A 1 kW infrared FEL, funded by the U.S. Navy, is under construction at what has been described by the Washington Post (2 March 1997) as "an otherwise nondescript Energy Department lab". This device will be driven by a compact, 42 MeV, 5 mA, energy-recovering, CW SRF-based linear accelerator to produce light in the 3-6.6 micron range. The machine, shown below, comprises a 10 MeV injector, a linac based on a single high-gradient Jefferson Lab accelerator cryomodule, a wiggler and optical cavity, and an energy-recovery recirculation arc.
Energy recovery limits cost and technical risk by reducing the RF power requirements in the driver accelerator. Following deceleration to 10 MeV, the beam is dumped. Stringent phase space requirements at the wiggler, low beam energy, and high beam current subject the accelerator lattice to numerous constraints. Principal considerations include: transport and delivery to the FEL of a high-quality, high-current beam; the impact of coherent synchrotron radiation (CSR) during beam recirculation transport; beam optics aberration control, to provide low-loss energy-recovery transport of a 5% relative momentum spread, high-current beam; attention to possible beam breakup (BBU) instabilities in the recirculating accelerator; and longitudinal phase space management during beam transport, to optimize RF drive system control during energy recovery and FEL operation. This site addresses the design process and design solution for an accelerator transport lattice that meets the requirements imposed by physical phenomena and operational necessities.
The FODOmat has developed the design for this accelerator; the
links provide a discussion of the project, the design process, specific
design requirements, and the lattice that has evolved during this
Basic Design Features
The driver lattice has been frozen (10 December
1996), and design revisions are now in configuration control. The most
recent available information can be obtained from FEL
electron beam optics related CEBAF/JLAB technical notes
list of updates to the 10 December 1996 baseline.
Archival information can be obtained from
to ICFA and PAC97 documents.
Coherent Synchrotron Radiation (CSR) has emerged as
a primary issue in machine performance. Links to
JLab studies of CSR are available.
Procedures for electron-beam optics-related tasks
are available (postscript format):
A machine modeling spreadsheet can be opened from within EXCEL
A longitudinal modeling spreadsheet can be opened from within EXCEL 97
Schedules for electron-beam optics-related tasks
are available as well:
(very) little FEL humor...
Last modified: 1 February 1999
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