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- C. P.J. Barty, R. Beach, D. J. Gibson, C. Hagmann, F. V. Hartemann, E. P. Hartouni, J. Hernandez, M. Johnson, I. Jovanovic, J. Klay, D. P. McNabb, R. Norman, M. Shverdin, C. Siders, R. Soltz, P. O. Stoutland, A. M. Tremaine
LLNL, Livermore, California
- J. B. Rosenzweig
UCLA, Los Angeles, California
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The Thomson scattering of picosecond and femtosecond duration laser pulses off of low emittance electron beams is an effective method of producing mono-chromatic, MeV-range gamma-rays with unprecedented peak brightness. With peak brightness at 1 MeV > 15 orders of magnitude beyond 3rd generation synchrotrons, these sources open the possibility for a host of new nuclear applications based on photons. In this presentation an overview of the requisite photo-gun, short pulse laser and linear accelerator technologies required for production of high brightness gamma-rays will be presented. Potential applications of these unique sources of radiation will be discussed with particular emphasis given to the excitation and use of nuclear resonance fluorescence (NRF) for isotope detection and imaging of special nuclear materials of importance to homeland security.
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- P. M. McIntyre, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas
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A polyhedral cavity structure has been devised for use in superconducting linacs. It has the same ellipsoidal side contour as a TESLA cavity but is configured as a polyhedron in its end view. Each segment of the polyhedron consists of a Nb foil bonded to a Cu wedge that has been machined to the desired ellipsoidal inner contour. There are no welds, and the seams between adjacent segments do not affect the high Q of the accelerating mode but block the azimuthal currents of deflecting modes. The power coupled into deflecting modes can be slot-coupled at the seams into dielectric-loaded waveguides integrated in the copper segments and conveyed to warm termination. The inner surface of each segment is accessible for polishing and characterization. It accommodates application of improved superconducting surfaces, such as the multi-layer thin-film Nb3Sn proposed by Gurevich. Refrigeration can be provided by gun-bored channels within the copper segments. The copper segments provide a rigid assembly that eliminates Lorentz detuning. The talk will discuss the mode properties and coupling strategies, the strategy for Nb/Cu bonding, and plans for building and testing of prototype cavities.
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