X-Ray Microtomography Using Compensation Filters with Complicated Form

Resumo

The influence of an aluminum compensation filter of complicated form on the signal-tonoise ratio in microtomography of geological cores was investigated. When scanning the core, a compensation filter in the form of an aluminum parallelepiped with a hole approximately equal to the diameter of the core was used. The filter is fixed rigid over the object table, the core is placed in the hole and rotates inside the filter. It is shown that the filter provides the maximal contrast of the useful signal over the entire dynamic range of the scintillation panel detector. After normalizing the projection of the core onto the filter projection without the core, the obtained projections were used in the standard reconstruction algorithm for cone beam tomography. The use of a compensation filter made it possible to increase the signal-to-noise ratio of the resulting tomograms by more than two times, as compared with the case of a conventional flat filter made of aluminum.