TH‐CD‐207B‐01: BEST IN PHYSICS (IMAGING): Development of High Brightness Multiple‐Pixel X‐Ray Source Using Oxide Coated Cathodes

Abstract

Purpose: To develop and characterize a high brightness multiple‐pixel thermionic emission x‐ray (MPTEX) source. Methods: Multiple‐pixel x‐ray sources allow for designs of novel x‐ray imaging techniques, such as fixed gantry CT, digital tomosynthesis, tetrahedron beam computed tomography, etc. We are developing a high‐brightness multiple‐pixel thermionic emission x‐ray (MPTEX) source based on oxide coated cathodes. Oxide cathode is chosen as the electron source due to its high emission current density and low operating temperature. A MPTEX prototype has been developed which may contain up to 41 micro‐rectangular oxide cathodes in 4 mm pixel spacing. Electronics hardware was developed for source control and switching. The cathode emission current was evaluated and x‐ray measurements were performed to estimate the focal spot size. Results: The oxide cathodes were able to produce ∼110 mA cathode current in pulse mode which corresponds to an emission current density of 0.55 A/cm 2 . The maximum kVp of the MPTEX prototype currently is limited to 100 kV due to the rating of high voltage feedthrough. Preliminary x‐ray measurements estimated the focal spot size as 1.5 × 1.3 mm 2 . Conclusion: A MPTEX source was developed with thermionic oxide coated cathodes and preliminary source characterization was successfully performed. The MPTEX source is able to produce an array of high brightness x‐ray beams with a fast switching speed.

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