Showing papers in "Journal of Physics E: Scientific Instruments in 1973"
TL;DR: In this paper, a fringe system is obtained showing contours of constant slope resolved in the direction of image displacement, which is a comparison with result obtained by holographic interferometry.
Abstract: The surface to be studied is illuminated with laser light and two images are formed, displaced relative to one another in the image. Speckle pattern interferometry is used to measure phase changes between the two images resulting from deformation of the surface. A fringe system is obtained showing contours of constant slope resolved in the direction of image displacement. A comparison is made with result obtained by holographic interferometry.
298 citations
TL;DR: In this paper, a general account of both the electrical and the mechanical aspects of the design of capacitative transducers and their associated electronic circuitry suitable for observing displacements of the order 10-2 to 10-11 mm.
Abstract: A general account is given of both the electrical and the mechanical aspects of the design of capacitative transducers and their associated electronic circuitry suitable for observing displacements of the order 10-2 to 10-11 mm. The lower figure is the order of magnitude of noise and drift averaged over a second, the drift over a day of the order 10-8 to 10-9 mm. Their application is illustrated by descriptions of an apparatus to explore the limits of performance, a moderately sensitive micrometer, and two geophysical instruments, a tiltmeter and a gravimeter. Full details of a general purpose electronic system are given.
160 citations
TL;DR: In this article, two micrometeoroid experiments based on the plasma emission caused by impacting hypervelocity dust particles are described, and the aim of these experiments is to measure the mass and speed of micrometers and to determine their approximate orbital elements.
Abstract: Two micrometeoroid experiments based on the plasma emission caused by impacting hypervelocity dust particles are described. Since 31 January 1972 the first has been flying on the HEOS 2 satellite orbiting the earth in a highly eccentric polar orbit. The second experiment will be flown in 1974 on the HELIOS probe which will orbit the sun with a perihelion of about 0.3 AU. The aim of these experiments is to measure the mass and speed of micrometeoroids and to determine their approximate orbital elements.
132 citations
TL;DR: In this paper, the thickness of a rapidly moving, wavy film of water can be continuously measured and recorded using a probe, which consists of two surface-mounted parallel conductors across which a high frequency AC signal is applied.
Abstract: The thickness of a rapidly moving, wavy film of water can be continuously measured and recorded using a probe, which consists of two surface-mounted parallel conductors across which a high frequency AC signal is applied. A theory is given which allows prediction of the electrical conductance of the probe as a function of the film thickness and shows how the useful range of particular probe designs can be assessed. The theory, which can be applied to probes in either flat or curved surfaces, also includes the effect of a step change in the film thickness, so that the resolution of the probe may be predicted.
129 citations
TL;DR: In this paper, a photogrammetric technique is described, which allows simple and accurate measurements of surface microgeometry with a scanning electron microscope, and simple working formulae are obtained with a proper choice of the reference axes.
Abstract: A photogrammetric technique is described, which allows simple and accurate measurements of surface microgeometry with a scanning electron microscope. Simple working formulae are obtained with a proper choice of the reference axes. The error evaluation is performed for an elementary case.
102 citations
TL;DR: In this article, a method for producing microneedles on field anodes was described, where field pyrolysis of benzonitrile causes the growth of these needles at a temperature of about 1200 degrees C. The needles prove to be resistant to chemical attack as well as thermal and mechanical stress.
Abstract: A method is described for producing microneedles on field anodes. Field pyrolysis of benzonitrile causes the growth of these needles at a temperature of about 1200 degrees C. They yield optimal emission qualities for field-ionization and -desorption mass spectrometry. The needles prove to be resistant to chemical attack as well as thermal and mechanical stress.
93 citations
TL;DR: In this paper, the theory of a beam modulation technique, hitherto not used in time-of-flight mass spectrometry, is presented, which is independent of the location where the ions are initially formed and proportional to the square of the length of the drift space.
Abstract: The theory of a beam modulation technique, hitherto not used in time-of-flight mass spectrometry, is presented. Salient features of this technique are: firstly, resolution is independent of mass; secondly, resolution is independent of the location where the ions are initially formed; and thirdly, resolution is proportional to the square of the length of the drift space.
87 citations
TL;DR: In this article, the use of diffraction gratings as beamsplitters in an oblique incidence interferometer and the application of that interferometers to measuring the flatness of non-optical surfaces was demonstrated.
