# Questions tagged [particle-accelerators]

A machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, collimate them in well-defined beams, and then collide them in order to induce interactions, decays, and creation of new particles. They are used for basic research in particle physics.

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• 31
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### How do charged particles accelerate away from an oppositely charged substance? Like in a cathode gun or gridded ion thruster

Like in the case of a gridded ion thruster, the positive ions are accelerated due to their attraction to a negatively charged gird at the back end of the thruster. Why don't the ions just stay by the ...
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### What advantages might the Circular Electron-Positron Collider have over the Compact Linear Collider?

Despite Chen-Ning Yang's objections, the Circular Electron Positron Collider (CEPC) project is progressing. The CEPC research team officially released its Technical Design Report (TDR) for the ...
• 619
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### Bending angle equation of particle in a magnetic and electric field

Using the equations for an Electric field and Magnetic field between two plates: $$E = \frac Vr$$ $$B=\frac{2I}{2\pi r}\cdot\mu_0$$ where $V$ is plate voltage, $r$ is plate separation, $I$ is ...
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### How does an Electromagnetic Accelerator work?

I've recently watched this video about an electromagnetic ring accelerator. I get how it works: it uses controlled electro-magnetic coils to accelerate metal balls' Passing trough one of the coils ...
• 103
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### Greatest acceleration theoretically or technically possible [duplicate]

Pretty straightforward question. Does there exist a theoretical upper bound for the acceleration of a point mass? If not, what is the greatest acceleration of a point mass ever recorded, or that will ...
• 427
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### Particle acceleration - why are colliders seemingly so limited?

I imagine this has been asked before but I am wondering why particle accelerators are so limited. - Why do they have to be big circles? Is there no other technique of accelerating charged particles? ...
• 149
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### How can it be "unfortunate" while this is what the experiments want?

In John Gribbin's Ten Tantalizing Truths, the author discusses the cyclotron: for a particular mass as the particles spiral outward, the rotation frequency stays constant, because the particles are ...
• 145
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### Potential yields of Np-237 using a synchotron

U238 releases a neutron when it is exposed to photons of around 11 MeV, and the resulting U237 promptly decays into the fissile Np237. In such a situation, what equations can I use to relate the ...
1 vote
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### How can I calculate the reflectivity of an electron gas with Thomson scattering?

I have to do a seminar presentation about the topic of using relativistic mirrors in integrated laser ion accelerator systems. The idea is (for context sake) to accelerate an electron bunch to ...
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### The physics behind a homemade particle accelerator

I have made a particle accelerator, like the one in the following image. homemade particle accelerator When a metallic pellet passes through the coil, it lights up and generates a magnetic field ...
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### What if we used massive voltages to create a Lichtenberg figure in acrylic?

https://en.wikipedia.org/wiki/Lichtenberg_figure I cannot find anywhere online what the result would be if I used, for example, 1GeV compared to the 10-20MeV which are usually used. This is all ...
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### Is it possible to collide two neutrons? [closed]

If it is possible to collide two neutrons, how is it so? What particle accelerator or pre-collision processes are necessary and what results can be expected? If the products of neutron-neutron ...
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### Pile Ups in the particle accelerator

Can anyone explain what Pile ups are in a particle accelerator experiments? How can anyone know that an event is a pile-up interaction and how can anyone get rid of these events?
• 171
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### Can high energy photons be used to accelerate particles?

So I know that particle accelerators use electromagnets to accelerate particles. However, since photons can be used to recoil particles (such as in Compton scattering), is it possible to use high ...
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### How do particle accelerators like the LHC bend beams of particles?

I know they use dipole magnets to curve the beams, and quadrupoles to focus them, but how do they know how powerful the magnets need to be so they bend the beams sufficiently but not too much so that ...
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1 vote
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### Having problems to find an equation for radioisotope production yield

I'm trying to find the required target mass for a specific nuclear reaction with a fixed yield and cross-section. I am trying to get a plot, or a result for target like this: I've found some ...
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### Recommendation for a source on particle detectors

I am looking for suggestions on a particle detectors book. I have average knowledge in high energy physics and nuclear physics.
1 vote
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### Why don't we utilize centripetal acceleration for particle accelerators or ion thrusters?

Acceleration of an object in a circle is determined by its radius (r) and speed (v). Acceleration = (v²)/r So, acceleration is greater at high speeds and in sharp curves (smaller radius). Centripetal ...
1 vote
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### Could you use a synchrotron particle accelerator in a descending spiral pattern to create ion thrust for space travel?

Would it be theoretically possible to use a synchrotron particle accelerator that utilizes a spiral pattern to create ion thrust for space travel? In this scenario, ions would be accelerated in a ...
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### Partially circular and partially linear particle accelerators

I know that circular accelerators, due to the radiation emitted by accelerated particles, are limited by their size in what energies they can reach. Linear accelerators (linacs) instead could reach ...
• 693
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### What does an LHC Beam Dump sound like?

