Detecting nuclear bombs
Dr Fine
Nuclear bombs fall into the hands of smaller and smaller groups.
It seems that one way to defeat the axiom is thru detection of such
devices. Even to someone as atomically challenged as myself, I
recognize that it becomes a problem of shielding and differentiation.
But even if manufactured and stored inside a mountain, such mountain
would not be perfectly enclosed? And the bomb would need to be
transported to be used.
I am sure governments have such techology already to some extent, but
I don't think to detect any such device. If that would be possible, I
wonder how far in the future?
Maybe this is the wrong group, but I thought that if my idea of an
accidental black hole could be demolished so readily, this question
should be a piece of cake...
David Hawk
"Dr Fine" <dr....@lycos.co.uk> wrote in message
news:ec6c611e.03012...@posting.google.com...
>
> Maybe this is the wrong group, but I thought that if my idea of an
> accidental black hole could be demolished so readily, this question
> should be a piece of cake...
Frankly, I don't think they really demolished your accidental black hole
idea - I believe I have one growing on my desk, from an accretion of story
and research notes, unpaid bills, and stray bits of cat hair. I fully
expect it to suck in my computer any moment now. I know it has absorbed a
few dozen pens - surely, if my cats were stashing all of them under the bed,
I would feel the pens piling up under there by now.
As for nuclear bomb detection, I have the impression that a nuclear
bomb/warhead is not particularly "hot" - that is, it can't be distinguished
from background radiation unless you are almost standing over it - or, of
course, it is in the process of detonating. I could be mistaken, not being
an expert in such things.
Hawk
Erik Max Francis
> My question concerns the axiom:
>
> Nuclear bombs fall into the hands of smaller and smaller groups.
>
> It seems that one way to defeat the axiom is thru detection of such
> devices. Even to someone as atomically challenged as myself, I
> recognize that it becomes a problem of shielding and differentiation.
> But even if manufactured and stored inside a mountain, such mountain
> would not be perfectly enclosed? And the bomb would need to be
> transported to be used.
>
> I am sure governments have such techology already to some extent, but
> I don't think to detect any such device. If that would be possible, I
> wonder how far in the future?
I'm really not exactly sure what your question is. Nuclear weapons emit
radiation. You can detect them with radiation detectors. If you want
to keep a weapon from being detected, you need to put a lot of material
between it and the detectors.
--
Erik Max Francis / m...@alcyone.com / http://www.alcyone.com/max/
__ San Jose, CA, USA / 37 20 N 121 53 W / &tSftDotIotE
/ \ Life is painting a picture, not doing a sum.
\__/ Oliver Wendell Holmes, Jr.
Crank Dot Net / http://www.crank.net/
Cranks, crackpots, kooks, & loons on the Net.
Richard Kennaway
> I'm really not exactly sure what your question is. Nuclear weapons emit
> radiation. You can detect them with radiation detectors. If you want
> to keep a weapon from being detected, you need to put a lot of material
> between it and the detectors.
But how much radiation, and how far does it travel?
Let's say I have a nuclear bomb in the back of my truck, driving to
where I'm going to set it off. Or more topically, hidden under the
floorboards of a military installation being inspected by the U.N. How
close would someone need to get with any sort of detector to have any
idea there might be something there?
How close, if I wrap it in roofing lead?
-- Richard Kennaway
Charles Dyer
(in message <1fplg7d.uib25rpydiguN%ar...@dircon.co.uk>):
> Erik Max Francis <m...@alcyone.com> wrote:
>> I'm really not exactly sure what your question is. Nuclear weapons emit
>> radiation. You can detect them with radiation detectors. If you want
>> to keep a weapon from being detected, you need to put a lot of material
>> between it and the detectors.
>
> But how much radiation, and how far does it travel?
It depends on what your bomb's built of. Pu-239 is an alpha emmitter. Alphas
can be stopped by a sheet of cardboard. It also does spontaneous fission,
during which neutrons of varying energies are emmitted. Depending on the
energy, you might need anthing from lead foil to large thicknesses of
concrete to stop the neutrons from getting out. During the storage phase it
doesn't do much spontaneous fission; that's why the critical mass is
critical. Below that mass, little happens. Above that mass, boom. Pu-240 is
similar, as is U-235. Pu-241 emits betas as well as alphas. Betas require
plywood or similar to stop. Most beta-emitting isotopes of Pu tend to be
unstable and it's not usually a good idea to build your nuke bomb out of
unstable stuff. (Half-life of Pu-239: 24,400 years. Pu-240 is 6580 years.
Pu-241 is 13.2 years. U-235 is 710,000,000 years. Building a bomb with Pu-241
is pretty much a use it right now or lose it situation.
>
> Let's say I have a nuclear bomb in the back of my truck, driving to
> where I'm going to set it off.
The alphas won't be detectable beyond more than 5-10 metres in air. The
neutrons may be detectable at ranges measured in kilometres, but anyone
sniffing for neutrons would have to be lucky or very, very, very paranoid to
both pick 'em up and and figure that they're not part of normal background
radiation.
> Or more topically, hidden under the
> floorboards of a military installation being inspected by the U.N. How
> close would someone need to get with any sort of detector to have any
> idea there might be something there?
A gieger counter would do. So would a gold-leaf electroscope. I'm sure that
there are much better radiation sniffers. However, the _best_ way would
probably be to sniff for traces of the explosives necessary to make the bomb
work. There are _very_ good chemical sniffers out there, and it's remarkably
difficult to build a bomb (nuke or otherwise) and hermetically seal it so
that no air gets in or out and still not leave _some_ traces of the
explosives on the outside. It can be done, but it's not easy. Looking for the
explosives has the advantage of finding non-nuke weapons.
>
> How close, if I wrap it in roofing lead?
That will stop the alphas and any betas. It'll even stop low-energy neutrons.
It won't do much for high-energy neutrons or gammas. If you want to stop 100%
of those, you'd better have a metre or two of lead and concrete handy.
You may want to consult books such as the Chemical Rubber Company's Handbook
of Chemistry and Physics, and a good univerisity freshman/sophomore-level
physics text. Be prepared for terms like 'particle intensity', 'decay
energy', 'thermal neutron cross-section', and 'particle energy'.
--
We are Microsoft of Borg. You will be assimilated. Stability is irrelevant.
Where _you_ want to go to today is irrelevant. We will add your currency to
our own. Bend over right now. Resistance is futile.
Jaak Suurpere
Use U rather than Pu.
