摘要:

This paper describes instrumentation for automatically measuring the phase and amplitude of randomly fluctuating pulsed radio signals reflected by the ionosphere. The phase detecting system is based on the null principle of servo‐mechanics, wherein the phase difference between transmitted and received signals is considered as an error to be annulled. The equipment is designed for pulsed operation at a carrier frequency of 60 kc, pulse width of 100 &mgr;sec, and a repetition rate of 12 pulses/sec. Amplitude and phase data are presented on a dual channel pen recorder.

ISSN:0034-6748    

DOI:10.1063/1.1718032

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A goniometer for single‐crystal diffraction work, based on the use of a gimbal system, is described. The gimbal is driven by the rolling of a spherical section in frictional contact with a movable plane. The special features of the device are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1718033

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A close‐wound helix of 0.010‐in.‐diam tungsten wire has been successfully bonded into the bore of a 24‐in.‐long, 0.625‐in.‐diam glass tube by shrinking the glass over the mandrel‐supported helix. The additional problem of furnishing a nonmagnetic glass‐to‐metal seal on one end of the glass cylinder has been answered by adapting a new seal combination of molybdenum and alumino‐silicate glass in cylindrical form.

ISSN:0034-6748    

DOI:10.1063/1.1718034

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A spark chamber, containing 40 Pb plates of one‐third radiation length each, has been exposed to electron beams of energy 85 to 750 MeV. The total number of sparks in the showers and their distribution is measured. For electron energies up to 200 MeV the results agree well with Wilson's Monte Carlo calculations. Above 200 MeV poor multiple track efficiency destroys the agreement. It is concluded that such a spark chamber is a good detector for electrons, and with further development could serve as a spectrometer.

ISSN:0034-6748    

DOI:10.1063/1.1718035

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Many devices depend for their operation upon the establishment of known, uniform electric fields. Unknown contact potentials between the parts of the device often impair its performance. An apparatus has been constructed to measure the magnitude as well as the variation of such contact potentials with an accuracy of ±1 mV under conditions typical of bakeable high vacuum systems.

ISSN:0034-6748    

DOI:10.1063/1.1718036

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A bridge circuit is described in this paper which permits tracing of both theI–Vand conductance curves of tunnel diodes. To insure accuracy, a constant voltage ac source employing feedback is used for the derivative measurement. Equipment used is relatively simple and the majority of it is commercially available. The circuit also allows fixed point measurements to be made at the user's option. Reproducibility and accuracy are mainly dependent on output indicator and the parameter being measured. Equations for small errors introduced by the bridge are presented (Appendix); they can be used to determine when a measurement is subject to excessive error. Measurements at other than room temperatures may be made with the bridge by physically isolating the high frequency circuitry containing the diode from the remainder of the bridge. Representative data from the bridge are presented.

ISSN:0034-6748    

DOI:10.1063/1.1718037

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Attention is drawn to a simple method of improving the signal‐to‐noise performance ratio of photomultiplier tubes used in scintillation counting. Representative results are presented and the underlying physical principles are discussed briefly.

ISSN:0034-6748    

DOI:10.1063/1.1718038

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

Pulse echo‐type instrumentation for ultrasonic attenuation studies is described. It incorporates a commercial ultrasonic pulse generator for operation from 10 to 200 Mc, and assembled components to extend the range to 350 Mc and higher. In addition to the transmitter, receiver, and display components, it includes circuits to select and measure the echo pulse and equipment for automatic recording. Details of the circuits and of the sample holder used at 350 Mc at liquid helium temperatures are presented.

ISSN:0034-6748    

DOI:10.1063/1.1718039

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

An examination of the results of a recent international exchange of tungsten strip lamps reveals that an addition can be made to its analysis. An application of the analysis of variance to the reported data demonstrates, with high probability, the existence of differences between laboratories. It also demonstrates, with the same high probability, the existence of a scale change error in some laboratories, but not in others, at the place where one changes from the H range to the XH range on a Leeds and Northrup pyrometer. Since both sorts of differences are, thus, demonstrably greater than the precision that is available in any one laboratory, the sources of them can, presumably, be found. Procedures for doing so are suggested.

ISSN:0034-6748    

DOI:10.1063/1.1718040

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The efficiency of 10‐ to 100‐keV ions of He, Ne, and Ar in producing developed grains in nuclear track plates was determined by counting the individual grains. This efficiency is compared with the estimated range of the ions in the emulsion.

ISSN:0034-6748    

DOI:10.1063/1.1718041

出版商:AIP    

年代:1962

数据来源: AIP