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Aug 1985

Volume 56, Issue 8, pp. 1505-1670

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Status of the multiply charged heavy‐ion source MINIMAFIOS

R. Geller, B. Jacquot, and M. Pontonnier

Rev. Sci. Instrum. 56, 1505 (1985); http://dx.doi.org/10.1063/1.1138145 (6 pages) | Cited 17 times

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The principles, construction, and performance of the MINIMAFIOS electron cyclotron resonance ion source (ECRIS) are reviewed. The source can operate either pulsed, with pulse width of >50 ms, or cw, with 1011 fully stripped light ions per second and much higher amounts of lower charge state ions. The source has excellent reliability and reproducibility. It has acceptable emittance and energy dispersion. The manner of operation and adjustment of the source is very simple since it depends only on the two parameters: gas feed and rf power injected. In addition, metallic ions can be produced directly. ECRIS is well suited for injection into heavy ion accelerators and for atomic physics. Its high ion fluxes in a quasicontinuous regime are useful for numerous other applications and open new fields for scientific research with multiply charged ions. Thus, more and better sources are desired. New ideas have been proposed and new sources have been built or are under construction. We present the latest performance data of MINIMAFIOS for gaseous elements as a reference for evaluating the performance of new ECRIS in various laboratories. For metallic ions we need more experimental results in order to establish basic data references.
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29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative

Experimental performance of a microwave cavity plasma disk ion source

Joseph Root and Jes Asmussen

Rev. Sci. Instrum. 56, 1511 (1985); http://dx.doi.org/10.1063/1.1138146 (9 pages) | Cited 18 times

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The detailed description and performance characteristics of a microwave ion source are presented. This ion source utilizes an internally tuned, single‐mode (or selective multimode) cylindrical cavity applicator to focus and match microwave energy into a disk‐shaped discharge zone. The combination of mode focus control and variable, internal cavity matching allows the efficient operation and beam extraction over a wide range of pressures, powers and gaseous inputs. Experimental measurements of ion beam current versus accelerating voltage and input microwave power in xenon and oxygen gas are presented. Ion source specific energy and mass utilization versus experimental variables are also determined. The experimental performance demonstrates the ability of this ion source to extract an ion beam with a well matched, stable, and continuous operation over a wide range of input gases, low pressures, and over input gas flow rates in excess of 100 to a few sccm. Double Langmuir probe measurements in xenon gas indicate high degrees of ionization, and electron and ion concentrations in excess of 100 critical densities in the microwave discharge zone. This ion source has many potential uses such as spacecraft electric propulsion, material ion beam processing, and neutral beam ion sources.
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29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative
52.50.Dg Plasma sources

Electron impact heated atomic hydrogen oven

G. A. Glass, L. H. Andersen, S. B. Elston, Peter Engar, R. Holmes, J.‐P. Rozet, D. A. Taylor, R. S. Thoe, S. D. Berry, M. Breinig, and I. A. Sellin

Rev. Sci. Instrum. 56, 1520 (1985); http://dx.doi.org/10.1063/1.1138147 (6 pages)

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The design, construction, and performance of an electron impact heated hydrogen dissociation oven for use in producing an atomic hydrogen gas target for ion–atom collision experiments are described. This novel design utilizes an electron beam focused by a spherical lens system to heat the oven to temperatures in excess of 2400 K. High dissociation fractions are found with cell pressures ≥5 mTorr. The compact design allows placement of an electron spectrometer close to the interaction region (length ∼1.5 cm), as well as direct measurement of the oven temperature by means of an optical pyrometer. The electron beam produces magnetic fields ∼40 mG ∼1 cm from the center of the interaction region. These low magnetic fields offer distinct advantages compared to low‐voltage, high‐current oven designs when observing relatively low‐energy electrons ejected in ion–atom collisions.
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07.20.Hy Furnaces; heaters
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques

Compact, inexpensive target design for steady‐state heat removal in high‐heat‐flux fusion applications

S. K. Combs, S. L. Milora, C. A. Foster, H. H. Haselton, M. M. Menon, and C. C. Tsai

Rev. Sci. Instrum. 56, 1526 (1985); http://dx.doi.org/10.1063/1.1138148 (5 pages)

