Questions tagged [accelerator-physics]

is appropriate for questions dealing with the physics of beams in accelerators (synchrotrons, cyclotrons, linacs, betatrons and other types of accelerators); the ways in which beams are generated; the accelerating, bending and focusing equipment; and the intrinsic limits that arise in trying to manipulate beams. DO NOT USE THIS TAG for questions that concern the use of the particle beams once they arrive in the experimental hall.

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1answer
35 views

Why did the RHIC luminosity decrease after 2010?

This physics today article about particle accelerator operation contains this figure, showing the evolution of peak luminosity over time for major proton-proton and proton-antiproton colliders. ...
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Accelerator terminology: betatron coupling, $\beta$-beat, chromatic coupling and beam tune

While reading papers on HEP, I often come across the following terms. Unfortunately, Google is not always helpful as it returns only papers related to the topic(s) and not something like a Wikipedia ...
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Are experiments being conducted towards the creation of micro black holes? [closed]

Apparently, there could be a way for our own particle colliders to create very transient black holes, if some things about the universe are true (as far as I understand, those have to do with the ...
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55 views

Next-to-Leading Order (NLO) di-boson production cross-section at the Future Circular Collider (FCC-ee)

is there anyone who knows a reference for a paper estimating the Next-to-Leading Order (NLO) cross-section prediction for the $$e^+e^-\to W^+W^-$$ inclusive process? The centre-of-mass energy I'm ...
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1answer
31 views

Accelerating a charged particle through more than one electrostatic field

If a charged particle is accelerated through a hole in a charged capacitor and makes a round trip back to the capacitor then the particle should come to a stop just before going through the capacitor ...
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1answer
19 views

What is the source of the electric field in a RF cavity that causes particle acceleration? [duplicate]

Charged particles are accelerated through a RF cavity: -Is the electric field accelerating the particles from the electromagnetic field itself? -Or, is the electric field accelerating the particles ...
2
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1answer
44 views

How does one create a polarized beam of particles?

I want to know how experimental physicists create spin-polarised beams of particles, say electrons, muons or quarks. My first guess is that one would polarise such a beam in a magnetic field. The two ...
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1answer
21 views

DC Electron beam acceleration with RF accelerator cavities without using buncher cavities

Can a low-emittance (as low as necessary) dc electron beam (about 100keV energy) be directly loaded to an long (long enough to self bunching and accelerating) RF accelerartor structure without using ...
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1answer
29 views

Bremsstrahlung in synchrotrons

In synchrotons electrons are accelerated by undulators or wigglers. However, I don't get how you produce Bremsstrahlung, because Bremsstrahlung is a 3-particle process: charged particles, ions and ...
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0answers
19 views

Are there more pile-up jets at high absolute pseudo-rapidity (|eta|) in particle physics detectors, and why?

Are there more pile-up jets at high absolute pseudo-rapidity ($|\eta|$) in particle physics detectors, and why ? Is there a dependence of the number of jets of pile-up produced with the ...
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2answers
70 views

Why is the opening angle of synchrotron radiation less than $1/\gamma$?

I am currently studying free-electron laser which accelerate electrons and use undulators to create synchrotron radiation. In a variety of graphics and diagrams I see an opening angle of $\pm 1/\gamma$...
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2answers
57 views

How the relativistic mass gain prob is overcome in synchrotron by adjusting the frequency of electric field to accelerate particles to high KE?

Cyclotron cannot accelerate particles beyond certain KE due to relativistic mass gain. I am from Chemistry background.
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1answer
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How would I go about calculating the energy input needed for a cyclotron reactor?

