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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenThu, 30 Nov 2023 19:55:52 +0000The sparkless sphere Gap voltmeter - II
https://resolver.caltech.edu/CaltechAUTHORS:20170906-151504237
Authors: Sorensen, R. W.; Ramo, Simon
Year: 1936
DOI: 10.1109/EE.1936.6539527
Further study of the method of measuring voltages by the force between spheres is reported in this paper, comparison being made of results obtained by means of 100 centimeter spheres with those obtained by other investigators and by a proposedâˆ— new A.I.E.E. standard for 50 centimeter spheres.https://authors.library.caltech.edu/records/zqqge-3g629Synthesis of a high frequency reactance
https://resolver.caltech.edu/CaltechAUTHORS:RAMjap39
Authors: Ramo, Simon
Year: 1939
DOI: 10.1063/1.1707283
Foster's reactance theorem (1) provides the necessary information for the synthesis of the most general dissipationless reactance provided the frequency range is such that lumped reactances, namely inductance coils and condensers, are available. At the higher frequencies these are difficult to obtain practically and the impedence elements must be treated in design as the transmission lines with distributed inductance and capacity which they truly are.https://authors.library.caltech.edu/records/859es-8cv42Space charge and field waves in an electron beam
https://resolver.caltech.edu/CaltechAUTHORS:RAMpr39
Authors: Ramo, Simon
Year: 1939
DOI: 10.1103/PhysRev.56.276
W. C. Hahn has shown that the basic characteristics of a new type of vacuum tube using a velocity modulated electron beam may be explained by means of waves propagating along the beam. For an "ideal" tube in which the beam was assumed to be of uniform density throughout its length he described the small amplitude, slow "space charge" waves which have axial symmetry. In the following paper a study is made first of the more general slow space charge waves which do not necessarily possess symmetry about the axis. Two cases are considered. First, a very high magnetic focusing field is assumed, so that the motion of electrons in any but the axial direction may be neglected. Then the magnetic focusing field is assumed to be completely absent, and waves having components of velocity of electrons in all directions are treated. Also in the following, attention is given to the fast "field waves" which may exist in the idealized tube under certain conditions. The waves have been termed "space charge" waves and "field waves" because, for the former type, the phase velocities are close to beam velocity and the wave energy is mainly in the electrons. In the case of the field waves, the phase velocities are large compared to beam velocity and the energy is mainly in the electromagnetic field.https://authors.library.caltech.edu/records/eehe9-m0y60High frequency behavior of a space charge rotating in a magnetic field
https://resolver.caltech.edu/CaltechAUTHORS:BLEpr40
Authors: Blewett, John P.; Ramo, Simon
Year: 1940
DOI: 10.1103/PhysRev.57.635
A theoretical discussion is given of the propagation of electromagnetic waves in a space charge which is rotating under the influence of a uniform magnetic field. Equations are derived for the relations between the amplitudes of the electric and magnetic fields, charge density, electron velocities, the applied magnetic field, the frequency, the phase velocities, and the effective dielectric constant of the space charge region. In particular, the natural frequencies are computed for such a space charge rotating about an infinitesimal conductor and enclosed by a coaxial conducting cylinder. The predicted resonant frequencies agree well with experimentally observed values for magnetron oscillators. The theory here developed is also applicable to other devices in which a rotating space charge is utilized.https://authors.library.caltech.edu/records/etvm2-fmr70Propagation of Electromagnetic Waves in a Space Charge Rotating in a Magnetic Field
https://resolver.caltech.edu/CaltechAUTHORS:LEjap41
Authors: Blewett, John P.; Ramo, Simon
Year: 1941
DOI: 10.1063/1.1712877
A theoretical discussion is presented of the transmission of electromagnetic waves of the symmetrical, transverse magnetic type by a space charge of uniform density, rotating under the influence of a uniform magnetic field. It is shown that the space charge presents to the wave an effective dielectric constant less than unity. By appropriate choices of magnetic field, the dielectric constant can be reduced to zero and can even become negative, so that the wave undergoes attenuation as it passes through the space charge. Experiments are described on the control of the propagation constants of 470-megacycle waves by variation of the dielectric constant of the rotating space charge medium. The results obtained are in agreement with the theoretical predictions.https://authors.library.caltech.edu/records/1bkeb-0a478A Simplified Electron Microscope
https://resolver.caltech.edu/CaltechAUTHORS:BACpr42
Authors: Bachman, C. H.; Ramo, Simon
Year: 1942
DOI: 10.1103/PhysRev.62.494
An electron microscope has been constructed to test a number of new methods of obtaining photographs. The aim has been to obtain in as simple a manner as possible both as regards operation and construction a resolving power in the range of the greatest present usefulness of electron microscopy (say ten times better than light microscopy), and to operate in a voltage range sufficient to obtain this resolution for the usual thin specimens. The instrument is a combined electron and light microscope and utilizes unipotential electrostatic electron lenses.https://authors.library.caltech.edu/records/2fpxy-8d954Electrostatic Electron Microscopy. I
https://resolver.caltech.edu/CaltechAUTHORS:BACjap43a
Authors: Bachman, C. H.; Ramo, Simon
Year: 1943
DOI: 10.1063/1.1714924
This paper, consisting of three parts, describes investigations made with the objective of developing a simplified, practical microscope of the type which yields magnified images of transparent specimens with a resolving power superior to that of the best light microscopes. The first part deals with the general problem of design, including the electron gun and the imaging lenses. A later part will describe a completed instrument embodying many of the results of the investigations.https://authors.library.caltech.edu/records/vpaas-c3v56Electrostatic Electron Microscopy. II
https://resolver.caltech.edu/CaltechAUTHORS:BACjap43b
Authors: Bachman, C. H.; Ramo, Simon
Year: 1943
DOI: 10.1063/1.1714953
This paper is a continuation of the description of problems arising in the development and design of an electrostatic electron microscope. The present article discusses depth of focus, lens and field stops, shielding, manufacturing tolerances, the choice of the number of stages of magnification, and alternative methods of viewing and recording the final image. A following paper will describe a completed instrument.https://authors.library.caltech.edu/records/eh3hh-pzh94Electrostatic Electron Microscopy. III
https://resolver.caltech.edu/CaltechAUTHORS:BACjap43c
Authors: Bachman, C. H.; Ramo, Simon
Year: 1943
DOI: 10.1063/1.1714968
This article, the final one of a series on the design of electrostatic electron microscopes, contains a description of an instrument which illustrates the principles previously discussed. The microscope described is believed to be the first constructed with the object of providing the greatest of simplicity in construction, operation, and maintenance with the design parameters balanced to give a particular range of resolving power. The range chosen is about ten times the light microscope. The instrument is permanently aligned and utilizes external photography. The over-all size and weight of the instrument, as well as the number and complexity of components, are materially less than previously described instruments.https://authors.library.caltech.edu/records/g5sj8-fmb80