how weird are the electronics actually used in nuclear weapons?

[coppercone2]

I mean if a standard engineer that maybe saw a taste of low end military was actually presented with a circuit, would we go 'holy crap that belongs in the art of electronics as its own chapter' or would it be more like 'they dotted their i's and crossed their t's'?

[raptor1956]

Timing is key so someone familiar with DSO front end design might appreciate the design.  I would suggest, however, that we avoid talking in any greater detail on this subject lest someone notice...


Brian

[retrolefty]

While no first hand knowledge, I've read enough to think that the electronics would fall into two categories:

1. Security, including safeties, interlocks, authentication, etc

2. Critical timing requirements for the detonators. Nuclear weapons require very high speed and consistent timing to insure the implosion is uniform enough to ensure critical mass is accomplished.

From wiki:

Krytrons and their variations are manufactured by Perkin-Elmer Components and used in a variety of industrial and military devices. They are best known for their use in igniting exploding-bridgewire and slapper detonators in nuclear weapons, their original application, either directly (sprytrons are usually used for this) or by triggering higher-power spark gap switches. They are also used to trigger thyratrons, large flashlamps in photocopiers, lasers and scientific apparatus, and for firing ignitors for industrial explosives.

 I did have military training and experience servicing teletype and some crypto equipment in the late 60s. Teletype was old tech even back then and I would classify it as mostly electrical rather than electronic. Crypto was a different animal and depending on the specific model the electronics was quite impressive at the time. The KG-13 was the newest design I saw and was very cool in design and construction, all solid state. The other I saw was the KW-26, which was older vacuum tube based and a great heat generator, kept the comm centers quite toasty.

[ajb]

Probably quite "weird" in the same way that all stuff that has to cope with severe mechanical stresses, have a long shelf life, and be 99.9999% reliable is.  Extreme attention to mechanical details, possibly unusual substrates/stackups, hiRel components throughout, etc.  I wouldn't imagine that the trigger mechanism is all that strange, there's definitely an art to getting timing right, but I wouldn't think it would qualify as "weird".  The associated guidance/fuse systems are probably more interesting in that respect.

[coppercone2]

but visually compared to stuff like russian missile electronics you can get off ebay, is it going to look much different? will unheard of amplifier topologies and stuff be used for the hi-rel reasons?

I figure they will put the best possible parts in the coolest packages and with the best strain relief and everything, but if you just look at the circuit diagram are you gonna think "why the hell....?"


i imagined like very wide input ranges and stuff like that, i.e. power supply that is 5V nominal ends up running fine off 500V.



did this ever happen to you with a teletype retrolefty? (watch last 1/3rd or so).
 

[CatalinaWOW]

Having spent a career in this I can offer some fairly accurate general observations.

1.  Engineers in defense have a wide range of skills just like everywhere else.  It shows in the designs.  A specific example of the low end I can mention is an amplifier circuit that had four inversion stages in series.  It was part of a control loop and there kept being confusion over the phase.  Successive engineers, rather than understanding what went before just added another inverter instead of removing one.  By the time I got involved there wasn't time to remove them (and go through all of the environmental qualification) before field test so it just went out that way.  But on the other end you occasionally come across some brilliant topologies or uses of parts.

2.  The vast majority of circuits can trace their pedigree to app notes.

3.  Environmental requirements do drive design a lot.  Other industries like automotive, space and oil field instrumentation have tough environmental requirements also, which is an aid in getting semiconductor parts that meet tough requirements, but are different as they are different from each other.

4.  Much military equipment is expected to sit in storage for many years and then work immediately when unboxed and turned on.  It turns out that that is very different from, and often more difficult than operating for the same number of years.

5. The defense marketplace is small, and currently not socially popular.  Thus you either make do with whatever the commercial world produces and do all of the characterization in your environment yourself, or pay the bill for a specialty manufacturer doing very limited production quantities.  If you use a commercial part and characterize it outside its commercial specifications you will likely have to start over every time they change a process (which often happens with no warning).  This leads to design choices that would seem strange in the commercial world.

[coppercone2]

what do you mean by non socially popular?

i assume a bunch of series inverter to extend bandwidth with specific impedance in mind?

[Brumby]

Society - that is, people - don't look upon defence suppliers with warm and fuzzy feelings.  A lot of the active social voice is happy to decry them as predators on human misery and destruction - and the silent majority is not showing signs of disagreement.

The patriotic reaction to war is not what it was 3 or 4 generations ago.  Certainly there is still a strong support of one's country - but increasingly these days the processes behind the scenes are held in contempt and cynicism abounds.

[coppercone2]

their actually effected by the minor protests we put up sometimes after camel strike #60434?

I know its bad in some countries like portugal when I spoke to some marine special guards but in general I thought it was a fart in the wind. Especially for nuclear. Also some places like Malta's airbases in the 19x0's (def not nuclear free) but now?

[T3sl4co1l]

Nothing very remarkable really, in terms of modern capabilities of timing or logic, or general reliability (the above discussion of military requirements notwithstanding).  The only standout is peak power of the firing pulse (its energy delivered in such a short time), which is much higher than you can do with most transistors.

Let's be real, they originally built these things with 1940s tech after all.

Tim

[coppercone2]

Nothing very remarkable really, in terms of modern capabilities of timing or logic, or general reliability (the above discussion of military requirements notwithstanding).  The only standout is peak power of the firing pulse (its energy delivered in such a short time), which is much higher than you can do with most transistors.

Let's be real, they originally built these things with 1940s tech after all.

Tim

keep in mind the weapons have different generations and weird stuff like tactical odd shapes, bunker busters, etc. who knows what kind of horrors were developed on a drawing board and possibly require different active technologies. given how many they made i am sure they were trying everything they could to make em smaller and cheaper and lighter etc.

[coppice]

There's nothing very special about the circuitry in nuclear weapons. However, missiles must withstand high G forces, so the packaging schemes can be quite novel to deal with those physical stresses.

[CatalinaWOW]

Socially unpopular.  Several major vendors refuse to sell their products to defense firms.  For a specific old example think of Motorola's decision to stop selling parts used in land mines.

My comments weren't specific to nuclear weapons, but nuclear weapons have much in common with other systems.  Arming and fuzing (plus the extra layers associated with nuclear safety).  navigation, guidance, built in test, power supplies...

[EEVblog]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

[coppercone2]

hmm they don't want middle men selling land mines (they get em right into your pocket?)

[coppercone2]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

i think once your that far up the equipment chain you are scared to talk to people at dinner because the KGB might rip your head off no?

nuclear might be better because they don't test it on goats anymore? worst case is what some ameoba or something getting fried in a super secret subterranean test, so long your not in north korea. i hope so anyway....

