Electronically gated multiemitter x-ray source for high-speed tomography

High speed X-ray tomography is being developed for on-line measurement of multiphase flow for well management in the oil industry. To reduce motion artifacts to acceptable levels a source is required that can scan about a 100 mm diameter pipe in approximately 20 ms, thus rendering a rotating source an impractical solution. In order to achieve a spatial resolution of 2 mm in the reconstructed image a total of 105 individual projections over a 210 degree arc are required. The large number of point sources means individual X-ray tubes are not practicable. Our solution is to use multiple electron beams where the active focal spot can be rapidly scanned across the target in an arc about the pipe with the use of electronic grids. This paper describes a prototype of such a tube designed, in the first instance, to cover a 30 degree arc and consisting of 13 individual emitters. Having proved the principle of operation a full system is now in the design stage and shall be briefly discussed.