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1 Dec 1959

Volume 30, Issue 12, pp. 1849-2042

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Investigation of the Temperature Variation of Noise in Diode and Transistor Structures

C. A. Lee and G. Kaminsky

J. Appl. Phys. 30, 1849 (1959); http://dx.doi.org/10.1063/1.1735079 (7 pages) | Cited 1 time

Online Publication Date: 16 June 2004

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Measurements of the white noise of transistors (principally, diffused‐base structures) and diodes have been made at temperatures ranging from ∼77°K to 300°K for a range of about two decades in injection level, and from 10 kc to 10 Mc. Comparisons of the noise measurements with calculated levels are presented. The germanium transistors show a progressively increasing deviation from the theory as the temperature is decreased, and most of the silicon transistors exhibited excess white noise at room temperature and below.

Theory of Oscillation of a Viscoelastic Medium between Parallel Planes

George B. Thurston

J. Appl. Phys. 30, 1855 (1959); http://dx.doi.org/10.1063/1.1735080 (6 pages) | Cited 5 times

Online Publication Date: 16 June 2004

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A theoretical description of sinusoidal oscillation of an incompressible viscoelastic medium between fixed infinite parallel planes is presented. The mechanical properties of the viscoelastic medium under sinusoidal shear are expressed by a complex viscosity coefficient. The general equation for oscillatory motion of an incompressible viscoelastic medium is developed. The solution to this equation is obtained for rectilinear motion parallel to a pair of infinite planes. The equation for the velocity distribution between the planes is developed and several typical profiles are presented graphically. The equation for the acoustic impedance per unit area of plane is obtained. Functions from which the acoustic resistance and acoustic reactance may be determined are presented in graphical form for media which range from a perfect viscous fluid to a perfect elastic solid. The applicability of the theoretical results to oscillatory flow in rectangular tubes is discussed.

Characteristics of a Plasma Thermocouple

R. W. Pidd, G. M. Grover, E. W. Salmi, D. J. Roehling, and G. F. Erickson

J. Appl. Phys. 30, 1861 (1959); http://dx.doi.org/10.1063/1.1735081 (5 pages) | Cited 10 times

Online Publication Date: 16 June 2004

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The operation of a cesium plasma thermocouple is described for a range of hot‐junction temperatures from 1600°K to 2600°K and for a range of cesium pressures from 10−5 mm Hg to 2 mm Hg. Electromotive force and short‐circuit current data are presented for cells containing three different emitter substances: Ta, ZrC, and (ZrC) (UC). In the range of pressure and temperature variation studied, the observed electromotive forces are between 1 and 4.5 volts. Short‐circuit current depends markedly on the current emission properties of the hot electrode. The largest short‐circuit current density observed for the (ZrC) (UC) emitter, is 62 amperes per square centimeter.

Studies of Cold Cathode Discharges in Magnetic Fields

John Backus

J. Appl. Phys. 30, 1866 (1959); http://dx.doi.org/10.1063/1.1735082 (4 pages) | Cited 19 times

Online Publication Date: 16 June 2004

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Some experimental studies of a cold cathode discharge in a strong magnetic field are described. Current densities of the order of half an ampere per square centimeter in various gases were used. For such a discharge, the current to the cathodes is about 75% ionic. Positive ions leaving the discharge by moving across the magnetic field were observed with a mass spectrometer and showed a temperature of about 1 v. Fast electrons from the cathode escape from the discharge across the magnetic field without losing the greater part of their energy. By considering the rate of ion production it is shown that the slow electrons in the discharge have a temperature less than about three volts. Fluctuations in charge densities must play a very important role in the mechanism of the discharge.

Thermoplastic Recording

W. E. Glenn

J. Appl. Phys. 30, 1870 (1959); http://dx.doi.org/10.1063/1.1735083 (4 pages) | Cited 6 times

Online Publication Date: 16 June 2004

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A new method is described for recording electrical signals. Information is written at extremely high density by means of an electron beam on a film consisting of a low melting thermoplastic material. This can be projected as a full color image, or can be converted to an electrical signal. The tape, which is processed by quick heating, can be readily erased and reused.

Low Friction of Metals in Reciprocating Sliding

Yasukatsu Tamai

J. Appl. Phys. 30, 1874 (1959); http://dx.doi.org/10.1063/1.1735084 (2 pages)

Online Publication Date: 16 June 2004

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A very low friction, about 10−2, has been unexpectedly observed in reciprocating sliding with gold, silver, copper, and platinum. It was found that the characteristics common to those metals were soft metal substrate and no surface oxide or soft oxide. Some discussion is given on this phenomenon.

