Two developments in the spring of 1944 offered hope for overcoming the asymmetry problems of the implosion weapon. The asymmetry arose in part because the detonation waves diverging from the various initiation points met and interacted to produce small regions of markedly increased pressure. Furthermore, the multiple detonations of the surrounding explosive were not adequately simultaneous. The first problem would be dealt with by the three-dimensional explosive lens, suggested by James Tuck in May and given its basic design by John von Neumann. The second problem could be solved, as Luis Alvarez had suggested in May, by replacing the original inherently variable Primacord detonation distribution systems with electric detonators of highly superior reproducibility, thus providing a means of achieving adequately simultaneous detonation at several points. Developing and producing practical explosive lens and electric detonator systems would require a concerted research and development effort right up to the Trinity test in July 1945.

In view of these difficulties, it seemed wise to try testing the device. The decision to do so was made early in 1944. By the fall of that year, the site selection committee had fixed on the Jornada del Muerto region of south central New Mexico.

Explosives

The research and development of high explosives – materials that detonate at supersonic speeds by a process involving chemical reaction and a shock wave – was (arguably) the most pivotal and problematic component of the implosion program.