I'm trying to do some math regarding cyclotron reactors. I've figured out how to calculate the radius of a particle's motion in the cyclotron, a rough way to calculate energy output, but I have looked ...
2
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0answers
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Simplified laser wakefield accelerator model

so I am working on a summer essay and trying to work my way through the following online material I found; https://www.cockcroft.ac.uk/wp-content/uploads/2018/04/LWFA_comp.pdf. However, there are ...
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1answer
44 views

Synchrotron radiation for protons

I know that due to the huge mass difference and dependence of radiated energy on mass, protons lose much less energy in synchrotrons than electrons. Can someone tell me how to calculate the energy ...
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Acceleration closed formula in strong gravitational field [duplicate]

We know that acceleration of a falling body relative to earth is G*M_earth/(R_earth)^2 What would the acceleration formula if the earth's mass is same as sun's mass but with same earth's radius? Is ...
2
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1answer
55 views

Origin of the energy distribution of synchrotron radiation

Is there an easy explanation why synchrotron radiation from a bending magnet (e.g. in an electron storage ring) has an energy distribution? In other words, given a specific magnet with a defined ...
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1answer
25 views

Why is the Proton Synchrotron Booster at four levels?

I wonder what the benefits of having a cyclotron at 4 levels are. Why do they split the proton beam into 4 bunches, accelerate them and merge them into one before the next accelerator?
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1answer
35 views

How is a proton beam separated into bunches in a particle accelerator?

I was wondering how exactly is a proton beam separated into bunches, each at interval of ${25}\,$ns after the previous?
2
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1answer
57 views

How did the Intersecting Storage Rings Actually Perform Tests

I am reading the book written in 1982 titled "Quarks, The Stuff of Matter" by Harald Fritzsch. In it he writes about the ISR at Cern, that slammed protons together and in some of those collisions, 2 ...
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1answer
394 views

How much current can be produced by Van de Graaff generators or Pelletrons?

The Van de Graaff generator is a source of high voltage at low current based on the transfer of static electricity, and its higher current successor the Pelletron could deliver more current by ...
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1answer
55 views

What happens with the energy released after a particles collision?

From the website of CERN: "Collisions in the LHC generate temperatures more than 100,000 times hotter than the centre of the Sun.". My question is, what happens to the energy released after the ...
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22 views

What devices are used in a proton accelerator to separate the protons from their electrons and send the protons into the vacuum chamber? [duplicate]

I understand the general idea of how they accelerate the protons once they get them isolated in the chamber, but what's the device they use to isolate them to begin with even called?
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37 views

The basics of neutrino telescopes

I'm trying to understand the basic operation of the ANTARES neutrino telescope. Here is what I've gathered: The detection of neutrinos relies upon the detection of muons. Cosmic rays and neutrinos ...
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2answers
166 views

How are pulsed neutron sources created and when are they used in particle accelerators?

Are pulsed neutron sources beams of neutrons that are not created continuously? If so what is the benefit of having a discontinuous beam of neutrons rather than a continuous one? Under what conditions ...
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2answers
161 views

Lead catalyzed fusion

Consider the following setup: A beam of deuterons is accelerated towards a lead target. With sufficient acceleration (in the MeV range, nothing fancy...), I would expect some of the deuterons to fuse ...
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2answers
86 views

Collider Luminosity basics

In a collider experiment, the Luminosity is defined as the proportionality factor between the interaction rate and the interaction cross section $dN/dt = L\times\sigma$, with units of $cm^{-2}s^{-1}$. ...
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1answer
62 views

Description of particles using co-moving frame in accelerator

I am learning particle accelerators and there is a basic concept as to description of particle beams in accelerators which confused me a lot. Moving orthogonal, right-handed coordinate system (x, y, ...
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1answer
52 views

How 'tightly' can accelerator pipes turn?

I am designing a particle accelerator for a class. I want to know how tight of a turn an accelerator pipe can make; is there a defined maximum? Is there a calculation that needs to be made ...
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1answer
72 views

Annihilation of matter and antimatter of different kind

What happens when antimatter of an atom interacts with matter of another atom? For example, if I collide antihydrogen and helium. I always heard that collision or interaction of antimatter and matter ...
2
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2answers
79 views

Relativistic speed Ion engine

I'm a newbie so this might be obvious to others but....if the specific impulse of an ion engine is limited by it's fuel load then why not accelerate singular fuel (krypton) ions to relativistic speeds ...
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1answer
94 views

Why is it easier to observe B-meson oscillations than D-meson ones?

