Hood was the largest atmospheric test ever conducted at NTS (and in continental U.S.). This was a test of a two-stage thermonuclear device designed by UCRL (University of California Radiation Laboratory), even though the U.S. government stated at the time that no thermonuclear tests were being conducted in Nevada. The design was intended to fill a gap in 300-400 lb. thermonuclear warhead technology, and was tested at reduced yield. The predicted yield was 60-80 kt. The device used a boosted Swan primary (which gave yields of 12-19 kt in other tests during Plumbbob). About 7 kt of the overall yield was from fusion. The device was a small diameter system (12.1 inches) and was 42.2 inches long. Total device weight was 393 lb. The test also included troop maneuvers by 2500 Marines, and air operations by 124 aircraft. Operation Plumbbob was conducted at the Nevada Test Site (NTS) from May through October of 1957. It was the sixth test series at NTS and consisted of 29 tests. Six of these...