Noise Propagation on Uniformly Accelerated Multivelocity Electron Beams

W. M. Mueller and M. R. Currie

J. Appl. Phys. 30, 1876 (1959); http://dx.doi.org/10.1063/1.1735085 (5 pages) | Cited 6 times

Online Publication Date: 16 June 2004

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The characteristics of noise propagation through a multi‐velocity region with linearly increasing dc potential have been calculated using the density‐function formulation of Siegman, Watkins, and Hsieh. [J. Appl. Phys. 28, 1138 (1957)]. This type of noise transducer approximates that found experimentally in electron guns which have produced noise figures of 3 db and less at S band. It is shown that arbitrarily low values of beam noisiness can be obtained by reducing the slope of the potential profile and that adjustment of this parameter provides the practical possibility of attaining very low noise figures in slow space‐charge wave amplifiers as frequency is increased. The calculated results are compared with experimental data at S band and X band.

Propagation Characteristics of Detonation‐Generated Plasmas

Melvin A. Cook, Robert T. Keyes, and Lex L. Udy

J. Appl. Phys. 30, 1881 (1959); http://dx.doi.org/10.1063/1.1735086 (12 pages)

Online Publication Date: 16 June 2004

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Studies are presented showing the electrical properties of the highly ionized, detonation‐generated plasmas ejected into various gaseous media at the bare surfaces of high explosives. These external plasmas are shown to originate from chemionization in the reactions of high explosive at free surfaces and are not produced by thermal ionization in the shock wave propagated in the surrounding gaseous medium. The initial external‐plasma length Lp* was found to be directly proportional to the length a0 of the reaction zone of the high explosive‐generating source. Conduction measurements in plasmas propagating in chlorine, oxygen, argon, nitrogen, helium, and air showed that the electron affinity of the gaseous medium is important in determining the rate of decay of the plasma and its ultimate disintegration. The lifetime of external plasmas are substantial in media of low electron affinity, exceeding appreciably 250 μsec in such media as argon, helium, and nitrogen. Free electrons contribute practically the entire conductivity of these plasmas. Interesting pulsations occur when the external plasmas are generated by a charge of diameter smaller than the constraining tube and upon passing from a smaller into a larger constraining tube. A striking confirmation of the quasi‐lattice or metallic‐like model of plasmas is the observation that the plasma finally ``explodes'' into a gas cloud many times larger when its ion density decays to a critical low level.

Electrical Measurements on Photographic Emulsion Grains. I. Dark Conductivity

J. F. Hamilton and L. E. Brady

J. Appl. Phys. 30, 1893 (1959); http://dx.doi.org/10.1063/1.1735087 (9 pages) | Cited 25 times

Online Publication Date: 16 June 2004

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By exposing with light flashes delayed by short time intervals after the application of electric field pulses, it is possible to measure ionic conduction on large silver bromide grains from a photographic emulsion. Values of conductivity were obtained by an analysis of the transient decay of internal field pulses resulting from the application of known pulses of the external field. The internal field was measured by means of its effect in causing displacement of latent‐image centers formed by the exposure flashes. The room‐temperature ionic conductance of these grains was found to be the equivalent of about 9×10−6Ω−1 cm−1 with an activation energy of about 0.42 ev. This conductance is several powers of ten higher than that reported for large silver bromide crystals of high purity and is thought to be primarily the result of surface effects. The implications of this result in terms of modern theories of photographic latent‐image formation are discussed.

Electrical Measurements on Photographic Emulsion Grains. II. Photoelectronic Carriers

J. F. Hamilton and L. E. Brady

J. Appl. Phys. 30, 1902 (1959); http://dx.doi.org/10.1063/1.1735088 (12 pages) | Cited 11 times

Online Publication Date: 16 June 2004

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Pulses of electric field applied to silver bromide grains of a photographic emulsion at short time intervals after the application of short light flashes cause displacement of photoelectrons and holes if their lifetimes are greater than the delay interval. The asymmetry in the location of the photoproducts—microscopically visible silver and bromine or developable latent‐image specks—is an indication of the fraction of carriers free at the time the electric field is applied. As the delay interval is varied, the decay of the number of free carriers may be followed. In the emulsion system studied, the number of photoelectrons was found to decay approximately according to a 1∕(1+αt) law, falling to half the initial value in 0.25 μsec. The lack of a dependence on intensity or temperature is taken to indicate temporary trapping in a distribution of shallow traps, perhaps at the grain surface. The number of free holes decays by an exponential law, with a mean lifetime of about 15 μsec. Indications are that hole mobility is very low, owing either to temporary trapping or self‐trapping. The implications of these results in terms of modern theories of latent‐image formation are discussed.

