As one of the people given a warning upon the closing of the other thread, I concur with Argos and Swift. There is a fascinating physics topic here that needs exploration. Just a reminder, it boils down to this: can neutrinos from nuclear explosions be detected by the current generation of neutrino detectors?

The daughter nucleus that Argos mentioned, Kr⁹², gives me hope that it can be done. If such detection is possible it gives us a more immediate means of determining whether a tremor is truly a nuclear explosion instead of a dud or a mock-up.

Later on (if this thread doesn't self-combust in the meantime! ) I will give a very crummy back-of-the-envelope calculation of how much neutrino flux might have reached Kamiokande. Which reminds me, is Kamiokande on-line? Sudbury? AMANDA? Soudan? Any other neutrino detectors that I may have missed?

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Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

This link has some history of neutrino detection, including efforts to detect from nuclear explosions or reactors. Most of the work discussed was from reactors and seems to have been mostly unsuccessful.

This link is a paper from Princeton U on "An Assessment of Antineutrino Detection as a Tool for Monitoring Nuclear Explosions". I just talk a quick look at it seems that with current detector designs, for a 1 kton explosion, the detector would have to be from 10 to 100 km of the explosion. I have not read the details of why.

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009

Swift,

Thank you for the links. The first one is also relevant to the discussion of the enormous time lag between the work and the award of a Nobel Prize for it. Forty years elapsed between Cowan and Reines detection of the neutrino and the recognition for it. One would think that if the Nobel committee waits long enough they won't have to give out any prizes at all.

I'll give the second link intense study shortly.

__________________
Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

I studied the paper in the second link, and I can see why it is impractical. I didn't take into account all of the continuously operating nuclear reactors around the world. There is just too much noise for all but the largest underground explosions. Too bad.

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Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

They easily could have had a "fizzle" or predetonation. They almost certainly had to go with a plutonium bomb (no supply of weapons grade uranium). Unlike a uranium bomb a plutonium bomb must be an implosion type. That's because there is always ²⁴⁰Pu contamination (you want ²³⁹Pu) which has a high rate of spontaneous fission. That makes it more likely to cause predetonation.

So it could be that they didn't design the bomb well, causing a poor or slow implosion. But there is another possibility. They may have plutonium with too much ²⁴⁰Pu, leading to predetonation even with proper design.

Anyway, there are a number of possibilities.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

Okay, I'm gradually moving away from the position it was faked by a big amfo bomb like I stated in the now closed thread.

I'm not saying anybody who could get as far as they did are ignorant of nuclear physics but are we going to brain storm for them and point out where they went wrong so they can do better next time? No offense VR, this is an interesting thought exercise and all, but did you see the thead I started in the Conspiracy Theory section, the one called, "If a Picture's Worth a Thousand Words? That second picture really comes to mind right now.

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Gimme a minute to read through Jay's latest observations...

(Looking up the thread.)

Ahem. Wonderful picture.

I'm talking basics that are available with a quick google. This has been public information for longer than I've been alive. If they didn't know this much, I wouldn't trust them building a wheel. Believe me, anybody working on a project like that knows a lot more than I do on the the subject.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

Now Van, your answer to their possible problem was succinct, intelligent and logical. Which is why it was so concerning. Maybe you don't live in a probable impact area, but I do. So do my kids. And the picture was a saterical variation of the "loose lips sink ships" posters. Which is how I meant it. I'm wouldn't rudely tell you to shut up. That would be unfriendly. I have no reason to be unfriendly to you.

We can still be friends, right?

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Gimme a minute to read through Jay's latest observations...

Hum,
indeed, one likely scenario, if we assume that they intended a larger explosion, is that the spherical bomb casing did not implode evenly - this would have lead to reduced yield.

