Beschreibung
Printed Neutron Converter Foils
Can conventionally printed neutron converters substitute costly coating processes?
The cost increase of helium-3 has sparked the development of alternative detection technologies, specifically the use of boron carbide (B4C) converters is one of the pillars of next-generation neutron detectors.
While producing high-quality films, sputter-deposition is limited in the deposition area, and requires costly and energy-intensive vacuum processing. Lithium fluoride (LiF) can reach a similar performance to 1.5 μm B4C at around 20 μm layer thickness. While its lower melting point and lower costs are advantageous, there are currently no ideal film deposition techniques for this material. Therefore, the investigation of new approaches for the fabrication of neutron converter foils are necessary to improve fabrication costs, deposition over large areas and explore a larger palette of materials.
The field of Functional Printing offers several advantages to face these challenges. It provides the cost-efficient, high throughput and large area fabrication inherent to printing techniques and enables the resource efficient deposition of functional materials. Furthermore, all processes are compatible with mechanically flexible substrates, which allows the converters to be inserted into different types of detectors.
In our recent project, we investigate the deposition of B4C and LiF materials via screen printing and bar coating to fabricate high performance neutron sensing flexible films. The aim is to investigate the correlation between printing process, film properties and neutron detection efficiency and to establish the material-process-functionality relations necessary to optimize the detector performance, specifically in terms of outgassing. First small-scale samples show encouraging results in terms of performance and mechanical stability. Thanks to the industrial readiness of printing technology we expect a potential pathway towards developing a new generation of printed neutron converter foils to support the development of state-of-the-art large-area instruments.
