gsmith@brahms.BERKELEY.EDU (Gene Ward Smith) (05/10/86)
In article <346@dg_rtp.UUCP> throopw@dg_rtp.UUCP (Wayne Throop) writes: >> From: rb@ccird1.UUCP (Rex Ballard) >> Reguarding plutonium vs. water vapor risks, remember that it >> only takes a few ounces of plutonium to trigger the fusion bomb. >Ounces, schmounces. Even the smallest thermonuclear weapon needs >several *pounds* (not ounces) of plutonium to trigger fusion. And most >> Some tactical weapons (the very small ones) are very small, only 1 or >> 2 Kilotons, enough to level a shopping center or (more likely) >> an airport. Their main advantage is that they are about the size >> of a ping-pong ball and are therefore easy to deliver but hard >> to shoot down. >Holy Shit! Excuse my french, but what planet did the bomb designer come >from anyhow? "Size of a ping-pong ball?" Just a supercritical mass of >plutonium itself is about the size of a softball (or maybe a baseball, >if a real genius of a designer is at work, maybe). And that doesn't >include the hardware to detonate it, nor space to keep it subcritical >until use. Granted, tactical nukes can be the size, say, of a >toaster.... but a *ping* *pong* *ball*? Get real. Maybe you haven't I was talking to an ex-LLL physicist once who told me that there is an isotope of Californium with a *very small* critical mass (a few grams, I think it was). This opened the theoretical possibility of a hand grenade sized nuclear weapon. ucbvax!brahms!gsmith Gene Ward Smith/UCB Math Dept/Berkeley CA 94720 Fifty flippant frogs / Walked by on flippered feet And with their slime they made the time / Unnaturally fleet.
jin@hropus.UUCP (Jerry Natowitz) (05/12/86)
> I was talking to an ex-LLL physicist once who told me that there > is an isotope of Californium with a *very small* critical mass (a few > grams, I think it was). This opened the theoretical possibility of a > hand grenade sized nuclear weapon. I used to wonder if an alloy of Uranium or Plutonium and a good neutron source like Americanium would have a very small critical mass. I have a vague memory that very few known element are fissionable, apparently the nucleous becomes increasingly stable after Plutonium (yes I know that there are some incredibly short-lived nuclides up there, but I thought the general trend is to stability). In any case a "spiked" nuclear device would not have a long shelf life, the rapid decay would mar those nice shiny surfaces. -- Yours in hair, Bear ihnp4!houxm!hropus!jin
jmc@riccb.UUCP (Jeff McQuinn ) (05/14/86)
> I was talking to an ex-LLL physicist once who told me that there > is an isotope of Californium with a *very small* critical mass (a few > grams, I think it was). This opened the theoretical possibility of a > hand grenade sized nuclear weapon. > Californium, isn't that one of those wonderful man-made elements whose shelf life can be measured in microseconds? No wonder it's "theoretically" possible. Jeff McQuinn just VAXing around
weemba@brahms.BERKELEY.EDU (Matthew P. Wiener) (05/16/86)
In article <684@riccb.UUCP> jmc@riccb.UUCP (Jeff McQuinn ) writes: >> I was talking to an ex-LLL physicist once who told me that there >> is an isotope of Californium with a *very small* critical mass (a few >> grams, I think it was). This opened the theoretical possibility of a >> hand grenade sized nuclear weapon. > >Californium, isn't that one of those wonderful man-made elements whose shelf >life can be measured in microseconds? No wonder it's "theoretically" possible. The theoretical possibility is not for a californium bomb--we're mellow remember--but for an xx-ium bomb where xx-ium has *very small* critical mass and long enough half life to assemble the bomb. There is the old conjecture that elements around 124 or so in atomic number are part of new stable range. Maybe that may only mean a ten day half-life at best, but the possibility is definitely there. ucbvax!brahms!weemba Matthew P Wiener/UCB Math Dept/Berkeley CA 94720
ran@ho95e.UUCP (RANeinast) (05/16/86)
