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A Large L-Band Rectangular Corrugated Horn

Description: This paper describes a lightweight, corrugated-horn antenna, constructed from sheet metal. Over a 1.3-1.7 GHz operating band, its half-power beam width is approximately 20{sup o} in the E-plane and varies from 17{sup o} to 13{sup o} in the H-plane. Quarter-wave choke slots at the aperture help to reduce the E-plane sidelobes below -55 dB at angles greater than 90{sup o}, while the H-plane sidelobes lie in that range both with and without choke slots. Return loss throughout the operating band is -25 dB or below. Critical dimensions are provided, together with useful guidelines for designing similar antennas.
Date: January 1, 1987
Creator: Witebsky, C.; Smoot, G.F.; Levin, S. & Bensadoun, M.
Partner: UNT Libraries Government Documents Department

An excitation-term modification for a certain class of electromagnetic aperture-coupling problems

Description: A simple technique is presented for modifying electromagnetic aperture-coupling integral equations that are based on an infinite-ground-plane assumption, to partially account for excitation modifications which result from plane-wave interaction with a side of an actual three-dimensional scatterer. The technique is based on incorporating the solution for a conducting wedge into the integral equations. Results are presented for coupling to coaxial connectors which are more consistent with experimental observations. 5 refs., 13 figs.
Date: September 1, 1987
Creator: Riley, D.J. & Bacon, L.D.
Partner: UNT Libraries Government Documents Department

SAFT-UT utilities: Guide to SAFT-UT principles and conventions

Description: This guide, the Guide to SAFT-UT (Synthetic Aperture Focusing Technique-Ultrasonic Testing), Principles and Conventions, is intended to provide the user with an overall background for practical implementation of SAFT-UT and the associated software utilities. It is not intended to exhaustively cover each related item, but rather to supply information from theory and experience that will assist the serious user in exploiting the robust nature of the SAFT technology. Chapter 1 gives an introductory overview from a historical perspective, emphasizing the need to maintain data integrity throughout the SAFT-UT imaging process. Chapter 2 includes a theoretical description of the Three SAFT-UT configurations currently being supported (single transducer pulse-echo, TSAFT, and TSAFT-2). A general description of the software tools is given in Chapter 3. It describes the major utilities and the general use of each one. Chapter 4 deals with the system resolution and sampling demands of SAFT-UT. A discussion of the strengths and limitations of the SAFT technique is provided in Chapter 5. The scanning conventions assumed throughout the implementation of the SAFT-UT utilities are detailed in Chapter 6. Chapter 7 lists an exhaustive supply of references for the user desiring to investigate the SAFT technology further. 26 refs., 19 figs.
Date: October 1, 1987
Creator: Hall, T.E.
Partner: UNT Libraries Government Documents Department

Improvement of the dynamic aperture in Chasman Green lattice design light source storage rings

Description: The Chasman-Green half cell illustrates a typical electron or positron storage ring lattice specifically designed for photon beams from undulators and wigglers located in each dispersion-free straight section. The need for a small particle beam emittance requires that the horizontal phase advance per cell should be in the neighborhood of 0.9 x 2 . Necessary chromaticity correcting sextupoles, S/sub D/ and S/sub F/, located in the dispersion straight section introduce non-linear perturbations which limit the dynamic aperture because of amplitude dependent tune shifts. Two families of sextupoles, S1 and S2, can be introduced into the dispersion-free region to moderate the more harmful effects of S/sub D/ and S/sub F/. The nature of the perturbations are discussed and some guidelines for the adjustment of S1 and S2 sextupoles are given.
Date: January 1, 1987
Creator: Crosbie, E.A.
Partner: UNT Libraries Government Documents Department

Simulation of beam loss in the Los Alamos proton storage ring

Description: The Los Alamos Proton Storage Ring experiences a significant beam loss as a consequence of scattering in the stripper foil. This paper reviews efforts to understand this loss by computer simulation using the Lie algebraic tracking code MARYLIE, and other special codes that give a very fast simulation of the foil scattering. Simulation results are compared to experimental data.
Date: January 1, 1987
Creator: Mottershead, C.T.; Lawrence, G.P.; Channell, P.J. & Schweitzer, L.B.
Partner: UNT Libraries Government Documents Department

Frequency locking in coupled free electron lasers

Description: The application of optical phased arrays to obtain high output power, beam agility, and large equivalent output aperture has received considerable interest. In this paper, we investigte the scaling of free electron lasers using the phased array concept.
Date: January 1, 1987
Creator: Chow, Weng W.; Appert, Q.D.; Saxman, A.C.; McVey, B. & Bender, S.C.
Partner: UNT Libraries Government Documents Department

Aperture studies on RHIC for 30 and 100 GeV/nucleon operation with random and systematic magnet errors

Description: Tracking studies on RHIC for the emittances and momentum spreads necessary for operation at 30 and 100 GeV/nucleon have been made when the effects of random and systematic magnet errors are included. All test particles are stable for the emittances required. Tune shifts from systematic b/sub 2/ are compensated by the chromaticity correcting sextupoles of the arcs. Tune shifts from systematic b/sub 3/ and b/sub 4/ are compensated by correction coils placed adjacent to the arc quadrupoles. The emittances required for operation are significantly smaller than the emittance corresponding to the dynamic aperture.
Date: January 1, 1987
Creator: Dell, G.F. & Hahn, H.
Partner: UNT Libraries Government Documents Department

Tests of compressed geometry acceleration tubes in the Oak Ridge 25URC tandem accelerator

Description: In an effort to further improve voltage performance of the Oak Ridge 25URC accelerator, the original acceleration tubes will be replaced with NEC compressed geometry acceleration tubes. In this paper, we report on tests in the 25URC accelerator of two prototype compressed geometry acceleration tube designs. One of the designs utilizes a novel aperture which provides enhanced electron and ion trapping.
Date: January 1, 1987
Creator: Jones, C.M.; Erb, K.A.; Haynes, D.L.; Mitchell, J.T.; Ziegler, N.F.; Raatz, J.E. et al.
Partner: UNT Libraries Government Documents Department

A single layer coil superconducting magnet for SSC (Superconducting Super Collider)

Description: The superconducting magnet under consideration for the proposed Superconducting Super Collider (SSC) uses a two layer coil geometry and is optimized for 6.6 T central field. In this paper we assess if it is possible to design a dipole having a realistic single layer coil configuration, using a cable having the same size as that used in the present SSC outer layer coil, can achieve a central field of about 6 T. The affirmative answer assumes a superconductor current density approaching the best achieved thus far in production, close-coupled cold iron with at most a very thin collar, a high but not unreasonable current density in copper at quench, and operation below 4.2 K. The performance under other operating conditions will also be discussed. We shall first describe the cable used in this design. We shall discuss the optimization procedure of the iron shape, particularly in the aperture region to minimize the effects of iron saturation. We shall outline the design of a realistic single layer coil geometry. Finally we shall discuss various operating parameters from the quench protection point of view.
Date: 1987
Creator: Gupta, R. C.; Morgan, G. H. & Thompson, P. A.
Partner: UNT Libraries Government Documents Department