General Fusion Publishes Peer-Reviewed Diagnostic Method for LM26 Fusion Machine

General Fusion Inc. published a peer-reviewed paper in the scientific journal Fusion Science and Technology demonstrating a key diagnostic system for measuring temperature milestones in its world-first, large-scale Lawson Machine 26 fusion demonstration machine. The paper details how the Vancouver-based company plans to read plasma temperatures in the MTF machine it needs to hit 100 million degrees Celsius.

LM26 is designed to reach target temperatures of 1 keV (10 million degrees Celsius) and 10 keV (100 million degrees Celsius) and ultimately achieve the Lawson criterion, demonstrating the company's Magnetized Target Fusion technology in a commercially relevant way. The Lawson criterion itself is the combination of fusion parameters that can produce net fusion energy in the plasma, making it the finish line every MTF program is chasing.

The diagnostic challenge at those temperatures is not trivial. Temperature analysis in LM26 will draw on multiple diagnostics, including ion temperature measurements through neutron counting. The new peer-reviewed research outlines the company's advancement of this diagnostic method for its MTF approach. For electron temperature, the machine will also be supported by data from absolute extreme ultraviolet (AXUV) diodes, with the comprehensive diagnostic suite further including magnetic sensors, neutron detectors, spectroscopy, and laser-based systems.

Mike Donaldson, Senior Vice President of Technology Development at General Fusion, said "ion temperature is a key parameter for fusion performance in our LM26 program," adding that "our work demonstrates a practical, scalable method to measure ion temperature using neutron counting" and that "as we move toward 1 keV and beyond, this technique will be an important tool for validating plasma performance in LM26."

The publication did not emerge from a standing start. General Fusion has more than 20 years of experience designing, building, and testing fusion prototypes and testbeds, and the Fusion Science and Technology publication builds on work from PI3, the world's largest and most powerful operational fusion plasma injector, now integrated into LM26. PI3 has been central to the company's published science before: Lawrence Livermore National Laboratory previously published simulation models using PI3 data to predict plasma edge behaviour.

The diagnostic paper lands at a commercially consequential moment. General Fusion announced in January 2026 that it plans to go public through a proposed business combination with Spring Valley Acquisition Corp. III (NASDAQ: SVAC), which would make it, according to the company, the first publicly traded pure-play fusion company. Peer-reviewed technical publications are exactly the kind of third-party-validated evidence that investors and regulators scrutinize as a company moves toward a public listing.

A key area of General Fusion's R&D collaboration for LM26 has been advancing cutting-edge diagnostic technology to precisely measure machine performance, with partners including the UK Atomic Energy Authority (UKAEA), TRIUMF, and Simon Fraser University developing a system spanning magnetic sensors, neutron detectors, spectroscopy, and laser-based diagnostics. The neutron-counting ion temperature method now has peer-reviewed standing in that broader suite, giving LM26's temperature verification framework a published scientific foundation before the machine attempts its first major plasma milestones.