High-precision laser differential confocal measurement method for multi-geometric parameters of inner and outer spherical surfaces of laser fusion capsules

Abstract

We propose a well-integrated, high-efficiency, high-precision, and non-destructive differential confocal measurement method for the multi-geometric parameters of the inner and outer spherical surfaces of laser fusion capsules. Based on the laser differential confocal measurement system with high tomography fixed-focus ability and high spatial resolution, the proposed method is used to perform the fixed-focus trigger measurement of the outer vertex, the inner vertex, and the spherical center of the capsule. From the rotation measurement around the Y-axis and the transposition measurement around the Z-axis, the inner and outer diameters, the three-dimensional inner and outer profiles, the shell thickness uniformity, and the shell non-concentricity of the capsule are measured with high precision and no damage. To the best of our knowledge, this is the first method to achieve the high-precision measurement for the multi-geometric parameters of the capsule inner and outer spherical surfaces with the same instrument.

On-Machine Measurement of Profile and Concentricity for Ultra-Precision Grinding of Hemispherical Shells

“…Hemispherical shell parts are widely used in hemispherical resonant gyroscopes [ 1 , 2 ] and the target capsules of inertial confinement fusion facilities [ 3 , 4 ]. Hemispherical shell resonators (HSRs) of Ψ-shaped fused silica are the core of the hemispherical resonant gyroscopes shown in Figure 1 .…”

“…However, due to the weak penetration of the electron beam, at best, shells within micrometer thickness can be measured with this method. Ma used the differential confocal method based on ray tracing to simultaneously measure the outer surface profile and concentricity using the same instrument in the same coordinate system [ 4 ]. However, this measurement method requires the coordination of a laser interferometric measurement system and a differential confocal system.…”