摘要:

An apparatus is described for the recording of electrical signals of frequencies below 100 cycles per second on magnetic tape for subsequent playback. A system of wide deviation frequency modulation of an audio frequency carrier has been employed to eliminate the difficulties normally encountered in the direct recording of low frequency and d.c. signals.

ISSN:0034-6748    

DOI:10.1063/1.1745455

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An apparatus capable of continuously measuring and recording electret strength is described. It consists of a mechanically driven condenser whose induced voltage, due to the electric field of the electret, is filtered and amplified before being applied to a recorder. Some experimental observations of the transition from heterocharge to homocharge are presented.

ISSN:0034-6748    

DOI:10.1063/1.1745456

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The percent beta‐ray transmission by thin Nylon and Formvar films (windows) was studied to obtain experimental ``absorption'' corrections to be used with G‐M counters employing such thin windows. It was found that window ``absorption'' included (1) energy loss of electrons traversing the films and (2) scattering of incident electrons by the film (a geometry effect). The results are plotted in several ways to exhibit the various factors involved and to permit easy use in applying the corrections. It was found that scattering of transmitted electrons was a factor of considerable importance, whereas the energy lost in traversing the film was not very important for the range investigated. The electron energy range investigated was limited to the region in which the ``absorption'' correction was considerable for the window thicknesses used. A scintillation counter was used as the detector, and the source of monoenergetic electrons was an electron gun with electrostatic focusing.

ISSN:0034-6748    

DOI:10.1063/1.1745457

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A description is given of a laboratory pulse generator producing pulses with rise and decay times less than 2×10−10sec. at a repetition rate of 120/sec. Three simultaneous outputs are available, variable in amplitude from 100 microvolts to 100 volts and accurate to a few percent.

ISSN:0034-6748    

DOI:10.1063/1.1745458

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745459

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

Thermal conductivities of from 2 to 500×10−4c.g.s. units are measured by comparing the flow of heat through a given sample with that through a standard material. On the basis of repeat runs and checks with literature values, an accuracy of about five percent is estimated for this method. The dimensions of the apparatus limit the face size of both the unknown and standard samples to a maximum of 10 millimeters square; thicknesses of 2 to 10 millimeters are suitable. Values at average temperatures between 30°C and 75°C are reported for nine materials:—sodium chloride, potassium chloride, potassium bromide, calcium fluoride, lithium fluoride (both air‐grown and vacuum‐grown), silver chloride, thallium bromide‐iodide, thallium bromide‐chloride, and fused silica.

ISSN:0034-6748    

DOI:10.1063/1.1745460

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The frequency of phase oscillation in a synchrotron is so low as to make possible resonances with harmonics of the power‐supply frequency. The interaction may take place through ripple in the magnetic field or in the frequency or amplitude of the accelerating voltage, the first two interacting very strongly and the third moderately. Thus, a small ripple in the magnet power supply output, though it produces only an extremely small ripple in the magnetic field because of the magnet's inductance, may tend to cause large phase oscillations. The detuning effect of the fall in phase oscillation on frequency with increasing amplitude limits the resulting amplitude, however, and may even reduce the amplitudes of initially large phase oscillations. The ripple in the accelerating field is unlikely to be sufficient at a resonant frequency to cause trouble. In addition to ripple, there will be noise which, particularly through modulation of the frequency of the accelerating field, may result in time in considerable phase oscillations because the noise contains a wide range of frequencies, one of which is always in resonance throughout the acceleration cycle.

ISSN:0034-6748    

DOI:10.1063/1.1745461

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A beta‐ray spectrograph has been constructed in which electrons move radially outward against a retarding electric field, and the current due to those electrons having more than any given energy is measured. Momentum resolution is one‐third percent. The insensitivity of current collection, as compared to single particle detection, is compensated by a large tolerable source area and a large useful solid angle subtended at the source by the detector.

ISSN:0034-6748    

DOI:10.1063/1.1745462

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The contribution of a portion of the solid angle of a two‐counter telescope to the total coincidence rate is studied for both isotropic and cosine squared law radiation fields. Formulas and graphs are presented for estimating the percentage of counts due to radiation from directions near the telescope axis. The average path length traversed by particles passing through the telescope is touched upon briefly.

ISSN:0034-6748    

DOI:10.1063/1.1745463

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745464

出版商:AIP    

年代:1950

数据来源: AIP