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 ...

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26
votes
4answers
2k views

Do free-electron lasers actually lase?

Free-electron lasers are devices which use the motion of highly energetic electron beams to produce bright, coherent radiation in the x-ray regime. More specifically, they start with a high-energy ...
18
votes
4answers
3k views

Why doesn't the LHC accelerate electrons?

Electrons have a much bigger charge density as the protons (and especially lead nuclei), aren't compound particles as the protons (and especially lead nuclei) are able to get a much bigger energy ...
10
votes
4answers
2k views

Why is the LHC circular and 27km long?

The LHC in Geneva is a circular accelerator, 27 km long, why is it like that ?
10
votes
1answer
619 views

Do particle accelerators centrifuge the quarks of a proton?

Is it right that circular particle accelerators use magnetic fields to deflect the particle beam? Using the simple equation of "a charged particle in a magnetic field": ...
10
votes
2answers
4k views

Relativistic centripetal force

The thought randomly occurred to me that a circular particle accelerator would have to exert a lot of force in order to maintain the curvature of the trajectory. Many accelerators move particles at ...
9
votes
3answers
2k views

Do particle accelerators produce (dangerous) radiation?

I was under the impression that particle accelerators were pretty harmless, but some article said that they produce harmful radiation when you're in the tunnel. Given that the Internet... isn't always ...
8
votes
2answers
2k views

What exactly is the difference between a sychrotron light source and a free electron laser?

Cyclotron radiation is radiation emitted by a charged particle being bent by a magnetic field. The only difference between cyclotron and synchrotron radiation is that the latter occurs at relativistic ...
7
votes
3answers
563 views

Particle colliders: why do they need an accelerator chain

Particle colliders like the LHC or the Tevatron use a complex accelerator chain to have particles at a given energy before being accelerated. For example: The CERN accelerator complex to inject in ...
7
votes
1answer
645 views

Production of antiproton at the Tevatron

The Tevatron is a proton-antiproton collider; it collides a beam of protons against a beam of antiproton. I can understand how we obtain the protons, but for the antiprotons ? How are they produced ? ...
7
votes
2answers
3k views

Can the technology behind Particle accelerators can be used for space propulsion?

As I understand, the kinetic energy of the proton beam in a hadron collider is quite large. Can you build a space propulsion system that is based on accelerating a proton bean to relativistic speeds ...
6
votes
2answers
454 views

How detectors in particle colliders can differentiate neutrons from antineutrons?

Their mass is the same. None of them interacts with EM fields. And their decay (around 1000s) is far too slow to see their decay products yet in the detector. How is it then possible to differentiate ...
6
votes
2answers
76 views

Does the Advanced Photon Source use electrons or positrons?

Synchrotron light sources like the Advanced Photon Source (APS) (as well as SPring-8 and the ESRF) are typically mentioned as accelerating electrons up to the GeV range to produce extremely high ...
6
votes
1answer
108 views

Why do we need to build photon colliders? Since electron-position colliders are very “clean”

What's the advantage of gamma-gamma colliders? What new physics can be done with it? Reference: http://www.slac.stanford.edu/pubs/beamline/26/1/26-1-kim.pdf
6
votes
1answer
170 views

What is the temperature of an LHC Bunch?

From various places, I've found that an LHC bunch seems to be about 100mm long, 0.1mm wide, and contains about $10^{11}$ protons or anti-protons. The de Broglie wavelength is about $10^{-18}$ meters, ...
5
votes
3answers
556 views

Why doesn't an electron feel an electric field, and thus accelerate whilst inside the drift tube of a linear accelerator?

Why is the resultant field strength inside the tubes of a linear particle accelerator zero (i.e. the particles move in constant velocity through the tube)? As in the diagram, the particle ...
5
votes
1answer
1k views

What are the advantages of the ILC over the LHC?

USA Today has an article on Japan's interest as the site for the $10 billion future International Linear Collider. This accelerator will utilize electron/positron collisions (like CERN's former LEP ...
5
votes
1answer
258 views

On these pictures of accelerator equipment, what are the blue metal things?

