Posts Tagged ‘John Coster-Mullen’

Visions

Installing the Bomb

Friday, January 20th, 2012

Old bomb casings are just that perfect outdoor arrangement for your museum about war. And hey, let’s be honest: we’ve got quite a few of them left over from the Cold War. Might as well use them for something!

Today’s photo of the week is the installation of a Fat Man casing at the Los Alamos Science Museum:1

I love this photo for it’s wonderful contrast of tone, and the man-meets-bomb aspect. It also highlights how physically large the Fat Man bomb was, something that can get lost when you see photos of it in isolation. I’m not sure if the bomb is literally whitewashed here, or if that’s just how it looks in a black and white photo, but that’s a nice aspect, too.

Some more thoughts on atomic bomb casings and their public history follow after the jump.

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Notes
  1. Source: National Archives and Records Administration, Still Pictures Branch, 454-RF-30. []
Meditations

You Don’t Know Fat Man

Monday, November 28th, 2011

Everybody knows “Fat Man,” right? The atomic bomb that was dropped on Nagasaki has been described in some detail in the last few decades. It, just like the “Trinity” “gadget,” was an implosion design bomb that used explosives lenses to compress its plutonium core.

A novel solution to the threat of "dirty bombs"? A "Fat Man" display casing being driven through a Los Alamos car wash. Vouched as legitimate (not Photoshopped) to me over e-mail by a scientist at Los Alamos who claims to have spoken to the truck's driver. The car wash appears to me (via Google Street View) to be the one attached to a "Shamrock" gas station at 1239 Trinity Drive.

Since the implosion concept was first declassified in 1951 as part of the Rosenberg trial,1 there has been a steady stream of information about the “Fat Man” and “Trinity” bomb designs. The most detailed ones on offer today come from Carey Sublette and John Coster-Mullen, two nuclear weapons design speculators who’ve pinned down a relentlessly detailed, fine-grained vision of what those two nearly-identical weapons were supposed to be:

Carey Sublette and John Coster-Mullen's version of the Gadget/Fat Man bombs.

And yet, after all this time, is there still more to know? More details? How wonkish can you get? Here’s my play for bomb-secret-speculator immortality: there was a very specific, small difference between the cores of the Trinity “gadget” and the “Fat Man” devices. (And the crowd goes, oooo.)

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Notes
  1. On the declassification of implosion, see Roger M. Anders, “The Rosenberg case revisited: The Greenglass testimony and the protection of atomic secrets,” American Historical Review 83, no. 2 (April 1978), 388-400. []
Visions

Posing with the Plutonium

Friday, November 25th, 2011

Everybody loves those moments when you feel yourself to be “part of history in the making.” I’m sympathetic with that. It’s exciting when you feel like you’re becoming part of a great movement, or something that people will look back on in wonder. No surprise today that, with the profusion of cell-phone cameras, you can’t go within five feet of anything “historical” without someone snapping their own grainy photo of it. It’s not that they think their cell phone photo of the Mona Lisa is going to be somehow a replacement of it — it’s some kind of act of documentation, some sort of “I was here” motion, in an age where getting accurate reproductions of famous things has become a trivial as typing their names into a search bar. But despite its obvious presence in modernity, the compulsion to self-document seems to be pretty old:

But I digress a bit. Today’s set of images is a grouping of self-documentation that I find fascinating. In the late summer of 1945, a group of scientists and technicians from Los Alamos went to the island of Tinian to prepare for the dropping of the atomic bombs on Japan. The first atomic bombs were big, clunky, ad hoc engineering creations and took a lot of work to put together, so the level of scientific talent was pretty high. Just to illustrate this, it’s worth noting that one of the people who assembled the final bombs was Luis Alvarez, who would later win a Nobel Prize in Physics:

Physicist and future Nobel Prize winner Luis Alvarez posing with a mysterious box on Tinian

