I was watching Manh(A)ttan last night, the not at all real story of U.S. development of atomic weapons during WW II, when a major character just tossed out the line, "We'll use exploding-bridgewire detonators...," as if it was the most obvious thing in the world, been around forever, yadda-yadda--
Except it's not. It was brand-spanking new and seriously classified. These characters have been wrestling with the problems of building an implosion-type device for a year or more, including running explosive experiments akin to RaLa (only without the radiation hazard) and one of the major problems is setting off all the implosion charges at the same time. It's a huge big deal -- conventional detonators, then and now, are sloppy things, three or four orders of magnitude* slower than EBW, and you can expect that order-of-magnitude variation within a single batch. Use them to fire off your implosion-type bomb and there's a very loud "bang!" with farty overtones as it barfs out one or more plumes of vaporized radioactive material at the low-pressure points -- a fairly slow plume, as such things go: it's not a bomb, just a very nasty mess.
The need for rapid and synchronous detonation became obvious during the development of the implosion-type atom bomb; Dr. Luis W. Alvarez and his student Lawrence H. Johnston invented (or possibly re-invented) them at Los Alamos, probably in 1944: it was a very big deal. It would not have been taken for granted.
Then again, that same series of episodes has the Nazis send the severed head of an Allied spy in the German nuclear program to the President Roosevelt, and I'm irked about exploding-bridgewire detonators? Yes; after spending so much time on the very real technical challenges of building a implosion-type bomb, the show throws away a major problem to concentrate on the fictional issue of not having a supply of primers for experimental work. It completely misses the point.
There has been, by the way, all manner of soap-opera interaction between the characters; diagramming who's-doing-who would be crowded on a whole sheet of paper. This builds dramatic tension and engages the viewer, just as it should -- is it too much to ask that they not bugger the technological history while they're at it?
(A much smaller quibble: most of the pencils seen onscreen have been Mirado "Black Warriors," a plausible choice since they were in wide use at the time [as Eagle "Black Warrior"] and are still made today; the black body and brass [probably anodized aluminum these days] ferrule with a maroon strip are very recognizable. Now I'm seeing some aluminum-ferrule versions, and I think that's an anachronism. [ETA: is it ever! Plastic ferrules replaced metal during WW II. We can safely assume Uncle Sam might be using up existing stock but silvery-metal ferrules were still rare.] Given the show's tendency to use "scientist-calculating-away-with-pencil" as a recurring image, it can be jarring. In an historical film, there's someone on the Internet who knows the history of every single class of object seen on the screen. With a lot of time and a huge budget, it can all look right. In reality, close often has to be good enough.)
* These would be engineering orders of magnitude, each 10n per step, and not astronomical ones, which I'm not going to be able to explain in a footnote.
6 days ago