What does an LHC Beam Dump sound like? Is it under a vacuum so that it doesn't make a sound, or does it go boom? Surely the heat generated instantly would make some kind of noise. This article https://...
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### Can we use the concept of a railgun or coilgun to design a small particle accelerator?

A railgun is used as a linear particle accelerator to project projectile at high speeds. Why not use this concept to build a circular rail particle accelerator. A conventional railgun uses extremely ...
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### Why do we even need RF cavities to accelerate particles?

Wouldn't it be easier to just apply a constant $E$ field along the beam axis? This would avoid all kinds of problems like synchronicity, phase change etcetera. Addendum. What puzzles me the most is ...
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### On the analogy between RF cavities and parallel RLC circuits

Every superconductive radio-frequency cavity can be seen as a parallel RLC circuit, as shown in the picture below: The thing is every parallel RLC circuit acts like a band-stop filter: at the ...
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1 vote
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### On slip factor and phase transitions in particle accelerators

In a uniform magnetic field $B$, a particle with mass $m$, charge $q$ and initial velocity $v$, undergoes a centripetal force (Lorentz force) which makes it travel on a circular orbit, with angular ...
• 1,644
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### Why do we get away with these assumptions of scattering theory?

The first questionable assumption I can think of is: The integration of the Hamiltonian density in the Dyson series is done over an infinite spacetime volume. Why do we get away with this assumption? ...
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1 vote
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### Experimental particle physics event shapes - why do different products have different event shapes?

Consider two interactions: $\mu^+ \mu^- \rightarrow d \bar{d}$ and $\mu^+ \mu^- \rightarrow gg$. The thrust of the down quarks will be different to the thrust of the gluon pair - why is this? More ...
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1 vote
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### Why do particle accelerators need to smash particles together?

In a particle accelerator particles gain a large kinetic energy before being smashed into each other. After the collision the kinetic energy goes into the rest mass of new particles. Why doesn’t the ...
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### What exactly do we observe in particle accelerators that we have named "particles"?

Do we observe dots on a position detector like in the double slit experiment? I doubt that because the double slit experiment is non-relativistic QM, and so a "position measurement" is ...
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### Accelerator physics text

Physicist here, looking for a suggestion for a very comprehensive, very detailed textbook on accelerator physics---particularly with a focus on cyclotrons/synchocyclotrons/AVF-cyclotrons. My work is ...
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### Pile-up events in collider experiments and the average number of interactions

Is the average number of interactions a measure of the amount of pile-up events (pollution background events to hard-scatter events)? if not, why is always presented as an indication and how accurate ...
1 vote
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### Does a free proton shrink when accelerated?

Reading about the charge radius of the proton and proton radius puzzle I started wondering if the cross section and therefore also the charge radius (i.e. size of proton) changes or more specifically ...
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### Cyclotron: why is there no work during the polarity shift?

From what I understand, the point of cyclotrons is to accelerate charges without requiring a huge potential difference: e.g. to accelerate a proton to 10 MeV, instead of using a single 10-megavolt ...
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### What happens in a particle accelerator? [closed]

How is the particle accelerated? Is it by increasing its energy? Is it only charged elementary particles that can be accelerated, because they are the only ones that can absorb photons and gain energy?...
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### Do virtual particles appear in a particle accelerator and cause a type of pollution?

please note (as may be obvious from my question) that I am not trained in physics so I apologize if this is a stupid question. Do virtual particles appear in a particle accelerator and get accelerated ...
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### Proton accelarating in homogeneous electric field

Hi I was studying for my physics exam, when I ran in to this problem. A proton in a particle accelerator uniformly accelerated in 3.23 ms over a distance of 1 km. The field in which the proton is ...
• 103
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### Why not use Neodymium magnets in cyclotrons? [closed]

I am wondering if we can make relatively strong cyclotrons /200-400MeV/ far less massive, in the range 10-20t. Why don't we use neodymium magnets in cyclotrons instead of electromagnets? Nd2Fe14B ...
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### Difference between X-ray device and linac

What is the difference between an x-ray device and a linac (for medical purposes)? In case both have to produce photons. Linac: source X-ray device: source As far as I see the major difference is, ...
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### Is time dilation connected to particles or space around?

Is kinematic time dilation considered connected to accelerated particles or the spacetime around the particles?
• 13
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### How many particles can a cyclotron accelerate per accelerating cycle?

What is the limit for how many particles can be accelerated in a batch per one accelerating cycle by a cyclotron /size of gap between D's?/? I've found simillar question - the answer was refering to ...
• 21
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### How are paths of particles tracked in particle accelerators?

I was wondering how they track the particles in particle accelerators that allow them to create images like this: http://www.supraconductivite.fr/media/images/Applications/image036.jpg At 27:50 into ...
• 774
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### Charged particle accelerate between charged plate [duplicate]

I have an electron that travel with a velocity v, and kinetic energy Ek. At some point it enter a region between two charged plate where there is an electric field that accelerate it. So the variation ...
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### Molecular accelerators

I wanted to know if we have accelerators for molecules just like particle accelerators. If so, what are they called and what is the maximum size of the molecules that can be accelerated in such ...