A 14-MeV High-Flux Neutron Source Based on Muon-Catalyzed Fusion — a Design Study

A design study is presented for an intense 14-MeV neutron source based on muon-catalyzed fusion to be used for first-wall and blanket material research for future fusion reactors. Negative pions are produced inside a 5- to 10-T magnetic field by an intense deuteron beam interacting with a 30- to 50-cm-long carbon target. The pions and the muons resulting from the decay of pions inflight are collected in the backward direction and stopped in a high-density deuterium-tritium (D-T) target. With an 18-MWdeuteron beam at 1.5 GeV (12 mA = 7.5 × 10¹⁶ d/s), ∼ 10¹⁶ π⁻/s can be generated, which will decay to muons of which up to 10¹⁵ μ⁻/s stop in the D-T mixture. Assuming X_c = 100 fusions per muon, muon-catalyzed fusion produces 14-MeV neutrons with a source strength of up to 10¹⁷ n/s, i.e., a neutron power of 200 kW. A neutron flux of up to 10¹⁴/cm²·s (10 dpa/yr) can be achieved in test volumes of several litres. These numbers, however, do not represent a technological limit. This source has about the same power efficiency for neutron generation as low-energy beams (d-Li stripping). It also has the advantage of producing the original 14-MeV fusion spectrum without tails, isotropically into a 4π solid angle. In addition, the power density and heat load of the primary target are a considerably smaller problem. The environment of the secondary target, the neutron source itself, can be made to resemble part of the tokamak ring to be simulated. The noninteracting part of the beam (30 to 40%) can be disposed of separately or reused for another facility (e.g., a spallation neutron source).