

If you put your hand in the Large Hadron Collider... - jlangenauer
http://kottke.org/10/09/putting-your-hand-in-the-large-hadron-collider

======
RK
By training I am a radiation physicist and actually do know about particle
beams hitting people. The LHC beam would certainly give someone an appreciable
radiation dose, although the secondary synchrotron X-rays would probably be
worse than the proton beam itself. In fact a much lower energy proton beam
would have a worse effect on your hand/body, since that beam would actually
stop inside you (protons deposit most of their dose at the very end of their
range).

Of course the injury you received would largely be determined by the length of
time your hand was in the beam. Really not fun results can be radiation ulcers
or radiogenic cancer. If the dose were high enough you could get a radiation
syndrome, where some/all of the fast growing cells in your body die off and
you die in a few days or months.

The only data I could find after a quick search indicated that the dose
present in the beam line would be on the order of 10^4 Gy per year. That means
if you managed to put your hand in the beam for 1 minute, you're only looking
at about 0.01 Gy, which isn't that much.

~~~
Anon84
There's actually a reported case of someone getting hit by a proton beam on
the head in 1978:

    
    
         Bugorski was leaning over the piece of equipment when 
         he stuck his head in the part through which the proton 
         beam was running. Reportedly, he saw a flash "brighter 
         than a thousand suns", but did not feel any pain.
    

<http://en.wikipedia.org/wiki/Anatoli_Bugorski>

He is still alive.

~~~
jules
In case people take what the first person in the video says combined with your
quote from wikipedia but don't read the entire wikipedia page I'll quote this:

    
    
        The left half of Bugorski's face swelled up beyond
        recognition, and over the next several days started 
        peeling off, showing the path that the proton beam 
        (moving near the speed of light) had burned through 
        parts of his face, his bone, and the brain tissue
        underneath.

------
Pinckney
In 1978, Anatoli Bugorski accidentally stuck his head through the 70GeV U-70
Synchrotron. <http://en.wikipedia.org/wiki/Anatoli_Bugorski>

He is alive, but suffered serious injuries. As I understand, the LHC is of a
similar design, at 100 times the energy.

~~~
sbierwagen
The beam path on the LHC is kept under high vacuum. At no point does it
intersect air at atmospheric pressure. There's no way for anything to
accidentally intersect the beams, which is good, since one of them is made of
antimatter.

EDIT: Nope! Wrong! Mistook the LHC for the LEP. The LHC does not accelerate
antimatter at any point.

Additionally, while the individual protons in the LHC may only be a hundred
times more energetic, there are quite a few more total particles in the beams.
I can't find any technical details of the U-70 synchrotron, but it came online
in 1957, so there's that.

~~~
fjh
Sorry about the nitpick, but no, the LHC does not use antimatter. Both beams
consist of protons (or heavy ions sometimes). Some of the accelerators at
CERN, like the LEP (Large Electron Positron) Collider, do use antimatter, but
the LHC does not.

~~~
sbierwagen
Thanks for the correction. Upvoted.

------
patrickyeon
The LHC has beam dumps, where they re-direct the beam if they need to shut it
down quickly. [http://lhc-machine-outreach.web.cern.ch/lhc-machine-
outreach...](http://lhc-machine-outreach.web.cern.ch/lhc-machine-
outreach/components/beam-dump.htm) "Each beam dump absorber consists of a 7m
long segmented carbon cylinder of 700mm diameter, contained in a steel
cylinder" They seem to expect that there'd be a lot of force there.

[http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach...](http://lhc-
machine-outreach.web.cern.ch/lhc-machine-outreach/beam.htm) also has some
comparisons regarding beam energy and aircraft carriers, cars, etc.

~~~
DougBTX
I know hardly anything about proton beams. However, here's a thought
experiment that's on my mind:

Instead of a beam of protons, lets think about something simpler: a reasonably
high powered bullet. Instead of a 7m segmented carbon cylinder, lets have some
slats of wood. So, in the same way as at the LHC, the bullet strikes the
wooden slats, it deposits all of it's energy in the wooden slats, breaking
them up and stopping the bullet.