U-235 has 30 000 times longer half-life than Pu-239. thus 30 000 times
weaker radiation.
How penetrating is the radiation either of these emits?
George William Herbert
>ar...@dircon.co.uk (Richard Kennaway) wrote:
>> Erik Max Francis <m...@alcyone.com> wrote:
>> > I'm really not exactly sure what your question is. Nuclear weapons emit
>> > radiation. You can detect them with radiation detectors. If you want
>> > to keep a weapon from being detected, you need to put a lot of material
>> > between it and the detectors.
>>
>> But how much radiation, and how far does it travel?
>>
>> Let's say I have a nuclear bomb in the back of my truck, driving to
>> where I'm going to set it off. Or more topically, hidden under the
>> floorboards of a military installation being inspected by the U.N. How
>> close would someone need to get with any sort of detector to have any
>> idea there might be something there?
>>
>> How close, if I wrap it in roofing lead?
>>
>Another obvious thing to do:
>Use U rather than Pu.
>U-235 has 30 000 times longer half-life than Pu-239. thus 30 000 times
>weaker radiation.
>How penetrating is the radiation either of these emits?
There are several types of radiation emmitted.
There is the "normal" decay chain which mostly determines
the half life of the isotope. For both Pu-239 and U-235 this
is an alpha decay, which will practically be shielded by
anything at all.
However, there are also alternative decay modes, plus
spontaneous fission.
And, no bomb could be made out of *pure* nuclear materials;
processing to create "weapons grade" U or Pu leaves in significant
contaminants of less desirable isotopes, whose characteristics
have to be factored in based on their relative abundance.
Spontaneous fission produces neutrons and gammas.
U-235 has a SF rate of 0.16 fissions/sec/kg. U-238
has a SF rate of 5.51 fissions/sec/kg. Pu-239 has a
SF rate of about 10 fissions/sec/kg. Pu-238 has a SF
rate of about 1.1x10^6 fissions/sec/kg. Pu-240 has a
SF rate of about 415,000 fissions/sec/kg. Pu-241 has
a low SF rate, but Pu-242 has a SF rate of about
800,000 fissions/sec/kg.
For alternate decay modes, there are alpha, beta, gamma,
neutron, SF, X-ray, electron... all sorts of things.
You have to look in detail at the isotope tables for
each one, a task which is beyond the scope of a single
Usenet posting.
See for example:
http://gawain.membrane.com/hew/Nwfaq/Nfaq6.html
http://t2.lanl.gov/data/map.html
What does this mean for bomb detection? Obviously looking
for alphas is a lost cause, as they will likely be stopped
by the chemical corrosion resistance plating on the fissile
material much less the cm to tens of cm of reflector, tamper,
explosives, casing, etc. You need to look to the alternative
emissions; neutrons, gammas, to some extent betas, x-rays, etc.
All of those are present, for real materials, in detectable
quantities. The parameters for detection range given assumptions
about shielding are complex and somewhat sensitive topics.
But you can remotely detect (order of tens of meters) typical
plutonium bombs which are not shielded by (order of) tens of
centimeters of lead or better.
-george william herbert
gher...@retro.com
Richard H. Araujo
news:0001HW.BA5E989E...@enews.newsguy.com:
> fission; that's why the critical mass is critical. Below that mass,
> little happens. Above that mass, boom.
What is critical mass for Plutoniam and Uranium respectively? Or more
specifically I'd like to know, what's the smallest size a nuclear bomb
can be?
--
Yrs,
Richard H. Araujo
"The most costly of all follies is to believe passionately in the
palpably not true. It is the chief occupation of mankind."
H.L. Mencken
Dr Fine
> "Dr Fine" <dr....@lycos.co.uk> wrote in message
> news:ec6c611e.03012...@posting.google.com...
> >
> > Maybe this is the wrong group, but I thought that if my idea of an
> > accidental black hole could be demolished so readily, this question
> > should be a piece of cake...
>
> Frankly, I don't think they really demolished your accidental black hole
> idea - I believe I have one growing on my desk, from an accretion of story
> and research notes, unpaid bills, and stray bits of cat hair. I fully
> expect it to suck in my computer any moment now. I know it has absorbed a
> few dozen pens - surely, if my cats were stashing all of them under the bed,
> I would feel the pens piling up under there by now.
>
"Bic" people are and using prime numbers to find out which color ink
is female.
George William Herbert
up to more, alt.war.nuclear (unmoderated, loud) and
alt.war.nuclear.biological-chemical-radiological-moderated
(moderated, more focused; disclaimer: I am the moderator).
Richard H. Araujo <rar...@optonlinee.net> wrote:
>Charles Dyer <char...@newsguy.com> wrote:
>> getting out. During the storage phase it doesn't do much spontaneous
>> fission; that's why the critical mass is critical. Below that mass,
>> little happens. Above that mass, boom.
>
>What is critical mass for Plutoniam and Uranium respectively?
See Carey Sublette's Nuclear Weapons FAQ:
http://gawain.membrane.com/hew/Nwfaq/Nfaq4-1.html#Nfaq4.1.7.1
About 48 kg for an unreflected 93.5% enrichment U-235 sphere,
14 kg for a 93.5% enriched U-235 sphere with 10 cm Be reflector,
and 18 kg for a 93.5% enriched U-235 sphere with 10 cm natural
Uranium (mostly U-238) reflector.
About 11.5 kg for an unreflected 90% Pu-239 sphere, and about
4.4 kilos with a 10 cm natural Uranium reflector.
>Or more specifically I'd like to know, what's the smallest
>size a nuclear bomb can be?
An interesting question.
Carey's treatment of this question is at:
http://gawain.membrane.com/hew/Nwfaq/Nfaq4-2.html#Nfaq4.2.3
We know that the W-54 device was about 28cm x 40cm, with variants
with yields from 10 tons to 1 kt (one test shot in its development
yielded 6 kt, but none of the production versions were that powerful;
the exact design goals for the higher yield test are unclear).
It weighed 23 kg, though one test unit's nuclear assembly was
only 16 kg, which is probably close to the final production W-54
bomb weight minus its casing.
