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Don't Cross the LHC Stream! (Maybe)
jamie points out this piece from always-entertaining Bad Astronomer Phil Plait, who asks this week the simple question "What happens if you put your hand in the beam of the Large Hadron Collider?" The thrill of discovery to me doesn't sound worth the worst-case scenario.
You get a built-in tool that makes it easier to masturbate.
But when I put my bottom in front of it I ended up with a huge black hole.
They'd just stick a pig foot in there.
"So it was in 1978 that when the proton beam entered Anatoli Bugorski's skull it measured about 200,000 rads, and when it exited, having collided with the inside of his head, it weighed in at about 300,000 rads. Bugorski, a 36-year-old researcher at the Institute for High Energy Physics in Protvino, was checking a piece of accelerator equipment that had malfunctioned - as had, apparently, the several safety mechanisms. Leaning over the piece of equipment, Bugorski stuck his head in the space through which the beam passes on its way from one part of the accelerator tube to the next and saw a flash brighter than a thousand suns. He felt no pain.
http://www.wired.com/wired/archive/5.12/science.html
This is a man who looked into a proton beam accelerator that he thought was non-operational. It's already happened once before.
Glad to know I'm not the only one fuzzy on the whole good / bad thing.
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Someone I know had the small child of a neighbor flash him in the eye with a cheap Chinese red laser pointer some time ago, and got a permanent scar on his retina and a second "blind spot" in one of his eyes. Apparently, the pointer was a little bit too powerful in the IR region than it should have been.
Moral of the story - avoid high energy beams regardless of the wavelength or the particle kind because you never know what will slip by even in a supposedly "safe" circumstances.
Why does anything exist at all, instead of nothing?
File under 'M' for 'Manic ranting'
An artist makes unusual "sculptures" by putting acrylic blocks into the beam path of a relatively small electron accelerator:
http://www.dailymail.co.uk/sciencetech/article-1232908/Captured-lightning-The-artist-traps-fossilised-bolts-electricity-inside-acrylic-blocks.html
I don't know of any red lasers that have IR components. Lasers are, by definition, monochromatic. That's the idea after all. The reason some have IR as well is they are DPSS. They produce IR radiation directly, a frequency doubler then takes it up to the visual range. That's a lossy process, so the IR is much higher than the final output, hence an IR filter is needed. Green lasers work this way, at least all the ones I've seen. However red laser pointers are all direct drive, the diode outputs the frequency you want. That's why they are used for CDs and so on, keeps the cost down.
That is also the big deal with Blu-ray lasers (actually quite violet, not blue). Again, direct diode lasers. Means they cost less, use less space and so on, and of course being violet have a higher wavelength.
I've never heard of a red DPSS laser pointer.
I'm sure Jamie and Adam are already working on a LMC (Large Mythdron Collider) and will be dropping some poor unsuspecting pig carcass in it any day now.
Sounds like a idea for a sci-fi channel b movie!
Someone calculated that about 4 joules of energy would be deposited. I assume that is in a single pass of the beam. However, if the beam recirculates (does it?), then the hypothetical hand will get hit by the beam many times. Then a huge amount of energy will end up in the hand in a short time and it'd probably be cut by the beam as you inserted it.
What also intrigues me is whether a fatal does of radiation would occur from the 4 joules/pass that you would get. I think it would be about 8 Gray of radiation dose into the hand. A 5 Gray whole-body dose of radiation is usually fatal. The hand is less vulnerable to radiation than the body in general, however, this cannot be a good thing.
Here's my take:
multiple passes: either hand is sliced as it is inserted into the beam, or the hand explodes
single pass: might lose the hand, owner of hand might get pretty sick
--PM
I suppose the effects would be similar to being exposed to very large doses of particles resulting from alpha and beta decay, added a huge dose of X-rays (more precisely synchrotron radiation). I don't think the speed of the particles makes much difference in this case.
The LHC is currently running with 10^13 protons per beam, which at 3.5 TeV amount to 5.6 megajoule of energy.
Which would be more than enough to vaporize 2 liters of water !
Moral of the story - avoid high energy beams regardless of the wavelength or the particle kind because you never know what will slip by even in a supposedly "safe" circumstances.
Incorrect. Moral of the story: Do not look into laser with remaining eye.
