Structural alongside functional smart materials play an important role in modern industry and technology. The behaviour of such materials is often governed by their structural properties. Knowledge on their specific grain formation and orientation is crucial for their development and use in prospective applications. Neutron diffraction plays a central role in the structural characterisation of such materials, in particular when assessing the representative volumes in bulk specimen the superior penetration of neutrons, as compared to other transmitting radiation, is required for many materials.
However, neutron techniques meet limitations, when high spatial resolution is required, e.g. to characterise protein crystals which typically can be grown only in tiny amounts. While the latest generation of neutron sources is meant to reach the flux to achieve the required performance, there is an immediate need of technological progress of neutron detectors providing flexible angular coverage and geometries, high spatial and temporal resolution. Only time resolutions better than μs allows taking advantage of state-of-the-art pulsed spallation neutron sources and a high space resolution (~100 μm) assessing the relevant structural in potentially down-sized experimental configurations.
We aim to develop an innovative detector for diffractive neutron imaging based on micro-Resistive WELL (μ-RWELL) technology: a compact, spark-protected, single-amplification stage Micro-Pattern Gas Detector. The proposed technology, developed in the framework of HEP experiments, can be exploited for high resolution thermal neutron imaging using a 10B coated cathode as neutron converter. The envisioned detector specifications for diffraction imaging will also satisfy the needs for other cutting edge high resolution time-off-flight diffraction applications.
Key-points are the scalability and production of large-area detectors as well as the mechanical flexibility that allows to adapt the design to different geometries and applications: cylindrical μ-RWELL detectors are under study for HEP but could also be exploited for large acceptance neutron diffraction for crystallography studies constituting a breakthrough for neutron instrumentation. The μ-RWELL, based on standard rigid and flexible photolithography processes, leads to a straightforward technological transfer to industry, which is one of the main goals of this project.
The project aims to prove these characteristics by developing and testing small planar prototypes with readout boards suitably segmented with strip/mini-pad readout, equipped with existing electronics. A full characterisation of the prototype will be done by means of a neutron beam test. This proof of concept can lead to the development of detectors for direct neutron imaging for which a multipixel anode coupled with suitable front-end electronics will allow fine reconstruction at high rate. Such a device will constitute a breakthrough in neutron beam diagnostic.