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
26 views

Does a low-gain free electron laser (FEL) emit coherent radiation?

For the low-gain free electron laser (FEL), an external field is injected into an undulator alongside an electron bunch. Due to phase slippage (because the light is faster than the electrons) the ...
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4answers
92 views

How long does the LHC take to accellerate a particle to its full speed? How long would a linear accellerator have to be to reach the same energies?

I'm wondering how long it takes the LHC to accelerate particles from rest to their top speed at 6.5 TeV. And related, how long a hypothetical linear accelerator would have to be to accelerate ...
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1answer
64 views

How can i shoot accelerated electron directly into the air?

I am trying to do an experiment in which I have to first accelerate the electron to 10eV and then shoot into the air directly. I need some kind of membrane which allows electron to pass and keep ...
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3answers
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How does a booster work in a particle accelerator like the LHC?

In the proton synchrotron booster (PS) booster at the LHC, protons are accelerated from $50 \, \text{MeV}$ to about $1.4 \,\text{ GeV}$. This takes about a second to accomplish. Since the radius of ...
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0answers
25 views

How do we derive the components of the magnetic vector potential from a known magnetic field?

The magnetic field is $\vec{B}(r,\theta)=B_{0} \cdot[1+\mu(r)] \cdot [1+f(r,\theta)]\hat{e}_{z}$ where $f(r, \theta)=\sum_{n}\left[a_{n}(r) \cos n \theta+b_{n}(r) \sin n \theta\right]$, and $\mu(r)$ ...
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2answers
82 views

Can muons be used to reach the island of stability of superheavy elements?

While reading about the island of stability of superheavy elements[0], experimental approaches and related difficulties[1], an idea has formed in my head. Since I cannot find considerations of such ...
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1answer
68 views

Why can the neutron not be measured in this fixed-target experiment?

Consider a fixed-target-experiment, where negatively charged pions are shot at protons (the latter being at rest). The kinetic energy of the pions shall be known. One possible reaction is $$ \pi^- + p ...
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1answer
33 views

Why are edge fields in undolators necessary to comply with Maxwell?

In our lecture scripts there is a paragraph about the magnetic field of an undulator: "Its [the undulators] magentic field can be described by \begin{equation} \vec{B}\equiv-B_0 \begin{pmatrix} ...
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1answer
58 views

Can neutrons be manipulated with magnetic fields? Can neutron particle accelerators be built?

Neutrons have no electric charge and do not respond to electric fields as in a conventional particle accelerator. However, they are magnetic and do have a small magnetic dipole moment. So it should ...
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1answer
61 views

In a synchrotron, do electrons make periodic recoils?

Synchrotron radiation happens because circular motion of electrons produce a tangential acceleration-- or something along those lines. Point is, photons are produced by these accelerated electrons. As ...
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1answer
227 views

Radiation in particle accelerators

I was reading about particle accelerators in Wikipedia and I came across this. Depending on the energy and the particle being accelerated, circular accelerators suffer a disadvantage in that the ...
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1answer
34 views

Using something like a linear accelerator, could a visible object to accelerated to thousands of miles per second?

I am wondering what problems would arise using the same process that accelerates protons, etc. on something as large as a bb or maybe just a grain of sand. Not sure the practical reason for this but ...
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How many atoms does a relativistic ion dislodge?

Given a large chunk of some hard, refractory material e.g. graphite, diamond, tungsten, at low temperature surrounded by vacuum, and an impacting relativistic ion – to be specific, say an alpha ...
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Electron gun voltages

I saw on the internet that catode of electoron gun should have negative potential to zero (ground). On the other hand catodes of tv CRTs were grounded and anodes were connented to positive high ...
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80 views

How is $s_{NN}$ defined?

$\sqrt{s_{NN}}$ is usually referred to as center-of-mass energy per nucleon-nucleon pair, although I have seen (probably erroneously) center-of-mass energy per nucleon. Taking that the first term is ...
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1answer
45 views

What is meant by spatial resolution in a particle detector?

