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“brighter than a thousand suns"
July 29, 2014 10:26 PM   Subscribe

What happens if you get hit by the main beam of a particle accelerator like the LHC?. "Well, fortunately (unfortunately?) we don’t have to guess, as this exact scenario actually happened to Anatoli Bugorski, a Russian scientist, way back in 1978."
posted by thatwhichfalls (43 comments total) 18 users marked this as a favorite

 
I can't decide if I want to imagine that scientists have managed to put objects (block of wood, dead chicken, Justin Bieber CD, etc.) in the beam just for kicks. Part of me really hopes such 'experiments' have been carried out. The other part of me hopes they're way too busy solving the fundamental questions of reality to bother with such hijinks.
posted by Ickster at 10:47 PM on July 29 [2 favorites]


Sounds like the Therac-25. Its victims were not so lucky.
posted by Chocolate Pickle at 11:05 PM on July 29


Slightly anticlimactic, eh?
It's so weird that the author assumes we want a bigger bang. If anything, I breathed a sigh of relief when I learned Bugorski survived.
posted by evidenceofabsence at 11:11 PM on July 29 [13 favorites]


Not as exciting as Soft Light but I'll take it. Knowing somebody actually got beamed with the thing takes it out of the realm of harmless fun. He really is pretty lucky, you'd think cancer and other nastiness would have been a concern, even surviving the initial damage.
posted by cj_ at 11:14 PM on July 29


OMG.

I used to work at the SLAC Linear Accelerator Center (in HR, in a student position). The one time I ventured near the accelerator itself, to drive some interns to a picnic, I saw a squirrel jump into a hole in the wall of the building housing the accelerator. I know the actual accelerator is buried 10 meters underground, and the thing you see under 280 is just the klystron gallery (whatever that means), but it was still kind of a D: moment. I wonder what happened to it.
posted by sunset in snow country at 11:22 PM on July 29 [2 favorites]


It became a godlike blue naked squirrel after reintegrating itself by sheer force of will and acorn hunger.
posted by benzenedream at 11:31 PM on July 29 [53 favorites]


Eventually, it could see all of time and space at once and this made it bad squirrel-boyfriend material.
posted by gingerest at 12:49 AM on July 30 [36 favorites]


It says he went on to get his PhD, I sincerely hope he got his name on the medical journal articles that I assume were written about this incident.
posted by biffa at 1:27 AM on July 30 [2 favorites]


Well, they wouldn't call him Dr. Oaktree unless he had gone on to get his PhD.
Wait, what are talking about?
posted by WaylandSmith at 1:31 AM on July 30 [14 favorites]


Klystrons are like giant microwave ovens. They provide power to the electrons, accelerating them as they go their merry way.
posted by Homemade Interossiter at 1:39 AM on July 30


Well that was disappointing. Not about the scientist, but that were unlikely to get some particle beam action out of the current generation.
posted by Tell Me No Lies at 1:46 AM on July 30


MeFi: we don't do threaded discussions because this is how you get mutant squirrels with PhDs
posted by fraula at 2:38 AM on July 30 [25 favorites]


extremetech just popped up a big banner saying "À propos des cookies sur ce site". I suspect they could save some money and improve the site quality by replacing their current set of web monkeys with a bunch of squirrels.
posted by effbot at 3:08 AM on July 30


And since we're sorta on the subject let's lob The Demon Core in.

