Cyclotron particle

A cyclotron is a particle accelerator that uses magnetic and electric fields to propel charged particles along spiral paths.

About this subject

The cyclotron was invented in 1932 by Ernest O. Lawrence at the University of California, Berkeley, for which he received the Nobel Prize in Physics in 1939. It is a type of particle accelerator that accelerates ions (charged particles) by applying an alternating potential difference between two D-shaped electrodes, called 'dees,' while a perpendicular magnetic field keeps the particles in a circular path. As the ions gain energy, the radius of their orbit increases, forming a spiral until they are extracted for collisions or radioisotope production.

Its operation relies on resonance: the frequency of the alternating electric field is tuned to the revolution frequency of the ions, which is constant for non-relativistic particles (f = qB/(2πm)). Each passage through the dees adds energy, allowing energies in the tens of MeV range. For higher energies, relativistic effects require corrections, leading to the development of the synchrocyclotron and the isochronous cyclotron.

Cyclotrons have important applications: in nuclear physics for studying nuclear reactions and structure; in nuclear medicine for producing radioisotopes such as fluorine-18 (used in PET scans); and in industry for materials testing and carbon-14 dating. Major facilities like Los Alamos National Laboratory (USA) and TRIUMF (Canada) operate advanced cyclotrons. In Brazil, the Instituto de Pesquisas Energéticas e Nucleares (IPEN) has a cyclotron for research and radiopharmaceutical production.

Interesting fact: the name 'cyclotron' derives from the cyclic path of the particles. The invention revolutionized experimental physics, allowing particle acceleration to high energies without the need for enormous linear voltages. Today, about 30 cyclotrons are in operation in Brazil, primarily in hospitals and research centers.

Frequently Asked Questions

What is a cyclotron?

A cyclotron is a particle accelerator that uses magnetic and electric fields to accelerate ions in spiral paths, reaching energies in the MeV range. It was invented by Ernest Lawrence in 1932.

What is a cyclotron used for in medicine?

In medicine, cyclotrons are used to produce radioisotopes such as fluorine-18, which is used in PET scans for cancer diagnosis and neurological disorders.

How does acceleration work in a cyclotron?

Ions are injected at the center and accelerated by an alternating electric field between two D-shaped electrodes. A perpendicular magnetic field keeps them in orbit, increasing the radius until extraction.