GHz as an rf stimulus, applies these signals to the levice under test, measures their characteristics, mathematically manipulates the data if necessary and butputs the data. The data output is available as a abulation on a teletype or high-speed printer, a plot or diagram on an electrostatic plotter, or may be viewed as polar or rectangular plots on an oscilloscope. The measured data is in complex form and may be reflection coefficient, impedance, renormalzed impedance, VSWR, attenuation, gain, or phase angle for passive quantities. Data output is in watts, volts, or fractional (decimal) parts thereof for active quantities. The connector types for connection to the automatic network analyzer may be in coaxial type such as APC-7, GR-900, type "N" male or female, and in all the waveguide sizes used in the above frequency range. These capabilities can be adjusted for either normal laboratory precision or for high accuracy standards and calibration type measurements. The NBS add-on system for high accuracy measurements and calibrations is presently undergoing evaluation. Applications: The automatic network analyzer is intended for design, measurement, and calibration of rf and microwave components such as terminations, attenuators, thermistor mounts, crystal detectors, FIM receivers, antennas, filters, amplifiers, transistors, etc. As described previously these may be of coaxial or waveguide type usage devices. Availability: To any qualified NBS research worker, after an initial training period with supervisor. In appropriate instances individual research workers from other Federal organizations can gain access to the facility. Contact: W. E. Little, Program Chief, Automatic Network Analyzer Applications, Radio Building, Room 4633, NBS Boulder, Colo. 80302, Phone 303-499-1000 ext. 3658. ELECTRO-OPTICAL FIELD MAPPING SYSTEMS State-of-the-art electrical and electro-optical measurement techniques are employed for measurement of high voltages, and for observation and probeless fringe-pattern mapping of high-intensity electric fields in insulating dielectrics. Apparatus allows operation under microsecond pulsed, and either steadystate direct or alternating voltages. Unique advantages afforded by the recently developed NBS electro-optical systems include their freedom from electro magnetic interference errors and their provision for direct visual observations (analogous to those used conventionally in photoelastic studies of mechanical stress) of electrical stress distributions. Capability, Operating Ranges, and Accuracy: 1) Pulsed Operation: peak voltages from 20 to 300 kV, risetimes of 0.5 to 2.0μs with durations up to 10μs, repetition rates to 4 pulses per minute, measurement accuracy within +1%. 2) DC Operation: from 0 to 100 kV, measurement accuracy 0.01%. 3) AC Operation: from 0 to 50 kV rms, from 40 to 200 Hz, measurement accuracy to 0.01%. Programs are available for automatic reduction and analysis of data, using NBS computer facility. Applications: For calibration of HV pulse-measuring devices; for design studies with visualization of both steady-state and dynamic electrical stress distributions in selected insulating dielectrics; for visualization of the effects of space charge, suspended particles, dissolved ionic impurities and electrode composition, polish and geometry on electrical conduction in selected insulating liquids; for mapping of electric field distribution around immersed solid insulator models; for measurement of Kerr electro-optical coefficients of liquids; for dynamic and steady-state electrical breakdown studies in selected dielectrics; etc. Availability: To qualified U.S. research workers from industry, government, and academic communities in cooperation with NBS supervisor. Scheduling is required to avoid conflict with in-house NBS research, calibration and testing programs. Literature: [1] NBS Tech. News Bull., Sept. 1972, Vol. 56, pp. 207-209. [2] Rev. Sci. Instr., June 1972, Vol. 43, pp. 886 893. [3] J. Res. NBS, Vol. 73C, pp. 5-13, Jan.-June 1969. Contact: Oskars Petersons, Chief, High Voltage Measurements Section, Metrology Building, Room B344, Phone 301-921-3121. NON-MAGNETIC FACILITY The non-magnetic building is located on an isolated area of the bureau grounds, in the center of a 600-ft square buffer zone. The building is a three-story structure (ground level plus two stories) constructed of non-magnetic materials and contains a minimum amount of electrically conducting materials. The building contains four isolation piers, one serving the ground floor and three serving the second floor level. A service building 300 ft from the non-magnetic building provides the general laboratory equipment and support. Experiments in the non-magnetic building can be controlled and monitored from the service building. 