Breadboarded nuclear detonator - Page 1
Forum section: electronics / general

author: hamster_nz
author_rank: Super Contributor
timestamp: September 04, 2017, 08:42:59 am
content: As seen on Twitter (@CyberQueenMara) - Apparently this prototype for a nuclear detonator is on display at Bradbury Science Museum in Los Alamos. Seems Legit, but also seems odd to have it on display.I wonder if it is authentic? Anybody been there?(the whole "Trust but verify" thing I guess!)

author: Gyro
author_rank: Super Contributor
timestamp: September 04, 2017, 08:57:20 am
content: Could they really have prototyped a nuclear detonator on something as potentially intermittent as a protoboard?

author: hamster_nz
author_rank: Super Contributor
timestamp: September 04, 2017, 08:58:59 am
content: Maybe the MILSPEC boards are better than the $5 Ali Express models?

author: Jeroen3
author_rank: Super Contributor
timestamp: September 04, 2017, 09:06:27 am
content: What differentiates a nuclear detonator, from a detonator?

author: IRFP460
author_rank: Contributor
timestamp: September 04, 2017, 09:14:03 am
content: one is nuclear, one isn'tI suppose the nuclear one has a few more safety features built in and, if i recall correctly, the nuclear one needs to have quite good timing in order to get the nuclear material to achieve criticallity, assuming they use the implosion assembly method.

author: tszaboo
author_rank: Super Contributor
timestamp: September 04, 2017, 09:18:46 am
content: I remember from a book written by Öveges, famous physics professor, in 1965, about nuclear warfare, they just have conventional explosives and they shoot plutonium together and it just blows up on its own.Maybe technology got better since. The book was also based on soviet technology.But I also just searched "nuclear detonator" on google, so I will probably have problems next time I go to the US of A.

author: nanofrog
author_rank: Super Contributor
timestamp: September 04, 2017, 09:19:20 am
content: Quote from: Jeroen3 on September 04, 2017, 09:06:27 amIt has to be sufficientlyradiation hardenedin order to function in that environment.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 04, 2017, 09:34:52 am
content: Presumably, it would be a research article, calibrated with oscilloscopes only, never connected anywhere near real explosives or nuclear material.Tim

author: grumpydoc
author_rank: Super Contributor
timestamp: September 04, 2017, 09:40:22 am
content: I'm left wondering who's prototype & what date, in particular when did that style of breadboard come into use?The US nuclear programme goes back to the 1940's - I can't see IC's and contact strip breadboard being part of the process back then.

author: EEVblog
author_rank: Unknown
timestamp: September 04, 2017, 09:58:57 am
content: Quote from: grumpydoc on September 04, 2017, 09:40:22 amNope, it's much more recent, at least the 1970's.

author: hamster_nz
author_rank: Super Contributor
timestamp: September 04, 2017, 10:01:12 am
content: It looks to be from the mid-70s - one chip looks to have a '74' date code. I guess it does the following tasks:- has to integrate info from sensors (e.g. radio altimeter, barometer, accelerometer) to ensure that the correct sequence of events occur that are required arm the weapon.- has to control the release of tritium to boost the core. Tritium is stored outside the core as it decays and needs to be swapped regularly- has to sequence the explosives used to compress the nuclear material (might be a non-spherical, which require complex timing)- has to fire a neutron source at the correct time to give the required yield. Yield is 'dialed' in - maybe the 'pre' and 'post' switches (e.g pre-detonate)- has to never go off by accident- has to always fire when required- has to sit around unused for years, hopefully until it is decommissioned.

author: EEVblog
author_rank: Unknown
timestamp: September 04, 2017, 10:06:32 am
content: That has nothing to do with detonating the timed explosive charges on an implosion plutonium gadget.(outside spherical shaped charges must be detonated simultaneously in order to compress the plutonium that is in an outer shell)That's got to be some other pre-trigger arming type device.Doesn't look like part of the Permissive Action Link protection system.From the Delay labels it's likely part of the delay protection system that prevents detonation until a set distance from the drop plane (assuming it's a free fall weapon)

author: daqq
author_rank: Super Contributor
timestamp: September 04, 2017, 10:21:00 am
content: QuoteWhy not? It's probably a proof of concept for tinkering and prototyping, that was never connected to anything else than a few scopes + simulated load or some such.