The demon core was a 6.2-kilogram (14 lb; 1 st), 3.5-inch-diameter (89 mm) subcritical mass of plutonium which went briefly critical in two separate accidents at the Los Alamos laboratory in 1945 and 1946. Each incident resulted in the acute radiation poisoning and subsequent death of a scientist. After these incidents the spherical plutonium pit was referred to as the "demon core."
posted by GallonOfAlan at 3:10 AM on July 30 [3 favorites]


let's lob The Demon Core in

Previously: "They filmed his last hours. They asked him to talk about what he was feeling. I remember his face was beet red and his hair was falling out. He was polite and responsive to the last, apologising when he didn’t remember things or started coughing."
posted by effbot at 3:44 AM on July 30 [1 favorite]


In the future perhaps it would be best not to prevent nuclear criticality from occurring by holding up a bunch of plutonium with a flathead screwdriver in your off-hand. Or your primary hand. Best not to do anything which requires preventing criticality with a manual screwdriver, really.
posted by Justinian at 3:49 AM on July 30 [4 favorites]


I can't decide if I want to imagine that scientists have managed to put objects (block of wood, dead chicken, Justin Bieber CD, etc.) in the beam just for kicks.

I'm sure they would have.

My husband works as a physicist. Their lab doesn't have anything as flashy as a particle accelerator, but they frequently put random objects in front of the laser beams in the lab just for fun. He came into work one day to find the experimentalists had gone through his entire box of emergency breakfast weetbix and burned a single hole right through the middle of each weetbix.
posted by lollusc at 4:12 AM on July 30 [38 favorites]


So basically, the Russians decided it was time to reboot the Phineas Gage franchise with an updated backstory?
posted by McCoy Pauley at 4:45 AM on July 30 [7 favorites]


It says he went on to get his PhD, I sincerely hope he got his name on the medical journal articles that I assume were written about this incident.

For a moment there I thought we were still talking about the squirrel.
posted by dances with hamsters at 4:49 AM on July 30


Just on a practical note, proton therapy is a moderately tested alternative to x-ray therapy for some types of cancers. The primary advantage is that it's easier to focus the beam(s) within a smaller space, and you don't get the full-body dose that's often the primary cause of radiation poisoning.
posted by CBrachyrhynchos at 5:14 AM on July 30 [1 favorite]


Justinian, is a sonic screwdriver acceptable?
posted by staccato signals of constant information at 5:20 AM on July 30


Reading more about the Therac-25 accidents, I came across this little tidbit (on the third page; one of the many software problems that machine had):
During machine setup, Set-Up Test will be executed several hundred times since it reschedules itself waiting for other events to occur. In the code, the Class3 variable is incremented by one in each pass through Set-Up Test. Since the Class3 variable is 1 byte, it can only contain a maximum value of 255 decimal. Thus, on every 256th pass through the Set-Up Test code, the variable overflows and has a zero value. That means that on every 256th pass through Set-Up Test, the upper collimator will not be checked and an upper collimator fault will not be detected.

The overexposure occurred when the operator hit the "set" button at the precise moment that Class3 rolled over to zero. Thus Chkcol was not executed, and F$mal was not set to indicate the upper collimator was still in field-light position. The software turned on the full 25 MeV without the target in place and without scanning. A highly concentrated electron beam resulted, which was scattered and deflected by the stainless steel mirror that was in the path.
That machine was like playing Russian Roulette with slightly better odds.
posted by double block and bleed at 5:30 AM on July 30 [2 favorites]


I can't decide if I want to imagine that scientists have managed to put objects (block of wood, dead chicken, Justin Bieber CD, etc.) in the beam just for kicks. Part of me really hopes such 'experiments' have been carried out. The other part of me hopes they're way too busy solving the fundamental questions of reality to bother with such hijinks.

Are you kidding? If I worked there, I would hit a canned ham with every beam configuration possible until it mutated enough to be hireable as the facility's receptionist.
posted by delfin at 5:39 AM on July 30 [8 favorites]


I can't decide if I want to imagine that scientists have managed to put objects (block of wood, dead chicken, Justin Bieber CD, etc.) in the beam just for kicks.

