The Moment We Activated the World’s Largest Cyclotron

1950 to 1979
Vancouver, British Columbia
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Canada’s first proton beam

On the afternoon of December 15th, 1974, researchers at TRIUMF in Vancouver, B.C. extracted Canada’s first accelerated proton beam. This momentous achievement marked the start of a new era in nuclear and particle physics research in Canada and around the globe.

A cyclotron is a type of particle accelerator in which charged particles in a vertical magnetic field accelerate outward in a spiral pattern, driven by a high-frequency electric field. The cyclotron at TRIUMF is the largest of its kind in the world, measuring almost 18 meters across. It produces intense beams of protons of up to 520 Million electron-Volts (MeV), corresponding to 75% the speed of light. Since 1974, TRIUMF has used the cyclotron’s primary proton beam (and secondary beams of pions, muons, neutrons, and rare isotopes) to conduct pioneering studies and establish Canada as a world leader in nuclear physics, particle physics, molecular and materials science, and nuclear medicine.

The Institute of Electrical and Electronics Engineers (IEEE), the world’s largest professional association for the advancement of technology, recognized the first high-energy proton beam extraction as a historic engineering milestone in 2010. “The cyclotron’s longevity underscores the quality of the initial design and engineering of the TRIUMF 500 MeV cyclotron,” said Dr. David G. Michelson, IEEE Chair and member of the Department of Electrical and Computer Engineering at the University of British Columbia. “Thirty-five years after the first full energy proton beam was extracted, the cyclotron is still the main engine of TRIUMF’s world-leading research program.”

With ongoing support from the Government of Canada, the 520 MeV cyclotron will continue to support cutting-edge research initiatives and technology development, including the production of medical isotopes for disease imaging, treatment, and research; proton-beam therapy for ocular melanoma; irradiation testing of aerospace components; characterising quantum materials; and many more new and exciting projects.


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