摘要:

A magnetic comparator for measuring the thickness of high conductivity, ferromagnetic films is described. The instrument compares the reluctance of a standard sample to that of a film of unknown thickness at the same value of magnetic field intensity to insure that the permeability is the same for both. The comparator utilizes an ac Hartshorn, mutual‐inductance bridge configuration and is designed to operate at low frequency and low magnetic field intensity to maximize the skin depth &dgr; and thus the measurable film thickness. The output of the comparator is linear in thickness for films less than &dgr;/2 and is capable of measuring films of thickness greater than &dgr; with some reduction in accuracy. The effects of the skin depth and magnetic properties of the film on the accuracy of the comparator are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1136228

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

With a hot plate and a spherical mirror, a highly efficient crucible heating furnace was theoretically calculated and constructed. The upper part of the crucible provides free access to the melt, as is needed in the Czochralski crystal growth technique. For the design, the heat radiation flow between the hot plate, a cylindrical crucible, and the enclosing ellipsoidal mirror was computed. The calculated temperature profiles on the crucible, for different values of the crucible diameter and the eccentricity of the ellipsoid are shown and a comparison is made with the constructed oven. Using a cylindrical crucible (od=5 cm, height=5 cm), the power consumption is 720 W during the growth of NaCl (≈800 °C).

ISSN:0034-6748    

DOI:10.1063/1.1136229

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A high pressure apparatus for determining PVT data of liquids and plastic crystals and volume changes which might accompany phase transitions is described. In the present investigation the PVT data of acetonitrile have been determined from +40° to −50 °C and up to 3000 bar, including the volume changes due to the melting and to a solid–solid transition. The procedure for calibrating this apparatus is discussed. The accuracy of the PVT data is supposed to be better than 0.1%, both for the liquid and the solid state.

ISSN:0034-6748    

DOI:10.1063/1.1136230

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A Kaufman‐type broad beam ion source, used for sputtering and etching purposes, has been operated with Ar, Kr, O2and N2gas inputs over a wide range of beam energies (200–1200 eV) and gas flow rates (1–10 sccm). The maximum ion beam current density for each gas saturates at about 2.5 mA/cm2as gas flow is increased. The discharge threshold voltage necessary to produce a beam and the beam efficiency (beam current/molecular current), however, varied considerably. Kr had the lowest threshold and highest efficiency, Ar next, then N2and O2. The ion beam current varied only weakly with beam energy for low gas flow rates, but showed a factor of two increase when the gas flow was higher.

ISSN:0034-6748    

DOI:10.1063/1.1136231

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A modified heat pipe employing Hg as the working fluid and utilizing gravity to return the liquid Hg from the condensative to the evaporative zone is described. This device provides an easy and rapid means of producing a fixed density of Hg atoms of high purity for any test cell configuration without employing elaborate Hg distillation techniques. Densities from 1016to 1020/cm3can be easily acquired with a variable inert gas density.

ISSN:0034-6748    

DOI:10.1063/1.1136232

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A low‐cost 8‐bit microcomputer interfaced with a sampling oscilloscope yields a versatile <0.35 ns rise time digital boxcar integrator. Firmware provides signal averaging, oscilloscope display of one or two transients, baseline stripping and restoration,X−Yplotting, tape punching and listing of data, and BASIC language data reduction.

ISSN:0034-6748    

DOI:10.1063/1.1136233

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A simple technique is described for constructing a plane guarded electrode which has a very small gap between electrode and guard ring.

ISSN:0034-6748    

DOI:10.1063/1.1136234

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A thyratron Pockels cell driver capable of optically switching Pockels cells of up to 2.5 cm aperture in 6 ns at repetition rates of up to 1000 Hz is described. The circuit is based on a modified HY‐2 thyratron.

ISSN:0034-6748    

DOI:10.1063/1.1136235

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A new quenching technique of the melt is described. By using this, it is possible to make uniform, flat and thin films. Cooling rate is fast enough to quench Bi2O3into an amorphous solid, which had been impossible by the gun technique.

ISSN:0034-6748    

DOI:10.1063/1.1136236

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Equipment has been developed to electromechanically polish metal spheres. Mechanical polishing is accomplished by the action of three cup‐shaped laps which rotate against the sphere. An abrasive slurry containing an electrolyte is continuously applied to the sphere and laps. Electrochemical etching is accomplished by applying a positive potential to two of the laps and a negative potential to the third.

ISSN:0034-6748    

DOI:10.1063/1.1136253

出版商:AIP    

年代:1980

数据来源: AIP