There were atomic artillery shells developed which were smaller
in some dimentions, but heavier; using linear implosion design
technology rather than true implosion, described in:
http://gawain.membrane.com/hew/Nwfaq/Nfaq4-1.html#Nfaq4.1.6.3 )
...these shells weighed as little as 55 kg and are 6" diameter
by 33 inches long in the W-48 model specifically, see for example:
http://gawain.membrane.com/hew/Usa/Weapons/Allbombs.html
Some people have hypothesized "briefcase bombs", but the smallest
we have been able to determine you can actually build looks like
a suitcase bomb (not less than 4-5" thick). Note that Carey did
the design for the bomb in the movie Bad Company, though he wasn't
credited. That particular design is one way we hypothesize a very
small bomb could be built, but it's still on the order of the size
and raw dimentions of the atomic artillery shell units.
-george william herbert
gher...@retro.com
John Schilling
>Charles Dyer <char...@newsguy.com> wrote in
>news:0001HW.BA5E989E...@enews.newsguy.com:
>> getting out. During the storage phase it doesn't do much spontaneous
>> fission; that's why the critical mass is critical. Below that mass,
>> little happens. Above that mass, boom.
>What is critical mass for Plutoniam and Uranium respectively? Or more
>specifically I'd like to know, what's the smallest size a nuclear bomb
>can be?
The two aren't as closely related as you might thing. First off, it
takes substantially more than a critical mass of Uranium or Plutonium
to make a bomb; exactly a critical mass or even 110% of a critical mass
won't do. Well, 110% of a critical mass will produce an explosion,
but no bigger than a modest conventional bomb. For even low kiloton
yields, you need ~1.3 times a critical mass.
Second, what constitutes a "critical mass" depends on the density and
geometry of the system, as well as what you wrap it with. An infinite
mass of plutonium in the form of a very long 10-gauge plutonium wire
is not critical. A 10.5 kg sphere of weapons-grade plutonium at room
temperature and pressure is critical; this is what is normally referenced
as the "critical mass".
But if I surround the plutonium sphere with ~2.5 cm of beryllium, the
critical mass is reduced to ~8 kg, as the Be reflects neutrons back into
the Pu. If I then double the density of the system, by squeezing *really*
hard (600 GPa or 90,000,000 psi), the critical mass is reduced further to
~2 kg.
Most nuclear weapons use rather less than 10.5 kg of weapons-grade
plutonium. They instead economize on expensive plutonium by using
cheap beryllium and even cheaper high explosives, the latter in the
form of an array of cleverly and precisely shaped charges focused on
the Be/Pu sphere to compress it.
The first American, British, and Russian atomic bombs all used about
six kilograms of plutonium. This is a good estimate for first-generation
bombs in general, what a nation working in secret could realistically
hope to accomplish. Quadruple that figure if Uranium rather than
plutonium is being used. So, for detecting cheap homemade nukes, you
need to look at what sort of radiation six kilograms of plutonium
puts out and how much of that makes it through the half ton or so of
beryllium, TNT, and whatnot surrounding it.
Nations with a fair bit of expertise in weapons design have learned to
economize still further on plutonium use. In theory, you could get away
with as little as one kilogram of Pu, but that would require many tons
of neutron reflectors, explosive lenses, and whatnot. What seems to
have been settled on as optimum, is ~4 kg of plutonium and ~1-200 kg of
explosives and reflectors. Newcomers to the nuclear field cannot make
these weapons; it takes test data from earlier generations of bomb
designs, and those tests get you noticed. Concievably one could be
stolen or illicitly sold, but the same expertise that goes into making
these impressive weapons makes for some very impressive security
measures to prevent unauthorized use.
You asked about the smallest possible bomb, which is really the wrong
question. Nuclear weapons have been made that fit inside 6" artillery
shells, and others which are of roughly basketball size and weigh only
fifty pounds or so. None of these have been impressively powerful on
the scale of nuclear weapons, and it turns out that they use a lot more
plutonium than the more traditional sort of bomb. With that size
package, you can't afford much in the way of bulky explosive lens
systems and whatnot, you can't substantially compress the plutonium,
and you are stuck with using nearly 15 kilograms of the stuff to get
a measly kiloton or two at most.
So, very small nukes, suitcase if not briefcase sized, are technically
possible and have been made, but turn out to be horribly uneconomical.
For the cost of the 15 kilograms of Pu that make for a nuclear
artillery shell, any army can afford to buy three large rockets
each with three times the range of the artillery shell, to carry the
three proper nuclear warheads that can be made from the same mass of
fissile material - and those warheads can each have ten times the
yield if you want it, or not. We scrapped our mini-nukes years ago,
putting their plutonium to better use, and it's an even bet the
Russians did likewise. Nobody else was stupid enough to build any
in the first place.
Same deal for spies and terrorists - one briefcase nuke uses the same
plutonium as three half-ton steamer trunk nukes, the steamer trunk nukes
are an order of magnitude more powerful, and if you can afford fifteen
kilograms of plutonium you can trivially afford three mid-sized SUVs
to carry them and thirty spooks or thugs to run interference while you
load the things and drive them to their targets.
Which brings us back to the real question - what are we looking for w/re
people sneaking nuclear weapons into or within our country? And the
answer is still, six kilograms of plutonium or twenty-plus of uranium,
wrapped in half a ton of other stuff.
--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
*schi...@spock.usc.edu * for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *
Ray Drouillard
"Erik Max Francis" <m...@alcyone.com> wrote in message
news:3E38DDEB...@alcyone.com...
> Dr Fine wrote:
>
> > My question concerns the axiom:
> >
> > Nuclear bombs fall into the hands of smaller and smaller groups.
> >
> > It seems that one way to defeat the axiom is thru detection of such
> > devices. Even to someone as atomically challenged as myself, I
> > recognize that it becomes a problem of shielding and
differentiation.
> > But even if manufactured and stored inside a mountain, such mountain
> > would not be perfectly enclosed? And the bomb would need to be
> > transported to be used.
> >
> > I am sure governments have such techology already to some extent,
but
> > I don't think to detect any such device. If that would be possible,
I
> > wonder how far in the future?
>
> I'm really not exactly sure what your question is. Nuclear weapons
emit
> radiation. You can detect them with radiation detectors. If you want
> to keep a weapon from being detected, you need to put a lot of
material
> between it and the detectors.
The above depends on what nuclear materials are used. For instance,
tritium is really easy to shield. Depleted Uranium is barely more
radioactive than a handful of sand (depending on the sand).
(Please note that the above materials will not, in themselves, make a
bomb. Both are merely components.)
How much shielding does it take to make the emissions from U235 or
plutonium indistinguishable from background? Certainly, putting it a
few feet underground is going to make it really difficult to find --
especially if you do it in an area that has a decent amount of natural
radioactivity.
Ray Drouillard
Conrad Hodson
> >
> > How close, if I wrap it in roofing lead?
