Application of resolution pattern based focal spot measurement technique during the development of a flash radiography system

Abstract

A flash X-ray radiography system is developed using a relativistic electron beam (REB) generator and a field emission cathode. X-ray source size in any radiography system is an important parameter to determine image quality. In the field emission targets the source size is controlled by the anode–cathode geometry which eventually influences the radiation output and peak X-ray energy. The geometry was optimized by progressive monitoring of the X-ray source (focal spot) size. A method based on resolution of different spatial frequencies was used for the measurement of focal spot dimensions. Optimum focal spot size of 2 mm and maximum radiation output of 2 R at 150 mm distance were achieved. Radiograph of a radioactive source pencil was taken to corroborate the observations and it detected the active source.