I think that fits the use case of the beam dumps, where all the force of the
beam gets dumped at once, and the important number is the total energy of the
beam, since you want to totally stop it.

Now, the thought experiment: replace the wooden slats with single piece of
paper. Now when the bullet strikes, it goes straight through - the mass of
energy in the bullet mostly stays in the bullet, only enough energy to rip
through a small circle in the paper gets dumped. The bullet will carry on it's
merry way.

So, relative to the LHC beam, which is your hand more alike: the sheet of
paper, or the slats of wood?

It's a simplistic model which ignores radiation from the beam, and lots of
other things, but I think it's informative. My guess is that the beam would
behave like a laser cutter: cutting a smallish hole, possibly with secondary
damage, but largely powerful enough to carry on it's way once it has punched
through.

~~~
dedward
A bullet going at relativistic velocity hitting a piece of paper might not
punch such a nice hole - it would bust up molecules and atoms, and some
subatomic particles, there would be tons of secondary radiation from that, and
the rest of the paper would be destroyed along the way by some type of
explosion.

------
sbierwagen
It would be pretty spectacular.

Each proton would, at the full power of 7 TeV, have 1.12 microjoules of
energy. 1.15x10^11 protons per pulse, 2808 pulses per beam and two beams, one
of antiprotons, and one of protons; for a total energy of 352,235,520 joules.
87 kilograms of TNT.[1][2]

Your hand would evaporate fairly quickly, then turn into a plasma, then get
hot enough to start radiating x-rays. There would be quite a lot of
bremsstrahlung from the hyperenergetic protons punching through the cloud of
plasma, and producing showers of secondary radiation,[3] which means you would
be quite well irradiated by the time the shockwave from the explosion killed
you.

1: All this is straight from the wikipedia page, but I double checked the
math.

2: I'm not including energy liberated from antimatter annihilation energy,
since the total mass of the antiprotons is quite small.

Typing that out, it sounds like a pretty lame excuse. Let's do the math.

3.2292x10^14 protons per beam. Atomic weight of 1, of course, so:

(3.2292x10^14)/(6.0221415x10^23)[4] = 5.362212x10^-10 grams. .536 nanograms of
antimatter.

Since annihilating antimatter gets you 9x10^13 joules per gram, you get...
48,259.9089 joules. That's actually larger than I expected, but .01% of the
kinetic energy of the beam.

3: Just how much secondary radiation, I don't know, since that depends on the
density of the cloud of plasma, which would change over time, be pretty
anisotropic, and be a general pain in the ass to model.

4: Avogadro's constant

Buncha edits: forgot HN uses the asterisk to style text.

~~~
sbierwagen
Can't edit this now, of course, but as fjh pointed out elsewhere, I confused
the details of the LHC for the LEP, partially. The LHC collides protons and
sometimes lead nuclei; but at no point collides antiprotons.

Posting after midnight: Not always a good idea.

~~~
mahmud
Don't worry, you had me at "bremsstrahlung".

~~~
ovi256
Braking radiation ? What they don't teach that in school anymore ?

Just kidding.

------
tkeller
I'm a big fan of the whole Sixty Symbols series. For those of you not
familiar: <http://www.sixtysymbols.com/>

There's also a "sister" site for chemistry: <http://www.periodicvideos.com/>

It's good stuff. I've enjoyed pretty much every video I've seen from both of
them.

------
atomical
Why don't we drop a pig into the LHC. If nothing happens, problem solved. If
something happens, dinner solved.

~~~
danfitch
Peta would be all over that.

~~~
aberkowitz
"You can do the same thing to a tofu pig without harming innocent animals"

~~~
Groxx
I'm sure _someone_ would take offense to it being shaped like a pig, or even
_referred_ to as a pig, as the implications are still remotely offensive.

Heck, to use the technique of some parents: some starving kid in Africa would
_love_ to eat that tofu. We, therefore, should clearly be offended at its
waste.

~~~
cabalamat
Gas pipelines have little machines crawling inside them for inspection and
maintenance purposes. These machines are called pigs.

The LHC is basically a big pipe, so maybe it does have pigs inside it already.

