I haven’t done any explosives blogging in a while, and a conversation over the weekend reminded me that I had two links pending:
Derek Lowe’s latest “Things I Won’t Work With”: chlorine azide.
A while back, Joe Huffman (of Boomershoot fame) exchanged emails with a gentleman named Lawrence Johnston. Dr. Johnston worked at Los Alamos during the war: specifically, he worked on designing the detonation mechanism for the implosion bombs. Mr. Huffman has a link to a presentation Dr. Johnston gave in 2006, on his experiences at Los Alamos.
In particular, the material about designing the detonators is fascinating stuff. The problem with the implosion device is that, in order to get it to work, they had to set off 32 separate explosions (in explosive lenses arranged around the core of the bomb) and all of those explosions had to take place within 1/10th of a microsecond. Using conventional detonation mechanisms gives you a timing of several tens of microseconds, which won’t work when you’re trying to get a bunch of explosive fronts to converge into one spherical wave. So how do you solve this problem? Dr. Johnston developed the exploding bridgewire detonator for this purpose, and there’s some great stuff in his presentation about things like the D’autriche test for detonator timing, determining the blast yield of the early bombs, and what daily life at Los Alamos at the time was like. I commend Dr. Johnston’s presentation to your attention, and regret not blogging it sooner.