>
> That will stop the alphas and any betas. It'll even stop low-energy neutrons.
> It won't do much for high-energy neutrons or gammas. If you want to stop 100%
> of those, you'd better have a metre or two of lead and concrete handy.
Roofing lead might be relevant to a vehicle, but hiding radioactives on
land--why not just dig a little deeper? Plain old dirt does a good job of
stopping radiation too, you can grow a crop or build a privy or something
to explain the disturbed soil, and you don't have to bust concrete when
the time comes to recover the stuff and do the terrorist thing.
Notice the way all those weapons inspectors are searching buildings and
bunkers? It's because they can't dig up every wheatfield and date palm in
Iraq. They couldn't even if every American citizen between 18 and 50 were
drafted and issued a shovel. Even a small country is an awfully big place
when you're searching at random, one foot at a time.
Conrad Hodson
Charles Dyer
(in message <Xns931CAC84D55D...@167.206.3.2>):
> Charles Dyer <char...@newsguy.com> wrote in
> news:0001HW.BA5E989E...@enews.newsguy.com:
>> getting out. During the storage phase it doesn't do much spontaneous
>> fission; that's why the critical mass is critical. Below that mass,
>> little happens. Above that mass, boom.
>
> What is critical mass for Plutoniam
IIRC 12 kg
> and Uranium
IIRC 10 kg. Don't rely on either of those figures, it's been a while since I
read up on the subject. Remember that you can make a bomb with most common
isotopes of plutonium, but you'll pretty much need nearly pure U-235 (IIRC
97% pure) if you want to make a uranium bomb. 99.275% of naturally found
uranium is U-238. You'll need some fancy equipment to extract the U-235. It
can all be done with 1930s/40s tech, because it _was_ done with 1930s/40s
tech. You're just not going to be able to hide the fact that you're doing it,
and you're going to be spending _serious_ money. Check out Rhode's
Pulitzer-prize winning book, _The Making of the Atomic Bomb_.
> respectively? Or more
> specifically I'd like to know, what's the smallest size a nuclear bomb
> can be?
If you know what you're doing you can fit a 5-10 kiloton weapon into a 155mm
(6") shell. Doing that requires pulling tricks with the design to make a
subcritical mass go boom. This is not a backyard science project.
If you don't want to have to move the bomb, and have access to a lot of
U-235, and a lathe which runs in an oil bath, you can make your very own
'gun' uranium bomb. Machine two subcritical masses of uranium down so that
they fit very precisely into each other, put one at the bottom of a long tube
and the other at the top, put some very fast acting explosive (RDX or PETN or
something of that order would be best. TNT doesn't have a good enough
propagation wave, and won't work. Gunpowder is right out.) above the upper
mass. Make sure that the tube won't rupture under the stress of the
explosion. Make sure that the two masses are lined up properly. If you do
everything right, you have a Hiroshima-type bomb. Maybe 12 kiloton. You're
not going to make a Nagasaki-type bomb, so don't even dream.
For further information, check out "How to make an atomic bomb and shake up
your whole neighborhood", Analog Magazine, I think in July 1977.
First warning: uranium is a heavy metal. Do not breathe the uranium dust
while you're machining the masses. Do not let any of it get into any open
cuts. Do not eat anything which uranium dust on it. You will die of heavy
metal poisoning before you can die of radiation poisoning. Heavy metal
poisoning is extemely unpleasant.
Second warning: uranium burns very nicely. It is very hard to extinguish. Be
very careful with that lathe. If one of the masses catches fire, you _will_
be in serious trouble, not least because the fumes coming off the burning
metal are toxic. Do not try to extinguish the fire with water, you _will_ be
sorry (for a very short time) if you try.
The above warnings are why the lathe has to operate in an oil bath.
Third warning: uranium is very dense and fairly hard. It is hard to work
with, especially by remote control in an oil bath.
If you think that I'm trying to scare you, you're right. It's not that
uranium (or plutonium, for that matter) are, as some no-nuke-kooks would have
it, the most dangerous substances around. They're not. Co-60, for instance,
is a far more lethal radiation source, and there are many poisons which will
kill you far faster with a far smaller dose. Aluminium burns _much_ better
than uranium ever could. That said, uranium should be handled with respect.
If Co-60 is a taipan, U-235 is, say, an asp. If you mess with Co-60, you're
_dead_. If you mess with U-235, you might live... but you'd know that you'd
been bit. (those interested can look up 'taipan' and 'asp' in Google. It is
not recommended that you go looking for the real thing. They're snakes, and
the taipan in particular has a very bad attitude.)
David Hawk
"Dr Fine" <dr....@lycos.co.uk> wrote
> The inhabitants on the other side are probably wondering who these
> "Bic" people are and using prime numbers to find out which color ink
> is female.
This - is a beautiful response. :D
Dr Fine
> My question concerns the axiom:
>
> Nuclear bombs fall into the hands of smaller and smaller groups.
>
> It seems that one way to defeat the axiom is thru detection of such
Sincere thanks to all who answered!
It seems that detection of such devices is not one way to defeat the
axiom. I'm confident that by posting the question here I'm getting
maximum thinking outside the box, so I infer that there is nothing
outside the reasonable 50-100 year box that is likely to defeat the
axiom either. Specifically, nothing envisioned with planet-wide scan
is going to penetrate simple shielding that will also be available in
the next 50-100 years, nor any necessary effects that could be
reasonably differentiated from many other sources of such affects.
In case anyone is wondering, including John Ashcr0ft or Adm.
P0indexter (Hi John, Hi John), the purpose of my question is only to
better conduct logical analysis of some political issues infrequently
arising in logic groups such as sci.logic, though this particular
question came up in comp.ai.philosophy. I myself am allergic to
anything more than six feet (3 U.S. legs) from my computer and haven't
found an appropriate ethnic group to hate yet. I'm currently
considering Eskimos since the price of water is rising sharply and
it's obvious who is deviously hoarding it as disguised building
materials. But even then it is not necessary for a person of my
stature to go to the trouble of mining U-whatchacallit. I would simply
argue them to death.
P.S. I'm not a real doctor. Just a tree surgeon (the one Dr. Howard
keeps slapping on the forehead).
Peter D. Tillman
gher...@gw.retro.com (George William Herbert) wrote, with his usual
well-informed erudition:
Almost certainly, professional bomb-sniffers use sensitive
gamma-spectrometers (among other devices). I haven't kept up with
state-of-the-art, but even 35 years ago portable gamma-specs could
easily differentiate the natural radioisotopes (which is usueful for
uranium-prospecting), and it would be trivial to program in the spectra
for bomb (and impurity) isotopes.