Abstract: This paper demonstrates the use of transmitting diffraction gratings as beamsplitters in an oblique incidence interferometer and the application of that interferometer to measuring the flatness of non-optical surfaces. Many different surfaces have been examined, ranging from lapped granite and steel to unworked metal and processed photographic emulsions. The fringe interval in the interferograms is independent of the illuminating wavelength, being one half of the diffraction grating periodicity, which in the interferometer described is 5 mu m. It is also demonstrated that the topography of large surface areas may be evaluated by the combinations of interferograms.
55 citations
TL;DR: In this article, a review is given covering the retarding field and electrostatic deflection energy analyser types, since these are the most suitable for use with both ions and electrons.
Abstract: A review is given covering the retarding field and electrostatic deflection energy analyser types, since these are the most suitable for use with both ions and electrons. Deflection analysers are considered for various field configurations; the main lines of development are discussed, including a guide to the numerous recent publications dealing with their design and performance.
51 citations
TL;DR: In this paper, a procedure for calculating background over the whole spectrum for measurements at 2.96 keV (Ar K alpha) and 9.87 keV(Ge K alpha ) is described.
Abstract: The rather broad peaks obtained with a Si(Li) detector often necessitate extrapolation of background over a considerable energy range. In many samples no background readings free of interference from peaks can be obtained below 2.7 keV. A procedure for calculating background over the whole spectrum for measurements at 2.96 keV (Ar K alpha ) and 9.87 keV (Ge K alpha ) is described. For samples consisting of elements below 30 in atomic number the background correction can be determined with an error not exceeding an equivalent concentration of 0.1 wt %.
50 citations
TL;DR: The use of calorimeters for measuring laser output energies and powers is broadly reviewed as mentioned in this paper, including disc, cone, hollow-sphere, bolometer, volume absorption, and partial absorption types.
Abstract: The use of calorimeters for measuring laser output energies and powers is broadly reviewed. Instruments are categorized as disc, cone, hollow-sphere, bolometer, volume-absorption, and partial absorption types.
TL;DR: In this article, the use of a limacon reference line for roundness measuring instruments has been discussed and a general expression which enables reference lines to be fitted to components having partial arcs or discontinuous circumferences very often met with in industry.
Abstract: Many methods of measuring the out-of-roundness of nominally circular components or holes have been based, for convenience, upon some form of graphical assessment in which the inspector uses a pair of compasses, a rule and a good measure of subjective judgement. This has changed in recent years with the introduction of methods which can be implemented in an analogue or digital form and which are based normally on a best-fit circle rather than on zonal methods. The author justifies the use of a limacon reference line for roundness measuring instruments and goes on to develop a general expression which enables reference lines to be fitted to components having partial arcs or discontinuous circumferences very often met with in industry. It therefore allows for the first time the meaningful objective assessment of the out-of-roundness or roughness of such parts.
TL;DR: In this article, the authors used thin-walled coils made of dense, ductile material to generate magnetic fields in the range 100-200 T with an inner diameter between 25 and 10 mm.
Abstract: Magnetic fields in the range 100-200 T are generated in lightweight coils with an inner diameter between 25 and 10 mm The rise time to peak field is 2 mu s Special design features of the 20 kV, 55 kJ capacitor bank facilitate the application to experiments Thin-walled coils made of dense, ductile material give superior performance in this field range
TL;DR: In this article, the theory and outline of the basic instrument and modifications which have been employed to increase the sensitivity of the method are described and an indication is given of the application to thickness measurement and optical constants for absorbing and non absorbing media.
Abstract: Ellipsometry is a technique which is suitable for the examination of thin films of materials and surface layers. The paper gives the theory and outline of the basic instrument and the modifications which have been employed to increase the sensitivity of the method. An indication is given of the application to thickness measurement and optical constants for absorbing and nonabsorbing media.
TL;DR: In this article, two hot wires are kept at different but constant temperatures by Joule heating, and the difference between the squared voltages across two wires can give information concerning the velocity of an air flow.
Abstract: If two hot wires are kept at different but constant temperatures by Joule heating, the difference between the squared voltages across two wires can give information concerning the velocity of an air flow. The electronic circuit and operating procedure for this are simple. With this technique velocity fluctuations up to 300 Hz have been successfully decoupled from temperature fluctuations in a heated wake. The limitation on the frequency is due to spatial inhomogeneity of the flow field.
TL;DR: In this article, a set-up for measurement of the deposition rate of transparent matrix materials typically used in matrix isolation spectroscopy is described, where the main features consist in measurement of intensity of interference fringes produced by the growing matrix layer on the light of a small laser by a simple power meter.