[floobydust]

Anyone remember the story of a defense contractor (engineer) that set up a store across the street selling electronic components. There was so much paperwork and approvals to procure a component through the military channels, taking months so he set up (his store) with Purchasing and walked across the street to get the parts him and others needed.

I remember it because the story said some Radio Shack capacitors ended up in cruise missiles.

[james_s]

Not really the same thing, but at a previous employer my boss once went to Costco to buy one of our own products because somehow it was cheaper for my group than acquiring it through the standard internal channels. I don't know how that works but there were some pretty convoluted arrangements.

[VK5RC]

In a similar but different vein, one large organisation I worked for had it's own mail section, with two full time staff, it would still take on average 5 working days to hit the mailbox. Any time critical mail, you would buy the stamp and walk it to the box yourself.

[0culus]

There's a reason the really high speed 'scopes and related test equipment from US companies are on the ITAR in the US, and nuclear weapon triggering is pretty much that. At the component level, even "old school" stuff like krytron switching tubes are export controlled.

https://en.wikipedia.org/wiki/Krytron

[hans]

In some colleges, courses about philosophy of engineering have become mandatory. Not only to teach the ethics in academia, like fraud and citing your sources, but also keeping in mind for what causes your inventions can be used.

We have had presentations from some military companies making some really cool systems with very sophisticated information technology in them. But in the end it is a military system, either used to determine defense or offense tactics. That can have ethical pros and cons , depending on which side you fantasize more with I guess.

Likewise, oil/fossil fuel companies have become incredibly non-popular to work for (i.e. internships etc.) in recent years. Having research groups that actively do work on green energy systems doesn't "help" neither.

[CJay]

There's a reason the really high speed 'scopes and related test equipment from US companies are on the ITAR in the US, and nuclear weapon triggering is pretty much that. At the component level, even "old school" stuff like krytron switching tubes are export controlled.

https://en.wikipedia.org/wiki/Krytron

That's just one reason, there are many others, some of which are obscure and non obvious without a little knowledge of how certain military technologies work.

[coppice]

There's a reason the really high speed 'scopes and related test equipment from US companies are on the ITAR in the US, and nuclear weapon triggering is pretty much that. At the component level, even "old school" stuff like krytron switching tubes are export controlled.

https://en.wikipedia.org/wiki/Krytron

Most of the ITAR restrictions, including scopes, relate to sensor technologies, not nuclear ones.

[james_s]

It would be pretty silly anyway, nuclear weapons have been around since the 1940s, plenty of less than friendly nations already have all the knowledge and tools they need to build them. Controlling exports on test equipment isn't gonna do a thing. Any entity with the budget and motivation to build a weapon will find ways around the export controls, there is no shortage of people willing to smuggle items for the right price.

[0culus]

Well, yes, the potential applications in the military space are quite broad, and the ITAR is fairly vague for this reason.

 

It would be pretty silly anyway, nuclear weapons have been around since the 1940s, plenty of less than friendly nations already have all the knowledge and tools they need to build them. Controlling exports on test equipment isn't gonna do a thing. Any entity with the budget and motivation to build a weapon will find ways around the export controls, there is no shortage of people willing to smuggle items for the right price.

I would assume that this is fairly obvious. I was commenting on the fact that a lot of this stuff is ITAR. Whether the ITAR actually prevents anyone from doing anything is another story.

[dmills]

I know a few HOBBYISTS that are having a lot of fun playing with experimental designs for EBW, EF and Slapper detonators and associated pulse supplies, the tech is out there, in the public domain and within the reach of a decent engineers home workshop (Electronics and possibly detonators, not the main physics package). Last I heard they were experimenting with having the things made as flexi PCBs, with printed planar transformers to get the drive impedance somewhat reasonable, and there was talk of saturating reactors for pulse compression right on the flexi.

We got **REALLY** lucky that heavy isotope enrichment is such a pain in the arse, it means that special materials availability is a very effective barrier even to nation state level actors. If there was a viable chemical approach to say uranium isotope separation, and is U235 percentages were a bit higher we would have a real problem. We also got lucky with Pu in that Pu240 isotopic contamination makes the stuff significantly less useful for weapons if you cook it too long.

Electronically, I would be guessing that the pulse power stuff is where the interesting electronics design hides (But is probably not actually that different to what you would find in something like a pulsed gas laser or old school radar set), and the mechanical design to survive the acceleration probably make for interesting assembly issues.
 
Some of the interaction of the electronics and physics for the timing to give variable yield is probably black magic, and I would expect that electronically configured delays may well form part of the positive control interlocks (So that these need to be configured based on information that can only be decoded if the correct arming data is entered).

I don't see the electronics as a big deal, probably simpler then something like a Rb or Cs frequency standard physics package driver.

Interestingly the spherical implosion design (With its timing complexities) really only makes sense if you are critically short on material, there are fairly obvious geometries requiring as little as two detonators instead of dozens of the things in the early devices and that makes the timing problem much less of a pain at the cost of requiring slightly more Pu.   

All just speculation of course.

Regards, Dan.

[coppercone2]

i really intended for this thread to be around the logic level/power supply level design stuff not the actual physics package detonator electronics. I thought there might be something to learn.

The nutristor/neutron tube electronics are interesting in their own right though and are both in a different category then the nuclear control system (the goal of this thread) and the detonator system. I don't know what the categorize them as. Nuclear process control system maybe.

I wonder if its dangerous to be around a nuclear weapon incase the neutron generators kick in by accident. It would be really nasty to get a dose of neutron radiation. Worst kind of radiation IMO.  There must be a interesting control loop there.

The movie broken arrow had a cool bit about the control board. what a great movie i might watch that again.

I did see a switch though, made with something like 200 MOSFET somewhere, on a single substrate, with something like 'special military uses' in it. I think it was a giant cascode. I assume it might be for the detonator circuit.


but i gotta say i have been looking at some pictures and video and I see some seriously shady shit, like the bomb cart they use for the b61. what the fuck, its just all exposed out there, you can probably crash it into a vending machine and ruin the bomb and cause a radioactive disaster. they could put a plywood cover on it or something at least. probably costs like 1 million dollar to replace a bomb fin too. the carts also made like shit (its like impossible to clean and you can hide a tracker in the shoddy construction (no caps welded on).

who thought this was a good idea? seriously?


these people need a bigger budget.

and yes, i am pretty sure once in my life some where i saw a big blast door that had MUNITIONS stenciled on it with a vending machine in the same room.

