8 Matching Results

Search Results

Advanced search parameters have been applied.

An electromagnetic induction method for underground target detection and characterization

Description: An improved capability for subsurface structure detection is needed to support military and nonproliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the DOE/NN-20 program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laboratories (SNL) initiated an electromagnetic induction (EMI) project to evaluate low frequency electromagnetic (EM) techniques for subsurface structure detection. Low frequency, in this case, extended from kilohertz to hundreds of kilohertz. An EMI survey procedure had already been developed for borehole imaging of coal seams and had successfully been applied in a surface mode to detect a drug smuggling tunnel. The SNL project has focused on building upon the success of that procedure and applying it to surface and low altitude airborne platforms. Part of SNL`s work has focused on improving that technology through improved hardware and data processing. The improved hardware development has been performed utilizing Laboratory Directed Research and Development (LDRD) funding. In addition, SNL`s effort focused on: (1) improvements in modeling of the basic geophysics of the illuminating electromagnetic field and its coupling to the underground target (partially funded using LDRD funds) and (2) development of techniques for phase-based and multi-frequency processing and spatial processing to support subsurface target detection and characterization. The products of this project are: (1) an evaluation of an improved EM gradiometer, (2) an improved gradiometer concept for possible future development, (3) an improved modeling capability, (4) demonstration of an EM wave migration method for target recognition, and a demonstration that the technology is capable of detecting targets to depths exceeding 25 meters.
Date: January 1, 1997
Creator: Bartel, L.C. & Cress, D.H.
Partner: UNT Libraries Government Documents Department

Programmable high power beam damper for the Tevatron

Description: A bunch-by-bunch beam damper has been developed for the Fermilab Tevatron. The system reduces betatron oscillation amplitudes and incorporates some useful machine diagnostics. The device is programmable via look-up tables so the output is an arbitrary function, on a bunch-by-bunch basis, of the beam displacement. We are presently using this feature to measure the betatron tune throughout the acceleration cycle. 4 refs.
Date: June 1, 1985
Creator: Crisp, J.; Goodwin, R.; Gerig, R.; Johnson, M.; Jones, A.; Kerns, C. et al.
Partner: UNT Libraries Government Documents Department

Characterization of diamond film and bare metal photocathodes as a function of temperature and surface preparation

Description: High current photocathodes using bare metal and polycrystalline diamond films illuminated by ultraviolet lasers are being developed at Los Alamos for use in a new generation of linear induction accelerators. These photocathodes must be able to produce multiple 60 ns pulses separated by several to tens of nanoseconds. The vacuum environment in which the photocathodes must operate is 10{sup -5} torr.
Date: July 1, 1996
Creator: Shurter, R.P.; Moir, D.C. & Devlin, D.J.
Partner: UNT Libraries Government Documents Department

Developments in accelerators for heavy ion fusion

Description: The long term goal of Heavy Ion Fusion (HIF) is the development of an accelerator with the large beam power, large beam stored-energy, and high brightness needed to implode small deuterium-tritium capsules for fusion power. While studies of an rf linac/storage ring combination as an inertial fusion driver continue in Japan and Europe, the US program in recent times has concentrated on the study of the suitability of linear induction acceleration of ions for this purpose. Novel features required include use of multiple beams, beam current amplification in the linac, and manipulation of long beam bunches with a large velocity difference between head and tail. Recent experiments with an intense bright beam of cesium ions have established that much higher currents can be transported in a long quadrupole system than was believed possible a few years ago. A proof-of-principle ion induction linac to demonstrate beam current amplification with multiple beams is at present being fabricated at LBL. 28 refs., 4 figs.
Date: May 1, 1985
Creator: Keefe, D.
Partner: UNT Libraries Government Documents Department

Magnetic switching

Description: Magnetic switching is a pulse compression technique that uses a saturable inductor (reactor) to pass pulses of energy between two capacitors. A high degree of pulse compression can be achieved in a network when several of these simple, magnetically switched circuits are connected in series. Individual inductors are designed to saturate in cascade as a pulse moves along the network. The technique is particularly useful when a single-pulse network must be very reliable or when a multi-pulse network must operate at a high pulse repetition frequency (PRF). Today, magnetic switches trigger spark gaps, sharpen the risetimes of high energy pulses, power large lasers, and drive high PRF linear induction accelerators. This paper will describe the technique of magnetic pulse compression using simple networks and design equations. A brief review of modern magnetic materials and of their role in magnetic switch design will be presented. 12 refs., 8 figs.
Date: April 14, 1989
Creator: Kirbie, H.C.
Partner: UNT Libraries Government Documents Department

Beam pipe design, wall-heating, and collective instability constraints for LAMPF II

Description: The rapidly changing magnetic fields of the LAMPF II rapid-cycling synchrotron will induce electric fields that will induce ohmic heating by wall currents in a beam pipe placed within these rapidly changing fields. A conducting beam pipe is required to remove high-frequency collective instabilities. Some compromise in design is required so that a beam pipe with low conductivity at the LAMPF II cycling frequency (f = 30 to 60 Hz) and high conductivity at high frequencies (f greater than or equal to 10 to 100 MHz) is obtained.
Date: August 1, 1984
Creator: Neuffer, D.
Partner: UNT Libraries Government Documents Department

Inductive power coupling for an electric highway system

Description: A Dual Mode Electric Transporation (DMET) system is under development in which energy is electromagnetically transferred from a powered roadway to moving vehicles. Energy from the roadway can be used for high-speed, long-range travel and for replenishing energy stored in the vehicle in batteries or flywheels. The stored energy is then available for short-range travel off the powered highway network. The power coupling between roadway and vehicle is functionally similar to a transformer. A source is embedded in the roadway flush with the surface. When the vehicle's pickup is suspended over the source, energy is magnetically coupled through the clearance air gap between pickup and roadway source. The electromagnetic coupling mechanism was extensively studied through computer models, circuit analyses, and by tests of a full-size physical prototype. The results of these tests are described.
Date: January 1, 1978
Creator: Bolger, J.G.; Kirsten, F.A. & Ng, L.S.
Partner: UNT Libraries Government Documents Department

Test of the performance and characteristics of a prototype inductive power coupling for electric highway systems

Description: Development of an inductively coupled power system for highway applications was begun in 1976. The power system was designed to provide energy to vehicles that also carry a supply of stored energy, thus providing a large measure of operational flexibility to the vehicles and reducing the necessary inventory of powered roadways. The highway power system can support the high-speed, long-range portions of driving cycles, while the stored energy can meet the requirements of driving on non-powered streets. The system thus has been referred to as a ''dual-mode'' system because of the use of the two sources of energy. The results of testing a prototype coupling are presented. No physical contact between the vehicle and the power source is required, i.e., the coupling magnetically links the power system of the vehicle to a power source in the roadway (inductive coupling). Tests were performed to determine the magnetic force and flux distribution, electrical characteristics, thermal efforts and acoustic noise. The test equipment and methods are discussed. The tests confirmed the technical feasibility of this type of non-contacting electrical power coupling, and demonstrated that its components are suited to ordinary materials and manufacturing processes. The test results were found to be consistent with expected characteristics in all important respects.
Date: July 1, 1978
Creator: Bolger, J.G.; Ng, L.S.; Green, M.I. & Wallace, R.I.
Partner: UNT Libraries Government Documents Department