o The TR-1 (Services) Group, responsible for construction, utilities, procurement, transportation, and communications
o The TR-2 Group, responsible for air-blast and earth-shock measurements
o The TR-3 (Physics) Group, responsible for experiments concerning measurements of ionizing radiation
o The TR-4 Group, responsible for meteorology
o The TR-5 Group, responsible for spectrographic and photographic measurements
o The TR-6 Group, responsible for the airblast-airborne condenser gauges
o The TR-7 (Medical) Group, responsible for the radiological safety and general health of the Project TRINITY participants.
Each of these groups was divided into several units. Individuals were also assigned special tasks outside their groups, such as communications and tracking the TRINITY cloud with a searchlight (3).
1.4 MILITARY AND CIVILIAN PARTICIPANTS IN PROJECT TRINITY
From March 1944 until the beginning of 1946, several thousand people participated in Project TRINITY. These included not only the LASL scientists, but also scientists, technicians, and workmen employed at MED installations throughout the United States. According to entrance logs, film badge data, and other records, about 1,000 people either worked at or visited the TRINITY site from 16 July 1945 through 1946 (1; 3; 8; 15; 16).