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A high‐heat‐flux target has been developed for intercepting multimegawatt, multisecond neutral beams at Oak Ridge National Laboratory (ORNL). Water‐cooled copper swirl tubes are used for the heat transfer medium; these tubes exhibit an enhancement in burnout heat flux over conventional axial flow tubes. The target consists of 126 swirl tubes [each 0.95 cm in outside diameter (o.d.) with 0.16‐cm‐thick walls and ≊1 m long] arranged in a V shape and inclined with respect to the beam axis. In tests with the ORNL long‐pulse ion source (13×43‐cm grid), the target has handled up to 3‐MW, 30‐s beam pulses with no deleterious effects. The peak power density was estimated at ≊15 kW/cm2 normal to the beam axis (>5 kW/cm2 maximum on tube surfaces). The water flow rate through the tubes was 0.33 l/s (5.2 gal/min) per tube (axial flow velocity=11.6 m/s) with a corresponding pressure drop of 1.14 MPa (165 psi). To date, the target has absorbed an estimated 25 000 full‐power (≊3 MW) pulses for a cumulative time of ≊100 000 beam seconds without failure. Other potential applications for swirl tube technology in the fusion area include plasma limiters, divertor collector plates, rf launchers, and Faraday shields.
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52.50.Gj Plasma heating by particle beams
44.30.+v Heat flow in porous media
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Cylinder radioactive source for slow‐positron beams

R. S. Brusa, R. Grisenti, S. Oss, A. Zecca, and A. Dupasquier

Rev. Sci. Instrum. 56, 1531 (1985); http://dx.doi.org/10.1063/1.1138149 (3 pages) | Cited 6 times

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The geometrical efficiency is calculated for a radioactive source‐moderator assembly, which is often used for the production of slow‐positron beams, and comparisons are made between a cylinder source, touching the circumference of the moderator, and a spot source, facing the center of the moderator. It is shown that higher beam intensity and brightness can be obtained with the cylinder source in most practical situations.
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29.25.Rm Sources of radioactive nuclei
07.77.-n Atomic, molecular, and charged-particle sources and detectors
29.27.-a Beams in particle accelerators

Compact magnetic electron energy analyzer

R. F. Schneider, C. M. Luo, M. J. Rhee, and J. R. Smith

Rev. Sci. Instrum. 56, 1534 (1985); http://dx.doi.org/10.1063/1.1138520 (3 pages) | Cited 5 times

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A compact magnetic energy analyzer designed for the measurement of electron energies in the range from 20 keV through 1.5 MeV is described. The simple device, based on the semicircular focusing principle, is constructed from a high induction permanent magnet enclosed in a soft iron case. The design and operation of the analyzer in pulsed electron beam devices are discussed.
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29.27.Eg Beam handling; beam transport
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
41.75.Fr Electron and positron beams

Two‐channel, elliptical analyzer spectrograph for absolute, time‐resolving time‐integrating spectrometry of pulsed x‐ray sources in the 100–10 000‐eV region

B. L. Henke and P. A. Jaanimagi

Rev. Sci. Instrum. 56, 1537 (1985); http://dx.doi.org/10.1063/1.1138150 (16 pages) | Cited 48 times

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A new spectrographic system has been developed and calibrated in this laboratory for the absolute spectrometry of high‐intensity pulsed x‐ray sources in the 100–10 000‐eV region. This spectral region is analyzed with fixed elliptically curved crystals and molecular or sputtered‐or‐evaporated multilayers of 2d values in the 3–160‐A range. Twin channels are utilized for simultaneous time‐integrated photographic recording and for time‐resolved x‐ray streak camera recording. Absolute calibrations of the elliptical analyzers, of the photographic film, and of the gold and CsI transmission photocathodes have been made using monoenergetic, cw laboratory x‐ray sources. The overall transmission characteristics of the spectrograph have also been determined. The instrument has been designed for mounting through a pneumatically controlled high‐vacuum valve onto a 4‐in. port of a 1‐m‐diameter source chamber and includes an appendage, high‐vacuum, sputter‐ion prepumping station. The initial dynamic testing and application of this new spectrographic system has been on the University of Rochester’s LLE 24 laser beam OMEGA source facility.
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52.70.La X-ray and γ-ray measurements
07.85.-m X- and γ-ray instruments

Microchannel‐plate intensified crystal spectrometer for use in soft x‐ray spectroscopy

