Diamond anvil cell developed for studying lower-temperature muon-catalyzed fusion reactions

Swapping out an electron for a muon in hydrogen isotopes, muon-catalyzed fusion has shown promise for achieving thermonuclear fusion at temperatures more than one ten-thousandth that of conventional thermonuclear fusion. Diamond anvil cells (DACs) can reliably contain high-pressure conditions while continuing to provide optical access.

Kalow et al. have developed a DAC to pressurize and heat hydrogen isotopes in efforts to better study muon-catalyzed fusion. Combining cryogenic loading, all-metal sealing, flexible bellows, and secondary containment, researchers can safely fill and compress the cell with deuterium-tritium, which is then set within a detector apparatus that is placed in front of a high-intensity muon beam.

“Our research showcases the intersection of techniques from high-pressure physics with the field of nuclear fusion,” said author Jonathan Kalow. “The techniques and instruments we have developed were designed to bring a mixture of deuterium-tritium to higher static pressures than we have seen in previous literature for the purpose of measuring muon-catalyzed fusion measurements at novel density and temperature combinations.”

As muons are approximately 200 times the mass of electrons, muonic atoms are proportionately more compact. Such contraction reduces internuclear spacing and enhances quantum tunneling through the Coulomb barrier.

The group’s anvils allow about 25 curies of tritium in a liquid deuterium-tritium mixture to be compressed to stable pressures up to 933 Megapascals and heated up to 400 K — higher pressures than previously reported and approaching the 800 K temperature that has been demonstrated for muon-catalyzed fusion.

While previous experiments have measured up to 150 fusions per muon, the team hopes to push this number upwards using higher densities and higher temperatures to move past this benchmark towards a goal of positive fusion energy gain.

The group hopes the paper stokes further interest in muon-catalyzed fusion, and they look to continue updating the DAC design to push its performance further.

Source: “The MuFusE large-volume diamond anvil cell for exploring muon-catalyzed fusion at higher pressures and temperatures,” by J.D. Kalow, J.T. Hinchen, G. Harris, E. Koukina, D.M. Harrington, P.C. McDaniel, N.J. Brennan, A. Golossanov, I.D. Spool, D. Zajac, M. Mundt, S. Varner, M. Russell, S. Bull, K. McCormack, D. Mayer, L.E. Knaian, M. Khandaker, W. Stadolnik, W.R. Cutler, A. Sampat, K. Lau, J. Betances, C. Fagan, C.R. Shmayda, M. Koch, K. Payne, N.J.L. MacFadden, J. Simon, K. Peterson, A. Gami, S. Machavarapu, A. Tejeda, J. Katz, J.A. Allen, R. Chaney, K. Kem, I. Kiniti, E. Garcia Badaracco, K.R. Lynch, P. Gandhi, C.J. Johnstone, E. Niner, C.C. Petitjean, A. Antognini, W.T. Shmayda, S.O. Newburg, and A.N. Knaian, Review of Scientific Instruments (2026). The article can be accessed at https://doi.org/10.1063/5.0337239 .