摘要:

The theory of conditioned probabilities is applied to the problem of momentum, charge, and mass determination from Coulomb scattered tracks in a magnetic field. An optimum procedure is derived, which makes use of both random and systematic track curvature.It is shown that application of this procedure to a highly relativistic nuclear emulsion track of 1‐cm length in a field of 300 000 gauss will yield the momentum information of a 9.2‐cm track in zero field. If the scattering information were neglected, the effective length of the track would be 8.2 cm. At 100 000 gauss, the improvement in effective track length due to the inclusion of scattering information is shown to be by a factor of 2.3.

ISSN:0034-6748    

DOI:10.1063/1.1715197

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

Over the last few years, a method has been developed for obtaining ionization probability curves with essentially monoenergetic electrons. A retarding potential is applied to the electron beam to yield an energy distribution with a sharp low‐energy limit. By varying the retarding potential slightly, a new low‐energy limit of the distribution can be selected. The difference in the ionization produced in the two cases is ionization by those electrons with a small energy spread selected from the original distribution. By pulsing the electrons and ions, it is possible to eliminate the adverse effect of the ion‐drawout field on the electron energy. With this retarding potential difference (RPD) method, a detailed analysis of ionization probability curves is possible. A full description of this method is given in this paper with a discussion of its advantages and limitations. The mass spectrometer used in this series of studies is described, particular attention being given to a description of the ion source. The various electrodes of the electron beam slit system are described in terms of their influence on the electron energy, and on the shapes of ionization probability curves.

ISSN:0034-6748    

DOI:10.1063/1.1715198

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

Two flip coils are rotated through 180° to give a precision measurement of the ratio of separate magnetic fields. The output voltages are connected in opposition and balanced in a resistance potentiometer using a sensitive galvanometer as a null indicator. The ratio of the fields is a linear function of the potentiometer setting. In fields of several thousand gauss and using a common shaft for the coils, readings were reproducible to within 0.01%. With separate selsyn motor drives the precision was 0.02%.

ISSN:0034-6748    

DOI:10.1063/1.1715199

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

The construction and design principles of a focusing atomic beam apparatus are reported. This apparatus, which is of the radio‐frequency magnetic resonance type and which has been used to measure the spins and hyperfine splittings of four radioactive nuclides as reported elsewhere, utilizes the six‐pole focusing magnet of Friedburg and Paul and of Korsunskii and Fogel but in a way which avoids velocity aberrations. From an analysis of the optimization of intensities in the conventional and the focusing types of atomic beam apparatus it is concluded that the latter has an advantage of a factor of roughly twenty‐five.

ISSN:0034-6748    

DOI:10.1063/1.1715200

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

An electronic system is described for modulating the beam intensity of a cathode‐ray oscilloscope in such a manner as to reduce variations in trace brightness due to differences in writing speed. A voltage derived by a push‐pull differentiating amplifier from the vertical deflection signal is added to the instrument's intensity‐control voltage. By use of this system, improved photographs of wave forms can be obtained.

ISSN:0034-6748    

DOI:10.1063/1.1715201

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

This paper describes in some detail a radiometer for measurement of ultraviolet radiation from sun and sky. As designed, the instrument is selectively responsive to a narrow band of wavelengths and is capable of detecting and measuring low‐energy levels. The radiometer consists of a photoelectric sensing element, an ultraviolet transmitting window, and a dry‐cell battery mounted in a small housing. Calibration of the instrument shows satisfactory agreement with Lambert's cosine law and a linear relationship between energy flux and output of the phototube. For recording the signal from the radiometer the output is fed to a direct current amplifier which in turn drives a recorder. A typical recording for a cloudy day is presented.

ISSN:0034-6748    

DOI:10.1063/1.1715202

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

A rotary device was developed to produce uniform drops of liquids in the diameter range of 50 to 700 microns. A horizontally rotating blade detaches drops in a steady stream of regular trajectory, from a stabilized liquid mass fed under constant head through a stationary capillary. Its operation is described, and performance characteristics with oil and aqueous test solutions are given. Drop size is calculated from the mass of drops emitted in a given interval at a known generation frequency. Variation in size of individual drops, electrostatic effects, and some uses for the machine are noted.

ISSN:0034-6748    

DOI:10.1063/1.1715203

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

Characteristics are described for the collection of cyclotron beams in a conducting medium separated from the accelerator by an insulating window. The measured current can be interpreted in terms of an absolute beam current if charge displacement within the insulator is taken into account. Collection of the beam in this manner is particularly advantageous in a region external to the cyclotron magnetic field where stray currents due to air ionization and secondary electron emission are pronounced. A comparison is made between particle energies determined by the charge‐input method and by calorimetry. A simplified arrangement for particle range determination is described.

ISSN:0034-6748    

DOI:10.1063/1.1715204

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

Two different constructions were investigated of copper gasket seals for a demountable vacuum system. These were 5½ inches in diameter and with both a leak rate lower than 10−6&mgr;l/sec could be obtained.

ISSN:0034-6748    

DOI:10.1063/1.1715205

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

A timing system is described which provides sharp, one‐millisecond, electric pulses at one‐second intervals. These pulses are used to actuate a trigger circuit which is used to control one or more relays. The accuracy of the time scale can easily be checked against radio station WWV. Auxiliary apparatus can be controlled for time intervals of any even number of seconds. The accuracy of this interval can be determined to better than one millisecond. This system has proved to be particularly useful in calorimetry.

ISSN:0034-6748    

DOI:10.1063/1.1715206

出版商:AIP    

年代:1955

数据来源: AIP