Manufacture of DT-filled, hollow glass microsphere, laser targets

Abstract

The fabrication of highly characterized DT-filled, hollow glass microsphere targets is described. The DT is loaded by gas permeation through the glass walls at 420 °C. The DT fill is nondestructively measured by counting the emitted x rays with a proportional counter. The counter system is empirically calibrated by individually crushing microspheres in an ionization chamber. Outer diameters are measured optically with a split-image eyepiece. Wall thicknesses and sphericities are measured by light interference. For a 40-μ diam microsphere and 1-μ walls, we estimate our best absolute accuracies of measurement to be, o.d., ±1.6%; wall thickness at any point, ±10%; overall microsphere sphericity, ±7%.