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Measurements of ICRF (ion cyclotron range of frequencies) loading with a ridged waveguide coupler on PLT

Description: An ICRF ridged waveguide coupler has been installed on PLT for measurements of plasma loading. The coupler was partially filled with TiO/sub 2/ dielectric in order to sufficiently lower the cutoff frequency and utilized a tapered ridge for improved matching. Vacuum field measurements indicated a single propagating mode in the coupler and emphasized the importance of considering the fringing fields at the mouth of the waveguide. Low power experiments were carried out at 72.6 and 95.0 MHz without… more
Date: November 1, 1987
Creator: Greene, G. J.; Wilson, J. R.; Colestock, P. L.; Fortgang, C. M.; Hosea, J. C.; Hwang, D. Q. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Polarizing holographic reflector for electron cyclotron resonant heating (ECRH) on the Tandem Mirror Experiment Upgrade (TMX-U)

Description: A reflector for electron cyclotron resonant heating on the Tandem Mirror Experiment Upgrade has been designed to convert the high-power TE/sub 01/ output of the circular waveguide system into a linearly polarized gaussian intensity pattern in the plasma. The reflector is a computer-generated holographic optical element with a twist polarizer. Its design, fabrication, and performance are discussed. Results of the low- and high-power tests are presented. Low-power tests were used to determine the… more
Date: November 14, 1983
Creator: Coffield, F.E.; Felker, B.; Gallagher, N.C. Jr.; Pedrotti, L.R.; Stallard, B.W.; Sweeney, D.W. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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First and second harmonic ECRH experience at gyrotron frequencies at LLNL

Description: Plasma heating of electrons in both mirror machines and tokamaks, using mm wave gyrotron sources, have been carried out in many experiments in recent years. The technology for both sources and mode-preserving waveguide transmission systems is well developed at power levels of 200 kW. At LLNL electron heating at 28 GHz in the TMX-U tandem mirror has been used to create hot electrons required for a thermal barrier (potential well). TMX-U, and other devices operating at lower frequency and power (… more
Date: November 1, 1987
Creator: Stallard, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microfabrication with femtosecond laser processing : (A) laser ablation of ferrous alloys, (B) direct-write embedded optical waveguides and integrated optics in bulk glasses.

Description: At Sandia National Laboratories, miniaturization dominates future hardware designs, and technologies that address the manufacture of micro-scale to nano-scale features are in demand. Currently, Sandia is developing technologies such as photolithography/etching (e.g. silicon MEMS), LIGA, micro-electro-discharge machining (micro-EDM), and focused ion beam (FIB) machining to fulfill some of the component design requirements. Some processes are more encompassing than others, but each process has it… more
Date: November 1, 2004
Creator: Guo, Junpeng; McDaniel, Karen Lynn; Palmer, Jeremy Andrew; Yang, Pin; Griffith, Michelle Lynn; Vawter, Gregory Allen et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Rf system design: compact ignition tokamak

Description: This report presents information on rf system design for the compact ignition tokamak. Topics discussed in this report include: frequency choice; plasma coupling analysis; launcher design; ORNL resonant double loop antenna; ORNL ''folded'' waveguide; recessed antennas; ICRH launcher R and D; and Faraday shield R and D. (JDB)
Date: November 1, 1985
Creator: Flanagan, C. & Yugo, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Changes and Developments in Electron Cyclotron Resonant Heating (ECRH) on the Tandem Mirror Experiment Upgrade (TMX-U)

Description: This paper will describe changes to the previously reported Electron Cyclotron Resonant Heating (ECRH) circular waveguide systems that deliver power to the Tandem Mirror Experiment Upgrade (TMX-U) machine. Four gyrotrons and associated waveguide systems, operating at 28-GHz and 200 kW each, helped establish electrostatic plugging in the end cells of TMX-U. A fifth gyrotron has been installed to power two resonant locations in the end plugs. This system and the pair of 10 kG heaters now use a sl… more
Date: November 14, 1985
Creator: Anderson, A. T.; Brooksby, C. A.; Calderon, M. O.; Ellis, R.; Felker, B.; Horton, R. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Active-passive waveguide array for wave excitation in plasmas

Description: A modified version of the standard waveguide grill for exciting lower hybrid plasma waves is proposed. This version should reduce both the number of RF drive components and the amplitude of the (undesirable) surface waves. Results from a simple 2-element array are presented.
Date: November 1, 1979
Creator: Motley, R. W. & Hooke, W. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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RF cavity development for the PEP-II B factory

