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

TL;DR

This paper presents a phase retrieval method for polychromatic neutron imaging that enhances contrast and signal-to-noise ratio, enabling detailed imaging of weakly absorbing samples like bone and D2O-filled canals.

Contribution

The authors develop and demonstrate a phase retrieval technique for propagation-based neutron imaging with polychromatic beams, improving contrast and enabling separation of different materials.

Findings

Significant improvement in signal-to-noise ratio for neutron images.

Successful separation of bone and D2O in imaging.

Enhanced capability for in situ flow experiments.

Abstract

We demonstrate the use of a phase retrieval technique for propagation-based phase contrast neutron imaging with a polychromatic beam. This enables imaging 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 pure phase 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 ratio were significantly improved and in 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.