>In article <684@riccb.UUCP> jmc@riccb.UUCP (Jeff McQuinn ) writes: >>> I was talking to an ex-LLL physicist once who told me that there >>> is an isotope of Californium with a *very small* critical mass (a few >>> grams, I think it was). This opened the theoretical possibility of a >>> hand grenade sized nuclear weapon. >> >>Californium, isn't that one of those wonderful man-made elements whose shelf >>life can be measured in microseconds? No wonder it's "theoretically" possible. > >The theoretical possibility is not for a californium bomb--we're mellow >remember--but for an xx-ium bomb where xx-ium has *very small* critical > >ucbvax!brahms!weemba Matthew P Wiener/UCB Math Dept/Berkeley CA 94720 Californium will work just fine, thank you. I just looked it up in the CRC handbook. (Doesn't anybody uses references anymore? Oh, yeah. I forgot. This is netnews.) Just for comparisons sake, U-235 has a thermal neutron cross-section for fission of 579.5 barns, and Pu-239's is 742.4 barns. There are two isotopes of Californium with large thermal neutron cross-sections for fission, Cf-249 at 1735 barns and Cf-251 at 4000 (!) barns. With such a large cross-section, I suspect Cf-251 would make a quite small device. And the half-lives? Cf-249 has a half-live of 360 years, and Cf-251's is 800 years, plenty long enough. By the way, the quoted error bars on the Cf-251 were quite large (about 25%). This suggests to me that either they haven't made enough of the stuff to measure it properly, or (more likely), the exact results are classified (because they're using the stuff to make hand grenade sized nuclear weapons). -- ". . . and shun the frumious Bandersnatch." Robert Neinast (ihnp4!ho95c!ran) AT&T-Bell Labs
ken@njitcccc.UUCP (Kenneth Ng) (05/16/86)
In article <684@riccb.UUCP>, jmc@riccb.UUCP (Jeff McQuinn ) writes: > Californium, isn't that one of those wonderful man-made elements whose shelf > life can be measured in microseconds? No wonder it's "theoretically" possible. Which californium? I have the half lives of 11 isotopes of californium listed, from atomic weights 244 to 254. The half lives vary from 25 minutes to 470 years. -- Kenneth Ng: uucp(unreliable) ihnp4!allegra!bellcore!njitcccc!ken bitnet(prefered) ken@njitcccc.bitnet New Jersey Institute of Technology Computerized Conferencing and Communications Center Newark, New Jersey 07102 Vulcan jealousy: "I fail to see the logic in prefering Stan over me" Number 5: "I need input"
gsmith@brahms.BERKELEY.EDU (Gene Ward Smith) (05/16/86)
In article <684@riccb.UUCP> jmc@riccb.UUCP (Jeff McQuinn ) writes: >> I was talking to an ex-LLL physicist once who told me that there >> is an isotope of Californium with a *very small* critical mass (a few >> grams, I think it was). This opened the theoretical possibility of a >> hand grenade sized nuclear weapon. [Gene Smith] >Californium, isn't that one of those wonderful man-made elements whose shelf >life can be measured in microseconds? No wonder it's "theoretically" possible. Consider the following table of isotopes of Californium: Isotope Half Life Cf 248 350 days Cf 249 360 years Cf 250 10 years Cf 251 800 years Cf 252 2.5 years Of these, Cf 248, Cf 249 and Cf 252 are all listed as having spontaneous fission as one decay mode. Especially if the isotope in question was Cf 249 (I don't remember) the thing seems theoretically feasible. ucbvax!brahms!gsmith Gene Ward Smith/UCB Math Dept/Berkeley CA 94720 "There are no differences but differences of degree between degrees of difference and no difference"
bl@hplabsb.UUCP (Bruce T. Lowerre) (05/16/86)
> > I was talking to an ex-LLL physicist once who told me that there > > is an isotope of Californium with a *very small* critical mass (a few > > grams, I think it was). This opened the theoretical possibility of a > > hand grenade sized nuclear weapon. > > > > Californium, isn't that one of those wonderful man-made elements whose shelf > life can be measured in microseconds? No wonder it's "theoretically" possible. Californium, symbol Cf, Atomic number 98, has the following isotopes: At. weight half life decay mode ---------------------------------------------------------- 244 25 minutes a, K 245 44 minutes a, K 246 35.7 hours a 247 2.4 hours K 248 250 days a 249 470 years a 250 12 years a 251 >>18 days a 252 2.2 years a 253 ~20 days B 254 55 days a = alpha, B = beta, K = orbital capture In any case, hardly microseconds.
