You can freely build on How Ernest Lawrence Invented the Cyclotron Particle Accelerator
This patent expired in 1952. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Research Corp
Patent granted
1934
Expired
1952
Forward citations
114
What this patent covers
The invention, known as a cyclotron, uses a vacuum chamber placed between the poles of a large electromagnet. Inside the chamber are two hollow, D-shaped electrodes. As ions are injected into the center, an alternating electric field switches the charge of these electrodes, pulling the ions across the gap and causing them to spiral outward in a circular path. By repeating this process, the ions gain massive amounts of kinetic energy before being directed at a target.
What is now free to use
All 0 claims of US 1948384 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover linear particle accelerators which move particles in a straight line rather than a circle.
Does not cover the specific chemical or radioactive properties of the particles being accelerated.
Does not cover non-magnetic methods of particle acceleration like electrostatic Van de Graaff generators.
Who is building on this today
Major research institutions like CERN and national laboratories in the US continue to refine accelerator technology. Companies like Varian Medical Systems build on these principles for clinical cancer treatment devices.
Products built on expired version of this technology
Modern proton therapy machines for cancer treatment
Radioisotope production for medical imaging
University physics research laboratories
How to cite this patent in your documentation
Research Corp. US Patent 1948384. Method and apparatus for the acceleration of ions. Granted 1934, expired 1952. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.