What Would Happen If . . .

You Stuck Your Hand in a Particle Accelerator?

IN JULY 1978 a Russian scientist named Anatoli Bugorski was inspecting Russia’s most powerful particle accelerator (a machine that speeds subatomic particles to near the speed of light), called the U-70, when the main particle beam hit him in the back of the head and passed through his nose. He felt no pain but reported seeing a flash “as bright as a thousand suns.” Russian doctors rushed him to the hospital expecting him to die from radiation poisoning, but, other than some facial paralysis, the occasional seizure, a touch of radiation sickness, and a small hole through his head, he was fine and went on to finish his PhD.

Does this mean you could stick your hand in Europe’s new Large Hadron Collider (LHC)? Would you get a cool scar but otherwise be unharmed? No. Unfortunately for you and your hand, the Russian U-70 accelerator had less than 1 percent of the power that the LHC does.

The LHC is the most powerful particle collider in the world. It accelerates protons around a 17-mile loop to 0.99999999 c (7 miles per hour less than the speed of light) and smashes them together in the world’s greatest demolition derby. It’s so powerful that a small but vocal community expressed concern that the smashing particles would create a black hole large enough to consume Earth (see p. 197 for what would happen if it did).

The beam is composed of 100 billion protons, which, when accelerated to near light speed, carry a huge amount of energy—similar to a 400-ton train traveling at 100 miles per hour.

The beam carries so much energy it can drill a hole through 100 feet of copper in a millisecond—which is why most accelerators are pointed into the ground, ensuring that if a malfunction occurs a killer beam is not shot through a city.

So you can see right away that there will be a few issues with sticking your hand in the beam, but let’s say you ignored the warning signs and did it anyway. The first problem? Your ears.

Carbon-fiber jaws guide the beam’s path. If the beam wanders, it strikes the carbon fiber, and for you the sound would be as loud as if you were standing in front of concert speakers. Then, when scientists are done experimenting, the beam’s energy is dumped into a graphite block used as a proton trap, which would sound like a 200-pound TNT explosion—loud enough to blow out your eardrums.

In other words, wear some earplugs. But, really, blown-out eardrums would be the least of your concerns. A bigger problem would be the power of the beam.

The protons would pass through your hand as if nothing were there at all. The beam is small, about the width of the lead in a pencil, and traveling so fast it would punch through your hand painlessly. There’s a good chance it would miss your bones and leave your hand fully functional, but that is only if you kept your hand very, very still.

The U-70 Russian reactor was not only less powerful than the LHC, it was also only a single shot, so Bugorski had only one hole in his head. The LHC is more like a proton machine gun—in two seconds it fires nearly three thousand shots. If you pulled your hand away after the first pulse, the beam would cut your hand in half.

So don’t do that.

As the beam passed through your (hopefully) steady hand, another far more troubling process would take place. Particles traveling as fast as these, by their nature, are accompanied by intense radiation. Even if you were many yards away from the beam you would be dosed with the equivalent of a full chest X-ray.

Exactly how much radiation you would receive if the beam hit you, though, is actually difficult to say. The beam itself carries a gargantuan amount of radiation, enough to kill you quickly (and many times over), but the vast majority of the radiation would miss you because although you might think your hand is solid, at an atomic level there’s actually quite a bit of space.

If an atom in your hand were enlarged to the size of a football stadium, then a marble sitting on the fifty-yard line would be the nucleus. Because the radiation bullets fired at you are also quite small, most of them would miss, saving you from instant death. Unfortunately, only most of them would miss. You would probably be hit with just enough radiation to kill you slowly and painfully.

In the end, because Bugorski nearly died of radiation poisoning despite the accelerator being less than 1 percent as powerful, we can be confident that a beam from the LHC would kill you. The particles created when the beam struck your hand would irradiate and poison your entire body with at least 10 sieverts of radiation, and your experience would likely mimic what two workers at the Tokaimura nuclear processing plant went through after an accident in 1999.

Hisashi Ouchi and Masato Shinohara were creating a small batch of nuclear fuel when they miscalculated the recipe and their mixture went critical. Even in lethal radiation exposures victims don’t always feel terrible right away. The symptoms can take a few hours to set in. But in extreme exposures—like yours, Ouchi’s, and Shinohara’s—there’s no delay.

Just after the beam pierced your hand, your vision would turn blue, the result of radiation passing through the liquid of your eyeball faster than the speed of light. The speed of light is 30 percent slower in water than in a vacuum and it produces an electromagnetic shock wave, called Cherenkov radiation, that appears blue. Both Ouchi and Shinohara reported that the room turned blue despite security cameras showing no change in color.

Besides appearing to change its hue, the room would feel hot even though the actual temperature would remain unchanged as the beam’s energy heated you.

You would also feel nauseated almost immediately as the radiation attacked the lining of your stomach. Your skin would be severely burned, you would have trouble breathing, and you might lose consciousness.

Your white blood cell count would drop to near zero, preventing your immune system from functioning, and the damage to your internal organs would slowly progress. Doctors would be able to treat your symptoms but would not be able to do anything about your irradiated organs. Depending on the exact dosage you received and the progression of the damage, you would die within four to eight weeks.

The hole in your hand, however, would be small enough that it should heal in time with only a small scar.