Heh. One of my first jobs, as an undergrad research asst, was to write a
program to reduce gamma-spec data for the geol. dept's hot new Wang
programmable calculator! There's been, er, some DP progress since then...
Cheers -- Pete Tillman
Consulting Geologist, Tucson & Santa Fe (USA)
Wil McCarthy
> I'm really not exactly sure what your question is. Nuclear weapons emit
> radiation. You can detect them with radiation detectors. If you want
> to keep a weapon from being detected, you need to put a lot of material
> between it and the detectors.
This is where a set of neutrino binoculars would come in really handy
-- see right through the Earth with 'em, and drop a team on anything
suspicious which is not in the global registry. Of course, if the
binoculars can stop a neutrino to detect it, someone will build boxes
out of the same material to hide their nukes. So then you need a
neutrino searchlight scanning through the Earth, and you drop a team
on any suspicious, unregistered reflections. So then the game
becomes, how many nukes can I hide behind apparently legitimate
echoes?
--
Wil McCarthy ( www.wilmccarthy.com )
Engineer, Columnist, Author, etc.
Never hurry / never rest. -- Goethe
Richard H. Araujo
$1...@gw.retro.com:
> Some people have hypothesized "briefcase bombs", but the smallest
> we have been able to determine you can actually build looks like
> a suitcase bomb (not less than 4-5" thick).
This is what I was wondering about. I would guess this is a "stripped"
down version too, with not much if any shielding to hide the tell tale
radiation from people who are looking, which makes it not a truly
genuine threat.
--
Yrs,
Richard H. Araujo
"It has often been found that profuse expenditures, heavy taxation,
absurd commercial restrictions, corrupt tribunals, disastrous wars,
sedition’s, persecutions, conflagrations, inundation, have not been able
to destroy capital so fast as the exertions of private citizens have
been able to create it."
Lord Macaulay
Richard H. Araujo
@spock.usc.edu:
> We scrapped our mini-nukes years ago,
> putting their plutonium to better use, and it's an even bet the
> Russians did likewise. Nobody else was stupid enough to build any
> in the first place.
Therein is where my question originated. I read recently that our
military is starting research on such mini nukes again for the purpose
of bunker buster type bombs. This and the possibility of a briefcase
nuke held by some putz with too much free time are what worry me
--
Yrs,
Richard H. Araujo
"The inherent vice of capitalism is the uneven division of blessings,
while the inherent virtue of socialism is the equal division of misery."
Winston Churchill
Richard H. Araujo
> everything right, you have a Hiroshima-type bomb. Maybe 12 kiloton.
> You're not going to make a Nagasaki-type bomb, so don't even dream.
I thought Hiroshima used implosion not the barrel type of weapon.
As for your warnings, I don't want to build one, I've just always been
incredilby interested in nuclear weapons. It's amazing such power can
be contained in such a small thing. Amazing and scary.
--
Yrs,
Richard H. Araujo
"Uneven economic and political development is an absolute law of
capitalism.
Nikolai Lenin
George William Herbert
>If you do everything right, you have a Hiroshima-type bomb.
>Maybe 12 kiloton. You're not going to make a Nagasaki-type bomb,
>so don't even dream.
The difficulty involved in producing an implosion bomb is
commonly highly overrated. The "Nth Country Experiment"
placed a maximum lower bound on the physics design problem
at about 3 man-years. See:
http://www.gwu.edu/~nsarchiv/nsa/NC/nuchis.html
(links are all the way at the bottom of the page)
In that experiment, the US government selected three
recent Physics PhDs (when the experiment was running,
in 1966-1967) with no specific experience in nuclear
physics or weapons, hired them, and put them into a
research project to develop a nuclear bomb based
entirely on open source information. Less than two
calendar years and three man-years of effort later,
they delivered a design for a reasonably compact
and deliverable plutonium implosion device.
Without tooting my own horn too much, there are several
people including myself who have never been associated with
the government nuclear weapons program who have done enough
research and developed enough expertise to be able to
replicate that feat. There is an unnatural concentration
of us on alt.war.nuclear and the new moderated newsgroup
alt.war.nuclear.biological-chemical-radiological-moderated
but several people there could put it all together if
they wanted to.
Proliferation concerns and US law which makes nuclear
weapon design details Restricted Data classified on
birth even if you are creating them independently
without any secret information have kept that set of
us from doing so, but there have been a number of
people who have gone "all the way" as it were over the
years, including John Aristotle Phillips (see his book
"Mushroom: The story of the A-bomb Kid") who did so
for his senior thesis project at Princeton, and at
least one high school student. The FBI turns up,
classifies all your notes, takes them away, and gives
you a long stern lecture.
-george william herbert
gher...@retro.com
Paul F. Dietz
> Almost certainly, professional bomb-sniffers use sensitive
> gamma-spectrometers (among other devices). I haven't kept up with
> state-of-the-art, but even 35 years ago portable gamma-specs could
> easily differentiate the natural radioisotopes (which is usueful for
> uranium-prospecting), and it would be trivial to program in the spectra
> for bomb (and impurity) isotopes.
However, the natural isotopes are usually in decay equilibrium
with their daughter nuclides, which tend to emit more gamma
radiation. This isn't the case for uranium metal.
Paul
George William Herbert
>This is where a set of neutrino binoculars would come in really handy
>-- see right through the Earth with 'em, and drop a team on anything
>suspicious which is not in the global registry. Of course, if the
>binoculars can stop a neutrino to detect it, someone will build boxes
>out of the same material to hide their nukes. So then you need a
>neutrino searchlight scanning through the Earth, and you drop a team
>on any suspicious, unregistered reflections. So then the game
>becomes, how many nukes can I hide behind apparently legitimate
>echoes?
Hmm. If someone invents a material which will stop neutrinos,
and we can build neutrino searchlights, this obviously leads to
the neutrino cannon and dropping or secretly inserting pellets
of neutrino absorber into hostile facilities, so you can blow
them up by focused intense beams of neutrinos when the War comes.
The Aliens, of course, laugh and wave a stellar grade neutrino
obliterator at us, and all the material worldwide flashes to
plasma and we're left trying to fight off their invasion forces
with crowbars and chunks of granite.
-george william herbert
gher...@retro.com
Erik Max Francis
> This is where a set of neutrino binoculars would come in really handy
> -- see right through the Earth with 'em, and drop a team on anything
> suspicious which is not in the global registry.
