X-Ray Measurement of Angle Between Crystal Axis and Surface of Larger Size GaF2[111]

This paper proposes a novel XRD analysis method for precisely orienting the [111] axis of large-size calcium fluoride (CaF2) single crystal lenses. By leveraging the geometric characteristics of the [111] axis, we first define the X, Y, Z axes and the tilting angles (ф, ω, θ). The outgoing X-ray is leveled in the XOZ diffraction plane to maximize photon intensity at 0°. Subsequently, ω/2θ and Ф scans are performed to align the [111] axis within the diffraction plane. To address the limitations of direct XRD on the [111] axis, higher-order crystal planes are scanned, ensuring compliance with diffrac-tion geometry requirements. The feasibility of the method is validated through XRD pattern analysis, achieving precise orientation of the [111] axis with an accuracy of 0.1°. This approach offers a cost-effective and efficient solution for the orientation of large-size single crystal lenses, with po-tential applications in deep ultraviolet excimer laser lithography.