C. J. Hailey, P. Rockett, M. Eckart, and P. G. Burkhalter

Rev. Sci. Instrum. 56, 1553 (1985); http://dx.doi.org/10.1063/1.1138151 (4 pages) | Cited 8 times

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A Bragg crystal spectrometer, utilizing a microchannel plate coupled to optical film as the detection medium, has been constructed for use in soft x‐ray spectroscopy. The sensitivity of this intensified gated camera to x‐rays has been compared directly with standard x‐ray film using a calibrated x‐ray source. In addition, this high gain, intensified crystal spectrograph (ICS) has been used in an experiment to precisely measure spectral coincidences between x‐ray lines in laser‐generated plasmas, thus identifying candidates for photoresonant x‐ray lasing schemes in the 10–21‐Å region. At long wavelengths the ICS was able to obtain useful data on faint lines in a single laser shot, rather than the multiple shots required by an adjacent spectrograph using x‐ray film. It also allowed line coincidences to be verified by a new technique utilizing split disk targets. The design and construction of the ICS and results obtained with it are compared with those obtained with standard x‐ray film.
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52.70.La X-ray and γ-ray measurements
07.85.-m X- and γ-ray instruments

Retarding‐field differential‐output energy prefilter for high‐performance secondary ion mass spectrometry

Patrick M. Thompson, James W. Taylor, and Ronald E. Negri

Rev. Sci. Instrum. 56, 1557 (1985); http://dx.doi.org/10.1063/1.1138152 (7 pages) | Cited 2 times

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A retarding‐field differential‐output energy prefilter has been optically matched to a quadrupole mass spectrometer to produce a high‐performance secondary ion quadrupole mass spectrometer. The sample area was designed to be field free to allow for sample charge compensation and to prevent secondary ion trajectories from being affected by electric fields. Design considerations for optically matching the energy prefilter to the quadrupole mass filter (QMF) are discussed. The overall transmission of the instrument was 1.8×10−4 at a mass resolution of 100 M/ΔM (1–100 amu range) for copper and 1.7×10−5 at a mass resolution of 400 M/ΔM (10–250 amu range) for tungsten.
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07.75.+h Mass spectrometers

Device to cryofracture cultured cells for ion microscopy

Mark T. Bernius, Subhash Chandra, and George H. Morrison

Rev. Sci. Instrum. 56, 1564 (1985); http://dx.doi.org/10.1063/1.1138153 (4 pages)

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A cryofracture device has been developed for freeze‐cleaving cultured cells grown on a polished substrate wafer. The fracture is made under liquid nitrogen and results in specimens suitable for ion microscopic analysis to reveal the intracellular elemental distribution. In performing this operation the nutrient media is also removed, precluding any need of prewashing the specimen and introducing any contamination or loss in subcellular ion concentrations. The design and performance of this device are described.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
06.60.Ei Sample preparation (including design of sample holders)
06.60.Sx Positioning and alignment; manipulating, remote handling
87.80.-y Biophysical techniques (research methods)

Ultralow‐load hardness tester for use in a scanning electron microscope

H. Bangert and A. Wagendristel

Rev. Sci. Instrum. 56, 1568 (1985); http://dx.doi.org/10.1063/1.1138154 (5 pages) | Cited 7 times

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A new ultramicrohardness tester for a load range between 2×10−2 and 5×10−5 N is described. The instrument is operated inside a scanning electron microscope. Load is applied and measured by means of electrical signals thus making fully automized experiments possible. Typical examples demonstrate the capability of the device and the general problem associated with ultra‐low‐load hardness testing. With experiments on thin films the complex situation for testing layered structures is shown and suggestions for a proper evaluation are given.
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07.10.-h Mechanical instruments and equipment
68.60.-p Physical properties of thin films, nonelectronic
46.55.+d Tribology and mechanical contacts
07.78.+s Electron, positron, and ion microscopes; electron diffractometers

High‐stability scanning tunneling microscope

G. F. A. van de Walle, J. W. Gerritsen, H. van Kempen, and P. Wyder

Rev. Sci. Instrum. 56, 1573 (1985); http://dx.doi.org/10.1063/1.1138155 (4 pages) | Cited 35 times

