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Title: Preliminary injector, accelerator, and beamline design for rf-linac-driven XUV free-electron lasers

Conference ·

The proposed Los Alamos National Laboratory XUV free-electron laser (FEL) facility requires exceptional beam quality at high peak currents. Although the beam quality needed for a demonstration machine lasing at 50 nm is not far from what can be expected with extensions of present linacs to higher energy, conventional injector technology will not meet the requirements needed for lasing at 12 or 4 nm. We have conceived a preliminary injector and accelerator design that will meet these requirements. Using the Los Alamos photoelectric injector, it appears that normalized 90% emittances of 24 ..pi.. dot mm dot mrad can be attained in a relatively straightforward manner, and emittances down to 4 ..pi.. doe mm dot mrad are possible. Beamline simulations have been performed with the particle-pushing code PARMELA, using particle-dump inputs from the particle-in-cell code ISIS. The latter models the photoelectric gun up to the range between 0.75 and 1 MeV. Designs including electron guns with Pierce geometries have also been studied. Using an injector with a large planar-cathode Pierce gun seems to satisfy the 50-nm lasing requirements. In addition, other beamline questions have been studied. Beamline bends have been designed that are achromatic and nearly isochronous. The threshold for cumulative beam breakup and the emittance growth caused by transverse resistive-wall beam instability have been calculated. Finally, we discuss the advantages and disadvantages of building a straight-line machine versus a recycling machine, including recycling instability current levels. 11 refs., 16 figs.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
5658582
Report Number(s):
LA-UR-87-3092; CONF-8709110-18; ON: DE88003185
Resource Relation:
Journal Volume: 272; Journal Issue: 1-2; Conference: 9. international free-electron laser conference, Williamsburg, VA, USA, 14 Sep 1987; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English