author: dmills
author_rank: Super Contributor
timestamp: September 04, 2017, 11:04:49 am
content: Prototypes got to start somewhere, and I would expect that for the most part an nuclear widget is similar to any other sort (Power supplies, state machines, timers, FMEA paperwork, all routine stuff), at least until you get down to close to the physics.Interestingly, none of the electronics looks hard by modern standards, accurate pulsed power is no longer only the domain of the kryton, and I would expect that a slapper or exploding foil could be fired with semiconductors these days (GaN for example, it only has to work once, and a two sided flexi pcb makes a lovely low Z transmission line!).I actually know of some amateurs who are playing with the design of slapper detonators (because, why not?), fascinating stuff.I had not known that the neutron pulse timing was used to control the yield, interesting, but it begs the question of how this was done in the W85 which as far as the public literature claims, does not look to have had much in the way of electronics (It is thought to be non spherical design with voids in the explosives used to shape the shock wave, very tricky as it was small (10 tons to 15kT, depending on settings as I understand), it was withdrawn largely because there was no way to add PAL to it.Open source design project anyone?

author: hamster_nz
author_rank: Super Contributor
timestamp: September 04, 2017, 11:18:59 am
content: Found the datasheet for some of the modules that can be seen on both the left and right hand sidehttp://www.cornucopiaplastics.com/ec2/products/Digital_Delay_Lines/logic_delay_modules/TTLDM_XXM.pdfQuoteThe date code on the left 5275 seems a little odd - the datasheet indicates that that is 75th week of 1952 - so must be wrong way around

author: retrolefty
author_rank: Super Contributor
timestamp: September 04, 2017, 02:17:50 pm
content: Quote from: Jeroen3 on September 04, 2017, 09:06:27 amMain difference is that a Nuc detonator is actually an array of detonators used with shaped charge explosives that must all be initiated within a specific time (microseconds?) window to insure criticality is reached and held long enough to ensure weapon's designed yield.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 05, 2017, 12:20:23 am
content: Quote from: retrolefty on September 04, 2017, 02:17:50 pmA bit overstated for most -- after Trinity (and I forget what others), spherical implosion devices went away for precisely this reason (and the awkward size, and precision timing, and cost of all the detonators probably, and....). They pretty quickly (in the 50s) solved the explosive lens problem for a two-point ignition condition, leading to devices slim enough to fit inside artillery shells and such.Tim

author: ez24
author_rank: Super Contributor
timestamp: September 05, 2017, 12:52:21 am
content: The picture would make a great jigsaw puzzle. Are there any high def straight on pics of this? Among the great pics posted on this forum like the one of Jim's workbenchAttached is a before picture, still impressiveThanks to the OP

author: WZOLL
author_rank: Regular Contributor
timestamp: September 05, 2017, 02:55:23 am
content: I took a trip to Albuquerque this summer and made sure to stop by Los Alamos. I went to that museum and saw that breadboard but i didn't take a picture of the whole display. If I remember correctly it was a test timing device for a detonator and not the detonator circuit itself. It was a very nice museum that covered the trinity tests, modern nuclear bombs, and the development of supercomputers.

author: WZOLL
author_rank: Regular Contributor
timestamp: September 05, 2017, 03:02:45 am
content: Here is a picture of the detonators from The Gadget at the museum. The timing relied on a few vacuum tubes and fast spark gap switches. Amazingly primitive tech for such a revolutionary device.

author: jh15
author_rank: Frequent Contributor
timestamp: September 05, 2017, 03:09:27 am
content: You could buy the book to see the details. I have a signed one, as does Dave.

author: Brumby
author_rank: Unknown
timestamp: September 05, 2017, 05:19:02 am
content: It is my understanding that in the beginning there were two basic types of nuclear bomb. One of each were used in the bombings of Hiroshima and Nagasaki. "Little Boy" and "Fat Man"."Fat Man" was an implosion device - and it did, indeed, require accurate timing for detonation and this was the design tested. After the failed "Thin Man" attempt, the subsequent "Little Boy" design was considered to be guaranteed to work - and it was never tested ... until it was dropped on Hiroshima.

