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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18
votes
4answers
4k 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 ...
6
votes
1answer
199 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, ...
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 ...
0
votes
1answer
63 views

Do accelerated particles change in size as they change in mass?

If a charged particle is accelerated to incredible energies in a particle collider, its mass increases. Does its radius increase as well and, if so, how does it compare to the change of mass? Could ...
0
votes
1answer
88 views

Why is the storage ring of a synchrotron a vacuum?

Why is the storage ring of a synchrotron a vacuum? I know that when the accelerated particles get to the storage ring they lose energy, releasing synchrotron radiation, but how does the vacuum make ...
6
votes
2answers
472 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 ...
2
votes
2answers
90 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 ...
1
vote
1answer
141 views

How does the number of events per bunch collision scale (as function of energy, luminosity …)

Looking at Table 1 of Burton Richter's recent article High Energy Colliding Beams; What Is Their Future? I'm wondering how the number of events per bunch collision ("$N_b$") scales for the collider ...
3
votes
3answers
236 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 ...
0
votes
2answers
199 views

Electron energy in a synchrotron storage ring vs. X-ray energy from the wiggler: why is the latter much lower?

I know in large synchrotron facilities some beamlines produce very intense X-rays by injecting the accelerated electrons into "wigglers". I have read that the typical energy of the electrons in the ...
-1
votes
1answer
132 views

Reusing the bremsstrahlung energy in circular accelerators?

I think the Bremsstrahlung happens as a strong radiation emitted by the accelerated particle stream. As in this question is visible, it is the main cause of the energy loss in such big particle ...
3
votes
1answer
231 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 ...
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 ...
1
vote
2answers
212 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 ...
0
votes
1answer
262 views

How does a synchroton work?

I know that a linear accelerator (linac) works by having terminals that get longer progressively and changes polarity due to AC current. And I also know that a cyclotron works by having two semi-...
5
votes
1answer
377 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 ...
1
vote
0answers
97 views

How do I build an alpha emitter?

I would like to build an alpha emitter. I suppose I had some vague idea of knocking the electrons off of some helium. But upon further examination the idea does strike me as...naive? My question is ...
3
votes
1answer
50 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 ...
1
vote
1answer
355 views

A comprehensive reference for RF linear accelerator's operation

I'm doing a research on RF linear accelerators (RF Linac), but while studying the material I encountered many problems. I cannot understand the basics of the RF linear accelerators in many ways, for ...
0
votes
1answer
168 views

LINAC: why are they being accelerated?

I have read the wiki page and I have seen this image, but I still don't understand why they are being accelerated. Could you easily explain it to me? Thanks a lot
7
votes
3answers
575 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 ...
1
vote
2answers
884 views

Muon production in particle accelerator

PAMELA is a particle accelerator which have two concentric rings, protons are accelerated in the inside ring. At ISIS muons are produced when a 800 MeV proton beam collides with a graphite target(...
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 ...
3
votes
1answer
215 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 ...
0
votes
1answer
59 views

When is the FAIR accelerator supposed to be finished? [closed]

The FAIR accelerator is a planned facility for antiproton and ion research. Ground water wells are being put in, the forest is being cleared... But when is it supposed to be completed? Does anyone ...
0
votes
2answers
100 views

Minimal voltage in linear accelerators to achieve relativity?

Could anyone tell me what is the minimal voltage between anode and cathode in a linear accelerators to achieve speeds where relativity starts to show? Let me ask in a different way: "What is the ...
1
vote
1answer
788 views

Velocity of electron in electrostatic field. Does radiation matter?

There's a voltage difference of 1000 Volts between two points 2 meters apart. An electron starts at the point of lower potential and is left to travel alone in a straight line until it reaches the ...
0
votes
1answer
100 views

Future of colliders and technical limitations

Are there any technical limitations (theoretical or technological) that prevent quark based colliders? ie. Colliding two quarks together.
3
votes
5answers
286 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 ...
5
votes
1answer
260 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
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 ...
3
votes
0answers
448 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 \...
1
vote
2answers
119 views

If U238 ions were circulating in a particle accelerator would their neutron absorption cross section spectra change?

If U238 ions were circulating in a particle accelerator would their neutron absorption cross section spectra change?
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 ...
1
vote
4answers
379 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?
7
votes
1answer
673 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 ?
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 ?