B-meson oscillations were observed several years ago by the CDF experiment B-oscillations, but D-meson could not be observed until very recently by the LHCb experiment. I'm wondering why is it more ...
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1answer
63 views

Invisible energy in hadronic calorimeters

Hadronic calorimeters are more difficult to be built than electromagnetic ones because the cascade containment is much larger for former. There is also some "invisible" energy that is not contained in ...
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2answers
85 views

Alternative way of bending electrons trajectory in synchrotron

I read that in synchrotron, the X-ray is produced whenever the electrons undergo acceleration, in particular at the bending magnet, the wiggler or undulator. Since these three devices all employ ...
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1answer
196 views

Does an electron accelerated in a linear accelerator lose any energy?

In a circular one, it would lose energy due to bremsstrahlung (synchrotron emission), but if it is accelerated from rest to ~GeV energies, does it lose any energy in this acceleration process?
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1answer
360 views

Spallation Neutron Source design

The Spallation Neutron Source (all details taken from this link) is described as firing a 1 GeV proton beam into a mercury target. As this makes the proton beam relativistic, a cyclotron cannot be ...
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1answer
63 views

What is the energy dissipation of an ideal launch loop?

Dynamical structures for space access use a stream of electromagnetically accelerated and levitated pellets that moves faster than escape velocity to maintain megascale structures and transmit force ...
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1answer
149 views

Find final velocity of partical traveling at relativistic speeds under constant force over set distance without time

What equation do I need to find the final velocity of a particle traveling at relativistic speeds given some initial velocity (say 0.3C) and exposed to a constant force. The relationship between ...
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1answer
82 views

Maximum energy reached by LHC

I was trying to compute what is the maximum energy reached by the LHC assuming it has a circunference of 27 km length and the magnetic field of the magnets is ~8 T. To do that, I tried comparing the ...
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1answer
61 views

Cyclotron-conservation of energy dilemma

In a cyclotron we increase the K.E. of a particle by allowing the E field to do work on it. But if I take the cyclotron and the particle as my system it's net energy only increases. How will the net ...
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4answers
2k views

How fast are cyclotrons?

I know this question is kind of vague, but I just want have a handle on how fast a average cyclotron can accelerate particles, and what kind of limits there are...
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1answer
33 views

If I put charged particles in the center of long hollow cylinder shaped electromagnet, in a vacuum, would it accelerate them?

If I put charged particles in the center of long hollow cylinder shaped electromagnet, in a vacuum, would it accelerate them? Is this how particle accelerators work? If so are there formulas I could ...
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1answer
35 views

Function of dipoles in particle accelerators

I know now that quadrupoles are used to focus the beam in a particle accelerator, but what about dipoles? Are they used to center or accelerate the beam? The number for the LHC magnets I think it is ...
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1answer
78 views

Quadrupoles in an accelerator

The quadrupole magnets in a particle accelerator are just to center de beam or do they have any other application?
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1answer
97 views

Spallation of Lithium by GeV protons?

If you direct a beam of, say 400 keV protons, against a Lithium target, you induce fusion reactions. This is the well known Cockcroft-Walton experiment. Now I would like to ask if you can induce ...
2
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1answer
77 views

What is the Shape of the Quadrupole Magnets Used for Beam Focusing?

This question comes from Particle Detectors by Grupen. Quadrupoles are used in accelerators for beam focusing. To achieve focusing effect, the angle at which the quadrupoles bend the particle beam ...
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1answer
74 views

Why motion of a charged particle experences perpendicular motion in a magnetic field? Physical answer please

I understand fleming's left hand rule. But why moving charged particle is deflected? Due to the magnetic field generated by charged particle and resultant direction of that mag. field and applied ...
2
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1answer
45 views

What is turn-around time of accelerator?

I was looking today through pdg table of collider parameters and I saw that some turn-around time for LHC is $\approx 200$ min. I tried to search on it, but everywhere it is kind of assumed that you ...
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5answers
8k views

Why do we need large particle accelerators?

The LHC is much larger than its predecessors, and proposed successors much larger still. Today, particle accelerators seem to be the main source of new discoveries about the fundamental nature of the ...
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1answer
90 views

What limit the maximum magnetic and electric fields usable for particle acceleration?

Progress in acceleration of particle is quite steady but slow, at least in my opinion. I was wondering what are the fundamental roadblocks to develop larger electric fields gradients (in any material) ...