摘要:

We have constructed a capillary ion source using the surface ionization of lithium on rhenium. Currents of 400 &mgr;A during 300 h, or 100 &mgr;A during 1000 h, can be obtained; the life span of the source is only limited by the capacity of the lithium reservoir.

ISSN:0034-6748    

DOI:10.1063/1.1684608

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

An improved design for a catalytic hydrogenation converter which can convert up to 5 liters·atm of CO2to methane with negligible losses is described. A palladium alloy hydrogen diffusion cell is used for selective removal of excess hydrogen after completion of the reaction. This innovation in purification technique permits quantitative methane recovery over a wide range of sample sizes and significantly reduces the number of man‐hours required to process a sample.

ISSN:0034-6748    

DOI:10.1063/1.1684609

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

In this paper a new method is described for the generation of monodisperse ultrafine aerosols using a transpiration cooled graphite anode in a high intensity arc operated in argon at atmospheric pressure. Electric current and transpirant mass flow rates are identified as decisive parameters for observed particle size distributions. The results indicate the potential and flexibility of this new method for generating well controlled monodisperse ultrafine aerosols.

ISSN:0034-6748    

DOI:10.1063/1.1684610

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Attention is drawn to the use of phase locking of two oscillators for the measurement of transient magnetic or dielectric changes of samples placed in a resonator. Improvements in speed and sensitivity are possible over other methods. A specific design for operation at 10 MHz is given for the measurement of magnetic susceptibility changes at low temperatures. As an example of the results obtained, the magnetic canting transition of KMnF3near 82 K is shown.

ISSN:0034-6748    

DOI:10.1063/1.1684611

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A simple method of pulsing constricted electric arcs to high power inputs is described. Using this method, peak power inputs six times greater than can be run continuously have been achieved. An analysis of this method has been made for argon to determine the maximum temperature to be expected as a function of arc channel diameter and generator construction material. In addition, a number of methods used for electric and spectroscopic diagnostic studies of the pulsed high current arc column are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1684612

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A molecular beam velocity selector is reported in which the beam passes diametrically across a rotating slotted disk. Alignment is checked without reference to assumptions about the source velocity distribution. The selector is compact, easily constructed, and is mounted directly on the driving motor shaft.

ISSN:0034-6748    

DOI:10.1063/1.1684613

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A wall stabilized arc is described which incorporates new design features in order to increase the versatility of this source for quantitative spectroscopic measurements, extending its useful range to lower pressures and to the study of molecular gases. Spectral measurements of different arc portions can be made radially and compared with measurements along the arc axis. It was thus established that in end‐on measurements of argon arcs an essentially homogeneous plasma is viewed by the spectrometer.

ISSN:0034-6748    

DOI:10.1063/1.1684614

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Precision etching of semiconductor wafers without continuous monitoring is not possible due to the variability of etch rate with time during etching, and due to the dependence of etch rate upon temperature, age, and rate of stirring of the etchant. Therefore, a method has been developed whereby the thickness of semiconductor wafers can be continuously measured to submicron precision during etching. Accuratein situmonitoring of wafer thickness is accomplished through the use of internal reflection interferometry. Experimental results indicate that a precision of 0.1 &mgr; is routinely achieved in gallium arsenide and silicon wafers with the interferometer source a 3.39 &mgr; wavelength helium‐neon laser. Infrared absorption data show that most semiconductors of current interest are sufficiently transparent at this wavelength to allow a wide variety of application of the technique.

ISSN:0034-6748    

DOI:10.1063/1.1684615

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A field ion micrograph approximately resembles a stereographic projection of a hemispherical tip. By a second imaging through an objective with a strong barrel type distortion (fish eye lens) one can obtain orthographic and gnomonic projections as well as perspective images of the hemispherical metal crystal. The method can be extended to generate stereoscopic pictures of the tip surface for 3‐D viewing.

ISSN:0034-6748    

DOI:10.1063/1.1684616

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A novel method of measuring the depth of ultrathin deep slots in metal surfaces is presented. This method is a noncontacting nondestructive application of microwave theory and practice involving the degeneration of higher cylindrical eigenmodes to the fundamental mode. Theoretical and experimental considerations show a proportionality between the detected signal and the length‐depth product. This method complements other procedures for measuring the depth of slots and cracks and provides a new and unique technique for measurement of very thin slots and cracks.

ISSN:0034-6748    

DOI:10.1063/1.1684617

出版商:AIP    

年代:1970

数据来源: AIP