Propagation-based neutron phase-contrast tomography was demonstrated on aninsect sample, using the ISIS pulsed spallation source. The tomogram withPaganin-type phase-retrieval filter applied exhibited an effective net boost of 23 ± 1 in the signal-to-noise ratio as compared to an attenuation-basedtomogram, implying an effective boost in neutron brilliance of over two ordersof magnitude. The phase-retrieval filter applies to monochromatic as well aspoly-energetic neutron beams. Expressions are provided for the optimalphase-contrast geometry as well as conditions for the validity of the method.The underpinning theory is derived under the assumption of the sample beingcomposed of a single material, but this can be generalized. The effective boostin brilliance may be employed to give reduced acquisition time, or may insteadbe used to keep exposure times fixed while improving contrast and spatialresolution.
|Publication status||Submitted - 2021|