摘要:

This article contains experimental reflection and transmission secondary emission yield curves obtained from a 475 Å unbacked MgO film. The film has a transmission yield maximum of 2.6 at a primary energy of 3 kev. An analysis, employing experimental transmission retarding potential characteristics also obtained in this study, proves a lack of proportionality between the production of secondaries and the energy dissipated by the primary beam in MgO. The extreme range of a 3600‐ev primary in MgO is found to be 475 Å.

ISSN:0021-8979    

DOI:10.1063/1.1728773

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

The electrical breakdown in borosilicate glass cells of plane parallel plate geometry with external electrodes was studied under static and 60‐cycle alternating potential using Linde spectroscopically pure grade Ar gas introduced under Alpert vacuum conditions at 7, 15, and 35 mm. Oscilloscopic studies at fast and slow sweep as well as measurement of charge, wall potential and of apparent leakage charge through the glass using a large series condenser with Keithly electrometer and recorder were made. Three differing modes of breakdown appear as potential increases. These are associated with space‐charge distribution and density. The two modes at lower potentials are Townsend discharges operating by photoelectric processes at the cathode. The third mode has streamer‐like characteristics and a rise time equal to one avalanche crossing time. All breakdowns terminate through counter potentials from charge accumulation on the glass electrodes. The fairly complete data lead to a clear understanding of the observed breakdown patterns with 60‐cycle alternating potential. The electrical properties of the glass involved are discussed in terms of recent findings.

ISSN:0021-8979    

DOI:10.1063/1.1728774

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

This paper analyses the maser oscillator equations which describe the interaction between the resonant cavity and the inverted population of the electron spin system of the paramagnetic substance. It is shown that these equations will not allow periodic solutions thus refuting the theory, based on computer solutions, that this interaction is responsible for the pulsed mode of operation of the oscillator.Characteristics of solutions of these equations are determined analytically, and the ambiguity of computer solutions is discussed with the aid of examples. Numerical solutions are presented which show that periodic solutions may be induced by supplementing the spin system equation with an additional term.

ISSN:0021-8979    

DOI:10.1063/1.1728775

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

This paper presents experimental and theoretical work on the behavior of rf currents in electron beams which possess a spread of dc velocity. Experimentally an attenuation or damping of rf current with distance is noted. This attenuation is studied as a function of both velocity spread and space charge. Simple ballistic theory suffices to explain the damping rate for the first half space‐charge wavelength. A more exact distribution function analysis fails to give agreement much beyond this point. Qualitative disagreement with the exact theory occurs at a distance of one space‐charge wavelength. Here distribution function theory predicts a recovery of the current maximum over its previous value whereas experimentally monatonic damping is found. The failure of distribution function analysis to explain the observed current behavior in this simple case makes the validity of its application to the noise problem in microwave tubes somewhat questionable.

ISSN:0021-8979    

DOI:10.1063/1.1728776

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A theoretical investigation is made on the mechanism of noise in magnetic recording tape coated with magnetic particles. It is shown that, for the tape in saturated remanence, noise does not originate from the finite size of particles, but from other factors such as finite concentration of particles, voids, aggregation of particles, and periodic imperfection. For demagnetized tape, however, those factors give a negligible noise. Hence, the origin of noise in the magnetized tape differs from that in the demagnetized one.It is also shown that the theoretical results agree with the experiments by taking into account the fact that the true volume of single particles is smaller than the apparent volume. The theoretical signal‐to‐wideband‐demagnetized‐tape‐noise ratio is independent of tape velocity and is about 56 db for the commercial audio tape of ¼‐in. track width.

ISSN:0021-8979    

DOI:10.1063/1.1728777

出版商:AIP    

年代:1962

数据来源: AIP

摘要:

A study has been made of the photovoltaic effect in Au‐CdS and Cu‐CdS photocells in an attempt to determine the origin of the conducting electrons. Evidence is presented to show that, for evaporated films of gold and copper on copper‐doped CdS, the entire photovoltaic current is due to electronic excitation in the depletion region of the CdS crystals.

ISSN:0021-8979    

DOI:10.1063/1.1728778

出版商:AIP    

年代:1962

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1728780

出版商:AIP    

年代:1962

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1728782

出版商:AIP    

年代:1962

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1728783

出版商:AIP    

年代:1962

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1728785

出版商:AIP    

年代:1962

数据来源: AIP