If particle accelerators’ internal temperature/beam can get to millions of degrees, how do they not melt or damage their surrounding encasing? The highest temperature resistant materials go only up to a few thousand degrees, so shouldn’t they easily be melted?
In: Physics
Temperature is a way of measuring the entropy/energy of particles. In a particle accelerator, a very small number of particles is given a large amount of energy. This makes those few particles very hot. But even though each particle has a ton of energy, it is only one very small particle and can’t really do that much damage if it gets lose.
The particles are also contained inside of a powerful magnetic field which prevents the particles from escaping or hitting the walls of the particle accelerator. The magnetic field also helps accelerate them to higher and higher speeds. When the particle has enough energy, it is shot into a measurement chamber where it collides with a target. The measurement chamber is full of sensors which absorb and measure the results of the impact.
There’s temperature, and there’s heat. The bit that’s reaching millions of degrees may only be a few hundred/thousand particles. Compared to the absurd number of particles that are in the particle accelerators structure (remember that 1 gram of a material is on the order of 10^20 molecules, so for a machine that weighs many tons, there’s a lot more cold material than the superhot material), this is very little. It’s like striking a match and holding it up against a tree. Yes, the temperature is hot enough to ignite wood, but the tree is so massive that you’ll never actually set the tree on fire. You can’t heat the tree up enough with a single match to get it burning.
Edit: generalized Avogadro’s constant.
As /u/Moskau50 correctly explained, there’s a big difference between heat and temperature.
But accelerator beams DO contain a great deal of kinetic energy, which is closely related to thermal energy. For a beam of particles, they are virtually the same thing. In a particle accelerator the beam is typically going at nearly the speed of light, but using particles with mass (unlike light), so there’s quite a bit of energy present. That’s kind of the point of them.
The particles don’t damage the beam tunnel itself because the beam flies through the center of a tube that is in vacuum, held there by very strong electromagnets. The tube must be evacuated so that the beam won’t hit air molecules and lose energy or interact with them. The electromagnets both accelerate the particles and keep them tightly focused near the center of the evacuated tunnel.
Until they meet their target, either a stationary target or a separate beam going the opposite direction. That releases a great deal of energy in the form of light and other particles. If something goes wrong during the process, the beam is typically steered off to something that can absorb the energy without any repercussions. I’ve seen one of these at one of the Stanford Linear Accelerator’s beams and it’s a large block of concrete.
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