[coppice]

I did see a switch though, made with something like 200 MOSFET somewhere, on a single substrate, with something like 'special military uses' in it. I think it was a giant cascode. I assume it might be for the detonator circuit.

That doesn't really make military circuits different. It just means a high BOM doesn't immediately make a military project a non-starter, as it would for almost anything civilian.

[coppercone2]

I did see a switch though, made with something like 200 MOSFET somewhere, on a single substrate, with something like 'special military uses' in it. I think it was a giant cascode. I assume it might be for the detonator circuit.

That doesn't really make military circuits different. It just means a high BOM doesn't immediately make a military project a non-starter, as it would for almost anything civilian.

i think a giant cascode is pretty weird. no one would make that discrete ever imo. i need to find it.

[LaserSteve]

  Long ago and far away (20 years now)  I worked for a surplus company that dismantled some prototype, training,  and manufacturing development modules made for a intermediate range missile. Lots of flexible circuit boards as interconnects.  Simple circuits and thru hole parts everywhere. Nearly all parts were 1% tolerance.  Massive amounts of gold plating and house marked parts.  Connectors were huge with big pins to withstand G.  Everything was conformal coated.  Wire bundles were used instead of cables and were dressed with flat nylon lacing tape.  The soldering was by wave machine and hand, with very tight specs on visual inspection.  Older "reliable" parts were used.  A high grade G10 everywhere, and massive hermetic sealing by using machined blocks and feedthroughs. A few custom packages, and most capacitors were in hermetic metal cans laid on their sides and held to the board by the conformal coating, A 4.7 uF tantalum would be a metal can part, not a plastic gumdrop as it would be on a civilian board.   

 We did get to set off one thermal battery that was used for taking pictures for the manual.. All the rest were dummies in "Inert" blue.

Mechanical stuff like the fin actuators had 10 turn or 360' sensing potentiometers made to mil spec and were all miniature wire wound in "servo" cans.  Everything was stock a gear motor, nothing exotic except the plating on the housings. Everything had baked on paint or corrosion resistant anodyne finishes. All labeling was black paint text stenciled on, except for the pcbs which had a white stenciled paint.
You got the feeling the overbuilt gear boxes for the fins would bend a car fender.  One memorable thing was solid tungsten balance weights installed where needed. And yes I'm sure it was tungsten.

FOR THE RECORD..
NO, I did not keep any parts for examples. My father in the plant across town was involved in building the things and I knew better... We recycled all the alloys in the proper ways.


Very "70s" and simple  inside. Wide spacing between components and wide, tinned, board traces. All wiring that carried current was white stranded Teflon  unless it was on a very heavy duty flex PCB made of something like Kapton. Wires soldered into forked terminals, like machined standoffs, never direct to the board.  Contrasted with early WIFI and barcode gear we were dismantling with massive amounts of SMD and VLSI, it looked simple, elegant, and tough.


Steve

[coppercone2]

why don't they use cables? for inspection requirements? or special weave for EMI/toughness?

i actually like the 70's look of gear, my own stuff ends up looking like that lol

[LaserSteve]

Making your own  cables from wire bundles is common in aerospace, more reliable, easier to qualify for testing, and more fireproof.  Until recently, whole jet airliners and things like space shuttles are wired this way. Differential signaling is used to mitigate the need for shielding.

Steve

 

[coppercone2]

it seems like you can slip a shield on easily.

how come the practice is going away now? whats replacing it?

[LaserSteve]

Power cables and a specialized  mil-spec optical fiber to local modules. Saves weight and is more reliable.

Uncle Sam likes SIMPLE and Tough. Getting the jacket off the wire requires strength and specialized tools, and an approved  mil-spec blade for your calibrated  wirestripper. (Hit the Ideal Custom Stripmaster web site and look at that expensive blade's price)

 One other thing, there was little or nothing in there directly useful if you found one laying on the ground un-used. That is by design.

Looks like this installed, scroll down a bit.

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjm6Oya1o7fAhVOpIMKHekKDHEQjRx6BAgBEAU&url=http%3A%2F%2Fecolift.com%2Farticle.php%3Fid%3D1435874233&psig=AOvVaw2JQiHKIzJPGv-imaNCstBS&ust=1544304875968019

and this is the shielded:

https://www.google.com/search?q=mil+spec+aircraft+wiring&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjpira01o7fAhWh6oMKHQ7jCSEQ_AUIDygC&biw=1366&bih=501#imgrc=q7fGsN7ztS4H2M:

This is installed, only for mil applications expect everything to be white (Even for Nato, Russian and Chinese Mil)  with numbers or identifiers custom  printed on the wire every few inches.
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjdhf_f1o7fAhXq8YMKHTEkAWMQjRx6BAgBEAU&url=https%3A%2F%2Fwww.aviationtoday.com%2F2016%2F04%2F01%2Fwire-and-cable-aircraft-ewis-and-swap-in-focus%2F&psig=AOvVaw1K1Jo2piSTn2q6EPPgHPdz&ust=1544305041346658

Steve

[coppercone2]

how do they quantify the reliability of the fiber optic assembly compared to the cable (if you know?)

It seems ridiculously difficult to design a test.

[coppercone2]

thats a fun activity though, making your own cables

[mc172]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

I did do that when I worked in the aerospace industry designing weapons. People tended to think I'm some kind of genius and were amazed rather than getting angry! I wasn't all that bothered about telling people what I did, but people would always say "tell Bob what you do!", "have you heard what mc172 does for a living?" etc.

[coppice]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

I did do that when I worked in the aerospace industry designing weapons. People tended to think I'm some kind of genius and were amazed rather than getting angry! I wasn't all that bothered about telling people what I did, but people would always say "tell Bob what you do!", "have you heard what mc172 does for a living?" etc.

The thing is to emphasise that you work on propulsion systems, because that makes you a rocket scientist.

[coppercone2]

'i make sure a jagged bit of metal severs an artery with 50% chance at 100 meters from where the man with the xbox controller decided the explosion should be'

then if the response is positive, you might wonder if you are sitting at dinner with the mason family. or if red white and blue runs down the toilet after dinner!

[duak]

The book "Command and Control" by Eric Schlosser is a popular account of the development of the safety systems in US nuclear weapons interleaved with the Titan II missile explosion in its silo in 1980.  The number of near missies shows that the designers of the gadgets were barely ahead of the circumstances that tried to accidently set them off.  The nerd in me wants to know more about the nuts and bolts of the safety system designs and how, by sheer luck, none have actually been fully circumvented.  I'd love to have a more technical analysis about some of the incidents.