Now that I think about it, I'm pretty sure everything I just said is completely wrong.
The total energy in the beam is 724 MJ (173 kilograms of TNT) (energy stored in magnets are 10x this) That is a bomb big enough to take out a school.
It would be hard to get your hand into vacuum, but imagine a space suit arm attached to a sandblast cabinet.
The beams energy would hit your hand in a spot d1mm. It would most certainly deposit all its energy there until that part of your hand became a vacuum. Probably similar to a laser knife. In addition, your flesh that obstructed the beam would give off a lot of radiation as it burned away. Imagine Hiroshima 1km away x10^8 on that part of your body.
Every proton would not hit something in your hand on first encounter, but if it missed, it would just loop around, and hit on a later time. The result would be the same. In a short time, your hand and your space glove would have a hole through it. More likely a straight cut from where you put it in. Anything nearby would be exposed to a good dose of radiation as these collisions would be quite "dirty".
don't cut it off www.mgmbill.org
You can look into you LHC & lasers and what not.
me, i'm waiting for the test of a gamma bomb, so I can sneak out on the test range.
Just don't make me angry.
Be seeing you...
Fermilab had a beam loss event in 2003 (beam came into contact with part of the ring). The beam drilled a 2.8 mm hole through a 5mm tungsten support. It also etched a groove 25 cm long and 1.5 mm deep into a stainless steel collimator (after passing through the tungsten). Apparently this took about 8.3 ms (over several turns of the beam) before the beam dissipated.
I'm guessing if you could insert your hand fast enough (not possible, even if there wasn't a vacuum tube) you would end up with a nice small hole drilled through your hand.
This is the report from the Fermi incident:
http://beamdocs.fnal.gov/DocDB/0011/001185/001/FN-751.pdf
In the event they need to dismiss the beam, a dump block is used.
The dump block is a cylinder of graphite and the beam is deflected with small oscillations
to disperse it and not have it all bore though a tiny spot in the center.
Other materials apparently are no good and sustain damage. Run the LHC beam straight
into copper and it'll bore a hole the length of which is measured in meters.
If the beam was deflected at a not too shallow angle, it could perhaps penetrate
the mass of earth atmosphere, and be usable in knocking out satellites.
ps. a bit of googling and http://spectrum.ieee.org/aerospace/astrophysics/cern-to-start-up-the-large-hadron-collider-now-heres-how-it-plans-to-stop-it says the dump block 10 tons and 8 meters long.
A man comes home from his work at the deli, and tells his wife, "I have a strong desire to put my penis in the pickle slicer."
"That's sick!" replies his wife. "You need help."
"I don't see any reason it would be sick", retorts the man, "I think it would be fun!"
Two days later, his wife comes home from an errand, and her husbands car is in the driveway. "You're home early", she says.
"Yes, I put my penis in the pickle slicer!" he smiles.
"Oh my God!", gasps his wife, "What happened?"
"I got fired! So did she!"
Why, without your clothes, you're naked, Miss Dudley!
> It would be hard to get your hand into vacuum...
The only "practical" way to do it would be to modify the line running to the beam dump by inserting an air gap (the windows would have to be tungsten or something). You'd place the hand in the gap and then divert the beam into the dump line.
> ...imagine a space suit arm attached to a sandblast cabinet.
As you swung your arm into position the beam would blow a hole in the edge of the glove. Hitting the glove would disrupt it enough that it would scatter into the walls of the tube before making it around again. You'd get a bad burn on the side of your hand and perhaps a notch. You might not lose the hand.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
I haven't read the article... here's my semi-educated guess: It would feel like you stuck your hand in the path of a lightning bolt. Then you'd die an unpleasant death from the massive radiation overdose resulting from the interaction of the high energy particles with the nuclei in your hand. I'm not recommending anyone try it.
That's bad. OK, all right, important safety tip. Thanks, Egon!
...after re-reading I see the guy worked at a deli, not at Dell...
