o The TRINITY Assembly Group, responsible for assembling and arming
the nuclear device

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