At 08:05 PM 2/22/96 -0500, Black Unicorn wrote:
Actually, your design still is vulnerable to my objection, as my objection was specifically to your intermediary chamber concept.
Your intermediary chamber, if surrounding the blasting cap, is likely to detonate to one side first, at a right angle to the axis of the chamber to the explosive assembly.
What I anticipated, to tell you the truth, was a long intermediary thin tube (again, 1 mm diameter for concreteness, just as an example) BETWEEN a chamber surrounding the cap, and the secondary chamber. (the secondary chamber would be carefully designed to spread the shock front evenly) I fully intended to avoid all of the possible consequences of weird explosive modes in common blasting caps. What really mystifies me is that you would think somebody who was intelligent enough to be capable of building a bomb could possibly be unaware of the strange behavior of common blasting caps? Do you think we're all stupid out here?!? Last time I talked to Dr. Edgerton in his lab (You _do_ know about Dr. Edgerton, don't you?!? EG+G?), in about 1978 or so, he showed me some interesting pictures he had taken of blasting caps exploding, and the weird patterns they made. Believe me, from that moment onwards I had no illusions about the predictability of the common blasting cap. BTW, the reason Edgerton paid a bit of attention to ME, as opposed to every other lowly undergrad at MIT, was the fact that I did something he had tried many times and failed to do: For my strobe laboratory project, I decided that I was going to photograph a popcorn kernel opening up at 10,000 frames per second. He called it "impossible": I called it a challenge. That is why I did the project. I showed him 11 frames taken a few weeks later. Dr. Edgerton was suitably impressed.
1> Interference from the milling shape and accuracy o f the openings to the tubes containing the liquid explosive.
Quantify, quantify. How much of a problem?
Clever question given that I am without any information as to the exact shape of your tubes, if they are bowled down towards the explosive assembly, or what their exact width (excepting your vague 1mm figure) might be. You make some guesses as to material, but these two are fairly flimsy even by your own admission.
I don't expect you to be able to "use ESP" and anticipate all the exact mistakes somebody could make. Rather, you should be willing to accept the principle, and explain how much inaccuracy is "too much," and try to give an example of an error that would produce an inaccuracy of this magnitude. So far you've done none of this. I have to conclude you were simply trolling, or intentionally spreading FUD (Fear, Uncertainty, and Doubt) without genuinely trying to get involved in an interesting hypthetical idea. BTW, while I do indeed consider this as purely hypothetical, on the offchance you're a FUDmeister from the government, you should be aware that _I'm_ fully aware that while the main form of radioactive emanation from Pu-239 is alphas which can be stopped by a piece of paper or a few inches of air, I am also fully aware that the decay produces a substantial quantity of gamma radiation (whose exact wavelengths and energies I can easily look up in my trusty CRC Handbook). So don't bother flying an airplane equipped with a gamma ray detector over my house; while I haven't the inclination to do the calculations, were it important to do so I'd calculate the minimum thickness of lead required to reduce the gamma intensity to below-background levels (using gamma-ray cross section tables and the appropriate equations), double or triple it, _and_ ensure that anything I did manage to acquire would be invisible to even a secretly-placed nearby detector at all times. And I'm also fully aware of ground-penetrating SAR (and the possibility of mobile variants) and JSTARS and terahertz radar, etc, so don't bother scanning.
All you need to realize to appreciate the problem is that if you do not have a precisely milled end, with a precise depth into the compressing high explosive outer face, you have differences in how and when the various faces of the explosive assembly are going to initiate. If you make your tubes narrow, it becomes very hard to mill the ends of your tubes, and if you widen the tubes, it exagerates the distortive effect of irregularities in the tube ends.
But you should be able to estimate the magnitude of the errors. Given a certain detonation velocity, for example, and assuming some sort of localized slowdown/speedup to to this velocity, you should be able to estimate (even if only accurate to a factor of 2-3) the amount of error present at that particular junction. Again, the fact that you have never done even this rudimentary analysis is quite telling. You've revealed nothing that I wasn't aware of, and that was apparently quite intentional.
I'm not in the business of designing nuclear initiators. I expose poorly thought out explosive engineering as a hobby. Your best solution is to mill each tube exactly alike, right down the the degree of bend and slope of arc as well as shape of either end. But you could have figured that out without me spelling it our for you.
More likely, I would have velocity-tested sample configurations down to 10 nsec accuracy, which would have revealed any unexpected error sources from temperature and/or pressure variation, as well as mechanical considerations such as bent tubing, etc... [stuff deleted]
But they don't. The timing problem is quite significant. Why do you think high speed and superaccurate switches are so well guarded? There isn't an easy grassroots substitute, if there were, the switches would be fairly useless.
Maybe that's the secret. I already anticipated this. If it's the government's motivation to keep "terrorists" from trying to build a bomb, then their first line of defense might be to make it appear more difficult than it really is. They also know that secrets which are actually turned into running, installed hardware eventually leak to the public, meaning that it might actually be better to keep THEIR bombs complicated, and to not use simplifying hardware.
Remember, kryonic switiches are necessary even when dealing with the speeds of electric conductivity. The velocities of even hydrazine based explosives are signigicantly lower. The margin for error is similarly lower.
How low? Be specific.
Again, I don't know what your dimentions are. Hydrazine explosives tend to detonate around 8500-10000 m/s. The speed of transmission of electric impulses through a given conductive medium is certainly much higher.
Why do you keep mentioning "hydrazine explosives" when I didn't? Are you some sort of "one-trick pony"?
Plutonium gun is still the easiest method for the home grown nuclear device, even if it requires more fissile material.
The "gun" design wasn't used with the plutonium, because IT WOULD NOT HAVE WORKED! "Fat Man," the bomb dropped on Nagasaki, used the implosion
method.
"Little Boy," the gun-method bomb, used U-235. Plutonium detonates far too rapidly to use the "gun" method. The scientists knew that in 1945. You seem to be at least 50 years behind the times.
You are correct this time. My fault. Uranium should have been in there. Typo on my part.
Finally! He's able to admit a MISTAKE!
Hey, be my guest. If you had a critical mass worth of plutonium you're playing around with the wrong list, and, I might add, wasting your time with anything but the black market for the material.
If I had some, or for that matter if I even wanted some, would I be advertising the fact on an "NSA-required-reading" list BEFORE I'd done all this work?