Transmission Electron Microscopy Studies of the Mechanism of Plastic Deformation

Aurel Berghezan and Angéline Fourdeux

J. Appl. Phys. 30, 1913 (1959); http://dx.doi.org/10.1063/1.1735089 (10 pages) | Cited 10 times

Online Publication Date: 16 June 2004

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Observation of the deformation of thin aluminum specimens inside the transmission electron microscope has revealed the intimate connection between deformation and the nucleation and motion of dislocations. Nucleation, slip propagation, and the progress of deformation to the point of rupture have been observed visually on the fluorescent screen and photographed by both ``still'' and motion pucture techniques. In this way even the detailed predictions of the dislocation theory of deformation have been confirmed, and the new phenomena of grain boundaries acting as ``donors'' or ``acceptors'' of dislocations have been discovered.

Effect of Impurity Scattering on the Figure of Merit of Thermoelectric Materials

Roland W. Ure

J. Appl. Phys. 30, 1922 (1959); http://dx.doi.org/10.1063/1.1735090 (3 pages) | Cited 4 times

Online Publication Date: 16 June 2004

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The thermoelectric figure of merit z=α2∕ρκ is calculated for an extrinsic semiconductor with mixed acoustic‐mode lattice scattering and ionized‐impurity scattering. The result is compared to the value for pure acoustic‐mode scattering. As the amount of ionized‐impurity scattering is increased, the figure of merit increases by less than 10% and then falls slowly.

Optimal Accuracy Rocket Trajectories

George A. Baker, Kenneth W. Ford, and Charles E. Porter

J. Appl. Phys. 30, 1925 (1959); http://dx.doi.org/10.1063/1.1735091 (8 pages)

Online Publication Date: 16 June 2004

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The rocket optimization formulation of B.D. Fried is modified slightly to facilitate the study of maximum accuracy trajectories. Various illustrative special solutions are obtained, particularly perturbation results valid for small thrust. For surface‐to‐surface rockets in a Kepler field, optimal thrust programs are obtained numerically, their accuracy is studied quantitatively, and comparison of range and of accuracy is made with rockets using a constant‐angle thrust program. Optimization leads to only a slight increase in range but to a substantial gain in accuracy. The possible application of rocket optimization methods to the focusing of charged particles is also suggested.

Isolation of Rotational Reversal in Ferromagnetic Films

Alfred L. Hanzel and Robert L. Conger

J. Appl. Phys. 30, 1932 (1959); http://dx.doi.org/10.1063/1.1735092 (5 pages) | Cited 3 times

Online Publication Date: 16 June 2004

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Quantitative data are presented which show the relative contributions of wall motion and domain rotation to the magnetization reversal process in thin ferromagnetic films for driving fields ranging from the coercivity to many times the anisotropy field. Also, an equation for the total magnetization reversal time is developed. This expression consists of two distinct components: one represents wall motion reversal time and the other reversal time due to domain rotation. The equation is similar to one published previously but contains a more realistic and more suitable wall nucleation distribution function.

Performance of Germanium and Silicon Surface Barrier Diodes as Alpha‐Particle Spectrometers

James W. Mayer

J. Appl. Phys. 30, 1937 (1959); http://dx.doi.org/10.1063/1.1735093 (8 pages) | Cited 12 times

Online Publication Date: 16 June 2004

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The characteristics of a germanium surface barrier diode operated at room temperature make it particularly useful as an alpha‐particle spectrometer. The small size, stability, energy resolution, and relative insensitivity to β and γ radiation of the units suggest applications in medical and nuclear research. Studies were made on Au☒Ge and Au☒Si surface barriers with a barrier width (≅1 μ) less than the range of the incident alpha particles. In the germanium units, the pulse‐height response to alpha particles increased linearly with energy up to 7.5 Mev and then increased monotonically but more slowly as the energy rose to 12 Mev. In silicon the deviation from linearity occurred around 6 Mev. The observed linearity between pulse height and energy depends simply on the fact that the number of carriers excited is proportional to the particle energy and that the time for the carriers to be collected at the barrier is less than the circuit time constant. The general theory of the transient response of the diode was developed and the calculated response compared with the observed behavior. The observed values of the energy required to create a hole‐electron pair, measured over the energy range of linear response of the junction, were ϵ(Ge)=2.96±0.1 ev and ϵ(Si)=3.9±0.3 ev.

