COOLING IN CRYSTALINE BEAMS

In particle beam physics the concept of cooling has a different meaning than in rest of physics. In, say , thermodynamics, cooling means the reduction of material temperature. In particle beam physics that is not adequate. In particular, as one focuses and de-focuses the beams the transverse temperature can easily be changed. The cooling of particle beams is based upon the concept of phase space and a theorem introduced by Liouville .

Cooling in this sense means that an actual reduction of phase space volume is acheived. In other words, phase space density increased. This can only be done by VIOLATING Liouville's theorem.

Number of cooling methods reducing phase space density have been devised. Of interest for Crystalline Beams are:

RADIATION COOLING

ELECTRON COOLING

STOHASTIC COOLING

LASER COOLING

IONIZATION COOLING

Pictorial representation of the most interesting, laser, cooling mechanism. The net effect of photon absorption and emissions is change in velocity of the ion! (Click on the picture for larger version).



Dusan Maletic