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We have constructed a scanning tunneling microscope for operation under UHV conditions (10−8 Pa). With this instrument topographic measurements can be made on metal and semiconductor surfaces by means of a scanning tip electrode, driven by piezoelectric ceramic elements. The maximum area covered ranges up to 4000×4000 Å2 with a resolution better than 10 Å laterally and 0.15 Å rms perpendicular to the plane. Because of its compact design, the scan unit is very insensitive to vibrations and has a response time down to 0.3 ms. This allows a high scan rate to be used. In order to minimize temperature effects, special attention is paid to the geometry of the construction and the materials used, resulting in a drift ≤4 Å/min along the surface and 0.5 Å/min perpendicular.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
73.40.Gk Tunneling

Millimeter‐wave detection of free radicals using pulsed laser photolysis

W. F. Kolbe and B. Leskovar

Rev. Sci. Instrum. 56, 1577 (1985); http://dx.doi.org/10.1063/1.1138156 (5 pages) | Cited 3 times

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The application of millimeter‐wave microwave spectroscopy to the detection of free radicals and other species generated by pulsed excimer laser photolysis is described. To detect the radical species, a newly developed 140‐GHz microwave spectrometer employing a high‐Q Fabry–Perot cavity was used. The technique is illustrated by the observation of SO and CS radicals produced by photodissociation at 193 nm of SO2 and CS2, respectively. SO absorption signals from the ground vibrational state transition at 138.17 GHz and the first and second excited vibrational state transitions at 137.28 and 136.45 GHz were measured. CS was detected in several excited vibrational states up to ν=4. Finally, as an example of the application of the technique to chemical kinetic studies, the reaction rate of SO with NO2 was determined. The measured rate coefficient at 298 K of (1.46±0.12)×10−11 cm3 molecule−1 s−1 is in excellent agreement with values reported in other studies. Millimeter‐wave spectroscopy is shown to be a sensitive and highly specific probe for the detection of short lived species in gas phase chemical kinetic studies.
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82.80.Dx Analytical methods involving electronic spectroscopy
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods
82.20.Pm Rate constants, reaction cross sections, and activation energies

Rapidly tuned frequency stabilized CO2 laser

C. J. Walsh and N. Brown

Rev. Sci. Instrum. 56, 1582 (1985); http://dx.doi.org/10.1063/1.1138521 (4 pages) | Cited 2 times

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A cw CO2 laser capable of tuning through a preselected number of rotational lines is described. The use of a line‐center servo lock technique allows rapid tuning and high‐frequency stability to be achieved.
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42.60.By Design of specific laser systems
42.55.Lt Gas lasers including excimer and metal-vapor lasers

Coaxial electrical pulse shaper for picosecond electronics

W. Margulis and R. Persson

Rev. Sci. Instrum. 56, 1586 (1985); http://dx.doi.org/10.1063/1.1138157 (3 pages) | Cited 5 times

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A miniature coaxial passive picosecond electric pulse shaper (PEPS) is described. The component is small and rugged, has high‐voltage capability, is compatible with 50‐Ω microwave and high‐speed electronics, and is of simple construction. Its performance has been tested in the shaping of pulses as short as <30 ps, and its uses include microwave pulse generation, high‐speed modulation, and picosecond electronic differentiation.
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84.30.Sk Pulse and digital circuits
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
29.50.+v Computer interfaces

Versatile infrared cell for in situ transmission IR studies of heterogeneous catalysts

Robert Mark Friedman and Harry C. Dannhardt

Rev. Sci. Instrum. 56, 1589 (1985); http://dx.doi.org/10.1063/1.1138158 (4 pages) | Cited 2 times

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An infrared cell is described that allows catalytic materials to be investigated by conventional transmission measurements at temperatures ranging from −196 to 600 °C over the spectral region from 10 to 6000 cm−1 using silicon windows and over any desirable spectral range using easily replaceable windows of choice. The sample environment can span vacuum to supra‐atmospheric pressure. The thermal response of the cell is rapid, allowing it to be used for temperature programmed desorption studies along with the spectral examination of the catalyst. The sample can be in the form of a self‐supporting wafer located at the center of the cell body and requiring the gas stream to pass through it. This configuration allows the cell to be used as a differential microreactor. The gas path length is short and the volume is small in order to minimize the spectral background from the ambient gas environment and to allow easy and rapid change of its composition.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
82.80.Dx Analytical methods involving electronic spectroscopy
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

FTIR sample cell thermal lag calibration using phase transitions in three molecular solids

