Intense ion beam transport in magnetic quadrupoles [electronic resource] : Experiments on electron and gas effects
- Berkeley, Calif. : Lawrence Berkeley National Laboratory, 2004.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 3 pages : digital, PDF file
- Additional Creators:
- Lawrence Berkeley National Laboratory and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Heavy-ion induction linacs for inertial fusion energy and high-energy density physics have an economic incentive to minimize the clearance between the beam edge and the aperture wall. This increases the risk from electron clouds and gas desorbed from walls. We have measured electron and gas emission from 1 MeV K⁺ incident on surfaces near grazing incidence on the High-Current Experiment (HCX) at LBNL. Electron emission coefficients reach values >100, whereas gas desorption coefficients are near 10⁴. Mitigation techniques are being studied: A bead-blasted rough surface reduces electron emission by a factor of 10 and gas desorption by a factor of 2. We also discuss the results of beam transport (of 0.03-0.18 A K⁺) through four pulsed room-temperature magnetic quadrupoles in the HCX at LBNL. Diagnostics are installed on HCX, between and within quadrupole magnets, to measure the beam halo loss, net charge and expelled ions, from which we infer gas density, electron trapping, and the effects of mitigation techniques. A coordinated theory and computational effort has made significant progress towards a self-consistent model of positive-ion beam and electron dynamics. We are beginning to compare experimental and theoretical results.
- Report Numbers:
- E 1.99:lbnl--56242
E 1.99: hifan 1362
- Published through SciTech Connect.
" hifan 1362"
The 33rd ICFA Advanced Beam Dynamics Workshop on High Intensity and High Brightness Haldron Beams, ICFA-HB2004, Bensheim (DE), 10/18/2004--10/22/2004.
Friedman, A.; Cohen, R.H.; Molvik, A.W.; Faltens, A.; Lund, S.M.; Seidl, P.A.; Bieniosek, F.M.; Prost, L.; Vay, J-L.; Kireef Covo, M.
- Funding Information:
View MARC record | catkey: 14072940