Design study of a transverse-to-longitudinal emittance exchange proof-of-principle experiment
Transverse-to-longitudinal emittance exchange can be achieved through certain arrangements of dipole magnets and a dipole mode rf cavity. Theory on such schemes has been developed in the past several years. In this paper we report our numerical simulations to optimize a low energy (E sime 15 MeV) proof-of-principle experiment planned at the Argonne Wakefield Accelerator (AWA). Parametric studies of the dipole magnets and cavity strengths, as well as initial beam parameters, are presented.
Transverse to longitudinal emittance exchange beamline at the A0 Photoinjector
The FNAL A0 Photoinjector is being reconfigured to test the principal of transverse to longitudinal emittance exchange as proposed by Cornacchia and Emma,Kim and and Sessler, and others. The ability to perform such an exchange could have major advantages to FELs by reducing the transverse emittance. Several schemes to carry out the exchange are possible and will be reported separately. At the Fermilab A0 Photoinjector we are constructing a beamline to demonstrate this transverse to longitudinal emittance exchange. This beamline will consist of a dogleg, a TMn110 5 cell copper cavity, and another dogleg. The beamline is designed to reuse the bunch compressor dipoles of the photoinjector, along with some existing diagnostics. Beamline layout and simulations are presented. Emittance dilution effects are also discussed.
CONTROLLING EMITTANCE GROWTH IN AN FEL BEAM CONDITIONER
It has been proposed [1] to ‘condition’ an electron beam prior to the undulator of a Free-Electron Laser (FEL) by increasing each particle’s energy in proportion to the square of its transverse betatron amplitude, or action. This conditioning enhances FEL gain by reducing the axial velocity spread within the electron bunch. In this paper we extend analysis proposed by A. Wolski for requirements to the conditioner which does not suffer from large emittance growth. We also present a possible quadrupole-undulator conditioner, with simulations showing that the emittance growth can be suppressed in a reasonable length system, but alignment tolerances are extremely tight.