Description: This paper describes the development of an RF cavity design for the proposed PEP-II asymmetric B factory. The high luminosity required of PEP-II provides challenges in the design of the RF cavities, most notably in the reduced higher-order mode (HOM) impedances that must be attained and in the power that must be dissipated in the cavity walls. This paper outlines the goals set in these regards, describes how the cavity has been developed to meet them, and presents the results of measurements on… more
Date: November 1, 1992
Creator: Rimmer, R.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Final design report, September 11, 1986

Description: The task is to design the quasi-optical microwave components for each of five different optical paths within the MFTF-B machine. Each path contains two reflectors. The function of the two reflectors in each path is to modify the output field of a waveguide to a desired pattern within the plasma. For all five beam paths, the waveguide output is assumed to be a TE 01 mode as decided at the July 18, design review. Each optical train consists of two reflectors. The first reflector is an off axis pa… more
Date: November 1, 1988
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Laser beam control and diagnostic systems for the copper-pumped dye laser system at Lawrence Livermore National Laboratory

Description: The laser system described in the previous paper is used for experiments in which success requires tight tolerances on beam position, direction, and wavefront. Indeed, the optimum performance of the laser itself depends on careful delivery of copper laser light to the dye amplifiers, precise propagation of dye laser beams through restricted amplifier apertures, and accurate monitoring of laser power at key locations. This paper describes the alignment systems, wavefront correction systems, and … more
Date: November 1, 1992
Creator: Bliss, E. S.; Peterson, R. L.; Salmon, J. T. & Thomas, R. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Summary of radiation-induced transient absorption and recovery in fiber optic waveguides. [Pulsed electrons and x-rays]

Description: The absorption induced in fiber optic waveguides by pulsed electron and X-ray radiation has been measured as a function of optical wavelength from 450 to 950 nm, irradiation temperature from -54 to 71/sup 0/C, and dose from 1 to 500 krads. The fibers studied are Ge-doped silica core fibers (Corning Low Loss), ''pure'' vitreous silica core fibers (Schott, Bell Laboratories, Fiberoptic Cable Corp., and Valtec Fiberoptics), polymethyl-methacrylate core fibers (DuPont CROFON and PFX), and polystyre… more
Date: November 1, 1976
Creator: Skoog, C. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

CLIC RF High Power Production Testing Program

Description: The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS te… more
Date: November 2, 2011
Creator: Syratchev, I.; Riddone, G. & Tantawi, S. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

X-Band Crab Cavities for the CLIC Beam Delivery System

Description: The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the extraction of spent beams. In order to recover the luminosity lost through the crossing angle a crab cavity is proposed to rotate the bunches prior to collision. The crab cavity is chosen to have the same frequency as the main linac (11.9942 GHz) as a compromise between size, phase stability requirements and beam loading. It is proposed to use a HE11 mode travelling wave structure as the CLIC crab cavity in order to min… more
Date: November 22, 2011
Creator: Burt, G.; Ambattu, P. K.; Dexter, A. C.; Abram, T.; Dolgashev, V.; Tantawi, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RF cavity development for the PEP-II B factory

Description: This paper describes the development of an RF cavity design for the proposed PEP-II asymmetric B factory. The high luminosity required of PEP-II provides challenges in the design of the RF cavities, most notably in the reduced higher-order mode (HOM) impedances that must be attained and in the power that must be dissipated in the cavity walls. This paper outlines the goals set in these regards, describes how the cavity has been developed to meet them, and presents the results of measurements on… more
Date: November 1, 1992
Creator: Rimmer, R. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RF/Microwave properties and applications of directly assembled nanotubes and nanowires: LDRD project 102662 final report.

Description: LDRD Project 102662 provided support to pursue experiments aimed at measuring the basic electrodynamic response and possible applications of carbon nanotubes and silicon nanowires at radiofrequency to microwave frequencies, approximately 0.01 to 50 GHz. Under this project, a method was developed to integrate these nanomaterials onto high-frequency compatible co-planar waveguides. The complex reflection and transmission coefficients of the nanomaterials was studied as a function of frequency. Fr… more
Date: November 1, 2006
Creator: Mayer, Theresa (The Pennyslvania State University, University Park, PA 16802); Vallett, Aaron (The Pennyslvania State University, University Park, PA 16802); Lee, Mark; Shaner, Eric Arthur; Jones, Frank E.; Talin, Albert Alec et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

PEP II: RF and feedback R&D

Description: The key elements of the PEP 11 approach to dealing with the problem of coupled-bunch instabilities are presented. The approach involves using warm copper RF cavities with damping waveguides (above the cutoff of the fundamental) attached to the cavity walls. These couple out the troublesome higher-order modes (HOMs) into absorbing loads, while the fundamental mode remains in the cavity. The Q of the worst HOM is reduced to below 70. Instabilities due to residual coupling are damped using a bunch… more
Date: November 1, 1992
Creator: Hindi, H.; Fox, J.; Eisen, N.; Linscott, I.; Oxoby, G.; Pendleton, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A theory of two-beam acceleration of charged particles in a plasma waveguide

