractometer device for external crystal adjustment if described and the attainable accuracy is indicated.