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 06, 2017, 12:52:23 am
content: Kim Jong-Un's grade 8 science fair project!

author: TheSteve
author_rank: Unknown
timestamp: September 06, 2017, 01:05:23 am
content: Pretty tubes are still used in the detonation of implosion type bombs to this day. Check out the "Krytron".

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: September 06, 2017, 10:34:25 pm
content: Posters EEVBlog and the gregarious rodent from down under have adequately summed the functions and the missing parts.Some guy dabbling in Tesla coils and such frivolities asked me totally sincere where he could order stuff such as triggered spark gaps and fast switching tubes. I will not forget the face when we explained to him that his order might result in his door going ballistic followed by VERY bright lights and lots of noise at 0400h(AM)!BTW: I simply love glass capacitors!!

author: hamster_nz
author_rank: Super Contributor
timestamp: September 06, 2017, 11:11:26 pm
content: If you ever want to waste a few hours, reading about high energy physics then read the Nuclear Weapons Frequently Asked Questions:http://nuclearweaponarchive.org/Nwfaq/Nfaq0.htmlesp sectionhttp://nuclearweaponarchive.org/Nwfaq/Nfaq4.htmlAnd as with the parts for your Tesla coils don't leave a copy of it sitting around on a train, unless you want a 0400(am) wake up call.

author: innkeeper
author_rank: Unknown
timestamp: September 08, 2017, 03:05:12 am
content: not saying its not real but, you gotta love the components with noting attached to them, and the jumpers to nothing.if it is real, my guess is they changed it enough that it wouldn't actually function.

author: ez24
author_rank: Super Contributor
timestamp: September 08, 2017, 03:31:59 am
content: Quote from: hamster_nz on September 06, 2017, 11:11:26 pm"Creating a symmetric implosion wave requires close synchronization in firing the detonators. Tolerances on the order of 100 nanoseconds are required."I was wondering what kind of "timing" was needed. Does this mean a good breadboard can do delays of 100 nanoseconds?If you drop a buttered piece of bread and it lands butter side down, would butter stick to the floor within 100 nanoseconds?

author: hamster_nz
author_rank: Super Contributor
timestamp: September 08, 2017, 04:32:29 am
content: Quote from: ez24 on September 08, 2017, 03:31:59 am100ns is 10MHz cycletime, and entire systems can run at that speed on a breadboard....Buttered bread falling 1m would be travelling a little under 5m/s when it hits the ground, so 100ns is slightly under 0.5um of travel...You would have to drop that bread very, very precisely for more than just the tip of a crumb on top of the butter touch the floor within 100ns.

author: Brumby
author_rank: Unknown
timestamp: September 08, 2017, 06:00:46 am
content: I noticed the mark of experienced engineering minds.At no time was there discussion on the low probability option of the buttered sidenothitting the floor.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: September 08, 2017, 01:09:16 pm
content: Quote from: Brumby on September 08, 2017, 06:00:46 amThe nuclear equivalent of something like this happening is called a 'fizzle'. If one happens, pray it was the physics package.

author: Don Hills
author_rank: Regular Contributor
timestamp: September 11, 2017, 07:52:33 am
content: Quote from: Brumby on September 08, 2017, 06:00:46 amExperienced engineering minds have already worked out the probability of the buttered side hitting the floor first.You can do it too.When you drop a piece of toast, you're usually holding it by one edge or corner. The other edge rotates downwards. With the dimensions of the piece of toast, the angle it reaches before it slips out of your hand and the formula for acceleration due to gravity, you can work out how long it takes to perform a 180 degree rotation. Knowing the height of your hand above the floor, you can also work out the time it will take to fall to the floor. From these, you can work out the "optimum" height above the floor for the toast to land butter side down. Because the toast will settle butter side down even if it doesn't hit exactly flat, there's actually quite a range of heights at which it will occur. It's a bit more complicated for toast that slides off the table, you have to factor in the velocity as it leaves the table which will determine the rate of rotation.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 11, 2017, 02:02:03 pm
content: How far away from a nuke would a dropped piece of bread have to be for it to become toast before it lands in a bowl of butter? Provided there is a wall on one side to prevent the toast from blowing away. Of course, it might be "hot" in multiple ways...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 11, 2017, 03:33:17 pm
content: Quote from: Cyberdragon on September 11, 2017, 02:02:03 pm1-10 km, depending on fireball size.It won't blow away because the shock wave travels a bit above the speed of sound. It will be "hot in multiple ways" if left unattended some minutes after the shockwave arrives, but until then, it will be fine.The main downside is the bread will be "raw" inside, only superficially toasted. This is the downside to most rapid-toasting propositions, whether nuclear, chemical or electrical.Tim