For a few years I designed parts of and worked on products that had hazards of one type or another.  It was a learning experience because they had to be fail-safe.  I don't think it's possible for everything, but I was at least confident that a single point failure wouldn't expose anyone to a hazard.  I kept asking our UL/CSA experts how toasters can get approval when their cases aren't even grounded?  I didn't get an answer but one allowed that he was happy that he didn't have to do it.

I'll bet the gadget's systems are electromechanical with serial and parallel connections for redundancy.  You can't trust semiconductors to not short out so they are backed up with good, old contacts.

[CatalinaWOW]

Do a google on FMECA, and then read MIL-HDBK-1512 and MS1316.  Then MIL-STD-882.  It will give a start to understanding how such things are approached.  Without even getting into the extra layers for nuclear.

The approach is methodical and enormous.  There are two big issues.  One problem is that it can only protect against the problems you can imagine.  Almost all of the near misses come from something no one imagined.  Some of them are obvious in hindsight, others less so.  The other problem is that because of the enormity of the documentation, it is easy to just throw paper at the wall with thinking much at all.  It is extremely hard to properly review thousands or tens of thousands of pages of analysis thoughtfully to find holes and omissions.  When time or money runs short the product quality is evaluated by using a scale.  More pounds of paper is better.

[Domagoj T]

My understanding of implosion type nukes is that you surround the fissile core with conventional high explosives and that the major problem is getting those conventional explosives to go bang as synchronized as possible.
My question is, wouldn't a single mechanical switch do just fine, with detonators connected in parallel, assuming you match the lengths of trigger wires that go to the conventional explosives? Yes, I understand that in order to get better sync you need high power, but the mechanical switch I have in my mind are two beefy blocks of copper that are pushed together by a small explosive charge (gun type).
However, the declassified data we have available suggests that this approach would not work, so what am I missing?

[T3sl4co1l]

Even explosively propelled switches close in microseconds (velocity of detonation ~ 10km/s, closing a gap of say 10mm is 1us).  There will of course be a spark along the way, but it is probably the case that the spark isn't efficient enough (it should still be sharp enough though).

The obvious solution to timing, implies that either the devices cannot practically be connected in parallel or series (perhaps as they come apart, the impedance changes too much, shunting power from others?), or that more precise timing is necessary, beyond what is reasonable with transmission lines (or that the transmission lines themselves are impractical -- they may be on the order of single ohm Zo, requiring a rather wide build and being quite lossy?).  Or that using transmission lines is prohibitively heavy (since this is typically a flown munition -- not that weight ever trumped strategic value with these things..).

There's also the oblate version, which only requires two detonators and some more precise explosive lenses.  That would presumably be even easier to fire with a power splitter and a single source (even if the impedances go wildly wonky, it should be practical to deliver enough excess to complete both?).

It may well be that the engineers involved, took the lazy way out -- reduce stray inductance and put the capacitor and switch right on top of the detonator, rather than trying to transmit power any distance, into any combination of detonators (including just one).  Maybe the impedance change during firing is so dramatic that transmission lines above a rather meager length simply aren't practical, let alone wiring in series or parallel?

Not that they needed to be lazy -- they certainly had access to top minds in all fields.  Though I don't know anyone offhand in EE specifically.  It seems they are rather overshadowed by the more famous physicists, in popular telling of the project.  (Checking at a glance, it looks that they're not completely forgotten, and indeed there is collected history, at least in brief, for many (most? all?) persons that worked on the Manhattan project.  It would probably be an easy history paper to research, concerning specific professions such as EE, ME, CE and such, on the project.)

Tim

[rstofer]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

Or work for a company that builds nuclear power plants!  That will be lively...  See what happens when you bring up waste disposal!

[Gary350z]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

Not a problem in my experience. In fact people are quite impressed.

[coppercone2]

considering the chinese are stealing clearance lists and stuff, you guys are not concerned telling people you work on damn weapons?

i honestly expected a shadowy mismash of smoke and mirrors as responses

[CatalinaWOW]

considering the chinese are stealing clearance lists and stuff, you guys are not concerned telling people you work on damn weapons?

i honestly expected a shadowy mismash of smoke and mirrors as responses

You don't think the lists they stole are a better source of information than this blog?  Or the lists they compiled from photographing cars on the way into the plants?

So no, I am not concerned.  At most they might get some information on who is willing to be careless with information that shouldn't be easy to get to.   

Your statement "damn weapons" implies an ethical judgement.  While I totally agree that it would be better if no one in the world worked on weapons, there is quite a bit of history to suggest that that solution is not easily achievable, and perhaps impossible.  So the ethical decision is not cut and dried.  I thought through my choice before accepting my first job in the area, and found reasons that were sufficient for me.  Those reasons are also part of the reason I am not concerned.   Doesn't mean I am right or that my decision is correct for anyone else.  Anyone who does not have doubts about their choice, whichever way they go, has not thought seriously about the subject.

[coppercone2]

no by damn weapons i mean its hot shit that alot of people are interested in.

you know like your walking through a bad flava and you pull out a damn rolex. in my mind alot of strange characters might get interested in you for mentioning such a fact.

i like all that stuff its better then dying of dysintary in a castle siege in the year 1305, i like all that peace through atoms stuff. can't say i have any love for bio chemical weapons though. I don't know if its much better once you start dealing with a world like 'the road' but it might be a bit of a upgrade to what war used to be. I think it lets a society set a savagery limit thats like, if you get this bad we will just kill everyone because we would rather not function in those extremes anyway. I also think that alot of 'creative' methods of waging war are basically not utilized so you have less weird contingencies to worry about.

[james_s]

What difference does it make? Anybody can say anything they want, I could post here that I work on weapons, it's not actually true but who would know and what could they get out of it? In my last job I worked with a guy who had previously worked on cruise missile guidance systems at one of the big aerospace companies, he also wrote a significant portion of the operating system for one of the popular 80s home computer systems, neither was any big secret.

Foreign nations already have networks of spies and other sources for information, they're not going to get anything useful from forum posts like this. There's nothing being discussed here that isn't already present on various other websites. The general information on how nuclear weapons work has been freely available for decades, that still doesn't make it easy to build one, as is true with many things, the devil is in the details.

[coppercone2]

i think its dangerous to attribute all knowingness to government intelligence agencies, they can get what they can get. Something can go from dubious to plausible or plausible to confirmed based on different information sources and something can occur because of this escalation. Or they might not want to do something without additional information for a psychological profile or whatever it is they want.

I mean its like your neighbors, they might be a peeping tom from their kitchen window with alot of ideas about why a car shows up in your drive at night, coming up with all kinds of crazy shit, but when they start going through your garbage and hanging out by your patio fence suddenly they become more of a pita because they know how you are so much more. The more people know you the less anxious they are about doing stuff.. quite a bit of crime, or asshole behavior (i.e. stealing food at work) occurs with people you know because they figure out your 'chill' or something.

