# How Ernest Lawrence Invented the Cyclotron Particle Accelerator

> This 1934 patent describes the cyclotron, a machine that uses magnetic and electric fields to whip particles into high speeds for scientific research.

- **Patent:** US 1948384
- **Original title:** Method and apparatus for the acceleration of ions
- **Owner:** Research Corp
- **Granted:** 1934
- **Status:** Public domain (expired)
- **Times cited:** 114
- **Field:** semiconductors, energy, mechanical

## What it does

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 it does NOT cover

- 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.

## The clever bit

Lawrence realized that by using a constant magnetic field, the time it takes for a particle to complete a circular orbit remains the same regardless of its speed, allowing for simple, synchronized acceleration.

## Real-world examples

1. Modern proton therapy machines for cancer treatment
2. Radioisotope production for medical imaging
3. University physics research laboratories

## Why it matters

This invention launched the era of high-energy physics. It allowed researchers to study the atomic nucleus by smashing particles into targets, leading to the discovery of new elements and isotopes. It remains the foundational design for many medical and research accelerators used today.

## Frequently asked questions

### What does How Ernest Lawrence Invented the Cyclotron Particle Accelerator cover?

This 1934 patent describes the cyclotron, a machine that uses magnetic and electric fields to whip particles into high speeds for scientific research.

### Who owns patent US 1948384?

Research Corp owns this patent, granted in 1934.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 1948384 cited by?

This patent has been cited by 114 later patents that build on its ideas.

### What problem does this patent solve?

This invention launched the era of high-energy physics. It allowed researchers to study the atomic nucleus by smashing particles into targets, leading to the discovery of new elements and isotopes. It remains the foundational design for many medical and research accelerators used today.

### What does this patent NOT cover?

Does not cover linear particle accelerators which move particles in a straight line rather than a circle.

**Full plain-English explainer:** https://patentbrief.org/patent/us/1948384/cyclotron-lawrence

**Original patent:** https://patents.google.com/patent/US1948384

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


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