author: SeanB
author_rank: Super Contributor
timestamp: September 11, 2017, 07:28:48 pm
content: Tim, the fast Gamma and X rays should make a pretty good approximation of denaturing all the proteins inside the slice, though you would have to be fast to eat it before the acoustic wave come past to smear the butter all over.Kind of like that Smallville episode, where young Clark Kent likes to eat his cereal before the milk makes it soggy.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 12, 2017, 12:07:50 am
content: Nah, not at that distance, only IR to UV.if it were close enough to get gamma'd, it would then soon be enveloped by the fireball! (Air is a pretty good absorber of these things, over distances of 10s to 100s of m.)Tim

author: Ampera
author_rank: Super Contributor
timestamp: September 12, 2017, 04:03:27 am
content: I do not believe it works unless it has fired off a nuke.

author: duak
author_rank: Super Contributor
timestamp: September 13, 2017, 07:36:50 pm
content: When I started my professional electronic design career in the late 70's, the senior engineers specing & reviewing designs would not allow monostables to be used for timing except for detecting things like clock loss. Delay lines were considered OK but generally impractical for delays above a few microseconds. The rationale was that monostables were not fully predictable and could be sensitive to noise. I never did find out the exact circumstances, but I understand that one of the designs used a few monostables but was plagued with random failures that were solved by designing the monostables out. Perhaps it was noise or a process or manufacturing problem with the chips or misuse on the designer's part but they were thereafter outlawed at this company. It looks like there are a few monostables in the detonator prototype's design and since they could be close to a radiation source, one critical stage could get a "go" signal and the rest would be history.Our designs would use synchronous state machines but at first not everyone appreciated D flip-flop metastability (ie., data setup and hold times relative to clock edge) leading to unpredictable and often not repeatable operation. Once the problem was understood, the solution was easy. Random failures and metastability weren't unheard of in the industry. I remember a few chips introduced at that time, in particular a DRAM controller, that suffered from transient failures that was traced to asynchronous refresh requests. I believe the chip was revised but then discontinued so maybe the problem wasn't solved.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 13, 2017, 07:59:02 pm
content: Seem to recall other stories of timer-averse designs -- mainly because if you've wired your, state machine let's say, so all the signals cascade from one to the next, just in the nick of time: you can't possibly modify it without adjusting every other damn timer in the design. And if the signal gets stuck somewhere (which could be as simple as a couple timers being out of tolerance), it's impossible to debug.Hardly a problem nowadays, what with logic being cheap and plentiful. No problem making a good old fashioned Moore FSM run fast enough to handle tons of real applications. Back then, though, there was real temptation to skimp on transistors and ICs.Personally, I wouldn't make anything more complicated than, say, an oscilloscope (your basic triggered sweep has three timers: delay, sweep and holdoff) with timers.I don't have any problem with using timers, but keep it in moderation.As for sensitivity problems, I don't know. Seems like a terrible design if it is. Maybe that was all they could afford back then, two-transistor monostables and the like? Well, you get what you pay for...Tim

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 13, 2017, 08:54:39 pm
content: Quote from: nanofrog on September 04, 2017, 09:19:20 amI won't pretend to be any kind of expert, but I'm fairly sure the set-up pictured isn't radiation hard

author: jh15
author_rank: Frequent Contributor
timestamp: September 14, 2017, 12:47:46 am
content: For survival after the blast, tape buttered toast or peanut butter, to back of a cat. The face first, land on feet will kick in and the package spins in space.Then use the tail for a power takeoff.When the poops out, eat them both.