[james_s]

You seem to live in a rather strange and paranoid reality, most people do not have neighbors peeping on them and going through their trash. Most people who post information on a forum like this are going to get suspicious and clam up if someone starts contacting them offline and picking their brain for information. It's just not a big deal, there's absolutely nothing being discussed here that is not publicly available and if one wants to find people who work on weapons, hanging out at bars and restaurants nearby aerospace companies is going to offer a much higher density of potential marks.

[raptor1956]

what do you mean by non socially popular?

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

Unless you're Tony Stark!


Brian

[coppercone2]

You seem to live in a rather strange and paranoid reality, most people do not have neighbors peeping on them and going through their trash. Most people who post information on a forum like this are going to get suspicious and clam up if someone starts contacting them offline and picking their brain for information. It's just not a big deal, there's absolutely nothing being discussed here that is not publicly available and if one wants to find people who work on weapons, hanging out at bars and restaurants nearby aerospace companies is going to offer a much higher density of potential marks.

It's pretty easy to piss someone off (i.e. fell trees next to a misguided environmentalist, from experience). Also dealing with the insurance company and possibly homeowners association is no fun either. All sorts of retarded animosity is developed here, for instance take this
a well implemented terrain feature to hide trash cans....

i had some old woman leering and doing noise complaints because of tree cutting. fucking annoying. the complaints for noise only started after the lumber was discovered. she got sensitive hearing all the sudden.

but foreign governments must be a little interested, why would this occur? (notice the 127pg clearance forms being stolen, that have psychological evals on em).
https://en.wikipedia.org/wiki/Office_of_Personnel_Management_data_breach

[m98]

most people do not have neighbors peeping on them and going through their trash.

You don't know German neighborhoods...

[coppercone2]

most people do not have neighbors peeping on them and going through their trash.

You don't know German neighborhoods...

old lady security network there?

[m98]

old lady security network there?

More reliable and invasive than any intelligence agency could ever be, yes. They once even found out that I own a car in another city and asked me about it a few days after I moved to my current apartment.

I remember it because the story said some Radio Shack capacitors ended up in cruise missiles.

Totally plausible. There's also one big hobbyist electronics distributor here who's probably not aware of how many of their components are currently in earth orbit and beyond.

[coppercone2]

security anywhere but UK in europe.

[ferdieCX]

There's also one big hobbyist electronics distributor here who's probably not aware of how many of their components are currently in earth orbit and beyond.

Big "C" perhaps ?

[LaserSteve]

Having been a guest at many facilities that handle odd things, I assure you the powers that be are well aware of blogging. They fear USB sticks, far, far more then they fear blogging. 

 BTW,  Blogging got me the interesting job that I held for a year and a half  before returning to the university.

Humorous anecdote.  At a recent family reunion,  about three years ago, my non-technical female  cousin asked me to explain what I was doing at the time. I was on the road going from  facility to facility to facility installing and repairing  lab lasers.   After trying to explain briefly why tunable lasers were important for lab measurements, and that my clients had interesting locations to travel to, I clammed up.
 
 After all why spoil dinner with nerd talk, other then the standard  story and my pics of a national lab  having  rented herds of goats or  to mow the  grass.   She still was puzzled about what I did, and pressed the issue.  So one of my other cousins, quite soused at the time,  blurts out "Steve helps with testing  Nuclear Bombs".  While nothing could be further from the truth, I assure you the answer was accepted, and there was no criticism, in fact people were impressed....   

Now if she only knew what her brother  across the table used to do at a building in the outskirts of DC, she might have really  been speechless.

Generally my corporate employers have been more woried about securing things then some of the places I visited as a guest.  The peace dividend resulted in most  of my then clients working on alternative topics.


Steve

[jmelson]

I mean if a standard engineer that maybe saw a taste of low end military was actually presented with a circuit, would we go 'holy crap that belongs in the art of electronics as its own chapter' or would it be more like 'they dotted their i's and crossed their t's'?

The early weapons were barely electronic at all.  The Los Alamos "gadget" (tested at Trinity site, and basically just put in a housing for dropping on Nagasaki (called "Fat Man") used a vibrator and rectifiers to to generate several thousand Volts to fire a spark gap that triggered the exploding wire initiators for the explosive lenses.  A capacitor dumped through the spark gap to a signal distributor that ran the firing pulse to the initiators through matched-length coax cables.  REALLY simple stuff.

The only electronics in Fat Man (and I'm guessing in Little Boy, also) were the altitude trigger, which was based on aircraft radar altimeters.
You can clearly see the radar altimeter's antenna on pictures of Fat Man.

Don't worry about a visit from the feds, this is REALLY old technology, and pretty well documented in many places.

Modern weapons have gotten a lot more sophisticated, using 2-point initiation and a neutron gun based on a linear accelerator, instead of a tiny neutron source at the center of the Plutonium.  So, there has to be some precise timing so the neutrons get to the center of the Plutonium "pit" right at the moment of maximum implosion.  I've never seen any mention of how they do this.

Instead of a spark gap, they use a gas device called a Krytron, also a pretty highly classified device.  They were in the news some decades ago as Iran, I think, was trying to buy some.  The pulse discharge capacitors are also classified, I think Saddam Hussain was trying to buy those, or get details of construction.

Finally, there are systems to prevent unauthorized use of these weapons, called Permissive Action Links.  These are REALLY restricted, as they want to make sure the guys trusted with handling the weapons do not know how to defeat them.  If the PAL is tampered with, it will fire the initiators in the wrong sequence, blowing the weapon to dust.  These are supposedly a mixture of electronic and mechanical parts.  DoE was at one time looking into using MEMS to make it harder to figure out how the PAL works or defeat it.  I don't know if that got implemented.

Jon

[coppercone2]

i think there is a entire season of 24 about something like the PAL.

there is patents and research about using krytron like devices to work as kind of precise/better GDT for circuit protection actually. I find that stuff very interesting. You can also buy them for large prices on ebay or used to be able to.

sandia labs 'nutristor' may interest you. I find it interesting but I don't really want to be around neutron radiation.

[jmelson]

I wonder if its dangerous to be around a nuclear weapon incase the neutron generators kick in by accident. It would be really nasty to get a dose of neutron radiation. Worst kind of radiation IMO.  There must be a interesting control loop there.