L. M. Casson and R. H. Herber

Rev. Sci. Instrum. 56, 1593 (1985); http://dx.doi.org/10.1063/1.1138159 (4 pages) | Cited 2 times

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The temperature dependence of four characteristic infrared absorptions accompanying phase transitions in three molecular solids have been used as ‘‘infrared thermometers’’ to estimate the thermal lag of KBr pellets held in an Invar sample cell in a Fourier transform infrared spectrometer at (variable) cryogenic temperatures. Due to the low power deposition on the sample in a typical FTIR spectrometer, thermal lags of less than 0.5 K can be routinely achieved at temperatures in the range 77≤T≤300 K.
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07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
07.20.-n Thermal instruments and apparatus
78.30.-j Infrared and Raman spectra
64.70.-p Specific phase transitions

High‐temperature Mössbauer‐effect measurements with a precision furnace

B. Kolk, A. Bleloch, D. B. Hall, Y. Zheng, and K. E. Patton‐Hall

Rev. Sci. Instrum. 56, 1597 (1985); http://dx.doi.org/10.1063/1.1138160 (7 pages) | Cited 5 times

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A furnace system is presented for Mössbauer‐effect spectroscopy at temperatures up to 1200 K with a temperature stability better than 0.03 K. This system allows the study of samples at high temperatures in an external magnetic field of a few kG with a homogeneity of better than 1%. Our measurements show that a few degrees above the Curie temperature TC, such an external field induces a considerable hyperfine field at 57Fe nuclei in iron. In addition, the magnetic hyperfine field and the isomer shift of 57Fe in metallic iron are measured over a temperature range of 300 to 1100 K. It is shown that a relatively small nonlinear behavior of the Mössbauer velocity drive system may result in a pseudodiscontinuity in the isomer shift δ near the Curie temperature, explaining the anomalous behavior observed for δ of iron and of some iron alloys in this region.
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07.20.Hy Furnaces; heaters
07.85.-m X- and γ-ray instruments
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques

Polarization interferometer for angular measurements

P. Niay, P. Bernage, and J. J. Ledee

Rev. Sci. Instrum. 56, 1604 (1985); http://dx.doi.org/10.1063/1.1138161 (4 pages) | Cited 1 time

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A new interferometric system measuring change of birefringence through anisotropic crystals induced by change in the direction of an expanded laser beam has been developed in order to measure small angular displacements of an external mirror. In a low‐cost version of the apparatus, pitch and yaw measurements were simultaneously performed with 0.1‐arc s sensitivity, 20‐Hz bandwidth, and a measuring range ±600 arc s at a working distance of 1 m. The major advantages of this interferometer are that it is fast, easy to use, and convenient to drive a servomechanism, locking the X‐Y angular position of a target moving in the Z direction.
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07.60.Ly Interferometers
78.20.Fm Birefringence
42.62.-b Laser applications

A goniometer using a continuously rotating grating

T. H. Barnes

Rev. Sci. Instrum. 56, 1608 (1985); http://dx.doi.org/10.1063/1.1138109 (4 pages) | Cited 2 times

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Goniometers incorporating continuously rotating gratings offer great potential for high‐accuracy angular measurement. Simple mathematical relations describing the limitations of this type of instrument are presented together with results showing 6 arc s accuracy from an experimental model.
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07.10.-h Mechanical instruments and equipment
42.79.Dj Gratings

Microwave interferometer for shock wave, detonation, and material motion measurements

Gene H. McCall, Wayne L. Bongianni, and Gilbert A. Miranda

Rev. Sci. Instrum. 56, 1612 (1985); http://dx.doi.org/10.1063/1.1138110 (7 pages) | Cited 5 times

