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Kenneth Ross MacKenzie (June 15, 1912 – July 4, 2002) In 1940, under the supervision of Ernest O. Lawrence, K. R. MacKenzie together with Dale R. Corson and Emilio Segrè discovered element number 85, astatine. The process and findings from the element discovery were published in the 1940 volume of Physical Review. They accomplished the element discovery by bombarding bismuth with alpha particles, successfully synthesizing the first man made element.

Below is an image of an Astatine electron shell diagram. Provided by Greg Robson.

Help with the Manhattan Project
Dr. K. R. Mackenzie’s family moved to Victoria, British Columbia when he was age 10. He received his bachelors and masters degree from the University of British Columbia, and began further study at the University of California, Berkeley in 1937. As a graduate student, Kenneth Ross Mackenzie was involved in the Manhattan Project to help solve how to separate the rare uranium-235 isotope from the identical dominant uranium-238 isotope at Oak Ridge, Tennessee. As an interesting side note, while working on the Manhattan project, MacKenzie and colleagues borrowed 14,700 tons of silver from the US Treasury and melted it into strands to replace old copper in their magnetic coils. After the war, the silver was melted and returned to the treasury.

The image below shows that Uranium-238 (blue) is in more abundance than Uranium-235 (red).



Cyclotron
MacKenzie received his PhD under Ernest Lawrence at Lawrence Livermore National Laboratory. Lawrence, MacKenzie, and their colleagues devised the first cyclotron. He was a professor of physics at UCLA, where he and Reg Richardson built UCLA's first cyclotron and later a bevatron. In 1958 he became president of Meva Corp an industry that built cyclotrons. Meva corp was eventually sold to Hughes Aircraft. Dr. MacKenzie later wrote a paper entitled “Space Charge Effects and Cyclotron Enhancement” in 1964.



Other Accomplishments and Studies
MacKenzie devised MacKenzie buckets which are plasma sources created by lining vacuum chamber walls with permanent magnets of alternating polarity to suppress plasma electron losses, that are widely used to this day. He later traveled around the world, helping to troubleshoot various country's cyclotron problems. Later in life, he studied plasma physics and dark matter.