I worked at a synchrotron and I put all kinds of weird shit in the x-ray beams that it produced, but putting things in the pipe where the electrons were circulating is a) impossible for various reasons including safety interlocks and b) a fantastically bad idea that would have shut down the facility for months.
posted by dorque at 6:29 AM on July 30 [3 favorites]


Although I did get to the Advanced Photon Source once to check in for beamtime, and while perusing the info/safety sheets left over by the previous group using the same station, discovered that they had been zapping live grasshoppers for science. (Insects are about as far as you can go these days as far as getting approval for live-animal synchrotron work.)
posted by dorque at 6:41 AM on July 30


The first part of this video and then this follow up are relevant to our interests.

I really don't know what would happen if you put your head (or hand) into the LHC beam, and contra the article, the Anatoli Bugorski incident only gives us a vague sense of what would happen in the much more powerful LHC. So let's do a Fermi-style thought experiment. Also known as writing down a bunch of numbers and then guessing from that.

Let's ignore the fact that you physically can't do this, since the LHC beam requires a very good vacuum in the beam pipe, so there are no gaps where you can stick your head. This vacuum is because Bad Things will happen if the beam hits free-floating particles (mostly to the beam itself, which must be very well collimated and have regular physical properties otherwise the experiments cannot extract as much useful data). Let's also ignore the radiation around the beam, which is so intense that you are not allow to go near the experiment at all while it is operating (or indeed, for many days afterwards due to activation of radioactive isotopes. Fire-fighting mechanisms for the LHC are automated, as if something bad happened, CERN would not be able to send humans in until the radiation levels dropped). We want a pure LHC-kill-beam thought experiment here.

In that case, we have two antiparallel beams of protons, each with 3.5, 4, or 6.5 TeV, depending on which run of the LHC we are discussing (3.5 and 4 are the Run I numbers, Run II starts in the late winter/early spring with 13 TeV beam-to-beam energy, so 6.5 TeV in each beam). The protons are organized in bunches, with a 50 ns spacing between bunches, moving down to 25 ns in each bunch (this means each bunch of protons is separated by about 7.5 meters in the 25 ns configuration). I'm now going to use nominal LHC beam parameters (as my dedication to this thought experiment is not great enough to sift through all the papers written on what the LHC was expected to do before turn-on, versus the parameters we are actually running with). There are 2808 bunches in each beam, and 1.15e11 protons in each bunch. Since the LHC ring is 27 km around, once you stick your head in the beam you will have 0.0001 seconds until the entire circulating beam piles into you, so all in all, your head will get to enjoy the presence of 3.3e14 protons, each with 6.5 TeV of kinetic energy (the protons only weigh a billionth of a gram, though adding in their kinetic energy it's about 7 millionths). Total energy of both beams I get as 670 MJ. The beams are separated though (until they reach the crossing points where the experiments are: CMS, ATLAS, ALICE, and LHC-b), and the beams are further apart than one human head usually (which means that the dipole magnet configuration is pretty nifty; its hard to get two beams of positive charge rotating in opposite directions with a single magnet). So we can only access half that energy to cause your head to explode, unless CMS or ATLAS lets you do this in their hall.

Now, what happens to that energy? Let's take the mm value as the width w of the beams at the point in which your head is inserted. We'll estimate the depth of head (d_h) as 30 cm, with a density of water -- this gives approximately the right mass for a human head, which should be about 20 lbs for an average man. This means that the mass in the way of the beam is approximately
m_target = \pi w^2/4 d_h \rho_water ~ 0.25 grams
so there are about 1e23 target nucleons whose day this beam is about to ruin.

The total inelastic cross section of proton-proton collisions at 14 TeV center of mass energy is 85 mbarn (mbarn = 1e-3 barn, the barn = 1e-24 cm^2 being the unit of area -- "size" -- that we use in particle physics. As in, "broad side of a"). However, the correct cross section should be at a lower energy, since the target head-nucleons are at rest. Eyeballing some plots of cross section versus energy, I estimate the appropriate cross section here is 40 mb. This makes the probability of a single beam proton hitting a single target nucleon the ratio of cross section to beam size, which works out to be about 1.3e-24. As there are 1e23 target nucleons, the probability for each beam proton to hit something in your head is about 13%.