The scientists heavily documented the Tinian mission. John Coster-Mullen has used a lot of these now-declassified photos to pretty extreme ends in figuring out exactly what they were doing in assembling these bombs. But my favorite set of photos are these ones the Tinian scientists took of themselves in front of Quonset hut with a funny little box in their hands:1

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Notes
  1. The original source for these are the TR- series of photographs from Los Alamos National Laboratory. These particular files were provided to me by John Coster-Mullen as part of a much larger set of TR- series photos. []
Meditations

The Mysterious Design of Little Boy

Tuesday, November 8th, 2011

On August 11, 1945 — just two days after the bombing of Nagasaki — the U.S. government issued a technical history of the Manhattan Project, written by Princeton physicist Henry DeWolf Smyth.1 The Smyth Report, as it came to be known (its official title was unpleasantly long), was meant to serve as the authoritative guide for what could be publicly said by Manhattan Project participants about the atomic bomb.

One of the areas that the Report was most sheepish about is how the actual charges of the atomic bombs — now called the “physics packages” — are designed. Implosion, the method used on the Trinity “Gadget” and the Nagasaki bomb (“Fat Man”), was ignored completely (and not declassified until 1951). Even the simple “gun-type” design used in the Hiroshima bomb, “Little Boy,” was treated only obliquely:

Since estimates had been made of the speed that would bring together subcritical masses of U-235 rapidly enough to avoid predetonation, a good deal of thought had been given to practical methods of doing this. The obvious method of very rapidly assembling an atomic bomb was to shoot one part as a projectile in a gun against a second part as a target.2

In the early days, most people assumed that meant shooting two halves of a critical mass together, or, in more “real-looking” depictions, such as this very early one from the Austrian physicist Hans Thirring’s Die Geschichte der Atombombe (1946), a small “projectile” being shot into a dense “target”:

“One of the possible constructions of the atomic bomb.” Click to see the full page.

On Thirring’s diagram,3 a “Phantasie” of “Details der Bombenkonstruktion” (you have to love the German here) based on the description in the Smyth Report, you can see that there is a projectile (P) which gets shot down an artillery barrel (R) by conventional explosives into the target (S), which is a larger amount of fissile material embedded in a tamper (T). The role of the tamper (which is discussed in the Smyth Report) is to reflect neutrons and hold together the fissioning mass a few milliseconds longer than it might otherwise be inclined. This allows for more fission reactions and more of an explosion.

So this is more or less how we’ve been talking about gun-type designs since 1945… until very recently. John Coster-Mullen, a trucker/photographer/bomb geek (and a friend of mine), dubbed “Atomic John,” by the New Yorker in 2008, found, through some painstaking research, that this old story was wrong on one important detail.

The actual “Little Boy” bomb was not a small “projectile” being shot into the larger “target.” It’s a large “projectile” being shot into a smaller “target.” That is, as John puts it, “Little Boy” was in fact a “girl”:

A Little Boy diagram from Wikipedia based on John Coster-Mullen’s description.

Now half of you are saying “so what,” the other half are saying “I already know this, I’m an atomic wonk,” and the two of you who are not in that category (and are left out of the halves by rounding errors) are saying, “Cooooool.

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Notes
  1. The paranoid pedant in me wants to point out that the date, August 11, is correct for the distribution date, whereas it is often quoted as August 12. In order to avoid any one newspaper getting the “scoop,” the government requested that none report on it until the morning of the 12th, however. So either date is technically fine. Don’t you feel better, knowing that? []
  2. See §12.19, “Method of Assembly,” in Chapter 12, “The Work on the Atomic Bomb.” []
  3. Those who are very into this bomb thing may recognize that this is the same image as the supposed “Nazi nuke” that made the rounds in 2005. Needless to say I am not super impressed with the claims that this was an actually working bomb and not just a visualization based on Thirring’s book, which itself was clearly based on the Smyth Report. The fact that the “Nazi nuke” refers to the fissile material as “Plutonium,” a name given to it in secret by Americans and only released after the bomb project was made project, makes it patently clear this is very much a postwar construction. []