Neutron shielding, straight off the print bed
Rapid 3DShield Boron Carbide is 50–60% boron carbide in a PLA-based binder. You print it on a standard FFF printer and use the part as printed, with no debinding and no furnace. Most of it ships on purchase orders to national laboratories, instrument makers and university research groups.
Why boron
Boron-10 (19.9% of natural boron) absorbs thermal neutrons with a cross-section of about 3,840 barns: ¹⁰B + n → ⁷Li + ⁴He + 2.79 MeV. Both products stop within microns and neither is long-lived radioactive. About 94% of captures also emit a 0.48 MeV gamma ray.
How thick?
At mid-spec loading, the calculated thermal-neutron mean free path in a 100%-infill print is about 0.4 mm. That means roughly 5–11% transmission at 1 mm, 0.3–1.3% at 2 mm and 0.01–0.15% at 3 mm for a narrow 0.025 eV beam. These are calculated, not measured. Epithermal and fast neutrons, scatter and infill voids all push the required thickness up, so verify against your source.
Printing essentials
- 0.6 mm hardened steel nozzle, standard flow
- Prints like PLA, with minimal to no warping
- 100% infill for shielding parts
- Do not dry. It is less hygroscopic than PLA, and drying degrades the binder.
- Not for sintering. B₄C needs about 1,956 °C.
Mixed fields
Boron carbide handles neutrons and tungsten handles photons. Put boron carbide on the neutron side and Rapid 3DShield Tungsten (up to 94 wt% W) behind it. The tungsten also absorbs the capture gamma.
Ordering by PO or in volume? Email [email protected]. Shop Boron Carbide Filament →