Borated Aluminium Neutron Guide

 metallic substrate with integrated shielding

In close collaboration with the ILL, we have developed a new substrate material for neutron guides based on a metal matrix composite (MMC).

With a boron content of 4% in aluminium, this material provides neutron shielding performance comparable to Borofloat (BK7) glass, while offering significantly improved mechanical robustness and resistance to breakage.

For an m = 2 supermirror deposited on AluBor, neutron reflectivity values exceeding 94% have been achieved.

The material was tested at the ILL T3 test station under high thermal neutron flux. A sample coated with an m = 3 supermirror was exposed to an accumulated fluence of 1.66 × 10¹⁸ n/cm². Compared to BK7 glass, AluBor exhibited lower density changes and no observable degradation of the mirror performance.

Using AluBor substrates, it is possible to manufacture self-evacuated neutron guides. The guide itself can be directly pumped, eliminating the need for an additional vacuum housing. While this approach is not feasible with glass, it is fully realizable with AluBor.

This makes AluBor an excellent solution for applications where space and weight are critical constraints.