Now, the big question, what does 13% of a 335 MJ beam do to your head? The beam will impart 43 MJ of energy in that mm wide beam, so I'm going to state with pretty high certainty that every atom in that beam is completely gone. Just totally vaporized. This is in contrast to the mere neuron-killing beam that Bugorski received. Two things go into this: the higher energy per proton for one, but also the much higher luminosity of the LHC compared to every other accelerator beam ever built. There's just more energy in the beam.

What about the rest of your head? Sadly after all the work that went into this, I don't know for sure. There are several considerations. First, most of the energy deposited will go into accelerating your ex-head nucleons in the direction of the beam, so to first order you might say that the surrounding tissue is not affected: the beam just removes a cylinder through your brain at nearly the speed of light. Downstream there's going to be a problem for the beam physicists, as they now have to deal with entirely too much radiation from your ex-head particles, which are now mostly ex-nucleons. The second consideration though is two-fold: first, there will be some scattering of energy transverse to the beam, which will deposit energy into the rest of your head. Too much energy and the rest of your head will either explode, vaporize, or just catch on fire. This is exacerbated by the 2nd effect, which is that collisions in the front of your head will have secondary interactions down-stream in your brain, which will likely increase the energy moving out of the beam path into the rest of your head.

It takes 18 MJ of energy to vaporize an 8 kg ball of water (ignoring the fact that said head of water is in a vacuum for the LHC beam to hit it). So I'm going to rule out complete vaporization the head, there's enough energy deposited, but too much of it would have to move transversely by my estimation. My best guess then is that -- in addition to your new mm sized hole -- you are probably going to get a region around that which gets to boiling or near boiling, which will likely kill you, but that your head won't spontaneously combust. You are certainly going to get a lethal dose of radiation from this, so regardless of physical damage, death is imminent. All this said, I think the only sure way to know is A) stick a head in the LHC, which sounds expensive and I'm sure some committee would nix it for the low scientific value, or B) we find an experimentalist with a copy of GEANT or similar code that simulates (among other things) the propagation of proton beams in matter, and ask them to mock up a head and hit it with simulated protons. You know, For Science.
posted by physicsmatt at 6:43 AM on July 30 [159 favorites]


Great comment physicsmatt!

What about the rest of your head?

I can comment on this from a medical perspective. The brain is pretty much completely encased in bone, with small holes for various nerves and such, the largest being the foramen magnum where the spinal cord goes. This is normally good for the protection of the brain, but in the situation you describe the intracranial pressure would rapidly rise, squeezing the (now possibly cooked) brainstem out through the foramen magnum in a process known as herniation that quickly results in brain death. Such patients are frequently good candidates for organ donation.
posted by TedW at 7:31 AM on July 30 [15 favorites]


Datapoint that I had to look up: 1 MJ is about one stick of dynamite.
posted by kiltedtaco at 7:37 AM on July 30 [1 favorite]


Total energy of both beams I get as 670 MJ

1kg TNT = 4.18MJ. So, we're looking at 160kg, or a 350 pounds of TNT worth of energy.

That's one scary set of beams.

but that your head won't spontaneously combust.

It might explode. That much energy is going to boil the water it contacts in the head quite quickly. The question is how much will it contact? The beam itself is very narrow, but at those energies, we're really looking at a fixed target experiment, aren't we?* So we're going to see collisions between those very high energy protons and the various and sundry (but mostly hydrogen, oxygen and calcium) atoms in the head, and those collisions will result in a spray of particles downstream. Thankfully, we don't have the very large magnetic field pulling charged particles in a different directions, which is another reason the human head makes for a very limited particle detector.**

It's certainly going to kill you in various and sundry ways. It doesn't take much of a rise in inter cranial pressure to kill you -- a rapid rise and you sort of try to squeeze your brain through the small hole in the bottom of the skull where the spine meets, and your brain responds poorly to be treated as toothpaste. You've mentioned the radiation hazard already.