A normal lump of fissionable material wouldn't emit neutrinos unless it
was a beta emitter. A fusion _explosion_ would emit neutrinos, of
course.
--
Erik Max Francis / m...@alcyone.com / http://www.alcyone.com/max/
__ San Jose, CA, USA / 37 20 N 121 53 W / &tSftDotIotE
/ \ I'm spreading my wings and I fly / I'm still as the night
\__/ Chante Moore
Lsystem / http://www.alcyone.com/pyos/lsystem/
A Lindenmayer systems explorer in Python.
Wim Lewis
Dr Fine <dr....@lycos.co.uk> wrote:
>Nuclear bombs fall into the hands of smaller and smaller groups.
>
>devices. Even to someone as atomically challenged as myself, I
>recognize that it becomes a problem of shielding and differentiation.
>But even if manufactured and stored inside a mountain, such mountain
>would not be perfectly enclosed?
Hiding it inside a mountain is a particularly interesting suggestion
since many mountains are made of granite and granite is fairly radioactive
as it is. I doubt it would be possible to differentiate the radiation
from a subcritical lump of refined uranium from the radiation coming
from all the uranium in the surrounding rock. I don't know if a Pu bomb would
be easier to detect --- do neutrons from Pu decay have a distinctively
different energy spectrum or anything? --- but I think it would still
be very difficult even if possible.
As I understand it, much anti-proliferation work focuses on the fact that
it's difficult to refine the isotopically-pure bomb material. The
refining process will probably be large and expensive and will use
materials that aren't very common in other industries.[1]
The other point is that if you're hoping to use this bomb in a
military way, instead of as a one-shot terrorist weapon, you'll
want to test your design before you base your strategy on it. Above-
ground tests are easy to detect, and below-ground tests can be
detected seismically. This assumes the organization doing the
detecting is a large nation with access to satellites and
globe-spanning seismic detector networks.
And of course, there's good old-fashioned espionage, using human
and financial approaches. But I'd think that that is harder to do
when you're watching more and more smaller and smaller groups,
instead of a few large nations.
[1] At least, that's the theory. On the other hand, one of my favorite
factoids is that Gore-tex(tm) --- expanded polytetrafluoroethylene ---
was originally developed for the diffusion process for separating
isotopes. So perhaps you could claim to be making clothing and hiking
gear and use the factory as a cover for a refining operation. Who knows?
--
Wim Lewis <wi...@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1
Peter D. Tillman
Right you are, of course -- I've been away from uranium work for, um
decades. [blushes at feebleness of excuse -- disequilibrium was a
constant bugbear in using gamma-specs for, eg, logging drillholes.]
I would suppose that some of the 'tracer' impurity isotopes are
gamma-emitters, but don't know enough about the manuf. process...
My offhand guess is, it would be pretty straightforward to smuggle a
(say) steamer-trunk size nuke into the US. As the daily experience of
the drug-smugglers so vividly demonstrates.
Note that Dave Barry(!) has a pretty good take on this, in his one novel
(whose title escapes me). It's pretty good -- especially the smuggling
scenes.
Let's hope the Russians kept better track of their bombs than
(realistically) seems likely. Another good reason not to live in NYC.
Cheers? -- Pete Tillman
Jaak Suurpere
>
> Proliferation concerns and US law which makes nuclear
> weapon design details Restricted Data classified on
> birth even if you are creating them independently
> without any secret information have kept that set of
> us from doing so, but there have been a number of
> people who have gone "all the way" as it were over the
> years, including John Aristotle Phillips (see his book
> "Mushroom: The story of the A-bomb Kid") who did so
> for his senior thesis project at Princeton, and at
> least one high school student. The FBI turns up,
> classifies all your notes, takes them away, and gives
> you a long stern lecture.
>
What are the experiences of people outside USA?
Charles Dyer
(in message <Xns931DB0F8934A...@167.206.3.3>):
> Charles Dyer <char...@newsguy.com> wrote in
> news:0001HW.BA5F42AE...@enews.newsguy.com:
>> If you do
>> everything right, you have a Hiroshima-type bomb. Maybe 12 kiloton.
>> You're not going to make a Nagasaki-type bomb, so don't even dream.
>
> I thought Hiroshima used implosion not the barrel type of weapon.
Nope. Little Boy was the long thin one. Two subcritical masses of uranium.
Fat Man was the modified spheriod. Multiple subcritical masses of plutonium.
>
> As for your warnings, I don't want to build one, I've just always been
> incredilby interested in nuclear weapons.
I figured that you might want info for story purposes. Your xters had better
know some things or they'll end up like most of the xtrs in _The Hot Car_.
(Basic plot: no-nuke-kooks steal a cobalt-60 irradiator. They do _not_ steal
the carrying case that the irradiator supposed to be placed in for transport.
They know that it's supposed to be placed under water, but not how much
water, so they place it in the radiator of a sports car. On their way back to
their hideout they pick up lethal doses of gammas and fast neutrons. The car
is stolen... hence the title, for two reasons.) IIRC one of the Arabs who
were guarding the cave where the bomb was being built in _The Sum of All
Fears_ breathes some plutonium dust. Oops.
> It's amazing such power can
> be contained in such a small thing. Amazing and scary.
you don't need nukes to do a thorough job of wrecking something. Look up the
stats on what high-end chemical explosives can do. Or, better, what an
electrical device with a really high power density can do if you short it
out. Or a fuel-air-explosive. It's _much_ easier to build those than to build
nukes.
John Schilling
>schi...@spock.usc.edu (John Schilling) wrote in news:b1chbb$706$1
>@spock.usc.edu:
>> We scrapped our mini-nukes years ago,
>> putting their plutonium to better use, and it's an even bet the
>> Russians did likewise. Nobody else was stupid enough to build any
>> in the first place.
>Therein is where my question originated. I read recently that our
>military is starting research on such mini nukes again for the purpose
>of bunker buster type bombs.
Those would be "mini" only in the sense of low explosive yield, probably
adjustable from 100 tons to 10 kilotons depending on the mission. The
actual weapons would probably weigh a ton or two. Strip away the (very
heavy, given the application) bomb case, and you'd find a stock U.S.
military issue atomic bomb, of the sort normally used to trigger hydrogen
bombs (B-61 or B-81, most likely). Only this time, no hydrogen bomb
attached, just lots of dense metal to punch deep into dirt, rock, or
concrete before detonating the atomic bomb.
