Tuning the Magnetic Transport of an Induction LINAC using Emittance [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2006.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- PDF-file: 5 pages; size: 0 Kbytes
- Additional Creators:
- Lawrence Berkeley National Laboratory
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- The Lawrence Livermore National Laboratory Flash X-Ray (FXR) machine is a linear induction accelerator used to produce a nominal 18 MeV, 3 kA, 65 ns pulse width electron beam for hydrodynamic radiographs. A common figure of merit for this type of radiographic machine is the x-ray dose divided by the spot area on the bremsstrahlung converter where a higher FOM is desired. Several characteristics of the beam affect the minimum attainable x-ray spot size. The most significant are emittance (chaotic transverse energy), chromatic aberration (energy variation), and beam motion (transverse instabilities and corkscrew motion). FXR is in the midst of a multi-year optimization project to reduce the spot size. This paper describes the effort to reduce beam emittance by adjusting the fields of the transport solenoids and position of the cathode. If the magnetic transport is not correct, the beam will be mismatched and undergo envelope oscillations increasing the emittance. We measure the divergence and radius of the beam in a drift section after the accelerator by imaging the optical transition radiation (OTR) and beam envelope on a foil. These measurements are used to determine an emittance. Relative changes in the emittance can be quickly estimated from the foil measurements allowing for an efficient, real-time study. Once an optimized transport field is determined, the final focus can be adjusted and the new x-ray spot measured. A description of the diagnostics and analysis is presented.
- Published through SciTech Connect.
Presented at: 2006 Linear Accelerator Conference, Knoxville, TN, United States, Aug 21 - Aug 25, 2006.
Brown, C G; Houck, T L; Paul, A C; Ong, M M; Wargo, P E; Zentler, J M.
- Funding Information:
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