Dr. J. David Bowman, or David as he was known to his friends, passed away on December 7th, 2024 at the age of 85. A celebration of David’s life will be held on Saturday, March 22, 2025 at 2:00 p.m. at Oak Ridge Unitarian Universalist Church. 

David was born in Pleasantville, New York. He was the son of Margaret Safronia Rasnick and Cecil Bowman, both of Dickenson County, Virginia. His mother, Margaret Rasnick, attended Berea College in Kentucky, where she was Salutatorian. Margaret worked as a public-school teacher. She taught in the town of Manuelito, New Mexico, on Navajo Nation, in the early 1940s, where David attended kindergarten and part of elementary school. He left New Mexico for New York as a child, where he resided with his aunt Phoebe Rasnick, and her husband, Tom Della Badia.

David was an exceptional student. He was recognized for his outstanding math and science ability after excelling on the New York Regents Exam. He attended Caltech for college, graduating with his Bachelor of Science in 1961 and earning his doctorate in Physics and Mathematics in 1967. While at Caltech, David was Richard Feynman’s teaching assistant and is one of few who solved all of Feynman’s equations. After completing his doctorate, David embarked on a long, fulfilling and influential career in medium energy experimental nuclear physics, which lasted fifty-six years from 1967 to 2023. David worked at Lawrence Livermore Laboratory, the University of Bonn, Germany, Los Alamos National Laboratory and Oak Ridge National Laboratory. Impressively, he continued to conduct experiments and publish physics articles at ORNL until he reached 2023. 

He received many professional honors, including being named a senior fellow of the National Laboratory system in 1981, and earning the Tom W. Bonner Prize in Nuclear Physics in 2002. His research focused on the fundamental interactions at the subatomic level. He published his discovery of Beryllium 14 and Boron 17 in Physical Review letters in 1973.

At the Los Alamos Meson Physics Facility (now LANSCE), David performed the first measurements on compound nuclei. In 1993, he began a research program on Time Reversal Invariance and Parity Violations in Low Neutron Energies. He also started the effort to build a cold-neutron beamline at Los Alamos.  According to Marcel Demarteau, Director of the Physics Division of the Oak Ridge National Laboratory, “he was a leading light in Nuclear Physics. . . further he lead the first suite of experiments to probe the nature of neutrons at the Fundamental Neutron Physics Beamline of ORNL’s Spallation Neutron Source.

In addition to his impressive accomplishments in physics, friends remember David as a charming and funny man who was committed to issues of social justice. He married his first wife, Wairimu Tabitha Gethaiga, who had immigrated from Kenya, in Los Angeles, California in 1964. He had two daughters with her, Warigia and Wangeci, and raised her daughter Njeri Bowman. He and Wairimu were avid organic farmers. Alongside his wife and mother, David filled their land in Piedra Loop with fruit trees, chickens, duck, geese and an extensive garden. David and Wairimu’s home was a gathering place and a refuge for any Kenyan visiting or residing in New Mexico. He was acknowledged as a Kikuyu elder in his wife’s hometown of Karema, Nyeri, Kenya, and was a significant contributer to educational causes in that region.  David used his scientific knowledge to become a creator of crabapple jam and mint jelly, and regularly won awards for his jams and jellies at the county level. He was extremely interested in issues of foreign affairs, national security and nuclear non-proliferation.

David met Rebecca Rumbaugh, his second wife, on Thanksgiving Day 2005. The connection was instant and grew into a bond that endured the test of time. David was there when Rebecca’s son, Jeremy, passed away and they were blessed to raise Jeremy’s two young sons, Logan and Evan Rumbaugh. They moved to Oak Ridge, Tennessee in 2008 and were fortunate to have many wonderful friends and neighbors. Their home was frequently filled with hearty laughter and memorable celebrations. David was a loving husband, outstanding father, and beloved member of the community as well as an avid mushroom hunter, art collector, and wine connoisseur. He and Rebecca were members of the Oak Ridge Unitarian Universalist Church and many organizations that strive for equality and social justice.

He is survived by his wife, Rebecca Rumbaugh Bowman, and his daughter Warigia Margaret Bowman, as well as eight grandchildren, Logan Rumbaugh, Evan Rumbaugh, Renne Ngaruiya, Ali James Ngaruiya, David Ngaruiya, Olivia Estacio Entrop, Evelyn Estacio Entrop and Hugh Allan. He is also survived by his daughters by marriage, Erica Entrop (Darwin Estacio) and Meredith Entrop (John Allan). His daughters Wangeci Bowman and Njeri Bowman pre-deceased him, as did his first wife, Wairimu Tabitha Gethaiga Bowman and his stepson, Jeremy Rumbaugh.