ISSN:0034-6748    

DOI:10.1063/1.1741234

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

A magnetic lens spectrometer has been built and tested. New features include (a) alignment with the earth's magnetic field to eliminate the deflection of the focal spot by this field, (b) use of a segmented coil to achieve a substantial reduction in spherical aberration, and (c) use of cathode rays for alignment, calibration, and for measurement of the aberration. Completely automatic operation has been achieved. Special attention is given to the effects of source backing and to focusing conditions for electrons in the very low energy region.

ISSN:0034-6748    

DOI:10.1063/1.1741235

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

The apparatus which the authors designed, constructed, and operated at the Institute of Physics of the National University of Mexico for the purpose of determining the azimuthal variation of primary cosmic radiation at fixed zenith angles consists essentially of four triple‐coincidence Geiger‐Mu¨ller telescopes mounted at zenith angles of 0°, 20°, 40°, and 60°, and are so arranged that, by rotation around a vertical axis, the directional intensity or counting rate can be measured at 16 equally spaced azimuths. The rotation and photographic recording are fully automatic. Several novel features of the apparatus are discussed here, most notable of which is the feature that, in contradistinction to the usual parallel connection of the three counters, as used in the conventional Rossi circuit and necessitating an amplifier tube for each Geiger‐Mu¨ller counter, a material simplification of the circuits was obtained by connecting the three counters in series feeding a single stage of amplification.

ISSN:0034-6748    

DOI:10.1063/1.4757299

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

A general equation for the shunt regulator is derived, giving the relation between the nominal required input voltage and the maximum shunt regulating current for any per unit variation of the input voltage, and for any load. The necessary relation between the shunt regulating current and the output current for maximum electrical efficiency is obtained. It is shown that, for a fixed load, the maximum average efficiency of any shunt regulator is (1 − (k)½)2, wherekis the maximum per unit variation of the voltage to the regulator.

ISSN:0034-6748    

DOI:10.1063/1.1741236

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

A new d. c. high voltage stabilizer, operating in the range from +5 to +50 kilovolts and for currents up to 50 milliamperes, is described. The stabilizer is of the usual degenerative type; but the series regulator tube, which is at high voltage, is inductively coupled to the feed‐back amplifier at ground‐potential. The signal from the amplifier amplitude‐modulates an r‐f oscillator, the output voltage of which is passed through a transformer, rectified, filtered, and applied as a d. c. correcting signal to the series tube grid. Insulation between high and low voltage circuits is provided in the r‐f transformer.As an example of the short‐term stabilizing action, a level of +35 kilovolts can be maintained to within 2 volts, for ±5 percent change in the input voltage, independently of load up to 50 milliamperes. The output ripple at this voltage and 20‐milliamperes load is 0.05‐volts r.m.s. Long‐term stabilization, which depends chiefly upon constancy of the reference level, has not been measured, but means to its attainment are suggested.

ISSN:0034-6748    

DOI:10.1063/1.1741237

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

An electronic eyepiece for the observation of near infra‐red of the spectrum is described. It can be attached to any spectroscope and consists of an image tube of the type 1‐P‐25 which converts an infra‐red image into a visible one. The spectrum is projected by the telescope system of the spectroscope upon the mosaic face of the image tube. The infra‐red radiation releases photoelectrons from the mosaic face of the image tube which are focused electron‐optically upon a fluorescent screen. The image appearing on the fluorescent screen can be observed directly or magnified optically. The visible range of a spectroscope equipped with an electronic eyepiece extends the visible range to approximately 1150 m&mgr; into the infra‐red and to 300 m&mgr; into the ultraviolet.

ISSN:0034-6748    

DOI:10.1063/1.1741238

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

A magnetic spectrometer for the measurement of beta‐ and gamma‐ray energies has been constructed. By using an inhomogeneous field varying radially in the proper manner, it is possible to bring electrons which leave the source with an extremely wide spread in angle to essentially a perfect focus in 180°. It has thus been possible to use a large mean radius of curvature of 40 cm in order to obtain high resolution combined with a reasonable transmission of about 0.1 percent of the total solid angle. Under operating conditions, with a 0.4‐cm wide source, the full width at half maximum for an internal conversion line is 0.5 percent. Scattering and background effects are negligible.

ISSN:0034-6748    

DOI:10.1063/1.1741239

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

The instrument to be described measures magnetic field strengths as determined from the Hall effect in germanium. The essential parts of this instrument include a small germanium probe, and a panel type microammeter calibrated directly in gauss. Its accuracy is ±2 percent at fields between 100 and 8000 gauss. At higher fields the readings are too low, the error amounting to 9 percent at 20,000 gauss. The chief advantages of this instrument are: (a) small size and portability, (b) continuous reading rather than ballistic as in ordinary field strength meters, and (c) a small non‐magnetic probe with which one can search in very narrow gaps.

ISSN:0034-6748    

DOI:10.1063/1.1741240

出版商:AIP    

年代:1948

数据来源: AIP

摘要:

The evaporation of liquid hydrogen caused by the heat of reaction of the ortho‐para conversion has been measured as a function of theo‐hydrogen concentration. The results are discussed, and a set of curves is given which describes all cases of practical interest. Methods of minimizing the rather serious evaporation of liquid hydrogen as the result of this effect are suggested.

ISSN:0034-6748    

DOI:10.1063/1.1741241

出版商:AIP    

年代:1948

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1741242

出版商:AIP    

年代:1948

数据来源: AIP