jablow@brahms.BERKELEY.EDU (Eric Robert Jablow) (05/17/86)
Some man-made isotopes are both relatively stable and very useful in non-martial processes. For example, an isotope of americium (243?) is used in almost all ionization-type smoke detectors. That's why they come with a warning not to throw them out, but to give old ones to your fire department for proper disposal. Respectfully, Eric Robert Jablow MSRI ucbvax!brahms!jablow
jablow@brahms.BERKELEY.EDU (Eric Robert Jablow) (05/17/86)
Anyway, I thought nuclear hand grenades already existed. Just ask Idi Amin. "The Israelis used nuclear hand grenades!" Of course, the blast radius would still be much larger than the throwing range, so .... Respectfully, Eric Robert Jablow MSRI ucbvax!brahms!jablow
g-rh@cca.UUCP (Richard Harter) (05/17/86)
In article <> jmc@riccb.UUCP (Jeff McQuinn ) writes: >> I was talking to an ex-LLL physicist once who told me that there >> is an isotope of Californium with a *very small* critical mass (a few >> grams, I think it was). This opened the theoretical possibility of a >> hand grenade sized nuclear weapon. >> > >Californium, isn't that one of those wonderful man-made elements whose shelf >life can be measured in microseconds? No wonder it's "theoretically" possible. > Isotope # Half Life Cf-249 360 years Cf-250 13 years Cf-251 800 years Cf-252 2.65 years "Californium-252, because 3 percent of its decay occurs by spontaneous fission, is industrially and medically important as a very intense point source of neutrons. One microgram releases 170,000,000 neutrons per minute." -- Encyclopedia Brittannica, 1979. I suppose that ill-informed, foolish remarks do have some merit -- they induce one to do a bit of reading to get the data to refute them. Richard Harter, SMDS Inc.
ken@njitcccc.UUCP (Kenneth Ng) (05/19/86)
In article <3484@hplabsb.UUCP>, bl@hplabsb.UUCP (Bruce T. Lowerre) writes: > > At. weight half life decay mode > ---------------------------------------------------------- > 251 >>18 days a I have 700 years for this isotope. My material is somewhat dated though. Where might I ask did you get your information from? I'd like to update my database. -- Kenneth Ng: uucp(unreliable) ihnp4!allegra!bellcore!njitcccc!ken bitnet(prefered) ken@njitcccc.bitnet New Jersey Institute of Technology Computerized Conferencing and Communications Center Newark, New Jersey 07102 Vulcan jealousy: "I fail to see the logic in prefering Stan over me" Number 5: "I need input"
bill@sigma.UUCP (William Swan) (05/19/86)
In article <3484@hplabsb.UUCP> bl@hplabsb.UUCP (Bruce T. Lowerre) writes: >>> I was talking to an ex-LLL physicist once who told me that there >>> is an isotope of Californium with a *very small* critical mass (a few >>> grams, I think it was). This opened the theoretical possibility of a >>> hand grenade sized nuclear weapon. >>Californium, isn't that one of those wonderful man-made elements whose shelf >>life can be measured in microseconds? No wonder it's "theoretically" possible. >Californium, symbol Cf, Atomic number 98, has the following isotopes: >[...] >In any case, hardly microseconds. Egad, what a letter bomb that'd make! :-) Seriously.. What kind of shielding would such a device require to handle it "safely" (reduce radiation levels to something approximating the levels in our Seattle rainwater)?? Could one still carry it?
