Julian N. Bernacchi had three main assignments in the Manhattan Project. The most significant was as the Security Officer of Dr. Arthur Holly Compton, who was director of the Metallurgical Laboratory of the Manhattan Project. Julian had this responsibility from early 1942 to April 1945. During this time period, if Dr. Compton didn’t need his services as his armed guard, Julian aided in setting up a police department in Oak Ridge, TN. In civilian life, Julian was a detective in the Chicago Police Department. While the Army had many guards in this rapidly growing construction town of Oak Ridge, there was no police force to handle the normal problems of a big city. Julian became a Detective in a newly created Detective Division.
In early July 1945, Julian was one of a group of special agents who were assigned to Santa Fe, NM. There, he was briefed on his duties for the day of the explosion of the first atomic bomb: Record his own observations, set up a barograph, and after the explosion, move within a few miles of the scene and take readings on the three Geiger counters to record the radiation. On July 16, 1945, in Alamogordo, NM Julian witnessed the explosion of the first atomic bomb, then completed his assignment.
Following the war and after he was honorably discharged from the Army, Julian returned to the Chicago Police Department where he remained until his retirement on January 16, 1972. He passed away on February 8, 1976.