Different ways of slowing down an individual particle

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In summary, there are several ways to slow down particles, including using materials that cause collisions with atomic electrons, using RF cavities to decelerate bunched particles, and collisions with low-mass nuclei for uncharged particles. Photons can also be slowed through various interactions. However, certain particles like neutrinos and dark matter may not interact at all and are not easily slowed.
  • #1
I was wondering how you can slow down a particle. I know you can have it run into something. I know if its charged, you can introduce it in an electric field. Is there any other way. I remember learning something about a specific type of field that slows down all mass passing though it, which increases the energy of the field. Can anyone help me out here?
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The most common way of slowing down charged particles (excluding electrons) is to use materials, such as beryllium, copper, or tungsten (among others) by making use of dE/dx, the energy loss based on collisions of the slowing particles with atomic electrons (not Coulomb scattering on nuclei). The major concern about using materials to stop the particles is multiple scattering, which increases the beam size (divergence). Very roughly, the energy loss is about 2 MeV of energy loss per gram/cm2 (gram per cm-squared) of the material. Positive and negative particles (positive and negative muons, pions) have a slightly (very small) different dE/dx stopping distance. If the charged particles are bunched in time, then RF cavities can decelerate them by properly phasing the RF power. If the beam current is sufficient, power can be extracted from the beam. Electrons are stopped by collisions with high-Z nuclei that produce bremsstrahlung and electromagnetic showers of large numbers of mainly positrons and electrons. Uncharged strongly interacting particles (e.g., neutrons) are best slowed by collisions with low-mass nuclei, like hydrogen, such as in water or hydrocarbons, or in graphite. Neutrinos are uncharged weakly interacting particles, and usually pass through the Earth without any interaction at all.

Photons interact by either electromagnetic or nuclear interactions. Photoelectric effect, (up to k-shell binding energies of atoms), Compton scattering (up to a few MeV), and pair production (of positrons and electrons) will attenuate photons. So will nuclear interactions, like gamma,n interactions, such as O16(gamma,n)O15.

Ultra-cold (1 micro electron volt) neutrons can be further slowed down by letting them drift vertically upward. Roughly half cannot reach an elevation of 10 meters before stopping and falling back down.

Dark matter?? dark energy?? WIMPS?? neutralinos?? tachions?? monopoles??
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1. How can temperature affect the speed of a particle?

Temperature can affect the speed of a particle by increasing or decreasing its kinetic energy. When the temperature is increased, the particles gain more kinetic energy and move faster. On the other hand, when the temperature is decreased, the particles lose kinetic energy and move slower.

2. Can friction slow down a particle?

Yes, friction can slow down a particle. When a particle comes into contact with a surface, there is a force of friction acting on it in the opposite direction of its motion. This force can reduce the particle's speed, ultimately slowing it down.

3. What is the role of air resistance in slowing down a particle?

Air resistance, also known as drag, can play a significant role in slowing down a particle. When a particle moves through a fluid, such as air or water, the fluid exerts a force on the particle in the opposite direction of its motion. This force can decrease the particle's speed, making it slower.

4. How do magnetic fields affect the speed of a particle?

Magnetic fields can affect the speed of a particle by exerting a force on it. When a charged particle moves through a magnetic field, it experiences a force perpendicular to its motion. This force can cause the particle to change direction and slow down.

5. Is it possible to slow down a particle using light?

Yes, it is possible to slow down a particle using light. This process is known as optical trapping, where a focused laser beam creates an attractive force on a particle, slowing it down and trapping it in place. However, this method only works on small particles and under specific conditions.

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