Speaker
Description
Over the last few decades, X-ray imaging has improved significantly as a high-resolution, non-destructive, and non-invasive tool for radiography and tomography, solving a major challenge of detecting internal structures of samples in different applications. Furthermore, since the enhancement of synchrotron sources, extremely coherent radiation has been used for non-traditional contrast techniques [1]. The conventional absorption contrast method is particularly beneficial for characterising medium-density samples or distinguishing materials with different attenuation powers, but not for low-Z materials, which exhibit poor contrast under X-ray irradiation. Phase contrast X-ray imaging (PC) is instead an effective technique for detecting low contrast details in weakly absorbing samples. This method is based on the observation of the interference pattern between diffracted and non-diffracted waves, caused by spatial variations in the real component of the refractive index introduced by a sample placed in the wave path [2]. PC X-ray imaging has great potential in medical, material science, and cultural heritage (CH) applications since it can deliver high-quality information on microstructural characteristics. A coherent X-ray beam is an appropriate instrument for developing phase-sensitive X-ray imaging; as a result, this technology has already been deployed at synchrotron facilities [3]. Among the PC methodologies, X-ray Grating Interferometry (GI), which provides differential phase and scattering (dark-field) images in addition to the standard absorption-based image, enables the realisation of systems that can be implemented in a laboratory setting. This framework opens interesting opportunities in the CH field, including conservation, archaeology, and anthropology.
The PITCH project (funded in the framework of PRIN2022) aims at designing, developing and characterising a laboratory GI-PC imaging setup based on a liquid-anode X-ray source, as well as at investigating and developing different data acquisition methods and algorithms for signal extraction and tomographic reconstruction. The system will be optimised for the analysis of various CH materials to characterise and better understand specific related issues.
References
[1] R. Fitzgerald, “Phase‐Sensitive X‐Ray Imaging,” Phys Today, vol. 53, no. 7, pp. 23–26, 2000
[2] M. Endrizzi, “X-ray phase-contrast imaging” Elsevier B.V., 2018
[3] R. Fitzgerald et al., “Phase objects in synchrotron radiation hard X-ray imaging,” Cambridge Univ Press, 2009