William Thomas Duffy Jr - Rest in Peace

By Mary Duffy Braun and Richard Braun

June 30, 1930 – March 4, 2025

William T “Bill” Duffy Jr, Professor Emeritus of Physics, passed away on March 4, 2025. He began at Santa Clara as an undergraduate and returned as faculty to teach thousands of students, chair his department, and win awards for his research. Bill was born in San Francisco. He served in the Navy after graduating from Bellarmine High School. He then attended Santa Clara and majored in Electrical Engineering, completing his undergraduate degree in 1953. He went on to graduate study at Stanford University; he earned an MS in Electrical Engineering in 1954. In 1959, he completed his PhD thesis (“A precise measurement of the magnetic moment of the triton in units of the magnetic moment of the proton”) under the supervision of Nobel Prize winner Felix Bloch in solid state physics. He also met his future wife Kay at Stanford, and they married shortly after he completed his degree.

He joined the Physics faculty at SCU later that year. For the 1961-62 academic year, Bill had a fellowship at the Kamerlingh Onnes Laboratory at the University of Leiden in the Netherlands. He rose through the ranks and served as department chair for 17 years. He also served on numerous committees around campus. He taught thousands of students over the years, from large section introductory courses to upper division specialty courses. He also guided students in independent research projects.

Bill was active in research, and was funded by the National Science Foundation. In later years, he worked on damping of metals and alloys near absolute zero temperature; the results were applied to gravitational wave antennas. His work contributed to the success of the LIGO project, the first instrument to observe gravitational waves in 2015. His work led to sabbatical visits to the Institut National des Sciences Appliquées de Lyon, France. He was recognized with the University’s Excellence in Scholarship Award in 1999.

Bill was close friends with faculty from all over campus, continuing to see many of them long after retirement in 2002. Between undergraduate study and faculty service, he dedicated 47 years of his life to Santa Clara.

Bill could be seen jogging 3 days a week around campus for decades. He regularly ran 5k and 10k races, and not uncommonly with his daughters when they were college-aged and beyond. He was very handy, building numerous features around the house, including a wine cellar. The wine cellar helped supply gatherings of family, faculty, and wine clubs over many years. He was an avid outdoorsman. Family activities often included backpacking and hiking. He instilled love of the outdoors in his children. He was a devout Catholic, and for many years, sang in the choir at Saratoga’s Sacred Heart parish.

He is survived by his devoted wife Katherine “Kay” Duffy of 65 years; his three children Judith Duffy '82 (BSCS), Mary Braun '83 (BSEE; Richard '83 BSME, MSME 87), and Christopher Duffy '92 (BS); three granddaughters Laurel Van Patten (Max Gindi), Rebecca Braun, and Elise Braun. Services will be private.