Frank E. Senftle, 91, a geophysicist who became chief of the nuclear solid-state physics laboratory at the U.S. Geological Survey, died Jan. 12 at the home of a daughter in North Potomac. He lived in Chevy Chase.

He had pneumonia and complications from Parkinson’s disease, a son, Patrick G. Senftle, said.

Dr. Senftle’s scientific specialties included radiation and the uses of radiation in the detection of minerals. During World War II, he studied the properties of uranium and did research for the Manhattan Project, the program that developed the atomic bomb.

Frank Edward Senftle was born in Buffalo. He graduated from St. Michael’s College, a division of the University of Toronto, in 1942 with a degree in physics. He received a master’s degree in physics in 1944 and a doctorate in geophysics in 1948, also at the University of Toronto.

Dr. Senftle was a researcher for the Canadian department of mines early in his career and did postdoctoral study at the Massachusetts Institute of Technology.

He came to Washington in 1952 to join the USGS. He worked on lunar rock samples from NASA space missions.

After retiring from USGS in 1988, Dr. Senftle taught physics at Howard University until last year. He was an adviser to physics graduate students and the author of scientific papers.

He enjoyed camping and was a member of Holy Redeemer Catholic Church in Kensington, where he taught Christian doctrine classes.

His wife of 60 years, Anne Keogh Senftle, died in 2009. Survivors include six children, Patrick G. Senftle of Montgomery Village, Theresa C. Quine of North Potomac, Frank P. Senftle of North Chevy Chase, Joseph T. Senftle of Darnestown, Anne-Francis Senftle of Germantown, and Mary M. Somogyi of Creve Coeur, Mo.; 18 grandchildren; and six great-grandchildren.

— Bart Barnes