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A microwave interferometer system which provides a continuous measurement of the position of interfaces, such as shock fronts, detonation fronts, or material surfaces, has been developed. The use of low‐mass microcoaxial cable, some of which is commercially available, and stripline for conducting the microwave signal into the interior of an experiment makes the perturbation of the measuring system on the experiment small. Other microwave systems have measured the time of peak amplitude of a reflected signal, but the present system with proper matching produces a continuous record of position as a function of time. It is believed that this technique can be used to replace most uses of electrical contact or fiber‐optic pins in high‐explosive experiments. The amount of data far exceeds that which it is possible to obtain from pins or optical fibers. The matching of the microcoax to the microwave generator has an important effect on the accuracy of the technique. The effect of matching on accuracy will be described in detail, and matching methods will be discussed. A position accuracy of 0.2 mm has been attained. Several methods for extracting position information as a function of time are possible. These techniques are discussed, and their application to the analysis of an experiment is demonstrated. The data from the interferometer system is compared to a streak camera record in a phased, shock‐breakout experiment. Agreement is quite good, and the superiority of this method over the pin method is demonstrated by comparing details of the streak and interferometer records.
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07.60.Ly Interferometers
84.40.Az Waveguides, transmission lines, striplines
62.50.-p High-pressure effects in solids and liquids

Semiautomated method for the determination of density profiles from Mach–Zehnder interferograms

Hai‐Tao Chen and Walter H. Christiansen

Rev. Sci. Instrum. 56, 1619 (1985); http://dx.doi.org/10.1063/1.1138111 (4 pages) | Cited 1 time

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The determination of a density field by means of digital imaging of a Mach–Zehnder interferogram and processing by a microcomputer is described. The apparatus used in this study are an optical single‐bit digitizer, a microcomputer, and a dot matrix printer. Photographs of the interferograms are semiautomatically digitized by the apparatus. The fringe count and the spatial locations of the fringes are calculated using basic programs, and the density field is plotted as an output.
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07.60.Ly Interferometers
07.05.Hd Data acquisition: hardware and software
07.05.Kf Data analysis: algorithms and implementation; data management
07.05.Rm Data presentation and visualization: algorithms and implementation
07.05.Bx Computer systems: hardware, operating systems, computer languages, and utilities
42.30.Va Image forming and processing

Automatic recording of direct current singularity amplitudes in Josephson junctions

G. Costabile, U. Gambardella, and S. Pagano

Rev. Sci. Instrum. 56, 1623 (1985); http://dx.doi.org/10.1063/1.1138112 (3 pages) | Cited 2 times

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We have designed and tested an electronic circuit to record the amplitude of any current singularity in the current‐voltage characteristic of a Josephson tunnel junction. The detection of the peak current occurs only when the junction voltage is within a range that can be centered and narrowed conveniently. We describe the circuit in detail and illustrate its operation in the recording of some typical dc singularities.
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85.25.-j Superconducting devices
84.30.-r Electronic circuits

On the magnetic field of rectangular coils

A. Briguet and J. Chankji

Rev. Sci. Instrum. 56, 1626 (1985); http://dx.doi.org/10.1063/1.1138113 (6 pages) | Cited 2 times

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A derivation of the magnetic field, created by rectangular single‐turn coils, is achieved with the aid of magnetic scalar potential. The transformation properties of spherical harmonics under rotation permit one to analyze the magnetic field of a system of several coils. Application to a four, rectangular coil system, generating a magnetic field gradient, leads to the optimal dimensions of each element of the system: h=1.732, b=2.486, when a=1 and β=45°, where a represents the half‐width of the rectangle, b its half‐length, h the distance between the origin of the reference frame and the center of each coil, and β is the angle between the directions of the normals to the planes of two neighboring coils.
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85.70.-w Magnetic devices
41.20.Gz Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems
07.55.-w Magnetic instruments and components

New specimen design for studying the growth of small fatigue cracks with surface acoustic waves

Blair London

Rev. Sci. Instrum. 56, 1632 (1985); http://dx.doi.org/10.1063/1.1138114 (3 pages) | Cited 1 time

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The study of small surface fatigue cracks in AISI 4140 quenched and tempered steel by a nondestructive surface acoustic wave technique is summarized. A novel cantilevered bending, plate‐type fatigue specimen is described that is compatible with the acoustic method. Small cracks are initiated from a 25‐μm deep surface pit produced by an electrospark machine. The importance of studying these cracks which closely approximate naturally occurring fatigue cracks is briefly discussed.
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62.20.M- Structural failure of materials
46.80.+j Measurement methods and techniques in continuum mechanics of solids
43.35.Zc Use of ultrasonics in nondestructive testing, industrial processes, and industrial products
43.35.-c Ultrasonics, quantum acoustics, and physical effects of sound
72.50.+b Acoustoelectric effects
73.50.Rb Acoustoelectric and magnetoacoustic effects
77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
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