No great proliferation or terrorist risk here, no more so than a normal
military nuclear weapon. First, even if you strip it down to the bare
minimum A-bomb parts, you're still talking a couple hundred pounds.
Second, you can't actually do that because the core A-bomb parts are
protected by anti-tamper systems that will melt key bits to slag if
you try to disassemble or detonate it without codes that you don't have.
Third, if you imagine salvaging the plutonium from the wreckage and
building your own bomb around it, these are sophisticated modern
nuclear weapons. They get away with using 4-5 kg of plutonium by
using sophisticated implosion systems you can't duplicate. As an
amateur, you need 6-10 kg of plutonium, and it just isn't there.
Thomas Womack
George William Herbert <gher...@gw.retro.com> wrote:
>About 48 kg for an unreflected 93.5% enrichment U-235 sphere,
>14 kg for a 93.5% enriched U-235 sphere with 10 cm Be reflector,
>and 18 kg for a 93.5% enriched U-235 sphere with 10 cm natural
>Uranium (mostly U-238) reflector.
>
>About 11.5 kg for an unreflected 90% Pu-239 sphere, and about
>4.4 kilos with a 10 cm natural Uranium reflector.
In _Project Orion_ by George Dyson, Ted Taylor is reported as talking
about boosted-fission designs fifteen centimetres in diameter and
using no more than a kilogram of plutonium, machined into a very thin
shell. I've not read about this anywhere else, but it sounds almost
plausible -- _Project Orion_ feels very strongly like a teaser for the
unlikely-to-be-published (but almost certainly extant and readable by
anyone with a Q-clearance and need-to-know) "Nuclear Weapons Design
1939--1970; a Technical History".
George William Herbert
I believe those specific details taken together in a single design
lie outside the relm of physical possibility.
The amount of energy needed to compress a kilogram of plutonium
to sufficient criticality to ignite fusion boosting (250 tons)
is more than the explosive energy contained in an explosive system
on the order of 15 cm in diameter, even assuming 100% efficient
energy transfer into the fissile material.
See:
http://gawain.membrane.com/hew/Nwfaq/Nfaq4-2.html#Nfaq4.2
Specifically, 4.2.3.2 Minimum Fissile Content
-george william herbert
gher...@retro.com
Robert Shaw
> Wil McCarthy <wmcc...@sprynet.com> wrote:
>> This is where a set of neutrino binoculars would come in really handy
>> -- see right through the Earth with 'em, and drop a team on anything
>> suspicious which is not in the global registry.
>
Higher energy neutrinos have an higher cross-section.
Eventually, at high enough energies, they become indistinguishable
from electrons.
At energies well short of that neutrinos will have a typical
path length in the earth in a useful range, say 100 km to
5000 km.
Produce massive amounts of such neutrinos at a handful
of sites, carefully tuned to emit with a known energy and
intensity, and they will be detectable with large instruments
built of current materials.
Such a system could produce a real time x-ray of the
earth, revealing anything suspicious, and it wouldn't be
blockable.
--
Matter is fundamentally lazy:- It always takes the path of least effort
Matter is fundamentally stupid:- It tries every other path first.
That is the heart of physics - The rest is details.- Robert Shaw
Richard H. Araujo
> uranium. Fat Man was the modified spheriod. Multiple subcritical
> masses of plutonium.
Never knew that. I guessit makes sense when looking at the bombs, so I
should have known.
> you don't need nukes to do a thorough job of wrecking something. Look
> up the stats on what high-end chemical explosives can do. Or, better,
> what an electrical device with a really high power density can do if
> you short it out. Or a fuel-air-explosive. It's _much_ easier to build
> those than to build nukes.
True, but aren't they a bit more bulky? As I understand a Fuel Air Bomb
pretty much destroys an area a mile or so in diameter. This as opposed
to a massive nuke that can take down a city the size of New York...
It's just a bit more impressive to me.
--
Yrs,
Richard H. Araujo
"What is history but the story of how politicians have squandered the
blood and treasure of the human race."
Thomas Sowell
Michael J Ash
> At energies well short of that neutrinos will have a typical
> path length in the earth in a useful range, say 100 km to
> 5000 km.
>
> Produce massive amounts of such neutrinos at a handful
> of sites, carefully tuned to emit with a known energy and
> intensity, and they will be detectable with large instruments
> built of current materials.
>
> Such a system could produce a real time x-ray of the
> earth, revealing anything suspicious, and it wouldn't be
> blockable.
Forget the weapons search, imagine the applications in geology! How
impractical would a system like this be?
--
"From now on, we live in a world where man has walked on the moon.
And it's not a miracle, we just decided to go." -- Jim Lovell
Mike Ash - <http://www.mikeash.com/>, <mailto:ma...@mikeash.com>
Robert Shaw
"Michael J Ash" <mik...@csd.uwm.edu> wrote
> On Mon, 3 Feb 2003, Robert Shaw wrote:
>
> > At energies well short of that neutrinos will have a typical
> > path length in the earth in a useful range, say 100 km to
> > 5000 km.
> >
> > Produce massive amounts of such neutrinos at a handful
> > of sites, carefully tuned to emit with a known energy and
> > intensity, and they will be detectable with large instruments
> > built of current materials.
> >
> > Such a system could produce a real time x-ray of the
> > earth, revealing anything suspicious, and it wouldn't be
> > blockable.
>
> Forget the weapons search, imagine the applications in geology! How
> impractical would a system like this be?
>
Colliding electron and positron beams, tuned to the right energy,
sounds like the simplest method, We have the technology
but not on the scale required.
Detectors could just be the current design, which work,
but more compact would be better. One suggestion
I've seen somewhere is to use a defect-free lead cube
kept at a temperature of, say, 10^-2 K.
At that temperature thermal noise is low enough that
individual phonons can be reliably picked out. When
a neutrino hits a electron in the middle of the cube, it
deposit momentum, exciting a phonon.
In essence, sensitive detectors could hear the rustle
of neutrinos ghosting through matter.
Further thoughts suggest there are going to be some
luminosity-resolution constraints on performance
Put the source and detector 10,000 km apart.
You need enough of a signal to detect above background
noise, and you need to detect small variations in the signal.
If you have an average of 5 events a day, with an average
of 2 from background noise, you can only measure the
received intensity to within around 20%. Resolution will
be poor, maybe only picking out features with a 1000km
length scale lasting for at least a day.
Ideally, we'd like to detect features a few metres across
lasting for just seconds.
