Plasma lens experiments at the final focus test beam

Abstract

We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing &vices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5x lOlo, tunneling ionization of a gas target by an electron beam -an effect which has never been observed before -should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

Final focus challenges for muon colliders at highest energies

“…At higher energies the 6-dimensional emittance is much further reduced. For these beam energies the small IP beta functions cannot be achieved with conventional magnets, but must be based on more exotic techniques, such as a plasma lens [32,33] or dynamic focusing [34,35,36]. The IP beta functions listed in the table correspond to the minimum values achievable with a plasma lens, as estimated in Eq.…”

“…We denote the beam size at the plasma lens by σ r , the beta function at the lens by β r , the rms transverse beam emittance by , the plasma density by n p and the distance between plasma lens and collision point by l * . If the plasma density is smaller than the beam density, the focusing strength of the plasma lens is [33] K = 2πr µ γ n p (18) and the reduction of the focusing field by the plasma return current is small as long as [33] …”