Abstract: A set-up is reported for measurement of the deposition rate of transparent matrix materials typically used in matrix isolation spectroscopy. Its main features consist in measurement of intensity of interference fringes produced by the growing matrix layer on the light of a small laser by a simple power meter. A typical example for an Ar matrix is shown.
TL;DR: An electrostatic probe with spatial resolution of 50 mu m has been developed to study the potential variation along a surface as mentioned in this paper, which yields a precision of 20 mV for a single pass, and a study of clean metal surfaces contaminated by fingerprints has shown surface potential variations as large as 400 mV.
Abstract: An electrostatic probe with spatial resolution of 50 mu m has been developed to study the potential variation along a surface. A turntable arrangement enables surfaces to be scanned at rates of 1.8-16 m s-1; the probe yields a precision of 20 mV for a single pass. Calibration of the instrument using a test grating is described. A study of clean metal surfaces contaminated by fingerprints has shown surface potential variations as large as 400 mV.
TL;DR: In this article, the 127I2 saturated absorption features used to stabilize the 633 nm He-Ne laser were measured with uncertainties approaching 10 kHz by a digital beat frequency method, using lasers locked to the absorption features by a third harmonic technique and having stabilities of 10 kHz ( delta nu / nu =2*10-11) for a 10 second observation time.
Abstract: Frequency separations have been measured of some of the 127I2 saturated absorption features used to stabilize the 633 nm He-Ne laser. The frequencies are measured with uncertainties approaching 10 kHz by a digital beat frequency method, using lasers locked to the absorption features by a third harmonic technique and having stabilities of 10 kHz ( delta nu / nu =2*10-11) for a 10 second observation time. Wavelength measurements are made on a laser locked to the 'd' absorption feature, using a krypton-86 lamp in conjunction with a scanning Fabry-Perot interferometer. The value lambda vac is 632991178.3 fm with a statistical uncertainty of +or-0.8 fm ( delta lambda / lambda =+or-1.2*10-9).
TL;DR: In this paper, a hot torsion testing machine was developed to simulate deformation schedules encountered in practical hot working operations such as rolling or forging, with a high speed clutch-brake system and a digital programmer.
Abstract: A versatile hot torsion testing machine has been developed to simulate deformation schedules encountered in practical hot working operations such as rolling or forging. Programmed deformation for strain rates covering seven orders of magnitude can be carried out. Two particular features of the machine are a high speed clutch-brake system and a digital programmer. The clutch is capable of accelerating the sample from 0 to 3000 rev min-1 in 2 ms. The programmer is capable of up to 60 steps, 10 output functions and time ranges from 1 ms to 105 s.
TL;DR: In this paper, the authors consider features of the design and development of stabilized laser and discuss the specification of frequency stability and reproducibility in terms of the Allan variance, particularly with visible lasers.
Abstract: This review considers features of the design and development of stabilized lasers and discusses the specification of frequency stability and reproducibility in terms of the Allan variance. The more important stabilization schemes which have recently been employed, particularly with visible lasers, are discussed. The saturated absorption stabilized laser, which has achieved a frequency stability and reproducibility of better than one part in 1010, is described, and finally both contemporary and future applications are discussed.
TL;DR: In this paper, the solid fat content of partially crystallized fats was measured using a digital voltmeter, with a standard deviation of 0.6% for a dilatometer-based approach.
Abstract: Pulse nuclear magnetic resonance is a good alternative to the slow, laborious dilatometer technique for determining the solid/ liquid ratio in partially crystallized fats and has some advantages over wide-line NMR. A processing unit is described which has the advantage that it displays directly the solid fat content on a digital voltmeter. Accepting a standard deviation of 0.6%, as is the case with the dilatometer technique, the solid fat content can be measured in 4 s.
TL;DR: In this article, a parallel plate X-ray proportional counter with position sensitive anode is described, which is capable of resolving 0.2 mm in the soft Xray region over a circular area a few centimetres across, while retaining good energy resolution.
Abstract: A parallel plate X-ray proportional counter with position sensitive anode is described. It is capable of resolving 0.2 mm in the soft X-ray region over a circular area a few centimetres across, while retaining good energy resolution.
TL;DR: In this article, a new technology for producing large volume microwave plasmas is introduced, Microwave energy is coupled into the plasma by means of a slow wave structure, and plasma volumes well in excess of 1000 cm3 can readily be achieved with 2.5 kW of microwave power at 2.45 GHz.