They only need a half dozen neutrons, delivered to the right spot at EXACTLY the right time (+/- a microsecond at the very most).  So, you would never know if the neutron source were turned on, from the neutrons, anyway.  Since everything is connected together, and a lot of this stuff is operated by exploding something, I suspect (but don't know) that the weapon has a fair likelihood of blowing up at SOME level if the neutron source was triggered.  All this stuff is designed for EXACTLY one use, and many parts of the weapon are performing their special task while something else is exploding just an inch away!  Crazy stuff to design.

Jon

[coppercone2]

i have read about logic gates formed with strip explosives before, it would make sense to have a interlock in the explosives that must be triggered electrically to allow for the correct detonation conditions to be present. like implementing the condition that the explosion must be occurring and then later that the explosion is occurring correctly (the explosive logic) to trigger  the neutron gun. It should make it more of a fizzle, since you want it as deenergized as possible unless its happening perfectly.

[jmelson]

The nerd in me wants to know more about the nuts and bolts of the safety system designs and how, by sheer luck, none have actually been fully circumvented.  I'd love to have a more technical analysis about some of the incidents.

After some near misses in the 1950's and 60's, with bombs that were in aircraft crashes and fires, they improved the PALs, and were so worried that they transferred the designs to the Russians, and asked them to implement something similar.  They apparently did, and told as few people as possible that this device was included.

A Soviet sub, K-129 went rogue in March, 1968.  They apparently planned to start world war III by firing a missile at Hawaii.  These Soviet subs could launch missiles while submerged, but the copy they sold to the Chinese could not, they had to surface to fire.  So, these guys surfaced and tried to fire a missile while they knew one of the US spy satellites was passing overhead.  What they didn't know was that the
Russian-version PAL would destroy the missile on launch.  The sub sank.

Then, the US mounted a mission to retrieve the sub.  Howard Hughes' Glomar company built the Glomar Explorer to precisely locate the sunk sub, and then built the Glomar Challenger to lift it from the ocean floor.  In the process of this, they saw pictures of the blasted top of the launch tube and eventually decided they had to tell the Russians about it.

This is all pretty public knowledge, see Wikipedia K-129 for a start on this incredible story.

Jon

[coppercone2]

is there actually plausible evidence to a false flag attack? I saw this occur in the movie Phantom.

[T3sl4co1l]

is there actually plausible evidence to a false flag attack? I saw this occur in the movie Phantom.

Outside of alt-right fantasies and conspiracy theories, no.

I don't know of any famously successful such missions, offhand, but someone more familiar can probably list some attempts and their successes or failures...

Tim

[LaserSteve]

Here, have a long, good read:

https://nuclearweaponarchive.org/Nwfaq/Nfaq0.html

Krytrons, at least from the usual supplier, have long been out of production. I had tried to order one for a pulsed ruby laser about a decade ago and was told the line was closed. The sales guy lamented the loss in commercial use sales, which was substantial, but MBAs often close production lines for marginal products or products outside the scope of their "core" business.  It pretty much would have been a swap, provide the old unit or its serial number and proof of a legit use.  Most of the ones made evidently never were used in the traditional, popular application of triggers, but evidently in commercial equipment with flashlamps, so he said. 

Steve

[Housedad]

Well, military hardware must be rugged.  that means that it is usually not bleeding edge stuff.  It takes a while for bleeding edge tech to mature to that level. 

Case in point and rather on subject, my brother was a Navy nuclear missile technician, submarine in the early 70's.  Even though there were quite a bit of advanced electronics available,  he lamented in much later years that the control systems even for new ordinance was woefully lagging the consumer world.  We are talking tubes here.  In advanced weaponry, long after it would be considered obsolete elsewhere. 

Why?  because it was tried and true hardened designs.  For instance, as he put it, they could only use a special variation of the tektronix 585, as that was the only scope certified to withstand the EMP of a nearby blast.   They understood that if they got a near hit and received a heavy Rad dose, the men would only have as short as 10 minutes of useful life.   In that time they had to do repairs and launch.  But the god-dang scopes and other equipment HAD to survive.  The men only needed to last long enough to launch.

[Kilrah]

Tell people at a dinner party you design nuclear or some other weapons system and see how well it goes down.

Not a problem in my experience. In fact people are quite impressed.

Well you have a USA flag in your profile, so yes, still OK there... but it most other parts of the world anything military is now commonly considered as disgusting.

[coppercone2]

yea but so is dealing with fundie islamists and commies

[Lord of nothing]

yea but so is dealing with fundie islamists

Found by the USA and UAE. 
How many Terrorist from the 11.9 Terror Attack was from the UAE? 
I know Bush had a sever Brain Damage and Choose the wrong Country just for Kicks. 

[N2IXK]

Anyone interested in the actual "nuts and bolts" of nuclear weapons needs to get a copy of John Coster-Mullen's book:

https://www.amazon.com/Atom-Bombs-Secret-Inside-Little/dp/B0006S2AJ0

I was amazed to see that it includes a schematic diagram of the "X-unit" that fired the Trinity and Nagasaki "Fat Man" plutonium bombs. The firing pulse to the detonators was generated by a hydrogen thyratron driving triggered spark gaps. Not all that different from contemporary radar pulse modulators, actually.

There are a couple of very interesting videos on YouTube that offer short glimpses of nuclear weapon electronics, as well:

[coppercone2]

yea but so is dealing with fundie islamists

Found by the USA and UAE. 
How many Terrorist from the 11.9 Terror Attack was from the UAE? 
I know Bush had a sever Brain Damage and Choose the wrong Country just for Kicks. 

ok so then you just have more commies to fight, what does it matter, their actually better at wrecking shit then terrorists. Terrorists don't seem to cause starvation for instance. Or cause ridiculous ecological disasters.

[coppercone2]

Anyone interested in the actual "nuts and bolts" of nuclear weapons needs to get a copy of John Coster-Mullen's book:

https://www.amazon.com/Atom-Bombs-Secret-Inside-Little/dp/B0006S2AJ0

I was amazed to see that it includes a schematic diagram of the "X-unit" that fired the Trinity and Nagasaki "Fat Man" plutonium bombs. The firing pulse to the detonators was generated by a hydrogen thyratron driving triggered spark gaps. Not all that different from contemporary radar pulse modulators, actually

I actually have a laser triggered thyratron pulser thats supposed to trigger something through a transformer. I think its a radar or experimental physics set. It's very pretty.

[David Hess]

My question is, wouldn't a single mechanical switch do just fine, with detonators connected in parallel, assuming you match the lengths of trigger wires that go to the conventional explosives? Yes, I understand that in order to get better sync you need high power, but the mechanical switch I have in my mind are two beefy blocks of copper that are pushed together by a small explosive charge (gun type).
However, the declassified data we have available suggests that this approach would not work, so what am I missing?