I often flick through Slashdot, and as a scientist, I always find these kinds of links interesting
http://science.slashdot.org/story/10/09/25/2150228/Dont-Cross-the-LHC-Stream-Maybe
In particular, they discuss what would happen if you put your hand in the beam of the LHC, they linked to this page
http://blogs.discovermagazine.com/badastronomy/2010/09/21/dont-cross-the-lhc-stream/
and bloody hell, if its not one of my old professor chums! The very very nice chap with glasses and the welsh accent is none other than Laurence Eaves who was (is?) at Nottingham University, we used to work with him a lot, he is big pals with my supervisor who was Maurice Skolnick up in Sheffield. I always knew "Lozza" ( as we called him, in reference to "Mozza" Skolnick) had way too much personality to be hidden away from the TV cameras, so it was very nice to see him there as one of the experts, even though he wasn't into the particle physics, at least not in the early and mid 90s when I liaised with him
Good on you Lozza!
Was that the New Delhi down the street? or the old one?
Getting caught looking at it will absolutely get you a one-way ticket out the front door, even if your boss isn't a Christian.
"When information is power, privacy is freedom" - Jah-Wren Ryel
The article changed after I posted this.
If video games influenced behavior the Pac Man generation would be eating pills and running away from their problems.
What I find interesting in his case is that the left side of his face did not age since the accident, nearly 19 years ago. Yes it is paralyzed, but it hasn't aged. I wonder if since the nerves and other parts of his brain were damaged, it affected the aging mechanism on that side of the face?
Tired of my customary (Score:1)
Having read the Fermilab report I see that there is no point in making the windows tungsten. I also see that if they really wanted to know what the beam would do to a slab of meat they could model it pretty accurately.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Read about it http://en.wikipedia.org/wiki/Anatoli_Bugorski
Incorrect. Lasers use a highly focused parallel high energy beam. Because it's high energy, it can burn. By projecting the focused parallel beam through a convex lens (the eye's lens) you refocus the beam and all the parallel high-energy photons focus on a point. This point light then burns the back of the cornea. Like looking directly at the Sun. Or focusing a magnifying glass on a leaf on a sunny day. Has nothing to do with IR and everything to do with optics and energy levels.
Every proton would not hit something in your hand on first encounter, but if it missed, it would just loop around, and hit on a later time.
You are forgetting about the minimum ionizing radiation that is induced by every charged particle at that energy that is passing through your hand. According to the Bethe-Block equation, that will be about 2 MeV, (assuming that your hand is made of water and is about one cm thick.)
One entire passage of the beam around the ring will then deposit:
2808 bunches * 1.15 10^11 protons * 2 MeV * 1.6*10^-13 Joule/MeV = 103 Joules
At the speed of light, the beam orbits 300000 km/sec / 27 km (LHC circumference) = 11,100 times per second.
So the energy deposition, without counting ANY hard (nuclear) interactions or ANY synchrotron radiation, is already > 1 MJ per second.
You're hand is going to get cooked in no time even without any nuclear collisions. .
I worked on researching a system that prevents the beam from damaging sensitive equipment if something goes awry. To accentuate the need for such a system, we had pictures of where the beam was dumped into metal plate targets. Even well under full capacity it ate holes straight through the targets with ease. I'd imagine you would get a hole in your hand and big dose of high energy radiation.
...tried it in 1978 at the IHEP. But not with his hand!
I was amazed at the ignorance displayed in this thread. In radiation therapy proton beams are used a lot to treat cancer so the problem is well known.
Of course you will need o know the fluence of the beam (e.g. number of particles/ square cm/ second) and the amount of time the hand has been in the beam.
Usually these beams are of relatively low flux, the particles in the beam do have a very high energy. The next thing you need to determine is
the amount of energy that will be transferred to the tissue. For this we use the notion of stopping power (i,e, energy deposited under the form of ionizing collisions per unit length). This quantity depends on the charge of the particle (squared) and the inverse of the speed of the particle (squared). This means, and most people find this counter intuitive, that the higher the energy, the lower the amount of energy being deposited. So in this case the deposited energy is very low, e.g. the beam passes almost right through the hand. I do not have any stopping power numbers for these type of energies handy but can only presume that they are very low. Some caveats, these line of thought only follows direct interactions and collisional interactions with electrons.
Most likely there is a larger component of nuclear interactions and ionizations coming from recoil events. Which will increase the dose.
In order to get the maximum effect with a proton beam one has to tune the beam in such a way that it comes to a complete halt inside the persons body
this is about 200MeV for a human, what is several orders of magnitude lower than the energies here at hand (pun unintended).
