Particle Accelerators
by Justin LeClair (Class of '05)
If you were ever wondering how to accelerate a proton at an extremely high energy and have it collide with another subatomic particle producing an anti proton I have just the device for you. Particle accelerators are devices usually used to accelerate charged particles in a vacuum. Today particle accelerators are some of the largest and most expensive instruments used by physicists. One might question the need to spend millions of dollars accelerating charged particles using huge electro magnetic fields. Despite the obvious answer (because its just sooo cool to fire a proton near the speed of light) particle accelerators are used to study the interactions between subatomic particles when they collide. That tells physicists a great deal about the laws governing the subatomic system. Furthermore it allows physicists to learn about unlocking vast amounts of power. You have all probably heard that if you could convert all of the energy contained in 1 kg of sugar, or 1 kg of water, or 1 kg of any other stuff, you could drive a car for about 100'000 years without stopping. This is possible because E=mc^2 tells us that mass is basically really concentrated energy. It is not very easy to convert matter into energy or we would power everything with it. The simplest way is to collide a proton with an anti proton (a proton with the opposite charge). But because all the antimatter got consumed milliseconds after the big bang it is very difficult to obtain. Through the use of a particle accelerator we can shoot protons at 300,000 km/sec (the speed of light) into matter creating temperatures exceeding 10'000'000'000'000 °C and converting the mass directly into energy. Unlocking a method of harnessing this energy could do untold things for the future of our species.
Another question you might ask yourself is; how does a particle accelerator work? To accelerate a particle to nearly the speed of light you need 3 things.
1) A source of particles
2) A tube with a partial vacuum
3) A way to accelerate the particles
You can get protons by stripping the electrons off hydrogen gas through ionization, whose atoms consist of one proton plus one electron. If you have heard anything about particle accelerators you probably have the notion that they require huge magnets. Magnets are not used to accelerate the particles, but to guide them. To accelerate the particles you use strong electric fields. Imagine a long track with a steel ball on it, you create an electromagnetic field 2 feet away from the ball. The ball rolls to the field, before it gets there you turn off the first field and turn on another one 2 more feet down. The ball continues past the first and towards the second, the whole time accelerating. You could continue this until the ball has reached your desired velocity. To do this fast enough you toggle the field’s sinusoidally so that the positive field is always just behind the proton and the negative field is just in front of it. It can take a long time to accelerate particles to nearly the speed of light. Some particle accelerators are 2 miles long. That is only to get an electron up to speed. To accelerate a proton one would need a far larger space. The easiest way to get around this (pun intended) is to have the tube form a circle. This way the particles can fly around the tube an infinite number of times. This method comes with many other issues. As the protons are guided around the circle, very powerful x-rays are given off which require intensive shielding, also you need to compensate for the loss of energy (think of it as friction from rubbing along the outer edge) that requires larger capacitors and thus more money.
References:
If you were ever wondering how to accelerate a proton at an extremely high energy and have it collide with another subatomic particle producing an anti proton I have just the device for you. Particle accelerators are devices usually used to accelerate charged particles in a vacuum. Today particle accelerators are some of the largest and most expensive instruments used by physicists. One might question the need to spend millions of dollars accelerating charged particles using huge electro magnetic fields. Despite the obvious answer (because its just sooo cool to fire a proton near the speed of light) particle accelerators are used to study the interactions between subatomic particles when they collide. That tells physicists a great deal about the laws governing the subatomic system. Furthermore it allows physicists to learn about unlocking vast amounts of power. You have all probably heard that if you could convert all of the energy contained in 1 kg of sugar, or 1 kg of water, or 1 kg of any other stuff, you could drive a car for about 100'000 years without stopping. This is possible because E=mc^2 tells us that mass is basically really concentrated energy. It is not very easy to convert matter into energy or we would power everything with it. The simplest way is to collide a proton with an anti proton (a proton with the opposite charge). But because all the antimatter got consumed milliseconds after the big bang it is very difficult to obtain. Through the use of a particle accelerator we can shoot protons at 300,000 km/sec (the speed of light) into matter creating temperatures exceeding 10'000'000'000'000 °C and converting the mass directly into energy. Unlocking a method of harnessing this energy could do untold things for the future of our species.
Another question you might ask yourself is; how does a particle accelerator work? To accelerate a particle to nearly the speed of light you need 3 things.
1) A source of particles
2) A tube with a partial vacuum
3) A way to accelerate the particles
You can get protons by stripping the electrons off hydrogen gas through ionization, whose atoms consist of one proton plus one electron. If you have heard anything about particle accelerators you probably have the notion that they require huge magnets. Magnets are not used to accelerate the particles, but to guide them. To accelerate the particles you use strong electric fields. Imagine a long track with a steel ball on it, you create an electromagnetic field 2 feet away from the ball. The ball rolls to the field, before it gets there you turn off the first field and turn on another one 2 more feet down. The ball continues past the first and towards the second, the whole time accelerating. You could continue this until the ball has reached your desired velocity. To do this fast enough you toggle the field’s sinusoidally so that the positive field is always just behind the proton and the negative field is just in front of it. It can take a long time to accelerate particles to nearly the speed of light. Some particle accelerators are 2 miles long. That is only to get an electron up to speed. To accelerate a proton one would need a far larger space. The easiest way to get around this (pun intended) is to have the tube form a circle. This way the particles can fly around the tube an infinite number of times. This method comes with many other issues. As the protons are guided around the circle, very powerful x-rays are given off which require intensive shielding, also you need to compensate for the loss of energy (think of it as friction from rubbing along the outer edge) that requires larger capacitors and thus more money.
References:
- A good description of how particle accelerators work, what they do, and the various kids., good as of 11/09/05
- A letter to “Straight Dope” about how particle accelerators work, good as of 11/09/05
- An article I read a long time ago about anti matter, and particle accelerators, good as of 11/09/05
Links to this post:
Create a Link
<< Home