The fusor: fusion demonstrated in a Fort Wayne laboratory

1962–1968 · FARNWORTH'S LAST INVENTION, PATENTED FROM THIS CITY

The device: Farnsworth's Fort Wayne years produced one more invention of the first rank, and its patent documents carry the city in so many words. Working for ITT in Fort Wayne with Robert L. Hirsch and Gene A. Meeks, Farnsworth developed the fusor — an inertial electrostatic confinement device, a spherical vacuum chamber in which a charged inner grid accelerates ions until some of them fuse. The patents are in his own name with Fort Wayne on the face of them: U.S. Patent No. 3,258,402, "Electric discharge device for producing interactions between nuclei," filed 11 January 1962 and issued 28 June 1966, assigned to ITT; U.S. Patent No. 3,386,883, "Method and apparatus for producing nuclear-fusion reactions," filed 13 May 1966 and issued 4 June 1968 — "Philo T. Farnsworth, Fort Wayne, Ind., assignor to International Telephone and Telegraph Corporation." Hirsch and Meeks patented alongside him (No. 3,530,497, 22 September 1970, both inventors of Fort Wayne). What the Farnsworth–Hirsch fusor achieved is stated in the technical literature's own measured words: it was the first fusion device that could clearly demonstrate it was producing fusion reactions at all. What it did not achieve matters as much, and the boosterish local telling — echoed on the ACGSI site — that Farnsworth "reportedly achieved self-sustaining fusion" in Fort Wayne is not carried by the record: the reactions lasted at most about thirty seconds, net energy was never approached, ITT's board pressed to terminate the work in December 1965, a final year was won on Harold Geneen's urging, and Farnsworth took medical retirement in the spring of 1967 and left for Utah, the quest unfinished. Demonstrated fusion in a basement-scale device, built and patented in Fort Wayne, is the true claim; it is large enough.

Sources:

1. U.S. Patents Nos. 3,258,402 (28 June 1966) and 3,386,883 (4 June 1968), the patents themselves, via Google Patents — Farnsworth of Fort Wayne, assignor to ITT; U.S. Patent No. 3,530,497 (22 September 1970) — Hirsch and Meeks, both of Fort Wayne.
2. "The Fusor: A brief history" (fusor literature) and Philo T. Farnsworth, Wikipedia — the device's demonstrated-fusion standing, the thirty-second ceiling, the December 1965 board pressure, the Geneen extension, the 1967 medical retirement.
3. ACGSI, Fort Wayne Historic Sites — the "self-sustaining fusion" form of the claim, tested here against the documented record.