Polychromatic neutron phase-contrast imaging of weakly absorbing samples enabled by phase retrieval

Abstract

The use of a phase-retrieval technique for propagation-based phase-contrast neutron imaging with a polychromatic beam is demonstrated. This enables imaging of samples with low absorption contrast and/or improving the signal-to-noise ratio to facilitate e.g. time-resolved measurements. A metal sample, designed to be close to a phase pure object, and a bone sample with canals partially filled with D2O were used for demonstrating the technique. These samples were imaged with a polychromatic neutron beam followed by phase retrieval. For both samples the signal-to-noise ratios were significantly improved and, in the case of the bone sample, the phase retrieval allowed for separation of bone and D2O, which is important for example for in situ flow experiments. The use of deuteration contrast avoids the use of chemical contrast enhancement and makes neutron imaging an interesting complementary method to X-ray imaging of bone.

Revisiting Neutron Propagation-Based Phase-Contrast Imaging and Tomography: Use of Phase Retrieval to Amplify the Effective Degree of Brilliance

“…This polyenergetic form may be advantageous, since there will be a significant boost in utilizable neutron flux on account of there being no need to energy-filter broadband polyenergetic neutron phase-contrast images. However, we must emphasize that the actual experimental evidence in the main text of our paper relates to the monochromatic case, with the experimental testing of the above polychromatic generalization to the theory being left to a subsequent paper [113].…”