Effect of Internal Heating on the Breakdown Characteristics of Silicon p‐n Junctions

B. Senitzky and P. D. Radin

J. Appl. Phys. 30, 1945 (1959); http://dx.doi.org/10.1063/1.1735094 (6 pages) | Cited 3 times

Online Publication Date: 16 June 2004

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The breakdown characteristics of two types of silicon p‐n junctions are studied. In the first type of junction which is commonly encountered, the breakdown occurs in many localized regions, the characteristic being determined by the aggregate effect of the localized regions; in the second type of junction the geometry is such that only one localized breakdown region occurs. Whereas the simple avalanche theory can explain the onset of breakdown for both types of junctions, the shape of the V‐I curve in the breakdown region cannot be explained without the inclusion of another variable in the theory. Experimental evidence obtained by the use of pulse techniques indicates that this variable is the temperature rise due to the current flowing through the junction. It is found that this self‐heating is the most important single factor in determining the shape of the V‐I curve and that almost the entire dynamic resistance in this region is due to this effect. A method is given for determining the temperature rise of the junctions, provided that the V‐I characteristic is known.

Some Experiments on the Dynamics of Liquid Films

W. E. Ranz

J. Appl. Phys. 30, 1950 (1959); http://dx.doi.org/10.1063/1.1735095 (6 pages) | Cited 31 times

Online Publication Date: 16 June 2004

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Experiments and theory are described concerning the rupture of soap films and the continuous formation, by impinging jets, of quasi‐stationary liquid sheets.

Theoretical Approach to the Asymmetrical Magnetization Curve

A. Aharoni, E. H. Frei, and S. Shtrikman

J. Appl. Phys. 30, 1956 (1959); http://dx.doi.org/10.1063/1.1735096 (6 pages) | Cited 45 times

Online Publication Date: 16 June 2004

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The method previously used to calculate the magnetization curve of an infinite cylinder is applied to the new Meiklejohn and Bean material which is made of Co particles in a CoO shell. It is assumed that the interface of the ferromagnetic and antiferromagnetic materials is held parallel to the cylindrical axis and does not change its direction for any value of the applied field. The crystal anisotropy is neglected.
It is shown that the easiest nucleation mode for small radii is buckling and for large radii is curling. The transition from buckling to curling is at about RIsA−☒=2, where R is the radius of the cylinder, Is is the saturation magnetization and A is the exchange constant.
Numerical solution of the nonlinear equations involved, yields two branches in the magnetization curve, which are both stable with respect to curling perturbations. The general stability is not tested.
A similar calculation is carried out for an infinite slab with the spins on the surface held at a fixed direction and with the crystal anisotropy neglected.

Note on the Saturation of the Main Resonance in Ferromagnetics

H. Suhl

J. Appl. Phys. 30, 1961 (1959); http://dx.doi.org/10.1063/1.1735097 (4 pages) | Cited 29 times

Online Publication Date: 16 June 2004

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The course of χ″ at resonance versus applied power is traced for various ratios of intrinsic to scattering line widths. It is assumed that the line width contribution from thermal spin‐wave agitation is negligible.

Absorption Correction in Precision Determination of Lattice Parameters

M. E. Straumanis

J. Appl. Phys. 30, 1965 (1959); http://dx.doi.org/10.1063/1.1735098 (5 pages) | Cited 12 times

Online Publication Date: 16 June 2004

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X‐ray powder and rotation patterns of six cubic substances (W, Si, Cr, TiO, Al, and V) using specimens of different thickness were made; the patterns were measured, the lattice constants calculated and plotted against the θ angle or against the Nelson and Riley function. Such curves for thin mounts, semitransparent to x‐rays (below 0.2 mm in diam), consist of two parts: a region of high slope (due to absorption) and one approaching a zero slope at high Bragg angles. The latter, varying in extent with the size and nature of the mount, indicates that due to the rapid decrease in absorption, the lines in this region are shifted, little if any, from their correct positions. Hence, lattice constants calculated from the reflections of the high θ angles lying on the horizontal portion of the curve need not be corrected for absorption. The constant, with negligible error, can be calculated from a single last strong α1 or β reflection. If an extrapolation is applied, the curve must be traced through points in the high back reflection region. Otherwise any extrapolation, disregarding the horizontal part, would lead to lattice constants too high in value. The amount of line displacement due to absorption in thin samples (below 0.2 mm in diam) agrees with the geometrical concept of Hadding and Buerger.

