Pre-Registered Prediction: Neutron Spectrum

The breeder predicts a 14.1 MeV D-T neutron peak with a stated tolerance, giving a sharp, early test of whether the plasma burns as modeled.

The prediction

D-T fusion emits a characteristic neutron at 14.1 MeV. The breeder (Hyperion) pre-registers the predicted neutron energy spectrum at representative detector locations: a dominant 14.1 MeV peak, its expected broadening from plasma temperature, and the softened tail from neutrons scattered in the blanket and structure.

The falsifier

A measured peak displaced from 14.1 MeV beyond the stated tolerance, or a peak-to-tail ratio outside the predicted band, refutes the neutronics model as configured. Because the whole product chain multiplies the neutron source rate, an early spectrum measurement is a low-cost, high-information check that the plasma and blanket behave as simulated.

Why the spectrum first

The neutron spectrum can be measured early and does not require long integrated operation. It tests the reaction identity, the plasma temperature, and the surrounding geometry at once, and it validates the model that the harder breeding measurement depends on. It is among the first predictions FOAK can decisively confirm or break.

Because it is early and cheap, the spectrum test also functions as a tripwire: a spectrum that disagrees with prediction signals that something upstream — the reaction mix, the temperature, or the geometry model — is wrong before the program has committed to the far more expensive breeding campaign. Catching a foundational error at the spectrum stage is far preferable to discovering it only in the tritium accounting.

This page describes a design-and-simulation study, not a built machine. Construction of the breeder (Hyperion) begins Q2 2027; first-of-a-kind first tritium is targeted near 2030. No hardware net-gain claim is made before FOAK.