I'm reading a document about a particle physics detector and its sub-detectors. They mention that: ' its drift chamber has a spatial resolution of 130 μm'. Can anyone please explain to me what is ...
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How is the nucleus-nucleus CM energy per nucleon related the proton-proton CM energy in a circular accelerator?

If I understand it correctly, the center of mass energy per nucleon pair in heavy ion collisions is given by $$\sqrt{s_{NN}}=\sqrt{(p_a/A_a+p_b/A_b)^2},$$ where $a$ and $b$ label each colliding nuclei,...
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Collision Energy for heavy ions

I found this formula in Sahoo Relativistic Kinematics: $$\sqrt{s_{NN}}=2\sqrt{s_{pp}}+\sqrt{s_{pp}}\sqrt{\frac{Z_{1}Z_{2}}{A_{1}A_{2}}}$$ But because English isn't my first language i got confused. So ...
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101 views

Can I destroy Bennu, if I shoot it with my electron gun? [closed]

The asteroid Bennu seems to be just a pile of rubble weakly held together by gravitational forces. Newton’s law, -Gm1m2/r2, and Coulomb’s law, +keq1q2/r2, have exactly the same form but opposite sign. ...
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0answers
18 views

Klystron beam current versus cavity wall current

is there any way to estimate (because it cannot be directly measured) the RF cavity wall current in a Klystron output cavity? It is related to the electron beam current and I have even seen a formula ...
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30 views

Polarized proton beam

Can someone explain to me or point me towards some references about how can one obtain experimentally a polarized proton beam. I find many talks about using siberian snakes to preserve the ...
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33 views

Which one is more efficient in producing high energy gamma rays?

According to https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf the big pulsed power accelerator, HERMES III, generate electron beam with peak energy at 22 MeV and average electron energy at 16 MeV ...
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Generating very large area gamma rays by other ways other than large accelerators

According to this link https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf, HERMES III at Sandia National Labs can generate very large area gamma rays by converting the electron beam into ...
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1answer
142 views

Functionality of an Einzel lens

An Einzel lens is a device for ion optics to focus a beam of particles. It consists of three ring electrodes, with the outer ones being on earth potential and the middle one being on high voltage (see ...
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Dirft Tube Linac Diameter

How to calculate dirft tube cavity diameter. Why it's so big. For electromagnetic frequency?
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When we use magnets in linear accelerators?

I'm searching particle accelerators. I couldn't see focusing magnets in Linear accelerators. When we need focusing magnets in Linacs? I'm sharing some photos of what ı found.
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2answers
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Do particle accelerators have to adjust for the sun's gravity due to length contraction?

I believe particle accelerators move atoms at 99.999% the speed of light. If the accelerator was oriented perpendicular to the sun, a particle moving at this speed would experience sizable length ...
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2answers
90 views

Why does the De Broglie Wavelength influence the scale in which a nuclear reaction occurs?

In high energy accelerator collisions, why does the De Broglie wavelength of the incident particle affect the type of interaction it has with the target nucleus? E.g. In 280 MeV proton, "direct ...
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3answers
56 views

How does a cyclotron release electromagnetic waves?

I am currently working on a project on fusion reactors and am researching the basics of them. During my research, I encountered "antenna" which produce ion and electron cyclotron frequencies to heat ...
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1answer
60 views

Relativistic mass and Electromagnetism in particle accelerators?

Dear Physics Stack Exchange, I've been rather troubled as of late on trying to see the problems or issues inherent in crank scientist or layman views on physics topics about special relativity. One ...
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1answer
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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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1answer
156 views

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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1answer
35 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
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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 ...
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1answer
70 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
24 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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2answers
50 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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2answers
102 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
83 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
38 views

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 ...
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0answers
21 views

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
59 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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18 views

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 ...
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1answer
83 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
36 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
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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?
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1answer
62 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
924 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
62 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 ...