The Trinity Test Site

Instrumentation and Bunkers

A complex set of labs, test instrumentation, bunkers, buildings and roads appeared where there had previously been only a few ranch houses and corrals in a near empty desert. Test equipment had to be designed, acquired, located, set up, protected, cabled, connected, calibrated and tested.

Starting in November 1944, military engineers built protective bunkers for instruments and people at 10,000 yards to the south, north, and west of ground zero. South 10,000 was used as the control bunker with the automatic triggering device that would start the timing sequence. It had a wooden periscope for viewing the explosion from inside the bunker. The lead scientist, Dr. J. Robert Oppenheimer, was at this bunker while other key personnel, such as Major General Groves, watched from the base camp.

The three bunkers have been dismantled. The small bunker still visible from the road 800 yards to the west of the tower held seismic and radiation detecting equipment. Instruments had three primary purposes:
– Capture the implosion, the simultaneity or time between detonation, and the release of gamma rays from the nuclear reaction.
– Measure the amount of nuclear energy and intensity of the gamma rays from the explosion.
– Measure damage, blast pressure, earth shock, and heat.

Technicians set up dozens of field experiments that included barrage balloons and fifty Mitchell 35mm and FASTAX high speed cameras to record the test. Cameras faced upwards at mirrors that faced ground zero. Hundreds of miles of wires were strung between base camp, the instrumentation, and the control bunker to carry signals from the automatic triggering system that turned on instrumentation and carried data signals back to protected recorders.  Each experiment and device had to be activated on its own schedule at different points in the count down.

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