University of Colorado Emeritus Professor Robert Arnold Ristinen died on September 10, 2021 at his home in Boulder. He was born in Park Rapids, Minnesota on April 2, 1934, the son of Arnold F. Ristinen and Katherine M. Koski. He grew up in Menahga, Minnesota where he graduated from Menahga High School in 1952. He attended the University of Minnesota for two years, then enlisted in the U.S. Army. He was assigned to a Field Artillery Battalion serving in Germany and Bavaria. He received a Bachelor of Physics degree from the University of Minnesota in 1959 and earned a PhD in physics from the University of Colorado. Post-doctoral work was done at Brookhaven National Laboratory on Long Island where he worked to develop new innovations in solid state devices for detection of nuclear decay processes. He returned to the University of Colorado as a Visiting Professor in 1966. The position evolved into a tenured professorship which he held until his retirement in 2001. Ristinen's research was based on experiments undertaken at the cyclotron at CU's Nuclear Physics Lab, where he also served a term as lab director. When CU's cyclotron was no longer in operation, his research moved to larger particle accelerators and included many experiments on pion-induced nuclear interactions at LAMPF in Los Alamos, NM, and at TRIUMF in Vancouver, British Columbia. In 1984 Ristinen and Jack J. Kraushaar co-authored the popular textbook Energy and Problems of a Technical Society ; this was revised in 1999 and 2005 as Energy and the Environment. A third edition was published in 2015. When Ristinen was growing up in Menahga, Minnesota, the very small, predominantly Finnish community was full of possibilities for a young man. He and his friends swam in the local lake, went hunting, fishing, and trapping; he worked in the general store established by his grandfather and managed by his father; he helped with field work on farms; he became an experienced electrician. Because he was a capable and intelligent sort, others sought him out to become involved in doing various things (fixing cars, building fiberglass canoes). He developed a can-do attitude and would tackle any project. Later he poured his own concrete driveway, rebuilt his automatic transmission, built Stirling engines in his home machine shop, all while pursuing professional interests in nuclear physics. On December 20, 1958 Ristinen married Elvah Bratburg whom he'd met while at the University of Minnesota. Survivors include their two sons, Keith (Reno, NV) and Kurt (Flagstaff, AZ); granddaughters Kimberly and Amber (Paul Waite); great grandson Harrison, and sister Kathleen Ristinen Jonas. He was predeceased by his parents; his sister, Elaine; his step-mother, Sylvia; two step-sisters Marilyn Anderson and Norma Bergstrom. No services will be held. The family requests donations to Amnesty International USA or your local Public Broadcasting service in lieu of flowers.
Published by The Daily Camera on Sep. 15, 2021.