Please Keep Your Hands and Heads Outside the Moving Proton Beam
I was most gratified when somebody finally asked the question that we all really wanted to know: What would happen to your hand if you stuck it into the proton beam at the Large Hadron Collider? Last September, our friends at Sixty Symbols (a collaboration between The University of Nottingham School of Physics and Astronomy and video journalist Brady Haran) asked precisely this of a number of high energy physicists. What was their answer?
In short, they really didn’t know. But there is one man who has some idea. Way back in 1978, a young Russian physicist, Anatoli Bugorski, was working on a broken component at the Soviet Union’s largest particle accelerator, the U-70 synchrotron, at the Institute for High Energy Physics. He leaned his head in, and somehow managed to put it directly into the beam. It was a bad call.
Anatoli Bugorski shortly after the accident. The left side of his face is swollen, and injuries are visible at his left nostril and the back of his head. The red lines show the path of the beam through his skull.
The beam went through his head, drawing a line from his left nostril to the back of his head. Anatoli reported seeing a light “brighter than a thousand suns” but felt no pain. Amazingly, he survived the accident, continued his career, and still lives in Russia today. His lasting effects were loss of nerve function to the left side of his face, and periodic seizures.
There doesn’t seem to be much information published about this accident (at least, not in English) beyond the contents in this 1997 article in Wired Magazine, written by Russian journalist Masha Gessen. Almost everything I found on the web was taken from this article.
There is one very important difference between what Anatoli went through and what would happen at the Large Hadron Collider: The beam energy is a lot higher. I couldn’t find any record of what energy level the U-70 synchrotron was operating at during the accident, but its maximum power was 70 GeV. Either of the LHC’s twin beams can go as high as 7 TeV, so it’s 100 times as energetic.
What would have happened to Anatoli at 7 TeV? I expect he would politely decline to test that for us.
Let’s get the Mythbusters on this right away!
I’m currently reading Mary Roach’s Stiff right now. Sounds like some interesting work for a cadaver. Maybe the next time they retire one of these machines (cough cough Tevatron) we can get a better answer.
Something doesn’t sound right. I thought the beams had to travel in a vacuum. Like in a vacuum tube.
I thought of this too, but hey it’s the USSR. Who knows. It’s not like safety or high-quality engineering were ever priorities.
Most types of vacuum tubes actually have quite a bit of air in them – the particle accelerators have far less air.
The thing I found most suspicious about this story is the neat entry and exit points. If you stuck your head into a dangerous place and immediately saw a light “brighter than a thousand suns” you’d probably pull it right back out. So if this happened, you’d think the beam would have made a fast transient slice through his skull and not a single neat line.
A lack of any corroborating reports is also a red flag, but since I didn’t check any Russian language sources it’s not too surprising.
There’s no information about the time span of the event, either. It’s possible he rapidly moved his head into the beam, left it there a moment before realizing what was going on, then rapidly removed his head from the beam. Those parts of his head exposed when he was moving would have vastly lower exposures than the part the beam was passing through when he was still, even if it was for less than a second.
Perhaps his head’s obstruction of the beam triggered some kind of automatic shut-off? Even by Russian standards, I would imagine that to be a basic safety protocol:
“In the event that the ultra high energy death ray does not land precisely where we expect it to, disconnect immediately so as to not bisect any important objects/structures such as gas tanks, facility visitors, or the moon.”
Maybe the beam was turned on for a microsecond.
That is, it’s not a stream, but pulses.
Here’s Google’s translation of the Russian article, “Personal Chernobyl of Anatoli Bugorski”
http://translate.google.com/translate?hl=en&sl=ru&tl=en&u=http://www.liveinternet.ru/users/rewiever/post132062905
Oh, very cool find, thanks.
That article says the beam is a sequence of packets flying through the air, not a continuous stream in a vacuum tube.
I suspect the *primary* thing that will happen is that a bunch of high-energy physicists come by and beat you up for ruining their experiment…
“but its maximum power was 70 GeV. Either of the LHC’s twin beams can go as high as 7 TeV, so it’s 100 times as energetic.
What would have happened to Anatoli at 7 TeV?”
A part from a mix of power and energy there is another error here. The energy of the particles in the beam is not the most relevant factor here. Instead the total energy of the beam during the time of exposure is what should concern us, i.e. the luminosity of the beam. The energy of each particle is not a very relevant issue. I would rather look into a weak UV lamp than a high-energy CO-laser even if the photon energy of the former is much higher. And both a 7GeV and a 7TeV proton have energy far above the threshold of causing non-thermal damage.
Now, the LHC beam not only has a very high energy, but also a high luminosity so I guess it would still be a bad idea to stick your hand in there. Given a certain luminosity L for every second in the beam the number of collisions would be L*s, where s is the cross-section of the reaction. s is not very strongly dependent on energy at high energies, so given similar luminosity the number of collisions for 7 GeV and 7 TeV should be similar.
However, even given the number of reactions it is uncertain how much energy would really be deposited in the hand. But at least at those energies the scattering angle should be small, and probably only a very small area should be affected. My guess is that the beam would very quickly drill a hole in the hand, and that most of the energy would not be deposited in the hand. Of course scattering would also affect the nearby tissue. Whether true or not, the Anatoli incident probably gives a rather accurate description of the injury that would be caused.
Oh, and in the case of circular accelerators, the beam goes round in some tens of microseconds (90us for LHC) so if interrupted, by e.g. a head, that would be the longest time of irradiation.
However, I don’t really get what happened here. Somehow the beam went out of the vaccumtube and into Anatoli’s head. But is should quickly be interrupted even by the air. So, it seems that instead of him putting his head into the beam, someone opened a valve or removed a beam dump to direct the beam into his head.
Doctor Manhattan!
It’s all fun and games until someone blows up Alderaan.