I know in the Fermi accelerator chain, there are places where the beam travels through atmosphere -- the beam pipe is cut off and each is capped with foil. This is so you don't have to keep the entire system at vacuum, and you can shut down one and lose vacuum without the other accelerators having to drop offline as well. This was most critical in the TeV/MI interface, where the MI could be doing a lot of work with the TeV or PBar offline.


* Hmm. I'm halfway tempted to write the proposal to see how long it will take before somebody notices what the fixed target actually is.

** Really, it's only a decent detector for a very limited bandwidth of electromagnetic energy centered on 545THz.
posted by eriko at 7:46 AM on July 30 [6 favorites]


Best not to do anything which requires preventing criticality with a manual screwdriver, really.

Yeah, you want two independent, robust, and redundant screwdrivers, at least.
posted by radwolf76 at 7:55 AM on July 30 [2 favorites]


to get into my office, I have to walk past a fission-pumped x-ray laser lab. collimated ANYTHING scares the ever-loving sh*t out of me. this is mostly why I work from home.

when the lab doors have ginormous signs for the sake of rescue workers, telling them exactly why they should not enter in case of emergency, that's... that just can't wendell.
posted by dorian at 9:12 AM on July 30 [2 favorites]


I'm going to state with pretty high certainty that every atom in that beam is completely gone. Just totally vaporized.

So we *do* get our particle beam weapon. Hoooray!

Thanks, physicsmatt.
posted by Tell Me No Lies at 9:34 AM on July 30


sunset in snow country: "OMG.

I used to work at the SLAC Linear Accelerator Center (in HR, in a student position). The one time I ventured near the accelerator itself, to drive some interns to a picnic, I saw a squirrel jump into a hole in the wall of the building housing the accelerator. I know the actual accelerator is buried 10 meters underground, and the thing you see under 280 is just the klystron gallery (whatever that means), but it was still kind of a D: moment. I wonder what happened to it.
"

Squirrel Girl.
posted by Splunge at 9:35 AM on July 30 [1 favorite]


Why does so much Soviet science sound like it was done in the least-safe manner possible? I can't let go of my lawn mower without the engine shutting off yet Bugorski was able to get into a particle accelerator and get zapped without much (apparent) trouble.
posted by tommasz at 9:48 AM on July 30 [2 favorites]


So no Dr. Manhattan, then?
posted by Renoroc at 10:04 AM on July 30


Why does so much Soviet science sound like it was done in the least-safe manner possible?

Well, this _is_ the Russian scientific method in a nutshell.
posted by delfin at 1:20 PM on July 30 [2 favorites]


I was expecting that link to go here.
(Yes, I know that's from a mocumentary.)
posted by radwolf76 at 2:34 PM on July 30


radwolf76: "Yes, I know that's from a mocumentary."

I missed that part of your post before I clicked the link. Needless to say, I was quite relieved to read it when I returned from the video.
posted by InsertNiftyNameHere at 4:31 PM on July 30


Well if we're doing Russian engineers...
posted by Tell Me No Lies at 6:32 PM on July 30 [4 favorites]


Such patients are frequently good candidates for organ donation

See, God never closes a door without opening a window
posted by thelonius at 9:33 AM on August 1


posted by physicsmatt at 8:43 AM on July 30

Eponynformative.
posted by DynamiteToast at 12:22 PM on August 1 [1 favorite]


Tell Me No Lies, the best part of that was the brick in the washing machine. Here's the full-length version. I laughed so hard I was in tears.
posted by tommasz at 1:03 PM on August 1 [1 favorite]


tommasz, my personal tastes go to the barge being rowed by an excavator.
posted by Tell Me No Lies at 2:30 PM on August 1 [1 favorite]


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