Abstract: A new technology for producing large volume microwave plasmas is introduced, Microwave energy is coupled into the plasma by means of a slow wave structure, and plasma volumes well in excess of 1000 cm3 can readily be achieved with 2.5 kW of microwave power at 2.45 GHz. General operating characteristics and some experimental data are presented.
TL;DR: In this article, a sample holder for Hall effect and sheet resistivity measurements and for anodic oxidation of silicon has been developed, which uses a Teflon edge instead of a rubber or Viton seal for defining the area to be stripped.
Abstract: A versatile sample holder for Hall effect and sheet resistivity measurements and for anodic oxidation of silicon has been developed. The main feature of the design is the use of a Teflon edge instead of a rubber or Viton seal for defining the area to be stripped. In this way very good sealing is obtained and severe problems in obtaining well defined etching areas are overcome. It is possible to etch areas from 1.25 mm diameter to 2 mm diameter with constant depth scale. Hall and sheet resistivity measurements can be performed without removing the sample from the holder.
TL;DR: In this article, the design and construction of two sets of coils providing orthogonal gradients are outlined, and their measured performance is shown, and applications and limitations to 'pulsed' diffusion experiments are discussed.
Abstract: Measurement of diffusion constants using NMR usually requires the generation of a large, known, linear magnetic field gradient. The design and construction of two sets of coils providing orthogonal gradients are outlined. Their measured performance is shown, and applications and limitations to 'pulsed' diffusion experiments are discussed.
TL;DR: In this paper, a system is described in which a quadrupole ion storage trap has been employed as the source for a quad-rupole mass filter, and a number of possible modes of operation have been examined and results are presented which compare storage characteristics and mass spectra obtained with established literature data.
Abstract: A system is described in which a quadrupole ion storage trap has been employed as the source for a quadrupole mass filter. A number of possible modes of operation have been examined and results are presented which compare the storage characteristics and mass spectra obtained with established literature data. Some potential areas of application are outlined and the results from a study of ion-molecule reactions in methane included as an example.
TL;DR: The sensitivity of a grazing incidence grating spectrograph has been derived from measurements of the absolute efficiency of the diffracting element, a Bausch and Lomb catalogue grating, and of the response of the recording emulsion, Ilford Q2 and Kodak Kodirex.
Abstract: The sensitivity of a grazing incidence grating spectrograph has been derived from measurements of the absolute efficiency of the diffracting element, a Bausch and Lomb catalogue grating, and of the response of the recording emulsion, Ilford Q2 and Kodak Kodirex. Results are presented for wavelengths between 8 and 44 AA, obtained as K-line emissions from electron-bombarded targets, incident on the grating at an angle of 88 degrees .
TL;DR: In this article, an electron spectrometer with essentially constant transmission characteristics in the energy range up to 200 eV was presented. But the performance of the spectrometers was limited to the (2s22p) 2P and 2s2p2) 2D resonances in the 21S and 21P inelastic channels.
Abstract: Details are given of an electron spectrometer possessing essentially constant transmission characteristics in the energy range up to 200 eV. As examples of its application, results are presented for resonant differential elastic scattering in He and for the (2s22p) 2P and (2s2p2) 2D resonances in the 21S and 21P inelastic channels, also in He.
TL;DR: In this article, a study of two RTC type B 419 BL channeltrons used as electron detectors is presented, in which the incident flux on the multiplier is precisely defined, permitting measurement of the absolute electron detection efficiency in the energy range 20 to 900 eV.
Abstract: A study of two RTC type B 419 BL channeltrons used as electron detectors is presented. An original apparatus in which the incident flux on the multiplier is precisely defined, permitted measurement of the absolute electron detection efficiency in the energy range 20 to 900 eV. The probable error is estimated to be 5%. The large disagreement between the various published efficiency is discussed.
TL;DR: In this paper, the method of free molecular evaporation has been applied in a modified form to enable construction of a simple apparatus for measuring rate of change of vapour pressure with temperature.
Abstract: The method of free molecular evaporation has been applied in a modified form to enable construction of a simple apparatus for measuring rate of change of vapour pressure with temperature. The design used introduces considerable restriction to free molecular flow and produces low apparent vapour pressures. These can, however, be corrected to yield the proper static values if the evaporation coefficient is known. The apparatus has been tested with anthracene, benzoic acid and naphthalene. Naphthalene has given spurious results because of self-cooling due to rapid sublimation.