------
mctavjb9
Sorry to be a buzzkill, but the LHC beam circulates in an extremely high
vacuum. There's no way a hand could even get in the beam without breaking the
vacuum, thereby causing the accelerator to shut down automatically. Also, it's
cryogenically cooled. Radiation dose aside, the hand would freeze and probably
fall off.

[http://www.lhc-closer.es/php/index.php?i=1&s=4&p=15&...](http://www.lhc-
closer.es/php/index.php?i=1&s=4&p=15&e=0)

Incidentally, when I was working at CERN in the mid 1990's, the Large
Electron-Positron Collider (the predecessor to the LHC) was shut down by an
act of sabotage involving 2 Heineken bottles placed in the beam pipe. The
electrons and positrons (and many physicists) were not happy bunnies.
[http://blogs.nature.com/news/thegreatbeyond/Beer%20bottles.p...](http://blogs.nature.com/news/thegreatbeyond/Beer%20bottles.pdf)

Update: Now I see that the vacuum point has already been made. There are no
heavy ions in the LHC main collider, they're produced by bashing protons into
a target in one of the secondary beamlines. Also, antimatter is frequently the
byproduct of extremely high center of mass proton-proton collisions.

------
DeusExMachina
It's a too little sample to be statistically significant in any way, but I
find interesting that no two men have the same favorite symbol, while both the
women coincidentally chose infinity and what its symbol represents.

------
hardy263
If the universe were to be remade, perhaps physical constants would change,
like gravity could be 7.1 instead of 6.67.

But mathematical constants like pi would remain the same, wouldn't it? A
circle is a circle no matter what kind of universe it's in, so the ratio of
the radius to the arc length would remain the same.

As I look at it, math is the universal truth of the universe, because
everything is derived using the first principles.

~~~
dedward
1) Perhaps yes. 2) Mathemtical contstans are purely abstact - pi only exists
in a perfectly euclidian plane. It's an abstraction that works for us in a
scertain scale because it matches close enough. In real life, there aren't
circles.. they're just close enough. So no - a universe could have completely
different maths required to describe it. 3) Math is purely abstract and
detached from the universe. It operates on theoretical models that try to
model reality. Math has it's own universal truths, but reality does not. The
universe came before math - math is a tool invented by man to analyze the
universe.

~~~
derefr
> So no - a universe could have completely different maths required to
> describe it.

That wasn't the question, though. Pi is the ratio between circumference and
diameter of a perfect circle, whether or not you can create a perfect circle
in your universe. We can't even create one in ours, and yet pi still "exists"
here. Undoubtedly, wiggly-space mathematicians would also have a conception of
pi, though it might be as esoteric to them as toroidial universes are to us.

To put that another way: Math has very simple axioms (e.g. set theory), and
everything else derives from them. What theories can be proven from those
axioms in this universe, can be proven from those axioms in any universe (and
a universe that doesn't obey those axioms likely wouldn't "function" as a
universe—it wouldn't have any reason to be causal, for example.) The maths
describing a particular universe is its _physics_ , which do change from
universe to universe—however, those physics are all just different _subsets_
of the set of mathematical physical models—which are, themselves, a subset of
the mathematical theories provable from the axioms.

------
erikstarck
The real question should be: what super powers would you get?

~~~
tfh
You are not allowed to joke in HN.

------
aspir
If you put a hot dog in the collider, will you get little smokies from the
spallation process?

I think I just solved world hunger guys...

------
CamperBob
So, these are not the same people who are in charge of determining whether or
not a black hole might form and persist, correct?

~~~
robryan
Except they have done research on the black hole possibility, there work
centres on the beams colliding not what happens if it hits a certain
combination of atoms that make up a human hand.

I guess it's kind of like someone saying to a programmer, hey can you fix my
computer, you work in computer right?

~~~
CamperBob
I guess it struck me as more like someone saying to a C programmer, "Hey, can
you help me find the bug in this Java routine?" The C programmer might not
know Java intimately but at least he's not going to stroke his beard and act
like it's something he's never considered before.

I _certainly_ wouldn't expect two or three competent C programmers to offer
wildly divergent opinions if asked a question that fell slightly outside their
everyday practice.

