Conditions for High-Yield Muon Catalyzed Fusion

Project Term:
08/01/2020 - 07/31/2022

Critical Need:

Controlled fusion has long been thought of as an ideal energy source—safe, clean, abundant, and dispatchable. Fusion is on the cusp of demonstrating net positive energy gain, spurring interest in both the public and private sectors to adopt a more aggressive development path toward a timely, grid-ready demonstration. A critical need today is to increase the performance levels and the number of lower-cost fusion approaches that might eventually lead to commercial fusion energy with competitive capital cost and levelized cost of energy. To address this need, the BETHE program supports (1) advancing the performance of earlier-stage, lower-cost concepts, (2) component-technology development to lower the cost of more-mature concepts, and (3) capability teams to assist multiple concept teams in theory, modeling, and diagnostic measurements.

Project Innovation + Advantages:

A muon is a short-lived subatomic particle with the same charge as an electron but 206 times the mass. When bound to an atomic nucleus, it orbits much closer to the nucleus than an electron does. In the context of a deuterium-tritium molecule, this screens the electric charge and reduces the “Coulomb barrier” that ordinarily prevents the nuclei from fusing. When a muon stops in a mixture of deuterium and tritium, even at ordinary temperatures, it causes nuclear fusion. In most cases, the muon is released following a fusion reaction and will catalyze additional fusions, but roughly 0.8% of the time it sticks to a resulting alpha particle and is removed from the catalytic cycle. This effect has hindered efforts to design a reactor based on muon-catalyzed fusion (µCF). Reducing this “sticking rate” by varying environmental conditions could open the door to a viable, cost-effective µCF reactor concept. Using modern experimental techniques from the field of high-pressure physics, the team will simultaneously heat, pressurize, and bombard a tiny volume of fusion fuel with muons, at pressures up to 100 times higher than what has been attempted previously, where it is hypothesized that the sticking rate will be reduced. They will measure the muon sticking fraction and cycling rate and other key parameters over a range of temperatures, pressures, and tritium concentrations. They will update publicly available computer models and databases based on their results, which, if favorable, may potentially lead to new µCF designs capable of net energy gain.

Potential Impact:

Accelerating and lowering the costs of fusion development and eventual deployment will enable fusion energy to contribute to:


Fusion energy will ensure the U.S.’s technological lead and energy security.


Fusion energy will improve the chances of getting to cost-effective, net-zero carbon emissions, while minimizing pollution and avoiding long-lived radioactive waste.


As a disruptive technology, fusion energy will likely create new markets, opportunities, and export advantages for the U.S.


ARPA-E Program Director:
Dr. Scott Hsu
Project Contact:
Mr. Ara Knaian
Press and General Inquiries Email:
Project Contact Email:


City University of New York - York College

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