Turn up the source power and resolution will go up, but
there will be side effects.
E.g, our detector is a 100m lead cube, detecting 10^6
events each day. A person next to it, with a volume
of 1 m^3 and one-tenth the density, will be hit
by an average of 0.1 neutrinos a day. That level
of exposure is harmless, and such a cube could
fits in most universities.
However, a person 1km from the source will
absorb 10^7 neutrinos a day. Some will just
ionise atoms, others will hit the nucleus. That
radiation level would, I think, be fatal.
To reduce the radiation hazard at 1km to safe levels
you need either to build a 10km cube detector (which
is not easy to find the space for) or produce steerable
neutrino beams, which adds to the technical difficulty
of building the neutrino source, and may still be a radiation
hazard to its neighbours.
For geology, you could just count events per year instead,
which reduces the luminosity needed to give any resolution
by 365, but means you won't spot daily fluctuations in density
and makes background noise more of a problem.
Another option is to put the sources and detectors
within a few hundred km of each other. This also lets
you turn down the luminosity, but restricts you to scanning
the top 1km or so. That may be adequate for detecting
nuclear weapons, but probably not for geology.
Paul F. Dietz
> Forget the weapons search, imagine the applications in geology! How
> impractical would a system like this be?
It's been proposed
http://www.tera.it/pubblicazioni/UA/tampere.pdf
I like the idea of using one in space to do neutrino tomography
of the Sun.
Paul
Timothy Little
>However, a person 1km from the source will absorb 10^7 neutrinos a
>day. Some will just ionise atoms, others will hit the nucleus. That
>radiation level would, I think, be fatal.
Well, even if each one deposited an MeV into tissue, that's a
whole-body dose of only about 20 nJ/kg. Biological effects are
typically detectable at levels on the order of 10-100 mJ/kg.
Depending upon type of radiation, fatalities are associated with doses
on the order of 0.5-5 J/kg or so.
To put it simply, the human body has a *lot* of atoms. 10^7 is
trivial.
- Tim
Paul F. Dietz
> Generating suitable neutrinos won't be easy.
> Colliding electron and positron beams, tuned to the right energy,
> sounds like the simplest method, We have the technology
> but not on the scale required.
What? Neutrino beams are generated by slamming protons into
a fixed target, and letting the pions (and other particles)
decay.
Paul
Erik Max Francis
> Well, even if each one deposited an MeV into tissue, that's a
> whole-body dose of only about 20 nJ/kg.
Converted to radiation units, that's 20 nGy, or if you prefer non-SI
radiation units, that's 2 urd. That's a really, really low dose.
That's just the "absorbed dose." Different types of ionizing radiation
do different amounts of damage, so there's a quality factor that relates
actual (massic) absorbed energy dose to something which scales to the
amount of physical damage done; the resulting unit is "dose equivalent"
and is measured in Sv (rem in old units).
It's been asked a few times in the past, but I haven't the slightest
idea what the quality factor for neutrinos is. In the limit Robert Shaw
was talking about, neutrinos start to look like electrons, and electrons
have a quality factor of 1, so we can turn that 20 nGy = 2 urd figure to
an actual dose equivalent of 20 nSv = 2 urem.
> Biological effects are
> typically detectable at levels on the order of 10-100 mJ/kg.
> Depending upon type of radiation, fatalities are associated with doses
> on the order of 0.5-5 J/kg or so.
You're talking orders of magnitude here, so we're okay (since only in a
few cases (very high energy neutrons, alphas and heavy nuclei) does the
quality factor rise above 10.
Working the problem backwards, a whole-body, short-term LD50 dose is 4
Sv = 400 rem. For electrons (Q = 1), that corresponds to 4 Gy = 4 J/kg.
> To put it simply, the human body has a *lot* of atoms. 10^7 is
> trivial.
Absolutely.
--
Erik Max Francis / m...@alcyone.com / http://www.alcyone.com/max/
__ San Jose, CA, USA / 37 20 N 121 53 W / &tSftDotIotE
/ \ It is not enough to succeed; others must fail.
\__/ Gore Vidal
Church / http://www.alcyone.com/pyos/church/
A lambda calculus explorer in Python.
John Schilling
>Thomas Womack <pmx...@merlot.uucp> wrote:
>>In _Project Orion_ by George Dyson, Ted Taylor is reported as talking
>>about boosted-fission designs fifteen centimetres in diameter and
>>using no more than a kilogram of plutonium, machined into a very thin
>>shell...
>I believe those specific details taken together in a single design
>lie outside the relm of physical possibility.
>The amount of energy needed to compress a kilogram of plutonium
>to sufficient criticality to ignite fusion boosting (250 tons)
>is more than the explosive energy contained in an explosive system
>on the order of 15 cm in diameter, even assuming 100% efficient
>energy transfer into the fissile material.
It's possible that Taylor was talking only about the pit dimensions;
fifteen centimeters seems only a little small for a highly efficient
flying plate design with a kilogram of Pu plus reflector/tamper. It
obviously takes a rather larger volume of HE, I get ~50cm diameter
minimum, to achieve supercritical compression, but I can see "15cm
pit" being confused to "15cm bomb" somewhere between the real design
and the book.
John Schilling
>Charles Dyer <char...@newsguy.com> wrote in
>news:0001HW.BA6154AF...@enews.newsguy.com:
>> you don't need nukes to do a thorough job of wrecking something. Look
>> up the stats on what high-end chemical explosives can do. Or, better,
>> what an electrical device with a really high power density can do if
>> you short it out. Or a fuel-air-explosive. It's _much_ easier to build
>> those than to build nukes.
>True, but aren't they a bit more bulky? As I understand a Fuel Air Bomb
>pretty much destroys an area a mile or so in diameter.
The largest fuel-air bombs, weighing on the order of a ton, will pretty much
destroy an area roughly a tenth of a mile in diameter. FAE weapons are
grossly over-hyped in the mass media and subsequent popular discussion;
they are not even close to being in the same league as typical nuclear
weapons.
George William Herbert
>[...]
>It's possible that Taylor was talking only about the pit dimensions;
>fifteen centimeters seems only a little small for a highly efficient
>flying plate design with a kilogram of Pu plus reflector/tamper. It
>obviously takes a rather larger volume of HE, I get ~50cm diameter
>minimum, to achieve supercritical compression, but I can see "15cm
>pit" being confused to "15cm bomb" somewhere between the real design
>and the book.
That explanation makes sense to me.
-george william herbert
gher...@retro.com