I have visited many accelerator, and these blue things can be seen where cryo technology is used. What are they (He valves?/safety valves?) Why is so many needed? Edit: Here there are more blue ...
5
votes
1answer
363 views

What are the strongest sources of collimated neutrons and protons?

I am imagining an unusual experiment which will require intense beams of either protons or neutrons. The experiment would work better with neutrons, but neutron sources are much weaker messier so I ...
4
votes
1answer
58 views

What technological advance would allow LEP3 to surpass LEP2?

I learned that for electron accelerators synchrotron radiation and acceleration are the limiting factors. This article, that I found in one answer to this question mentions that one would not use the ...
4
votes
1answer
194 views

How many particles can a particle accelerator accelerate at once?

Does a particle accelerator lose its accelerating effectiveness as the number of particles being accelerated increases? According to Wikipedia, the mean acceleration of a proton in the Large Hadron ...
4
votes
1answer
72 views

Is accelerating particles through a chain of accelerators a continuous or batch process?

At the Advanced Photon Source, they use two accelerators before injecting the electrons into the large storage ring. Is the addition of particles to the storage ring done in "batches" (however ...
4
votes
1answer
148 views

Why would an alpha-beryllium neutron source generating a radioisotope not produce controllable net power?

I have a question. I was looking through the table of nuclides and noticed that the energy needed to produce certain radioisotopes was less than the energy given off by the radioactive decay of that ...
3
votes
4answers
3k views

Is an electron/proton gun possible?

In the 1944 SF story “Off the Beam” by George O. Smith, an electron gun is constructed along the length of a spaceship. In order to avoid being constrained by a net charge imbalance, it is built to ...
3
votes
5answers
285 views

How do we recognize hardware used in accelerator physics [closed]

When I see a new accelerator in real life or on a picture, I always find it interesting to see how many thing I can recognize. In that way, I can also get a small first idea of how the accelerator is ...
3
votes
1answer
54 views

In the LHC, how is the proton separated from the electron in the hydrogen? [duplicate]

I know that we use protons in the LHC. So my question is, how is the proton separated from the electron in the hydrogen?
3
votes
1answer
203 views

Why don't we use quater-circular dees instead of semi-circular dees in a Cyclotron

This is the setup, I have in my mind: O1, O2, O3 and O4 are 4 oscillators. The arrows in between the Dees represent the alternating EMF the Oscillators will generate. I think we can easily adjust ...
3
votes
1answer
71 views

Question about linacs

Why are the electrodes of a linac connected to an alternating voltage? Within an electrode the electron moves with a constant speed, and once it is outside of the electrode it accelerates uniformly, ...
3
votes
1answer
33 views

Ion beam optics software

I'm starting a new project that requires the simulation of a ion source test facility. I don't have much knowledge of beam optics so I want to find a beam optics software that is easy to learn/use. ...
3
votes
1answer
49 views

What would happen if the electric field was cut to a cyclotron half-way?

After accelerating say a proton, half way, if the alternating electric field was cut, would the proton maintain a perpetual circular motion at the same radius? I know that any charged particle moving ...
3
votes
1answer
77 views

How are the two proton beams at the LHC accelerated in opposite directions?

At the Large Hadron Collider (LHC), how are the protons in the two beams accelerated in opposite directions?
3
votes
1answer
209 views

Why did it take a long time to discover top quark?

In high school physics, I learned that it took a long time before the top quark was discovered. One of the reasons that was given in my book was that the top quark has a large mass, much larger than ...
3
votes
2answers
1k views

An Introduction to particle acceleration and particle accelerator

I am preparing to write my paper about particle acceleration recently, and i need some general knowledge to get my feet wet about it. May you please give me an introduction of what particle ...
3
votes
1answer
83 views

Why is an electrostatic accelerator so inefficient at converting wall power to beam power?

I was reading up on electrostatic particle accelerators when I read a statistic stating the efficiency of converting wall electrical power (the electrical power from the outlet) into beam power in an ...
3
votes
0answers
427 views

How to integrate over rapidity for Parton Luminosities in LHC?

