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J. Rathke,
A. Ambrosio,
M. Cole,
E. Peterson,
T. Schultheiss, H. Bluem,
A.M.M. Todd,
I. Campisi,
E. Daly,
J. Hogan,
J. Mammosser,
G. Neil,
J. Preble,
R. Rimmer,
C. Rode,
J. Sekutowicz,
T. Whitlatch,
M. Wiseman
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ABSTRACT: Advanced Energy Systems has recently completed the design of a four cavity cryomodule for use as an FEL injector accelerator on the JLAB Injector Test Stand. Fabrication is nearing completion. Four 748.5 MHz single cell superconducting cavities have been completed and are currently at Jefferson Lab for final processing and test prior to integration in the module. This paper will review the design and fabrication of the cavities and cryomodule.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
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A. Todd, H. Bluem,
V. Christina,
M. Cole,
J. Rathke,
T. Schultheiss,
I. Campisi,
E. DaIy,
D. Douglas,
G. Neil, [......],
T. Whitlatch,
M. Wiseman,
P. Colestock,
J.P. Kelley,
S. Kurennoy,
D. Nguyen,
S. Russell,
D. Schrage,
R. Wood,
L. Young
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ABSTRACT: A key technology issue on the path to high-power FEL operation is the demonstration of reliable, high-brightness, high-power injector operation. We describe two ongoing programs to produce 100 mA injectors as drivers for 100 kW free-electron lasers. In one approach, in collaboration with the Thomas Jefferson National Accelerator Facility, we are fabricating a 750 MHz superconducting RF cryomodule that will be integrated with a room-temperature DC photocathode gun and tested at the Laboratory. In the other approach, in collaboration with Los Alamos National Laboratory, a high-current 700 MHz, normal-conducting, RF photo-injector is being designed and will undergo thermal management testing at the Laboratory. We describe the design, the projected performance and the status of both injectors.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
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[show abstract]
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ABSTRACT: A key technology issue on the path to high-power FEL operation is
the demonstration of reliable, high-brightness, photo-cathode injector
operation. The physics and engineering conceptual design of a
high-current superconducting RF injector has been completed and will be
presented. The system, which is an outgrowth of the existing injector on
the Jefferson Lab IR FEL, consists of an integrated room temperature DC
photocathode gun and a 500 MHz superconducting RF accelerator. The
device is compact and produces high-brightness beams. After DC
acceleration in the gun, emittance compensation techniques are utilized
to reduce the RMS normalized emittance by over a factor of two to ~2
π mm-mrad at the output of the RF accelerator. The design is based
upon the existing geometry of the Jefferson Lab DC gun and will be
capable of operation at 100 mA average beam current
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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J. Neumann,
E. Elson,
D. Feldman,
R. Feldman,
J. Harris,
A. Shkvarunets,
M. Virgo,
P. O'Shea,
H. Freund, H. Bluem,
A. Todd
[show abstract]
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ABSTRACT: The Maryland Infrared Free Electron Laser is being constructed at
the University of Maryland, and is expected to lase in the far infrared.
The accelerator driving the laser is a 10 MeV linac which is being
assembled in an "in-line" configuration. The design work for the
accelerator was accomplished using Trace-3D and PARMELA computer
simulations. When the accelerator is completed, it will be able to
accommodate several additional experimental sections within the beam
line itself in order to further study accelerator physics
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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[show abstract]
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ABSTRACT: The Next Linear Collider (NLC) Collaboration is planning to
construct an Engineering Test Facility (ETF) at Fermilab. As presently
envisioned, the ETF would comprise a fundamental unit of the NLC main
linac to include X-band klystrons and modulators, a delay-line
power-distribution system (DLDS), and NLC accelerating structures that
serve as loads. The principal purpose of the ETF is to validate stable
operation of the power-distribution system, first without beam, then
with a beam having the NLC pulse structure. This paper concerns the
possibility of configuring and using the ETF to accelerate beam with an
NLC pulse structure, as well as of doing experiments to measure
beam-induced wakefields in the rf structures and their influence back on
the beam
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001; 02/2001
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[show abstract]
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ABSTRACT: The first experimental demonstration of a harmonic free-electron laser amplifier utilizing a periodic position instability is described for a planar wiggler configuration. The interaction occurs at the even harmonics of the fundamental. A maximum gain of 7 dB was observed over a frequency band ranging from 14 to 15 GHz. The experimental results are compared with predictions from the three-dimensional simulation code WIGGLIN with excellent agreement. Improvements due to a tapered wiggler for this interaction are discussed
Electron Devices Meeting, 1991. IEDM '91. Technical Digest., International; 01/1992
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[show abstract]
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ABSTRACT: A fully three-dimensional nonlinear analysis of the harmonic ubitron/free-electron laser, which is valid for arbitrary harmonic number, is discussed. The analysis has been performed for a configuration consisting of a beam propagating through a loss-free rectangular waveguide in the presence of a planar wiggler field. The advantage of harmonic operation is that relatively high operating frequencies can be obtained with relatively modest beam energies; however, this occurs at the expense of a greater sensitivity to beam thermal effects. In addition to enhancing the extraction efficiency, a tapered wiggler has been shown to reduce the sensitivity of the interaction to such effects. Suppression of the fundamental is accomplished by the careful choice of the beam energy, waveguide radius, and wiggler period in order to ensure that no resonance is possible at the fundamental. A third-harmonic experiment operated at 15 GHz with a 55-keV electron beam is discussed
Plasma Science, 1989. IEEE Conference Record - Abstracts., 1989 IEEE International Conference on; 06/1989
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[show abstract]
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ABSTRACT: An ultrashort linear wiggler design has been developed that is compatible with microfabrication techniques and is capable of producing uniform, multikilogauss fields at millimeter and submillimeter periods. The design evolved from a prototype wiggler that consists of a multiply counterwrapped copper winding around a series of iron pole pieces. The counterwrapping produces a number of benefits, including reduction of end effects, elimination of edge asymmetries, current multiplication, and elimination of stray fields and excessive inductance from long, unshielded current supply leads. This wiggler has good uniformity and gives excellent agreement with calculations using the two-dimensional finite-difference code POISSON. It was found that even better intrinsic uniformity (<0.2% based on code calculations) could be obtained by putting a large iron bus along the top of the wiggler. By scaling down all dimensions proportionately to the ratio of the lengths and reducing the current by a like amount, it is possible to attain fields in the small wiggler that are the same as those attainable in the larger-period wiggler. On the other hand, the power density scales unfavorably, increasing as the inverse square of the scaling factor. Cooling may be required for CW operation. This can easily be provided due to the wiggler's small size and its construction geometry
Plasma Science, 1989. IEEE Conference Record - Abstracts., 1989 IEEE International Conference on; 06/1989
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[show abstract]
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ABSTRACT: The operation of a ubitron/FEL amplifier is reported. The experiment has been operated using the fundamental wiggler harmonic interaction with the TE<sub>11</sub> circular waveguide mode. Small-signal gains as high as 12 dB have been observed at a voltage 15% below design level with a minimum instantaneous bandwidth exceeding 25%. A gain per free-space wavelength approaching 0.9 dB/ lambda has been achieved. Experimental results are compared with small-signal calculations, and future plans are discussed. Reasonable agreement has been obtained between measurements and theory concerning gain, bandwidth, and general performance characteristics. In particular, higher values of gain per free-space wavelength have been achieved due to the combination of helical wiggler and circularly polarized waveguide mode.
Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International; 02/1988
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Free Electron Laser Conference, 1989. Proceedings of the Eleventh International;
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Free Electron Laser Conference, 1989. Proceedings of the Eleventh International;