Description: The progress made in recent years in the field of high-current relativistic electron beam (REB) generation has aroused a considerable interest in studying REB potentialities for charged particle acceleration with a high acceleration rate T = 100MeV/m. It was proposed, in particular, to employ high-current REB in two-beam acceleration schemes (TBA). In these schemes high current REB (driving beam) excites intense electromagnetic waves in the electrodynamic structure which, in their turn, acceler… more
Date: November 1, 1993
Creator: Ostrovsky, A. O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

PEP II: RF and feedback R&D

Description: The key elements of the PEP 11 approach to dealing with the problem of coupled-bunch instabilities are presented. The approach involves using warm copper RF cavities with damping waveguides (above the cutoff of the fundamental) attached to the cavity walls. These couple out the troublesome higher-order modes (HOMs) into absorbing loads, while the fundamental mode remains in the cavity. The Q of the worst HOM is reduced to below 70. Instabilities due to residual coupling are damped using a bunch… more
Date: November 1, 1992
Creator: Hindi, H.: Fox, J.; Eisen, N.; Linscott, I.; Oxoby, G.; Pendleton, R.; Sapozhnikov, L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nanoscale Bio-Molecular Control Using EC-OWLS

Description: A recently developed technique termed ''Electrochemical Optical Waveguide Lightmode Spectroscopy'' (EC-OWLS) [1] combines evanescent-field optical sensing with electrochemical control of surface adsorption processes. Initial EC-OWLS investigations efficiently monitored molecular surface adsorption and layer thickness changes of an adsorbed polymer layer examined in situ as a function of potential applied to a waveguide1. A layer of indium tin oxide (ITO) served as both a high refractive index w… more
Date: November 20, 2002
Creator: Bearinger, J P; Voros, J; Hubbell, J A & Textor, M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Integrated laser with low-loss high index-contrast waveguides for OEICs

Description: Photonic integrated circuits require the ability to integrate both lasers and waveguides with low absorption and coupling loss. This technology is being developed at LLNL for digital logic gates for optical key generation circuits to facilitate secure communications. Here, we demonstrate an approach of integrating InGaAs DQW edge emitting lasers (EEL) with electron beam evaporated dielectric waveguides. The EELs are defined by electron cyclotron resonance etching (ECR). This approach results in… more
Date: November 22, 2004
Creator: Welty, R J; Bond, T C; Behymer, E; Pocha, M; Loomis, G; Wolfe, J et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ribbon Fiber with Multiple Antiguided Phase-Locked Gain Cores

Description: We report on the first experimental demonstration of a scalable fiber laser approach based on phase-locking multiple gain cores in an antiguided structure. A novel fabrication technology is used with soft glass components to construct the multiple core fiber used in our experiments. The waveguide region is rectangular in shape and comprised of a periodic sequence of gain and no-gain segments having nearly uniform refractive index. The rectangular waveguide is itself embedded in a lower refracti… more
Date: November 20, 2002
Creator: Beach, R J; Feit, M D; Mitchell, S C; Cutter, K P; Dawson, J W & Payne, S A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Anomalous dispersion enhanced Cerenkov phase-matching

Description: The authors report on a scheme for phase-matching second harmonic generation in polymer waveguides based on the use of anomalous dispersion to optimize Cerenkov phase matching. They have used the theoretical results of Hashizume et al. and Onda and Ito to design an optimum structure for phase-matched conversion. They have found that the use of anomalous dispersion in the design results in a 100-fold enhancement in the calculated conversion efficiency. This technique also overcomes the limitatio… more
Date: November 1, 1993
Creator: Kowalczyk, T. C.; Singer, K. D. & Cahill, P. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hollow core and other infrared waveguides for instrumentation in intense radiation environments.

Description: The purpose of this LDRD was to study the effect of steady-state neutron and gamma irradiation on the transmission of waveguides designed to operate well in the near- or mid-IR region of the electromagnetic spectrum. In this context, near-IR refers to the region between 1.3 {mu}m and about 2.4 {mu}m, and mid-IR between 3.0 {mu}m and 4.5 {mu}m. Such radiation environments could exist in nuclear power plants or nuclear weapons. Pulsed and steady-state radiation effects had been extensively studie… more
Date: November 1, 2007
Creator: Weiss, Jonathan David
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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