bl@hplabsb.UUCP (Bruce T. Lowerre) (05/22/86)
> In article <3484@hplabsb.UUCP>, bl@hplabsb.UUCP (Bruce T. Lowerre) writes: > > > > At. weight half life decay mode > > ---------------------------------------------------------- > > 251 >>18 days a > I have 700 years for this isotope. > My material is somewhat dated though. Where might I ask > did you get your information from? I'd like to update > my database. You're material is probably more "up-to-date" than mine. My info is from CRC, 1963. I'm sure a lot more has been discovered in the last 23 hears. The 700 years is a probably a better figure.
throopw@dg_rtp.UUCP (Wayne Throop) (05/22/86)
> gsmith@brahms.BERKELEY.EDU (Gene Ward Smith) >> throopw@dg_rtp.UUCP (Wayne Throop) >>> rb@ccird1.UUCP (Rex Ballard) >>> Reguarding plutonium vs. water vapor risks, remember that it >>> only takes a few ounces of plutonium to trigger the fusion bomb. >>Ounces, schmounces. Even the smallest thermonuclear weapon needs >>several *pounds* (not ounces) of plutonium to trigger fusion. >>> Some tactical weapons [...] are about the size >>> of a ping-pong ball and are therefore easy to deliver but hard >>> to shoot down. >> "Size of a ping-pong ball?" Just a supercritical mass of >>plutonium itself is about the size of a softball [...] >>Granted, tactical nukes can be the size, say, of a >>toaster.... but a *ping* *pong* *ball*? Get real. > I was talking to an ex-LLL physicist once who told me that there > is an isotope of Californium with a *very small* critical mass (a few > grams, I think it was). This opened the theoretical possibility of a > hand grenade sized nuclear weapon. *First* of all, I was talking about plutonium. *Second*, when somebody says "theoretically", they mean "not really". *Third*, a ping-pong ball is quite a bit smaller than a hand grenade. (Trust me... I've seen both.) There are several reasons to suppose that californium wouldn't make a practical material for weapons production, among them the fact that those with the smallest critical mass also have the greatest thermal neutron production (and thus must be sheilded the most, and ought to have short shelf-life due to neutron activation of the trigger). Note that I agree that a multi-kiloton fission weapon *can* be made the size of a ping-pong ball in *theory*. It is merely far, far beyond current engineering practice (well, I'm pretty sure it is). In theory, it is possible to make a multi-gigaton weapon that size (antimatter), maybe even a planet-buster (anti-neutronium, or maybe anti-just-short-of-black-holium). Or let's get *really* freaky, several unstable quantum black holes in a time-stassis. Again, there is a little matter of implementation... -- Wayne Throop <the-known-world>!mcnc!rti-sel!dg_rtp!throopw
hoffman@hdsvx1.UUCP (05/23/86)
In article <684@riccb.UUCP> jmc@riccb.UUCP (Jeff McQuinn ) writes: > >Californium, isn't that one of those wonderful man-made elements whose shelf >life can be measured in microseconds? No wonder it's "theoretically" possible. Actually, a lot of these "designer elements" have longer half-lives than you might suspect. We use them commercially to produce neutron and gamma sources, and of course a decent longevity is a requirement. We have considered the use of Californium itself; Cf 249 has a half-life of 360 years and is happy to spend them donating alpha particles to our cause, and occasionally undergoing spontaneous fission. Other isotopes of Cf have half-lives ranging from fractions of seconds to more than 800 years! DISCLAIMER: I have no idea which isotope we will REALLY use, or if we will decide to use Cf at all. The above information is offered just as an example of the existence of commercially useful, long-lived artificial isotopes, and should not be construed as any indication of my company's plans or intentions. --Richard Hoffman / Schlumberger Well Services / hoffman%hdsvx1@slb-doll.csnet