James Edward Zimmerman
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James Edward Zimmerman (February 19, 1923 – August 4, 1999) was a coinventor of the radio-frequency superconducting quantum interference device (SQUID).[1][2]
Zimmerman was born in Lantry, South Dakota and grew up on a ranch. He received a B.S. in electrical engineering from the South Dakota School of Mines and Technology in 1943.[1] Afterward, he joined the Westinghouse Research Laboratory in Pittsburgh, Pennsylvania. He received a Ph.D. in physics from the Carnegie Institute of Technology in 1953.[1]
Career
From 1953 to 1955, Zimmerman worked for the Smithsonian Institution and moved to California to work at the Table Mountain Observatory. [2]
In 1955, Zimmerman began working at the Ford Motor Company in Dearborn, Michigan. He co-invented the SQUID while working at Ford in 1965, and the term "SQUID" was coined in 1966.[2] Zimmerman left Dearborn in 1967 due to disagreements with SQUID collaborator James Mercereau. He joined Aeronutronic, a defense division of Philco-Ford.
In 1970, Zimmerman joined the National Bureau of Standards, where he worked until 1985. While at NIST, Zimmerman introduced two important innovations in SQUID magnetometry:
- Fractional-turn SQUID, improving the coupling efficiency
- SQUID gradiometer, improving sensitivity to nearby fields
In addition, in the late 1970s and early 1980s, he also contributed to the development of low-power closed-cycle Stirling refrigerators, to reach temperatures in the range 4K - 8K with the purpose of cooling SQUID devices and small-scale superconducting electronics without resorting to liquid helium dewar vessels. [2]
A major achievement was the use of plastic parts made in the laboratory, which would be assembled in a totally non-magnetic cryocooler (refrigerator), in order not to interfere with highly sensitive SQUIDs. Later, he was also involved in the development of pulse tube cryocoolers.
