摘要:

Properties of TE011cylindrical, microwave cavities containing cylindrical samples of various radii and dielectric constants are calculated. The properties considered are the resonant frequency, quality factor (Q), relevant magnetic filling factor for spin transitions (&eegr;), and a signal sensitivity factor (Q&eegr;) for a lossless sample. Sample sizes range from zero radius to full cavity radius with some experimental data on less than full length samples. The choice of dielectric constants ranges from one to sixteen. The data are presented in dimensionless form since they will be of use to other ESR experimentalists. It is shown that use of large samples is undesirable even if they are lossless. Furthermore, elongated cavities (D/Lratios less than one) are to be preferred over shortened cavities.

ISSN:0034-6748    

DOI:10.1063/1.1686258

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

An inexpensive beam current integration system is described which measures the total integrated charge in a direct current accelerator beam during electron damage or ion implantation experiments over a wide range of positive or negative beam currents used in these experiments.

ISSN:0034-6748    

DOI:10.1063/1.1686259

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A highly simplified, alternate approach to the gas chromatograph‐mass spectrometer has been developed. In this approach, a low temperature trap replaces the entire GC portion of the combined GC‐MS instrument and no carrier gas is necessary. Using the cold trap technique, the sample is first passed into a chilled trap. Depending on the trap temperature, many compounds are condensed or trapped out (most at − 196°C). Those which are not, such as helium, neon, and nitrogen, pass through the trap directly into the spectrometer for analysis. Then the trap is programmed to increase in temperature at an appropriate rate. This allows evaporation (or sublimation) of the trapped materials according to the specific vapor pressure characteristics of the compound, providing some temporal separation between constituents. These partially resolved components are directed to the MS as they evolve from the trap. The total efflux pressure changes in the ion source are analogous to the GC output, and positive identification can be performed within the limits of detection of the spectrometer. The technique has been demonstrated to have a broad application in the field of organic analysis.

ISSN:0034-6748    

DOI:10.1063/1.1686260

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

This paper presents a description of and design optimization criteria for a series resonant single coil system suitable for use in pulsed nuclear magnetic or quadrupolar resonance. The design is adaptable to the frequency range 1–100 MHz, and permits both efficient use of transmitter power and signal reception with a high signal‐to‐noise ratio. An example of the design of a system to operate at 10 MHz is worked out and compared against the ideal case. An active damping circuit to speed the recovery following an rf pulse is also discussed.

ISSN:0034-6748    

DOI:10.1063/1.1686261

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A description is given of a reliable Teflon cell with up to about ten electrical leads and a Thermocoax thermocouple for pressures up to 40 kilobars in a piston‐cylinder device. The temperature can be varied from 100 to 600 K. The cell is 12 mm i.d. and 27 mm high.

ISSN:0034-6748    

DOI:10.1063/1.1686262

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Details of a new and inexpensive technique are described for the production of thin airfoil models for aerodynamic testing. Using this technique, spanwise uniform models of arbitrary cross‐section may be fabricated with a high density of instrumentation.

ISSN:0034-6748    

DOI:10.1063/1.1686263

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Calculated flexural frequencies of right circular cylinders are presented as a function of diameter‐to‐length ratio for a Poisson's ratio of 0.333. The uniform spacing between modes observed for large length/diameter vanishes for wavelengths comparable to the diameter, with some adjacent modes changing order. Experimental verification of the results is presented.

ISSN:0034-6748    

DOI:10.1063/1.1686264

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The probability that a set of counts of particles transmitted over a measured path through a gas at a sequence of pressures can correspond to a particular value of the total cross section is calculated. From this, recipes are given for determining the best value of the cross section and of its mean square deviation, for evaluating the random and systematic errors in the cross section caused by random fluctuations in gas pressure and errors in the reading of gas pressure, and for prescribing the parameters of an experiment to achieve maximum precision in a given time of measurement.

ISSN:0034-6748    

DOI:10.1063/1.1686265

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A novel type of electron gun is described in which a spherically symmetric field is simulated. The structure is hemispherical: The inner hemisphere is a space‐charge‐limited emitter, and the outer concentric hemisphere is the anode. The hemispheres are terminated by a plane electrode with a radial potential variation designed to match the field between concentric spheres. This field is known from a new numerical solution to Poisson's equation. The energy distribution produced by the gun is measured and compared with the calculated distribution.

ISSN:0034-6748    

DOI:10.1063/1.1686266

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The physical design of a cylindrical x‐ray source, producing Al Karadiation (1486.6 eV) for use with a spherical photoelectron spectrometer, is presented. Design requirements, such as maximum efficiency and maximum intensity of characteristic radiation for minimum bremsstrahlung, are included in the presentation. The electron trajectories from filament to anode are calculated for various geometries. A brief description of the calculations, involving a numerical solution of Laplace's equation in cylindrical coordinates is given. Experimental evidence is presented to confirm the adaptation of these calculations in the design of the source.

ISSN:0034-6748    

DOI:10.1063/1.1686267

出版商:AIP    

年代:1973

数据来源: AIP