Emittance and phase space exchange for advanced beam manipulation and diagnostics

Abstract

Alternative chicane-type beam lines are proposed for exact emittance exchange between transverse phase space ðx; x 0 Þ and longitudinal phase space ðz; Þ, where x is the transverse position, x 0 is the transverse divergence, and z and are relative longitudinal position and energy deviation with respect to the reference particle. Methods to achieve exact phase space exchanges, i.e., mapping x to z, x 0 to , z to x, and to x 0 , are suggested. Schemes to mitigate and completely compensate for the thick-lens effect of the transverse cavity on emittance exchange are studied. Some applications of the phase space exchange for advanced beam manipulation and diagnostics are discussed.

Overview of phase space manipulations of relativistic electron beams

“…For advanced surgery to the phase space, it is desirable to eliminate the dependence on x . Further studies show that this can be achieved by adding quadrupoles before and after an EEX beamline [40]. By suitable lattice matching, one can achieve phase space exchange (PSEX) in which both the beam emittance and coordinates are exchanged, i.e.…”

“…However, this scheme introduces offset in beam trajectory which might be undesirable in some cases. Recently a chicane type exact EEX beam line was also proposed [40] where a pair of quadrupoles is used to form a negative unity transfer matrix for the transverse plane in the chicane. The negative unity section reverses the dispersion of the first half of the chicane, which is optically equivalent to flipping the sign of a dogleg.…”

Precision Control of the Electron Longitudinal Bunch Shape Using an Emittance-Exchange Beam Line

“…There are several different beamline configurations [27,28] that can exchange the horizontal and longitudinal emittance, as long as the beamline satisfies the general EEX condition [29]. We used the double dogleg EEX beamline since it has the simplest form making it an ideal candidate for understanding the fundamental beam dynamics of the bunch shaping process.…”

Imaging nanometer-scale beamlets arrays of relativistic electron beams

“…Novel schemes on how to introduce such fine structures in the beam phase space and how to control their evolutions during subsequent beam transport are continuously being proposed and investigated [6]. For a relativistic beam, starting with a transverse density modulation is an attractive option as it has been showed that with emittance exchange technique the beam transverse structure can be effectively transferred to the longitudinal plane [7,8,9,10,11].…”