What are the limits of particle accelerators?

In summary, the physical limitations on particle accelerator size are due to the electric fields and magnetic fields needed to accelerate the particles. These fields are limited by the strength of the particles and the materials used to build the accelerator. However, plasma wakefield acceleration may one day provide a way to overcome these limitations.
  • #1
accdd
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What prevents making a particle accelerator better than the LHC but only a few centimeters big? After all, you accelerate objects with very small masses. Are there insuperable physical limits? What are the physical limitations?
 
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  • #2
accdd said:
What prevents making a particle accelerator better than the LHC but only a few centimeters big? After all, you accelerate objects with very small masses. Are there insuperable physical limits? What are the physical limitations?
Have you looked on the CERN or Fermilab websites?
 
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  • #3
The acceleration which increases the speed is provided by an electric force ##F_E=qE##. Since ##q## of a particle is small, in order to have a strong ##F_E## you need strong electric field ##E##. But there are limits to how strong an electric field can be generated, and this limits the acceleration. So, to reach the high speed you need more time, that is more distance. This distance can be either a long line, or a circle that is traversed multiple times. To make the trajectory a circle you need a centripetal force that is provided by a magnetic force ##F_B = q(v \times B)##, but this is also limited by the maximum strength of the magnetic field ##B## provided by the superconducting magnets, so the circle has a large radius.
 
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  • #4
Furthermore, Synchrotron radiation - the accelerator will "leak" energy and will not be efficient. The smaller the radius, the bigger the centripetal acceleration and higher amount of synchrotron radiation is emitted.

Note that Synchrotron radiation can be a desired outcome, one can use it to study structure of materials and molecules and such. But, not in an accelerator where you wish to attain maximal center of mass energy and high luminosity for particle creation.

This, and the limitations of magnets, causes lot of gain for a large radius for your accelerator
 
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  • #5
Centimeters?

  1. Please work out the electric fields needed to accelerate a particle in a few centimeters.
  2. Please calculate the electric fields needed to ionize an atom. Hint: when the applied field exceeds the field of the nucleus, what happens to the electron?
  3. Given the answers to (1) and (2) what will you make your accelerator out of?
 
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  • #6
Vanadium 50 said:
Given the answers to (1) and (2) what will you make your accelerator out of?
Nuclear matter of course, atomic matter is for suckers!
 
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  • #7
Vanadium 50 said:
Centimeters?

  1. Please work out the electric fields needed to accelerate a particle in a few centimeters.
  2. Please calculate the electric fields needed to ionize an atom. Hint: when the applied field exceeds the field of the nucleus, what happens to the electron?
  3. Given the answers to (1) and (2) what will you make your accelerator out of?
Plasma wakefield acceleration shows this is not a limit.
We still can't build centimeter-sized multi-TeV accelerators, but it might be possible to shrink the length to a kilometer or so in the future.
 
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  • #8
mfb said:
Plasma wakefield acceleration shows this is not a limit.
That is the answer to my last question then - don't build it out of atoms.

However, while plasmas can have gradients taht are very high, if you want the beam, you know, actually focused, you need a much larger system than centimeters.
 
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  • #9
mfb said:
it might be possible to shrink the length to a kilometer or so in the future
How would one minimize synchrotron radiatio then, or are you thinking of linear acclerators?
 
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  • #10
I think he's talking about a linear machine. High gradients make it more feasible. But plasma wakefields have notoriously poor quality beams. Essentially you have a beam energy spread that is more or` less equally populated from zero to the maximum energy. Totally unbsuitable for collision science. Staging has been demonstrated for stunts, but it isn't realistic.

If you use dielectric wakefields, these problems go away. Beam quality is high, and the machine can be staged. But you're back to atoms. You can get a gradient a factor of 2 better than copper today, and maybe ultimatley an order of magnitude or more. But not hundreds of thousands. Because atoms.
 
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  • #11
accdd said:
What prevents making a particle accelerator better than the LHC but only a few centimeters big? After all, you accelerate objects with very small masses. Are there insuperable physical limits? What are the physical limitations?
While you can't get a tiny size, if you build it in deep space, you can build a simpler one with fewer materials. In space, a very simple linear accelerator with an immense length is no big deal.
 
  • #12
ohwilleke said:
if you build it in deep space
When NASA and CERN unite!

ohwilleke said:
build a simpler one with fewer materials
Free vacuum! This will sound great for the funding proposals!
 
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  • #13
drmalawi said:
When NASA and CERN unite!Free vacuum! This will sound great for the funding proposals!
And now that we have a proven Sun Shield technology, you can cut way down on the energy it takes to keep the superconducting magnets superconducting! :smile:
 
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Related to What are the limits of particle accelerators?

1. What is a particle accelerator?

A particle accelerator is a scientific instrument that uses electromagnetic fields to accelerate and collide particles at high speeds. This allows researchers to study the fundamental building blocks of matter and the forces that govern them.

2. How do particle accelerators work?

Particle accelerators use electric fields to accelerate charged particles and magnetic fields to steer them into collisions. The particles are then directed into a circular or linear path and accelerated using radiofrequency waves until they reach very high speeds.

3. What are the limits of particle accelerators?

The limits of particle accelerators are primarily determined by the amount of energy they can produce. The higher the energy, the more massive particles can be accelerated and the more precise the collisions can be. However, there are also physical limitations such as the size and cost of building larger accelerators.

4. What are the potential applications of particle accelerators?

Particle accelerators have a wide range of potential applications, including fundamental research in particle physics, medical imaging and cancer treatment, industrial material processing, and environmental and energy research. They also have practical applications in fields such as aerospace engineering and nuclear power.

5. Are there any risks associated with particle accelerators?

Particle accelerators are generally considered safe for both researchers and the general public. However, there are some potential risks, such as radiation exposure and the accidental release of hazardous materials. These risks are carefully managed and monitored by scientists and regulatory agencies to ensure the safety of all involved.

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