The Acceleron Fusion team at the High Intensity Proton Accelerator facility at the Paul Scherrer Institute in September 2024. (Photo: Acceleron Fusion)
Cambridge, Mass.–based fusion startup Acceleron Fusion announced that it has closed a $24 million Series A funding round co-led by Lowercarbon Capital and Collaborative Fund. According to Acceleron, the funding will fuel the company’s efforts to advance its low-temperature muon-catalyzed fusion technology.
Acceleron said its technology uses subatomic muons to achieve fusion reactions at temperatures below 1,000°C, rather than the 100 million degrees Celsius temperatures required by traditional plasmas.
Muon-catalyzed fusion: First discovered in the 1950s, muon-catalyzed fusion is a proven and well-understood physical process. In the mid-1980s, several groups worldwide demonstrated more than 100 fusion reactions per muon, raising the possibility that the process could be used to generate energy. However, calculations done at the time concluded that it would take more energy to power the muon source than could be released by the fusion.
A major obstacle to reaching the break-even point in the process is what is known as the “alpha-sticking” problem, in which there is approximately a 1 percent probability of the muon sticking to the alpha particle that results from deuterium-tritium (DT) fusion, thereby effectively removing the muon from the muon-catalysis process altogether.
Acceleron is developing an intense, high-efficiency muon source to produce beams of muons using less energy than current facilities, and a high-density fusion cell to allow each of these muons to catalyze larger numbers of fusion reactions. In October, the company ran its machine with highly compressed DT fuel, capturing data on 28 hours of continuous fusion after more than 100 hours of testing with deuterium. The team is using the High Intensity Proton Accelerator and Swiss Muon Source at the Paul Scherrer Institute in Switzerland.
Quote: “We are thrilled to have the support of Lowercarbon Capital and Collaborative Fund, whose deep experience in the fusion space makes them ideal partners as we push the boundaries of what’s possible with muon-catalyzed fusion,” said Ara Knaian, chief executive officer and cofounder of Acceleron Fusion. “This investment will allow us to accelerate our R&D, grow our team, and bring us closer to demonstrating a viable commercial prototype.”