One key element is the initiator or Neutron trigger; Which is needed to obtain a sufficient number of neutrons , within the supercritical core, at the right time.
If the chain reaction starts too soon, the result is only a 'fizzle yield'.
A tried and tested method is to use a radioactive isotope of polonium (Po-210), which is a strong alpha ray emitter combined with Beryllium which will absorb alphas and emit neutrons.
To supply the initiation pulse of neutrons at the right time, the polonium and the beryllium need to be kept apart until the appropriate moment and then thoroughly and rapidly mixed by the implosion of the weapon.
This method of neutron initiation is sufficient for the slower gun combination method, but the timing is not precise enough for an implosion weapon design.
So, the simplest technique, the gun method, can only really be used for U-235 because of the relatively long amount of time it takes to combine the materials, making predetonation likely for Pu-239 which has a higher spontaneous neutron release due to Pu-240 contamination.

For Pu-239 assemblies a contamination of only 1% Pu-240 produces so many neutrons that implosion systems are required to produce efficient bombs. To keep the 240Pu contamination down you can simply expose the device to a neutron source.

Of course, the Korean device may be quite sophisticated and may somehow work around those problems.
But, it is indeed likely that the `implosion` method was used, which uses conventional explosives surrounding the material to rapidly compress the mass to the supercritical state.
If the compression isn't symmetrical then the result is only a 'fizzle yield'.

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`Irony` actually does mean `metal like`...

The sniffed planes have found no trace of any radioactive particles.

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`Irony` actually does mean `metal like`...

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`Irony` actually does mean `metal like`...

Preliminary US military data now indicates that radioactive particles have been found.

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`Irony` actually does mean `metal like`...

WC-135 Constant Phoenix

The WC-135 was retired and brought back to service as an OC-135 Open Skies - a photo-reconnasainse platform to take advantage of the Open Skies Treaty of 1992.

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In the progress of this discussion I shall endeavor to give a satisfactory answer to all the objections which shall have made their appearance, that may seem to have any claim to your attention.

Alexander Hamilton, Federalist No. 1

Yeah, right. There's a possibility they might use tritium to enhance a fission bomb test, but a real fusion bomb would be much harder. I seriously doubt they'd have fusion bombs any time soon. I would also expect their fission bombs would be pretty bulky, not easy to put on a rocket, assuming they had an accurate long distance rocket in the first place.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

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The Leif Ericson Cruiser

Well, maybe. Here's the link to an MSNBC article on it:

http://www.msnbc.msn.com/id/15249383/

U.S. official: N. Korea test likely ‘nuclear fizzle’
One test shows consistency with an atomic explosion, others don't

I'm betting it was a fizzle, due to either design problems or fuel issues, but it is early, and the evidence and the news reports haven't settled down yet. I wouldn't yet rule out a fake of some kind.

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I say there is an invisible elf in my backyard. How do you prove that I am wrong?

Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

more on it

U.S. intelligence statement: N. Korea radioactivity detected
http://www.cnn.com/2006/WORLD/asiapc...a.test.sample/

Could you ellaborate on this? And which websites?
Only pictures of conventinal explosive tests in nuclear context I recall are the ones of The 100 Ton Test, Sailor Hat and Minor Scale, but I doubt anyone ever claimed them to be real nuclear detonations.

Hum,
sry i don't have any links.
But, it was my understanding that movie footage of early nuclear tests were faked to stop giving the soviets any clue as to their design, however unlikely that may sound.
i suspect that photos of early nuclear tests were not made public until the late 1950s.

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`Irony` actually does mean `metal like`...

This subject has become an embarrassment for some it would seem.
The fact that That small defiant nation has snubbed the western world and shown to have a nuclear capability is a little unsettling. I will however point out that as we all know. The having is in its self the weapon. Its the best deterrent there is. To postulate and further threaten North Korea with trade sanctions is foolish. What is it they would hope to achieve. Learn from history., Has this sort of thing worked in the past. No. They attacked Perl Harbor.
As to the question of where they got this bomb. Or was it really a nuclear devise. All seems a little pointless now. They have shown to have detonated a below ground nuclear devise. They have not declared war.