Speaker
Description
Building neutron optics devices, including neutron guides, necessitates effective shielding of construction materials against neutron radiation (thermal and cold neutrons) to prevent material damage such as embrittlement. Additionally, neutron radiation escaping from these devices is disturbing the neutron science experiment as so-called background.
Common shielding materials in neutron science include boron, cadmium, and gadolinium. Boron-based materials are preferred because they produce only low-energy gamma radiation, which can be easily shielded. However, boron carbide (B₄C) materials are very hard and rather expensive to process. The present standard shielding material, BORAL, consists of a matrix of B₄C in aluminum, with B₄C enrichment ranging from 20 to 35 wt%.
To replace BORAL, we have developed boron-enriched filaments for 3D printing applications using FFF printing technology. These filaments incorporate boron carbide (B₄C) at concentrations of 25-45 wt%. The B₄C is embedded within a plastic matrix containing approximately 10 wt% hydrogen, thereby enhancing the shielding properties of the material. A disadvantage of B₄C is its carbon content, which is highly abrasive, leading to frequent replacement of 3D printer components. To mitigate this, we developed a novel filament containing 25 wt% of boron 10 isotope, which is less abrasive and offers better shielding performance.
In addition, we have manufactured filaments containing up to 40 wt% gadolinium oxide. To counteract the secondary gamma radiation emitted, we created composite filaments that contain both B₄C and tungsten, with enrichment levels reaching up to 80 wt%.
With these filaments we are aiming to produce various types of collimators and flight tubes. Initial prototypes have been manufactured and tested.
We will present the progress of the last year and of our developments and applications, including the limiting factors and challenges associated with the 3D printing technology. First prototypes are installed at Poldi, Neutra, SANS- LLB, DMC and CAMEA.
