User talk:Fastfission

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[edit] Little Boy

I understand you have been in touch with John Coster-Mullen. I have posted three modified diagrams at the following URLs

http://commons.wikimedia.org/wiki/Image:Gun-Type_Fission_Weapon.gif http://commons.wikimedia.org/wiki/Image:Little_Boy_Internal_Components_(no_labels).GIF http://commons.wikimedia.org/wiki/Image:Little_Boy_Internal_Components.gif

John Coster-Mullen has agreed to these postings, since the last two are made from scanned copies of his work. I hope the licensing is ok, and they don't get deleted.

The .gif format introduces some dithering because of its 250 color limitation, but it is the only lossless compression format I know how to use. I would like to put them into the Little Boy Wikipedia article, but how to do that is not not obvious.

Could you do it?

Thanks, Howard Morland

Heh. Great minds think alike... I have Fastfission's page here on my watch list, saw Howard's comment here, and I dashed off an email note to Carey Sublette well before Fastfission asked me here about it...
Looking at the diagrams, I have to admit that I haven't been focusing on Little Boy's design much in the last couple of years; I've been focused more on the W33, when I spend time looking at gun-type weapons. I was aware of Coster-Mullen's book but hadn't read it yet, and didn't know that it contained the suggestion that the projectile was the annular hollow section of the fissile assembly, with a fixed cylindrical target.
As I pointed out in my email to Carey, this immediately raises suspicions on my part that it's wrong. The primary reason is that it's the least efficient way to assemble the tamper/reflector and target.
Gun weapon target mass is essentially limited by criticality of the reflected target assembly before the projectile arrives; it has to be some reasonable safety factor less than one reflected critical mass just to be safe to assemble the target/reflector assembly. Mc for 93.5% HEU (spherical) with 2 inch / 5 cm WC reflector is around 20-22 kg; for a roughly 2:1 ratio cylinder it's going to be really close to 25 kg, and 3 cm of emtpy space around the target will reduce reflector efficiency a bit (a bit more of the neutrons bounce back into other parts of the tamper/reflector than would reenter the target if the T/R was in close contact). But the assembly seems very very close to prompt fast criticality by itself.
If the target were the hollow assembly, on the other hand, you gain the 1/density^2 factor in criticality reduction. The standard notional components are a roughly 16 cm diameter 16-17 cm long assembly, with a 10 cm diameter projectile and 16 to 17 cm diameter annular target. The target by itself takes up about 3/5 of its enclosed volume - the criticality decrease is about 9/25 or to something like 36% of the full assembly's criticality, which would reduce the notional 30-ish kg target assembly down to about 40% of the reflected critical mass. Much safer that way.
Annular projectiles in other designs, some soviet ones and the W33 for example, make sense. But I think that if you have a fixed reflected target, you want the annular portion to be the fixed target.
As I mentioned, I zapped a note off to Carey to bounce the issue off him. I am currently unaware of the details which Coster-Mullen had available when writing his book. I am open to having my mind changed, but this suggestion seems wrong on first impression.
Howard, I haven't had any contact with you previously, but I've worked with Carey and some others in depth going back over a decade. Perhaps we should exchange email addresses; you can send an email to me via Wikipedia (there's an "Email this user" link on people's home page if they have it turned on) with your contact info and possibly John Coster-Mullen's as well.
Thanks. Georgewilliamherbert 01:12, 28 March 2007 (UTC)

How do I exchange email addresses with User:Georgewilliamherbert? He can get mine from Carey Sublette, along with my March 27 email to the 400k list. HowardMorland 03:43, 28 March 2007 (UTC)

Go to Special:Emailuser/Georgewilliamherbert. ~ trialsanderrors 04:34, 28 March 2007 (UTC)
For what it's worth, I just sent Howard an email via Wikipedia; Carey Sublette hasn't responded to either of my messages today yet. I don't know how busy he is these days, it's been a little while since I last talked to him, but hopefully he sees it and responds sooner.
I am curious what the "400k list" is. I see something related to Technorati, but I'm not sure if that's it or not. Georgewilliamherbert 05:30, 28 March 2007 (UTC)

[edit] Maison Kammerzell

I replaced the edited version with a new one based on your objections. Pls let me know if that alleviates your concerns. Take care, ~ trialsanderrors 19:52, 27 March 2007 (UTC)

[edit] Converting jpg to svg

Hi :) You've got a pretty impressive portfolio! Is there anyway you could convert Image:Hoffman voltameter.jpg to svg? Thanks in advance — Jack · talk · 17:52, Wednesday, 28 March 2007

[edit] Your unprotection of Albert Einstein

I encourage you to reconsider your unprotection of Albert Einstein. In the 24 hours since you unprotected it, it has been attacked 17 times by 13 different anon vandals. If you still feel it does not need long-term semi-protection, please watch the page and revert any vandalism yourself. --teb728 20:28, 29 March 2007 (UTC)

Actually the semi-protection policy says “Indefinite semi-protection may be used for … Articles subject to heavy and continued vandalism, such as George W. Bush.” The Bush article is also heavily watched and quickly reverted; so that is not a reason why an article vandalized 17 times a day like Albert Einstein should not be indefinitely semi-protected. And in the midst of such heavy vandalism sometimes vandalism is not quickly reverted even on a heavily watched page; for example this edit was not reverted until that edit over four hours later. (What happened was that 3 minutes after the vandal edit, the page was blanked, and when the blanking was reverted, the earlier vandalism was not noticed.)
I do not agree that unprotection encourages editing: I for one feel inhibited about editing into heavy vandalism (or revert wars) for fear that my work will be lost in a revert. I also waste time monitoring changes and posting user warnings instead of working on content. --teb728 20:26, 30 March 2007 (UTC)
Having said that, however, I must admit that in the last day vandalism is down and useful contributions by anons are up. So I would be content with deferring reprotection of the article. --teb728 21:53, 30 March 2007 (UTC)
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