Helium-3 Purity and Grades
Quantum cryogenics and neutron detection demand very pure helium-3, free of residual tritium and helium-4; purification and assay set the product grade.
Purity defines the use
Helium-3 harvested from tritium decay is not immediately product-grade. It can carry residual tritium (a radioactive contaminant), helium-4 (from any ⁴He present and from tritium handling), and trace impurities. Different applications set different purity requirements, so the foundry produces to a specification and assays each batch.
Why residual tritium must go
For quantum-computing dilution refrigerators, residual tritium is unacceptable: it is radioactive, and any tritium in the ³He/⁴He mixture contaminates a closed cryogenic system that customers expect to be clean. For neutron detectors, tritium background and impurities degrade counting performance. Purification to remove residual tritium and unwanted helium-4 is therefore essential.
Grades and assay
- Isotopic purity: fraction that is genuinely ³He vs ⁴He
- Radiopurity: residual tritium below the required threshold
- Chemical purity: freedom from moisture and other gases
- Assay: mass spectrometry and gas analysis certify each batch
Traceability
Because helium-3 comes from decayed tritium, its provenance and radiopurity must be documented for regulated uses. Assay and certification tie back to the tritium accountancy system, so a delivered batch carries a verified composition. Grade specifications are a design-and-process matter, described physically and with no commercial content on this page.
This page describes a design-and-simulation study, not a built machine. Construction begins Q2 2027; first-of-a-kind (FOAK) first tritium is targeted near 2030. No net-gain claim is made before FOAK.