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The fabrication of millimeter-wavelength accelerating structures

Description: There is a growing interest in the development of high gradient ({ge} 1 GeV/m) accelerating structures. The need for high gradient acceleration based on current microwave technology requires the structures to be operated in the millimeter wavelength. Fabrication of accelerating structures at millimeter scale with sub-micron tolerances poses great challenges. The accelerating structures impose strict requirements on surface smoothness and finish to suppress field emission and multipactor effects. Various fabrication techniques based on conventional machining and micromachining have been evaluated and tested. These will be discussed and measurement results presented.
Date: November 1, 1996
Creator: Chou, P.J.; Bowden, G.B. & Copeland, M.R.
Partner: UNT Libraries Government Documents Department

Monitoring the beam position in the SLC interaction region

Description: The Stanford Linear Collider requires special Beam Position Monitors near the Interaction Point (IP) to bring the two beams (e/sup +/ and e/sup -/) into collision. These beams pass through two monitors on each side of the IP with a short time separation (about 20 and 50 ns). The mechanics of the monitors as well as the electronics will be described. In order to bring beams of several microns diameter into collision at the IP, these monitors measure beam deflection induced by the presence of the opposite beam.
Date: March 1, 1987
Creator: Denard, J.C.; Bowden, G.B.; Oxoby, G.J.; Pellegrin, J.L. & Ross, M.C.
Partner: UNT Libraries Government Documents Department

RF measurements of a traveling-wave muffin-tin accelerating structure at 90 GHz

Description: A measuring system at the table-top scale was developed for RF measurements of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz). Both perturbation and non-perturbation methods are employed to characterize the RF properties of a muffin-tin structure. Conventional bead pull measurements are extended to millimeter wavelengths. Design of the measuring system and preliminary results of RF measurements are presented.
Date: May 1, 1997
Creator: Chou, P.J.; Bowden, G.B.; Copeland, M.R.; Menegat, A.; Pritzkau, D.P.; Siemann, R.H. et al.
Partner: UNT Libraries Government Documents Department

Design and fabrication of a traveling-wave muffin-tin accelerating structure at 90 GHz

Description: A prototype of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz) was built for research in high gradient acceleration. A traveling-wave design with single input and output feeds was chosen for the prototype which was fabricated by wire electrodischarge machining. Features of the mechanical design for the prototype are described. Design improvements are presented including considerations of cooling and vacuum.
Date: May 1, 1997
Creator: Chou, P.J.; Bowden, G.B.; Copeland, M.R.; Menegat, A.; Siemann, R.H. & Henke, H.
Partner: UNT Libraries Government Documents Department

A semi-automated system for the characterization of NLC accelerating structures

Description: *A system for characterizing the phase shift per cell of a long X-band accelerator structure is described. The fields within the structure are perturbed by a small cylindrical metal bead pulled along the axis. A computer controls the bead position and processes the data from a network analyzer connected to the accelerator section. Measurements made on prototype accelerator sections are described, and they are shown to be in good agreement with theory.
Date: June 1, 1995
Creator: Hanna, S.M.; Bowden, G.B.; Hoag, H.A.; Loewen, R.; Vlieks, A.E. & Wang, J.W.
Partner: UNT Libraries Government Documents Department

Design, analysis and measurement of very fast kicker magnets at SLAC

Description: Recent experience with SLC has shown that very fast, ferrite-loaded, transmission-line, beam-kicker magnets can cause significant and undesirable distortion of a 1.5-2.5 kA, 20-4- kV pulse as it travels through the magnet. In general, there is a net lengthening of the pulse, with increases in its rise and fall times, a decrease in amplitude, and an unsymmetrical rounding of the flattop. In this partially tutorial treatise, a number of practical design considerations are discussed in terms of equivalent circuits, magnet circuit dispersion and dissipation, undesired circuit shunting and coupling, high-voltage breakdown problems and high-order-mode losses that lead to beam tube heating. These effects are linked to the properties of the materials, the presence of radiation and realizable magnet topologies. Measurements and calculations of some of these characteristics for several magnet designs are reviewed. The results presented come from a truly eclectic effort. 8 refs., 1 fig.
Date: March 1, 1989
Creator: Weaver, J.N.; Bowden, G.B.; Bulos, F.; Cassel, R.L.; Donaldson, A.R.; Harvey, A. et al.
Partner: UNT Libraries Government Documents Department

Studies of Room Temperature Accelerator Structures for the ILC Positron Source

Description: There are many challenges in the design of the normal-conducting portion of the ILC positron injector system such as achieving adequate cooling with the high RF and particle loss heating, and sustaining high accelerator gradients during millisecond-long pulses in a strong magnetic field. The proposed design for the positron injector contains both standing-wave and traveling-wave L-band accelerator structures for high RF efficiency, low cost and ease of fabrication. This paper presents results from several studies including particle energy deposition for both undulator based and conventional positron sources, cooling system design, accelerator structure optimization, RF pulse heating, cavity frequency stabilization, and RF feed system design.
Date: March 15, 2006
Creator: Wang, J.W.; Adolphsen, C.; Bharadwaj, V.; Bowden, G.B.; Dolgashev, V.A.; Jones, R.M. et al.
Partner: UNT Libraries Government Documents Department