Experimental investigation on focal spot measurement by schlieren method

The experimental results of focal spot measured with schlieren method were reported in this paper. The far field focal spot was enlarged by an imaging lens and collected by a scientific-grade CCD camera with 12 bit. Schlieren data were taken by shading the central lobe of focal spot with a certain size spherule and controlling the receiving attenuation. When the schlieren data were added to the central lobe data, the relative intensity profile of focal spot was achieved. The schlieren method can provide larger effective dynamic measurement range and improve the measurement precision of focal spot.