1 Capability: Typical earth's magnetic field gradients are 10 nT m-1 in the vertical direction and 3 nT⚫m-1 in the horizontal direction. Three-dimensional Helmholtz coils are available for cancelling the earth's magnetic field. Variations in the earth's field can be reduced by servo-ing to a magnetometer system in the magnetometer station located nearby. A precision solenoid is available to provide a magnetic field of 1.2 X 10-T which is uniform within a 4-cm diameter sphere and accurate to about 0.5 ppm in terms of the NBS electrical standards. Equipment for automation and data acquisition is available. Applications: The facilities of the non-magnetic building provide an environment where accurately known uniform magnetic fields can be applied to an experiment or where the earth's magnetic field strength and variations can be reduced a known amount. Currently the gyromagnetic ratio of the proton and the absolute ampere experiments are housed there. Availability: The facility is available, when neither of the above two experiments are in active operation, for a compatible experiment which will not compromise the non-magnetic environment. Literature: [1] R. L. Driscoll and P. T. Olsen, The Review of [3] B. N. Taylor, D. N. Langenberg, and W. H. Contact: Dr. E. R. Williams, Absolute Electrical Meas- REACTANCE BRIDGE FOR POWER LOSS A typical high voltage inductor or shunt reactor or power transmission line has a reactive power rang of 100 megavolt-amperes and a power loss of abo 220 kilowatts. Thus the power losses are of econom significance, but it is difficult if not impossible: measure them by conventional wattmeter methoc because of the low power factor, i.e. the presence very large reactive or circulating power. The shur reactors are used to "tune out" the capacitances transmission lines. A reactance bridge has been de veloped and constructed which in conjunction w readily available high-voltage standard capacitors car measure accurately such losses. Inductance and capac itance can also be measured. The instrument is de signed for measurement of devices rated at moderat to extra high voltages-several hundred volts to on megavolt. Capability: The instrument can be used at either the NBS or a commercially available high voltage labora tory. The voltage and power ranges depend princ pally on the capability of the power supply in the laboratory-for the NBS laboratory these are 220 200 kVA. Some commercial laboratories have capa bilities of the order of 1 MV and 100 MVA. When used in conjunction with a typical high voltage stand ard capacitor having a capacitance value of 100 of the inductance range of the specimen is from 0.12 H to 600 H; the range for capacitors is from 100 pf 50μF. The power losses can be measured to about one-percent accuracy; the inductance and capac tance to about 0.01 percent to 0.1 percent accuracy Applications: Primarily power loss measurements of large capacitors and inductors such as energy storage and power factor correction capacitors, high voltage shunt reactors (inductors); also impedance measure ments of the same. Availability: To any qualified NBS research worker or The use of the instrument is also available to outside Contact: Oskars Petersons, Chief of High Voltag tion using dendrites of aluminum-tungsten; identification of material in micrometeoritic lunar craters; distinguishing chrysotile from termolite; qualitative chemical analysis of microscopic particles; effect of polishing on dental materials; rusting through pinholes in enameled steel; bonding and defects in microcircuitry wafers; hydrogel coating on aortic catheters; wear of currency papers; sharpness of tungsten field-emitter tip. Availability: To any qualified NBS research worker, after an initial training period. Over 30 NBS scientists have become competent operators. In appropriate instances individual research workers from other Federal organizations can gain access to the facility. Literature: NBS Tech. News Bull., March 1972, Vol. 56, No. 3, pages 60-63. Contact: Dr. Arthur W. Ruff, Jr., Chief of Lattice Defects and Microstructures Section, Materials Building, Room B118, Phone 301-921-2991. Photomicrograph of a stainless steel powder, magnified 600 times. The large depth of focus of the SCANNING ELECTRON MICROSCOPE is demonstrated in this photomicrograph. SCANNING ELECTRON With resolution and depth of focus well beyond that of optical microscopes, this device uses a fine electron-beam probe to explore the minutiae of surface structure of materials such as lunar rocks, bridge structure fractures, microelectronic circuits, and dental restorations. For rough specimens, stereo-pair photography permits three-dimensional examination. Selected area electron channelling patterns can be obtained, and divergent-beam x-ray (Kossel) patterns can be prepared for use in determining local stressstrain configurations. Capability: Replica or actual specimen up to 2.5 cm diameter and 1 cm thick. Resolution of 25nm, and maximum magnification of 100,000x. Electron beam of about 10 nm (100Å) diameter is driven across specimen, while secondary electrons, backscattered electrons, and x-rays are each detected and amplified to modify the brightness of a CRT raster. A data acquisition system and data reduction programs are avail able. Applications: Behavior of grain boundaries in embrittled copper-palladium welds; checking of resolu TRANSMISSION ELECTRON MICROSCOPE, 200 kV This instrument