Anyway interesting question and at my next exam I will be sure to put it in. Now we will see if any of my students read slashdot ;-)
My local pub offers hadron flavoured beer.
Sent from my ASR33 using ASCII
I'm afraid you're missing one point.
Sure all the local effects would be as described.
But your hand is composed mostly of water. About 2mm diameter by some 2cm length cylinder inside your hand would turn into massively superheated steal over few nanoseconds. Steam that hot, from that amount of water, in that volume has enormous pressure. Maybe the resulting explosion would end near your wrist, but I suspect shrapnels of your own hand bones would kill you.
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
Incorrect. It has to do with IR inasmuch as you _do not see IR light_. Thus, the apparent brightness is a _lot_ lower than the true light output. Obviously, the fact that IR is great to transport heat helps in burning tissue.
Also, with lasers, you do not need to focus any more precisely _because_ the beams are parallel (it gets focused within the laser's casing). This (and the fact that they waves are in sync) is why a laser can cut steel while a flashlight can't.
The value of a house is determined by three things, location, location and location.
Were the brain is injured is important!
So did they guess about creation of black holes, too?!
Here is some info about the LHC Beam Dump System.
http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/components/beam-dump.htm
Also, from
http://www.telegraph.co.uk/science/large-hadron-collider/3352114/Large-Hadron-Collider-could-it-defrost-a-pizza.html :
Each absorber consists of a seven metre long segmented carbon cylinder of 700mm diameter, contained in a steel cylinder, which is water cooled, and surrounded by about 750 ton of concrete and iron shielding.
For the dump to work, the beam has to be diffused, because in its compressed form it would drill a hole tens of meters long in any material. Dr Rüdiger Schmidt, deputy leader of the LHC hardware commissioning team, said in response to the ongoing pizza discussions: "Stacks of frozen pizza have never been considered for the LHC's beam dump."
I saw the special on PBS in which they show'd the workers and scientists building it. They specifically asked the lead guy what would happen if they lost confinement of the beam and he said the total energy in the beam is about equivalent to a buss traveling at 65mph. He went on to say they believe and area of approximate 8feet by 8feet would be instantaneously vaporized... and it why the facility is underground. It's been a couple of years since I saw that episoned so I might have a couple of the numbers wrong.
With his right brain?
You don't expect him to be able to complete a PHD with his wrong brain, do you?
I'm pretty sure plenty of scientists must have looked at this, after all someone had to design the beam dumps. From http://www.symmetrymagazine.org/cms/?pid=1000570
In 2003, two-thirds of the superconducting magnets in the Tevatron’s six-kilometer ring quenched at the same time. The beam drilled a hole in one collimator and created a 30-centimeter groove in another. That accident, while serious, was the only one in the accelerator’s 20-year history, and the machine was back up and running within two weeks. Could something similar happen on a larger scale at the LHC?
“In a bad accident, the beam could go off course and drill a hole through one or two magnets,” says Schmidt. While this would not destroy the LHC, it would still require time and money for repair.
I'm pretty sure something that can drill a hole in a super conducting magnet would make a hole in someone's hand...
I think I might go try that.
Whoops, second one was the wikipedia article
and the site is already slashdotted? or is the link plain wrong?
What happens if you put your hand in the beam of the Large Hadron Collider?
What do you mean exactly? What happens to your hand - or which results could you expect from the experiment?
The experimental data are hard to predict - a hand is a very complex target, and many reactions are possible. Quite likely the measurements will be too overcrowded to make much sense.
What will happen to the hand is perhaps easier to predict. Firstly there is the hard vacuum, which will make the blood boil - the resulting water vapour will disrupt the beam, so nothing further will happen until the hand has completely desiccated and vacuum has been restored. When the beam has been started up again, it will start interacting with the remaining tissue of the hand, breaking down chemical bonds and releasing further gases into the vacuum, this time not only stopping the beam, but also depositing a film of sticky hydrocarbons which will need to be cleaned away. Once that has been done - after, say 2 years - we will probably start seeing the beam mainly blasting atoms apart, if the target hasn't by lost its structural integrity due the chemical decomposition.
In all, I don't think I can't recommend this experiment. The scientific benefits are modest compared to the operational costs involved.
Wait a minute! Wait aminute, I thought you guys said that crossing the streams was a bad idea?