I looked into this at one point and concluded that the parallel impedance of the transmission lines going to the detonators is too low to drive so separate switches are required.  I do not even think a transmission line switch would work because of power limitations at such a low impedance when what you really want is closer to 25 ohms to save weight and space.

[coppercone2]

how do you know the modern bombs don't try to do fine pulse control to try to match the electric detonators/control the plasma (and we really don't know what they choose to use, slapper, bridgewire or other)?

They might also run some kind of tests on the individual detonators (because the above would probably require a giant shed of insane equipment) and electrically match their timing rather then try to choose parts, maybe there is even some kind of a predetonation scan done to adjust the timings to account for explosives properties drift ETC. Or with the new bunker busters and shit they might have to scan the explosives some how to account for any deformation in the plastics due to the high g-forces to redesign the compression wave geometry.

All the above is probably too far out and its probably really bootleg.

[dmills]

The civilian exploding foil stuff uses flexi PCB for the transmission lines to get the low Z required, I would not be that surprised to see something similar.

I have seen an interesting civilian hydrogen spark gap triggered by UV light from an external arc tube, seemed likely to be low jitter if you mounted a few around a suitable pulsed UV source.

Fact is it was difficult in 1950, but I would bet if you actually looked at the requirements for that design (which nobody would design today) the timing is probably not all that tough by modern standards.
Now a modern weapon with variable yield, electrically fired neutron source (Possibly timed to provide that variable yield) and sophisticated PAL, that might be tricky.

Regards, Dan.

[coppercone2]

how many pages can this thread get to before we disappear?

[T3sl4co1l]

Nothing that's been discussed here hasn't been declassified for decades.

Tim

[coppercone2]

Nothing that's been discussed here hasn't been declassified for decades.

Tim

i was hoping a bit of gangster pep would lead to independent discovery 

[LaserSteve]

Oh, it led to my finding one blog on potential ways of  making Alternative Materials  without huge plants and resources of only a small  nation that I do not wish to link.  Trade off sophistication and yield  for time and making a core is simpler.

Steve

[CatalinaWOW]

Modern times and electronic controls, ultra precise machining and a number of other technologies have made fabrication of unique devices far easier than it once was.  Add that to the option to do something over a decade or two instead of the three or four years that it took the first time around doesn't make it easier to sleep at night for those who worry about such things.

On the other hand the same technology growth has made it far easier to detect such attempts.  For example, in my stash of goodies I have a Cutie Pie.  It is one of the top secret radiation detectors used during the initial bomb development, given a silly code name to hide its purpose.  By today's standards its sensitivity and other metrics are laughable.  At best. 

So far at least the publicly available evidence says that the good guys are at least staying even in this race.

[jmelson]

is there actually plausible evidence to a false flag attack? I saw this occur in the movie Phantom.

Just look up K-129 on Wikipedia, and follow some of the links.  There seem to be a lot of people who know something about this.
The Soviets apparently sunk one of our subs in retaliation, believing we sunk the K-129.  Exactly why the sub sank is not totally clear, but the evidence is that a missile was launched and self-destructed as it was coming out of the launch tube.

Jon

[dmills]

Yep, and people always forget about the other fissionables, U and Pu are NOT the only things that could work if you do the sums.

I am somewhat surprised that Am241 is not more of an issue, you could wrap a reflector around a surprisingly small mass and get criticality by my back of an envelope, cannot be bothered to do the sums to see if it would work for a bomb, but a reactor looks workable to me.

I also wonder about (but again cannot be bothered to do the sums) a reactor using a two stage process, start with neutron bombardment of something that will capture the neutron and start a decay chain emitting a few alphas, then bombard beryllium with the alphas to make neutrons.... Probably tricky to get the losses low enough for criticality, but maybe, just maybe.

I wonder if there is something that can be hit with a neutron to get you to one of the Astatine isotopes, that would get you 3 alphas in the decay chain within a few minutes.

Hum, turns out that Bismuth can capture an alpha getting you onto the polonium chain, which would then give you two spare alphas from its decay chain, thats fun if the energies work out, not exactly what I had in mind, but interesting none the less!

Regards, Dan.

[coppercone2]

Modern times have made electronic controls, ultra precise machining and a number of other technologies have made fabrication of unique devices far easier than it once was.  Add that to the option to do something over a decade or two instead of the three or four years that it took the first time around doesn't make it easier to sleep at night for those who worry about such things.

On the other hand the same technology growth has made it far easier to detect such attempts.  For example, in my stash of goodies I have a Cutie Pie.  It is one of the top secret radiation detectors used during the initial bomb development, given a silly code name to hide its purpose.  By today's standards its sensitivity and other metrics are laughable.  At best. 

So far at least the publicly available evidence says that the good guys are at least staying even in this race.

is that still classified or can you share it?

[Housedad]

Nothing that's been discussed here hasn't been declassified for decades.

Tim

Absolutely.
No one that knows classified info, even very old info would be stupid enough to put it on the net, much less even talk in private about it.  Some things stay classified almost forever.   Those that know that kind of info also know how to keep the mouth closed.

[Housedad]

Modern times have made electronic controls, ultra precise machining and a number of other technologies have made fabrication of unique devices far easier than it once was.  Add that to the option to do something over a decade or two instead of the three or four years that it took the first time around doesn't make it easier to sleep at night for those who worry about such things.

On the other hand the same technology growth has made it far easier to detect such attempts.  For example, in my stash of goodies I have a Cutie Pie.  It is one of the top secret radiation detectors used during the initial bomb development, given a silly code name to hide its purpose.  By today's standards its sensitivity and other metrics are laughable.  At best. 

So far at least the publicly available evidence says that the good guys are at least staying even in this race.

Some Tech is used forever.  Even in the face of massive tech advances.

[GeoffreyF]

Try to buy a Krytron with fast enough switching speeds so that shaped charges all go off with the necessary precision to compress the fissionable material.  How fast?  Faster than what you can buy.

If you do try - make sure you have a really good defense attorney.

I can't tell you more. I would have to kill you if I did.

[jmelson]

Yep, and people always forget about the other fissionables, U and Pu are NOT the only things that could work if you do the sums.

I am somewhat surprised that Am241 is not more of an issue, you could wrap a reflector around a surprisingly small mass and get criticality by my back of an envelope, cannot be bothered to do the sums to see if it would work for a bomb, but a reactor looks workable to me.

Well, you have to have something that has a long half life, has a good neutron capture cross-section, neutron capture results in prompt fission, and that fission releases several neutrons.  U235 works, but only releases 2.x neutrons, so it takes a fair amount to achieve a critical mass.
Pu239 is better, as it releases 3.x neutrons, so you need less atoms for a critical mass.

