h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

According to what I remember to have read, you can get away without the photoelectric cell. You just have to design the two subcritical masses properly: One as a ball with a hole in it, the other one as a cylinder that fits exactly into that hole. The ball is attached to one end of the pipe, with its hole pointing towards the pipe. The other piece (the cylinder) waits at the other end, ready to be fired into the ball. If you glue the neutron emitter (let's say a small disc of polonium) to the cylinder and its counterpart (a small disc of beryllium) into the ball, the impact will cause a massive shower of neutrons from the polonium/beryllium right in the middle of a (now) hypercritical mass of U235, thus giving the chain reaction a flying start.

This information is publicly available all over the internet.

Jeremy

I'll take you're word that the properties of polonium/beryllium would result in neutron emissions, sounds like it should work ok, it means a little more machining of the U235, but nothing you couldn't do with a household lathe (and a gas mask)

Don't take my word. A short google search with the keywords

"polonium beryllium initiator"

might give you some more valualbe results.

Jeremy

hmm, came up with a small problem,
as I understand it a polonium beryllium initiator works because when beryllium is exposed to alpha radiation it gives off neutrons. The source for the alpha particles is usually the polonium. In implosion type devices the two metals are at the centre of the ball of fissile material, but the beryllium must be seperated from both the polonium and any other source of alpha radiation.

As I'm using U235, which is a source of alpha radiation, just gluing a beryllium disk to its surface might not be a very good idea.

However, I'm sure it would be possible with a little simple mechanical engineering.

(Please note moderators, I am talking theoretically here)

Hmmm ....

I'm afraid I'll have to crossread the "Fourth Protocol" tonight. As I mentioned before, the whole process of smuggling the parts to GB (Great Britain, not Galaxy Babe) and assembling them to a functional "device" is described very precisely.

I'll call back tomorrow.

Jeremy

OK then, I just freshed up my memories:

The A-bomb in "Fourth Protocol" has 11 substantial parts:
- an electric fuse
- half a pound of plastic explosives
- one Polonium disc, 1" thick, 2" diameter
- one Lithium disc, same diameter, a little thinner
- one steel disc with a thread on the perimeter
- one steel tube, 1 ft long, 4" outside diameter, 2" inside diameter
- one delayed action trigger
- one cylindric piece of U235, 2" diameter, 5" long
- one ball of U235, 5" diameter, with a hole of 2" drilled through its center
- two steel hemispheres, 5" inside diameter, each with a 2" hole in the center

Plus: some nuts and bolts, glue, padding etc. ...

The U235 ball is placed within the hemispheres, then one of the holes is closed with the steel disc after the lithium disc has been glued to it. The explosives are stuffed into the tube, then the U235 cylinder is pushed into the tube after the Polonium disc was lued to it. The "loaded" tube is attached to the other hole of the steel ball, the fuse and the trigger are connected with the explosives.

That's all. Now that I read it again, it is really frightening. I'm no engineer. The tools I have at hand are nothing but some standard household tools. But if I had the parts at hand, I'd be able to put them together in less than 10 minutes and that f*****g thing would work.

And it's all described in a book of a bestseller author, not in some obscure scientific magazine.

Jeremy,
frightened beyond imagination