How is CERN SPS Achieving 33 TeV Energy Levels?

[Nitox33]

hello,
I open this thread to ask some questions about
SPS, it seems it is mounted 33 TeV, but how
he has been able to reach him such energy?
Is not it supposed to go up "only" 450 Gev Env?
Good week

 

[Orodruin]

I open this thread to ask some questions about
SPS, it seems it is mounted 33 TeV,

Please provide references to where you have found this figure when asking questions like this. Otherwise it is virtually impossible for us to check your sources.

 

[Nitox33]

Hello
http://fr.wikipedia.org/wiki/Super_Proton_Synchrotron
sorry I am not able to translate
this French site; the mention is made of
33 tev and plasma of quarks and gluons

 

[Orodruin]

My French is not very good, but the 33 TeV seems to refer to the energy of accelerated lead ions smashed together in order to create a QGP, not to the energy of accelerated protons.

 

[Nitox33]

Re hello,
thank you for your reply, I begin to think
wikipedia that it was mistaken in citing this energy!

I think I got the answer to my question! , Thank you;)

 

[Orodruin]

Here is a CERN link about lead acceleration up to 33 TeV using the SPS: http://na49info.web.cern.ch/na49info/Public/Press/general.html
Note that it is easier to accelerate lead to 33 TeV than it would be to accelerate protons to 33 TeV (just as it is easier to accelerate protons to high energies in a circular collider than it is to do it with electrons). The higher mass of the lead ions means you can get to higher energies with less losses in the form of synchrotron radiation.

 

[ofirg]

Here is a CERN link about lead acceleration up to 33 TeV using the SPS: http://na49info.web.cern.ch/na49info/Public/Press/general.html
Note that it is easier to accelerate lead to 33 TeV than it would be to accelerate protons to 33 TeV (just as it is easier to accelerate protons to high energies in a circular collider than it is to do it with electrons). The higher mass of the lead ions means you can get to higher energies with less losses in the form of synchrotron radiation.

Just to state that the important difference between the lead ions and the protons here is the charge, not the mass. A lead ion has a charge of 82 times the proton charge, which means you can accelerate it to 82 times higher momentum with the same magnetic field. Unlike electrons, synchrotron radiation is already not the limiting factor for proton and ions, but the curvature of the motion in the magnetic field is.

 

[Orodruin]

Just to state that the important difference between the lead ions and the protons here is the charge, not the mass. A lead ion has a charge of 82 times the proton charge, which means you can accelerate it to 82 times higher momentum with the same magnetic field. Unlike electrons, synchrotron radiation is already not the limiting factor for proton and ions, but the curvature of the motion in the magnetic field is.

This is what I guess for just dealing with elementary particles I guess.
But of course this is true, the gyroradius is given by
$$
r_g = \frac{p}{qB}
$$
and for highly relativistic particles $p \simeq E$ so for fixed $r_g$ and $B$, the energy would be directly proportional to the charge (surprise, surprise, $82\times 450\mbox{ GeV} \simeq 37\mbox{ TeV}$).

 

[mfb]

Protons at design energy lose about 10 keV per turn in the LHC, at the SPS the energy is lower by a factor of ~15 and radiated power scales with $\gamma^4$, so even with the smaller curvature radius the energy loss should be in the range of tens of electronvolts per turn - completely negligible.
Lead ions lose a factor of $82^2$ more energy at the same gamma-factor, but that is still no problem to compensate.

Proton and ion synchrotrons are always limited by the dipole magnets for the curves, so the maximal energy is proportional to the charge of the accelerated particles.

 

[Vanadium 50]

To avoid exactly this confusion, physicists usually use GeV per nucleon instead. So at the SPS, the beam energy is 177 GeV per nucleon.

 

[Nitox33]

hi
Thank you for all the answers
good all week