Rolf Widerøe

Rolf Widerøe was a pioneering Norwegian electrical engineer and particle physicist whose foundational work was instrumental in the development of modern particle accelerators. He is best known for inventing the betatron, a type of circular accelerator, and for his early conceptual work on the linear particle accelerator. His innovations provided critical tools for advancements in nuclear physics, radiation therapy, and high-energy physics, influencing major laboratories like CERN and DESY.

Early life and education

Rolf Widerøe was born in Kristiania (now Oslo) and demonstrated an early aptitude for engineering and physics. He initially studied at the Norwegian Institute of Technology in Trondheim before pursuing advanced education in Germany. Widerøe earned his doctorate in engineering from the Technical University of Karlsruhe in 1927, where his thesis on accelerating voltages laid the groundwork for his future breakthroughs. His academic journey was significantly influenced by the scientific environment in interwar Germany and mentors in the field of electrical engineering.

Career and contributions

Widerøe's career was defined by his work at the intersection of electrical engineering and experimental physics. He held positions at various industrial and research institutions, including Brown, Boveri & Cie in Baden, where he applied his expertise to high-voltage technology. His most significant early contribution was the conceptual design and construction of the first operational linear particle accelerator in 1928, which proved the principle of phase stability using alternating current radio frequency fields. This work directly inspired later developers like Ernest Lawrence, who invented the cyclotron, and Luis Walter Alvarez, who advanced linear accelerator technology.

Development of the betatron

Widerøe's most famous invention, the betatron, was conceived in the 1920s and realized in practical form in the 1940s. The device accelerates electrons to high energies using a changing magnetic field, rather than the constant high voltage required by earlier designs like the Cockcroft–Walton generator. The first working betatron was built in 1940 at the University of Illinois Urbana-Champaign by Donald Kerst, who credited Widerøe's theoretical designs. The betatron became a vital source of X-rays and gamma rays for both radiation therapy in medicine and fundamental research in particle physics, influencing projects at institutions like the Stanford Linear Accelerator Center.

Later work and legacy

After World War II, Widerøe continued his innovative work, contributing to the design of synchrotrons and colliders while working for companies like BBC Brown Boveri and as a consultant for CERN. He played a role in the development of the Proton Synchrotron at CERN and other accelerators at the Deutsches Elektronen-Synchrotron (DESY). His legacy is honored through awards such as the St. Olav's Medal and the Röntgen-Plakette, and his principles remain embedded in the design of modern facilities like the Large Hadron Collider. The Widerøe's Flyveselskap airline, founded by his brother Viggo Widerøe, also bears the family name.

Personal life

Rolf Widerøe was the brother of Norwegian aviation pioneer Viggo Widerøe. He married and had children, maintaining a family life alongside his intensive research career. During World War II, his work in Germany led to complex post-war scrutiny regarding his activities, though he was ultimately cleared of any wrongdoing. He spent his later years in Switzerland, continuing to write and consult on accelerator physics until his death in Obersiggenthal in 1996. His autobiography, *The Infancy of Particle Accelerators*, details his scientific journey and contributions.

Category:Norwegian electrical engineers Category:Particle physicists Category:1902 births Category:1996 deaths