allows high resolution examination of surface replicas and actual, thin-foil specimens of metals, ceramics, and polymers. Analysis of microstructure and lattice defects in crystalline materials can be made by electron diffraction contrast and selected area electron diffraction. Compared to conventional transmission electron microscopes (100 kV), specimens which are 70% thicker can be examined. This facilitates specimen preparation, increases foil rigidity, and reduces surface effects. Capability: Accelerating voltages of 50, 100, 150, and 200 kV. Selected area electron diffraction and electromagnetic beam tilting (±3°) for dark field imaging. Side entry goniometer stage with: double-tilt (X = +60°, Y±45°), rotation (360°)-tilt (60°), and heating (to 1000° C)-tilt specimen holders for specimens up to 3.05 mm in diameter. Resolution (line) of 0.7 nm (7 A) and maximum magnification of 150,000x. Data recorded on 34 X 4 inch glass photographic plates. Applications: Examination of the surface regions of various ceramic materials after abrasive and smoothsliding wear; analysis of deformation and fracture mechanisms in ceramics as a function of temperature; analysis of cracks and crack healing processes in ceramics; microstructure characterization of mented carbides; determination of stacking fault ce structure (ground level plus two stories) constructed! of non-magnetic materials and contains a minimum amount of electrically conducting materials. The building contains four isolation piers, one serving the ground floor and three serving the second floor level. A service building 300 ft from the non-magnetic building provides the general laboratory equipment! and support. Experiments in the non-magnetic building can be controlled and monitored from the service building. Capability: Typical earth's magnetic field gradients are 10 nT-m-1 in the vertical direction and 3 nT⚫m-1 in the horizontal direction. Three-dimensional Helmholtz coils are available for cancelling the earth's magnetic field. Variations in the earth's field can be reduced by servo-ing to a magnetometer system in the magnetometer station located nearby. A precision solenoid is available to provide a magnetic field of 1.2 X 10 T which is uniform within a 4-cm diameter sphere and accurate to about 0.5 ppm in terms of the NBS electrical standards. Equipment for automation and data acquisition is available. Applications: The facilities of the non-magnetic building provide an environment where accurately known uniform magnetic fields can be applied to an experiment or where the earth's magnetic field strength and variations can be reduced a known amount. Currently the gyromagnetic ratio of the proton and the absolute ampere experiments are housed there. Availability: The facility is available, when neither of the above two experiments are in active operation, for a compatible experiment which will not compromise the non-magnetic environment. Literature: [1] R. L. Driscoll and P. T. Olsen, The Review of [3] B. N. Taylor, D. N. Langenberg, and W. H. Contact: Dr. E. R. Williams, Absolute Electrical Meas- REACTANCE BRIDGE A typical high voltage inductor or shunt reactor or power transmission line has a reactive power rat of 100 megavolt-amperes and a power loss of abe 220 kilowatts. Thus the power losses are of econom significance, but it is difficult if not impossible": measure them by conventional wattmeter method because of the low power factor, i.e. the presence: very large reactive or circulating power. The sh reactors are used to "tune out" the capacitances transmission lines. A reactance bridge has been de veloped and constructed which in conjunction readily available high-voltage standard capacitors ca measure accurately such losses. Inductance and capa itance can also be measured. The instrument is de signed for measurement of devices rated at modera | to extra high voltages-several hundred volts to on megavolt. Capability: The instrument can be used at either the NBS or a commercially available high voltage labora tory. The voltage and power ranges depend princ pally on the capability of the power supply in th laboratory-for the NBS laboratory these are 220 M 200 kVA. Some commercial laboratories have capa bilities of the order of 1 MV and 100 MVA. When used in conjunction with a typical high voltage stars ard capacitor having a capacitance value of 100 the inductance range of the specimen is from 0.12 to 600 H; the range for capacitors is from 100 pf " 50μF. The power losses can be measured to abou one-percent accuracy; the inductance and capac tance to about 0.01 percent to 0.1 percent accuran Applications: Primarily power loss measurements 5 large capacitors and inductors such as energy storaz and power factor correction capacitors, high volta shunt reactors (inductors); also impedance measure ments of the same. Availability: To any qualified NBS research worker The use of the instrument is also available to outside Contact: Oskars Petersons, Chief of High Voltag With resolution and depth of focus well bevorTIC PE Capability: Replica or actual specme Applications: Behavior o ...G.. |