Investigation of defective structure of tungsten powders by electron-positron annihilation method

Defective state of high-dispersed and standard tungsten powders is comparatively studied by the method of angular distribution of annihilating photons. Spectra have been measured at a plant with a geometrical angular 1.0 mrad resolution. Their parameters were computerized using the DOLLY program. Narrowing of the angular distribution curve and increasing of the counting rate at a maximum in going from standard powders to high-dispersed ones is shown to be due to excess vacancy concentration in the latter