I'm not so sure anything else meets ALL these criteria.

Jon

[CatalinaWOW]

Modern times have made electronic controls, ultra precise machining and a number of other technologies have made fabrication of unique devices far easier than it once was.  Add that to the option to do something over a decade or two instead of the three or four years that it took the first time around doesn't make it easier to sleep at night for those who worry about such things.

On the other hand the same technology growth has made it far easier to detect such attempts.  For example, in my stash of goodies I have a Cutie Pie.  It is one of the top secret radiation detectors used during the initial bomb development, given a silly code name to hide its purpose.  By today's standards its sensitivity and other metrics are laughable.  At best. 

So far at least the publicly available evidence says that the good guys are at least staying even in this race.

is that still classified or can you share it?

It isn't classified now, and AFAIK hasn't been since shortly after WWII.  They were available in open catalogs by 1950.  I don't have time to take a picture of mine at the moment, but if you google with the search term "cutie pie radiation detector" you should get enough information to satisfy your curiosity.  The Star Trek pictures are of a newer model, and they were obsolete enough by the Star Trek era to be used as movie props.  It is also interesting to google with just "cutie pie".  It will show you why that was such a clever cover name.  Talk about burying in a pile.

[jmelson]

is that still classified or can you share it?

Los Alamos National Lab is the home of a lot of weapons-related research, but it is ALSO the home of a bunch of agencies essentially doing the opposite.  There is the Defense Threat Reduction Agency, quietly doing a lot of non-proliferation work in the background.  In 1963, the US launched the first Vela satellites, designed to monitor for space, and later, open-air nuclear tests, to verify compliance with the test ban treaty.
Los Alamos has continued to update these systems.  They apparently also detect rocket and missile launches worldwide.

The current stuff is certainly classified, but the basic existence of the program has been pretty well-known for decades.

Jon

[jmelson]

is that still classified or can you share it?

As for radiation detectors, you can buy quite decent Geiger counter units on eBay!  This was big stuff right after the Fukushima accident.

Jon

[coppercone2]

I was asking specifically about the cutie pie. Keep in mind it got classified because it was literally mind boggling for them at that point, no one knew how fast these weapons would develop and some people even thought they could ignite the atmosphere for a while. I never heard that name before.

[Lord of nothing]

ABC News (Australia) ->

[jmelson]

I was asking specifically about the cutie pie. Keep in mind it got classified because it was literally mind boggling for them at that point, no one knew how fast these weapons would develop and some people even thought they could ignite the atmosphere for a while. I never heard that name before.

Certainly, the Cutie Pie is no longer classified.  It was made by Nuclear Chicago back in the 1950's, and used at least one vacuum tube.
Much better ionization chamber devices have been made since, none of these are classified, you can buy new, certified and calibrated (yes, really expensive) from a variety of manufacturers like Victoreen, Canberra, Ortec, etc.  for a couple thousand $, or not-so calibrated ones on eBay for under $100.

Geiger counters detect Gamma radiation, and if they have a thin window, can also detect Alpha and Beta.  They are very real sensitive.

Ionization chambers are much more sensitive to Alpha and Beta.

Scintillators have much higher efficiency for detecting Gamma radiation.

Jon

[dmills]

I'm not so sure anything else meets ALL these criteria.

For a bomb, possibly not (I think Am242 would but that is harder to make then weapons grade isotopically pure Pu).

However for a reactor delayed neutrons are actually a good thing, you want a reasonable space between delayed and prompt critical (Nobody likes an accidental prompt criticality, it decreases property values).

Regards, Dan.

[schmitt trigger]

Back to the original OP:

In 1961's Goldsboro nuclear near-accident, a simple switch which would have armed the bomb, fortunately remained in the "Safe" position.

That lowly switch prevented what would have been the world's largest nuclear mishap, as all other arming mechanisms had successfully completed the arming sequence.

[jmelson]

No one that knows classified info, even very old info would be stupid enough to put it on the net, much less even talk in private about it.  Some things stay classified almost forever.   Those that know that kind of info also know how to keep the mouth closed.

Well, they are not SUPPOSED to.  10-15 years ago, the entire technical manual of the Hellfire missile was online!  It had detailed description of the arming mechanism, which told you how far away from the launch you needed to be for the warhead to go off, among other details that you really would NOT what your adversary to know about!  Some months later, that manual was gone, thankfully!

In the nuclear area, the same thing has happened, and it was reported in the press, some decades ago, that a whole bunch of stuff that was highly classified ended up getting sent out to university and maybe even public libraries.  They had to send people out to find those documents and retrieve them.

Jon

[coppercone2]

yea but that stuff is probobly ultra compartmentalized in different special access programs specifically so you can't have a document fuckup cause a security problem.

I am sure there is ultra basic classified shit that we would think like hurr durr when we saw it but they know that if you research it you will be inclined to do it some other way thats conceptually better and the hurr durr method that works great might take a while to realize for whatever reason etc.

lol i want to find that manual though it sounds like a fun read. something to leave near the toilet seat perhaps for bored guests? reminder not to shit on the floor like a drunken baffoon (like the fly drawings they put in urinals)

[GeoffreyF]

Nobody has caught the bit about Krytron's or - sprytron's?  This was about electronics.  That actually is the crucial electronic thing.   If you ever saw a picture of the trinity test, did you sort of wonder why the wires to the slapper detonators are not uniform in length?  If you look up Krytron's you will learn how much current and voltage go to the slappers.   Look it up in the wiki.   For fun, calculate the velocity factor of a very sharp spike of current and voltage through a wire.

[jmelson]

I wonder if there is something that can be hit with a neutron to get you to one of the Astatine isotopes, that would get you 3 alphas in the decay chain within a few minutes.

Astatine is the rarest element in the universe.  Supposedly, there's no more than 5 g in the whole earth!  There must be good reasons related to neutron capture cross sections or something that prevents much of it from ever being created.

Jon

[dmills]

It is the tiny half life and the fact that it is mostly a decay product of things having **very** much longer half lives.

There is a route via Bismuth capturing an alpha particle which is interesting, but I don't think the cross section works to get that to go directly as a chain reaction which is a pity.

If the cross sections were better, you could build a pile of bismuth, hit it with a few alphas and watch as the thing gradually ramped up a mixture of Alphas (that would actually be driving the reaction) and betas plus heat, longest half life in the main line of the resulting decay series would be ~30 minutes which would make it a cool play toy for the shed, but with a delayed alpha gain of 3 it does not work.

Back to the drawing board on that one....

Regards, Dan.