I want to make a comparison of parton luminosities between Tevatron and LHC. According to Factorization theorem the cross section in hadron colliders, as long as the partonic cross section has $\hat ...
3
votes
1answer
140 views

Is “microbunching” in a free electron laser limited by the Pauli exclusion principle?

As I understand it, a free electron laser can basically be pictured as a synchrotron light source with an undulator which by the particular setup causes the electrons to self-attune so that they ...
2
votes
1answer
347 views

At CERN - What do you call the moment (event) particles crash together in the particle accelerator? [closed]

At CERN - What do you call the moment (event) particles crash together in the particle accelerator? At CERN they crash different particles together and measure what comes out. What is the name of the ...
2
votes
3answers
221 views

Can lightly-ionized atoms be accelerated to relativistic speeds with current technology?

I know there're lots of various particle accelerators, which can accelerate particles to TeV's of energy, but it seems they all work on electrons or nuclei or other elementary of tightly-bound ...
2
votes
1answer
146 views

Why can't a high intensity beam be injected into the LHC when the machine is empty

Watching this YouTube video about the LHC at around 3 minutes and 50 seconds into the video the narrator says... For machine protection reasons we are not allowed to inject a high intensity beam ...
2
votes
1answer
46 views

How would the CLIC accelerator work?

After reading what I could find about the CLIC accelerator, I still don't understand how it would work. If someone could explain how the CLIC would work, I would greatly appreciate it.
2
votes
2answers
81 views

Meaning of SIS in accelerators

With reference to accelerator facilities, the term "SIS" is often used. e.g. SIS-100, SIS-300 etc. What does SIS stand for, in this context? (The last S is probably for Synchrotron) Google appears ...
2
votes
1answer
65 views

Electron beam in magnetic field - increase or decrease the field?

When I fire an electron beam into homogenous magnetic field ( eg. inside Helmholtz coil ) it will bend into a circle => it will form a coil ( = current loop ) itself. The magnetic field created by ...
2
votes
1answer
66 views

How would one build an RF cavity?

How does an RF cavity, such as the RF cavities in the LHC, work mechanically and mathematically? How would one build an RF cavity? What equations govern the speed of a charged particle in an RF ...
2
votes
1answer
45 views

Beam excited RF cavity modes

When beam (bunch of electrons) transverse RF cavity, it will excite modes (resonant frequencies). The mode for steady state is quite well described, I am wondering is there any theory describe the ...
2
votes
1answer
82 views

Creating a stream of single file atoms

How do you go about creating a stream of single file atoms? The aim is to fire a stream of single file atoms (hydrogen, helium) down a vacuum and detect there arrival on the opposite end. Any ...
2
votes
0answers
78 views

Is muon muon annihilation already realised?

As muon colliders do not yet exist, has muon-muon annihilation already been realized experimentally?
1
vote
4answers
376 views

Why is it so hard to accelerate macroscopic objects?

It seems all we're capable of accelerating currently are atomic particles. Why can't we, say, accelerate a clock to relativistic speeds?
1
vote
6answers
270 views

Do the particles made in a collider exist outside the collider?

Below is the transcript of a section from Demystifying the Higgs Boson with Leonard Susskind. Around 1:02:23 Susskind says that the heaviest of the fermions is called the top quark. Top quark is ...
1
vote
2answers
209 views

Are there moments in particle collision experiments where the particle beam is in open air?

I keep encountering the story of Anatoli Bugorski, who apparently got hit in the head by a proton beam at the U-70 PS in Protvino, Russia. I find it difficult to believe that this is actually ...
1
vote
2answers
119 views

What physics does the Super Proton Proton Collider intend to explore in the $\lesssim 100\:\mathrm{TeV}$ range?

Chinese scientists have completed an initial conceptual design of a super giant particle collider which will be bigger and more powerful than any particle accelerator on Earth. With a circumference of ...
1
vote
1answer
35 views

Can spin polarisation restrict the possible types of LHC proton-proton collisions?

Despite the massive luminosity at the LHC, it's probably correct to say that no two collisions are ever identical, even up to symmetry. Not only are there all possible impact parameters, but the ...