Effect of Fission Recoil Fragments on the Thermal Conductivity of Graphite

L. P. Hunter

J. Appl. Phys. 30, 1969 (1959); http://dx.doi.org/10.1063/1.1735099 (7 pages)

Online Publication Date: 16 June 2004

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The variation of the thermal conductivity of uranium‐impregnated graphite is measured continuously while under neutron irradiation. The temperature is continuously monitored and results are reported which show the effects of the uranium oxide particle size as well as the effect of the neutron bombardment as separated from the fission recoil bombardment.

Eddy‐Current Method for Measuring the Resistivity of Metals

C. P. Bean, R. W. DeBlois, and L. B. Nesbitt

J. Appl. Phys. 30, 1976 (1959); http://dx.doi.org/10.1063/1.1735100 (5 pages) | Cited 305 times

Online Publication Date: 16 June 2004

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A method for measuring the resistivity of metallic specimens is described. The measurement is made by noting the rate of decay of flux from a bar situated in an external magnetic field that has been rapidly reduce to zero. The method is suitable for specimens greater than 5×10−3 cm in diameter. For a specimen 1 cm in diameter, resistivities from 10−11 to 10−3 ohm‐cm may be measured with an error of less than three percent. The method requires no contact to the specimen, and local values of resistivity may be measured. Several applications are described.

Heat Treatment Centers and Bulk Currents in Silicon p‐n Junctions

D. J. Sandiford

J. Appl. Phys. 30, 1981 (1959); http://dx.doi.org/10.1063/1.1735101 (6 pages) | Cited 6 times

Online Publication Date: 16 June 2004

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A set of small‐area, alloy, p‐n junction diodes was made from a slice of heat‐treated n‐type silicon. The carrier lifetimes of the diodes were found to be in the range of 2.5×10−8 sec to 3.5×10−6 sec. Measurements were made of the lifetime and of the current‐voltage characteristics in the forward and reverse directions as a function of temperature from room temperature to 165°C. An analysis of the results and, in particular, the correlation of current flow with lifetime values, showed that for the diodes with the shortest lifetimes, centers situated 0.48 ev at 0°K from either the conduction or valence bands were responsible for large space‐charge currents. For the diodes with lifetimes in the microsecond range, surface leakage currents were predominant. Evidence was found of a field‐dependent emission probability, β, for these centers. The results showed that β∼E0.35 when E, the electric field, is in the range of 2×104 to 8×104 v∕cm.

Measurement Broadening in Magnetic Resonance

Orlo E. Myers and Eugene J. Putzer

J. Appl. Phys. 30, 1987 (1959); http://dx.doi.org/10.1063/1.1735102 (5 pages) | Cited 28 times

Online Publication Date: 16 June 2004

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Phase‐detection techniques used in recording magnetic resonances are the source of a measurement broadening. Results of a general mathematical treatment for arbitrary line shape and of machine computation for a Lorentz line shape lead to a series of curves which may be used to correct observed widths under circumstances where the Lorentz shape may be verified and effects of finite modulation frequency may be ignored.

Temperature Diffuse Scattering of X‐Rays in Cubic Powders. I. Comparison of Theory with Experiment

David R. Chipman and Arthur Paskin

J. Appl. Phys. 30, 1992 (1959); http://dx.doi.org/10.1063/1.1735103 (6 pages) | Cited 32 times

Online Publication Date: 16 June 2004

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Temperature diffuse scattering of x‐rays (TDS) has been examined in cubic powders to test the reliability of current TDS theory. Measurements are reported of the diffuse scattering of copper and lead along with the Bragg reflections of these metals at room and liquid nitrogen temperatures. These measurements were made using a scintillation counter diffractometer and crystal monochromated CuKα radiation. The TDS so otained is compared with TDS calculations based on the one‐ and two‐phonon calculation as well as on the Warren (modified one‐phonon) calculation. Both formulas are found to fit the magnitude of TDS by choosing appropriate Debye characteristic temperatures. The Debye Θ's which fit the copper and lead TDS data at room temperature are: 324° and 96° (one‐ and two‐phonon) and 269° and 64° (Warren formula) as compared to values of 307° and 79° taken from the temperature dependence of the Bragg reflections and 315° and 88° from specific heat values for copper and lead, respectively. Evidence is also found for extra diffuse scattering in the low‐angle region. This extra scattering is tentatively ascribed to a multiple scattering process.
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