ISSN:0034-6748    

DOI:10.1063/1.1749047

出版商:AIP    

年代:1933

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1749048

出版商:AIP    

年代:1933

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1749049

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

An x‐ray generator is described which is especially adapted to the production of strong scattered and fluorescent x‐rays. Geometrical conditions are well suited to the study of spectra of scattered radiation. The essential novelty of the apparatus is a ring‐shaped target 3 inches in diameter. Sample spectra are presented.

ISSN:0034-6748    

DOI:10.1063/1.1749050

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

A detailed structural design of a parallel plate ionization chamber for measuring low voltage x‐ray intensities in roentgens is described. Intended for use in dosage‐meters where stability and simplicity are important factors, it permits the entire apparatus to be housed in a single cabinet without external accessories. Air absorption corrections are made directly and conveniently.

ISSN:0034-6748    

DOI:10.1063/1.1749051

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

The twenty‐one foot normal incidence vacuum spectrograph previously described by the writer has been improved by the provision of 30,000 line per inch glass and speculum gratings in addition to the 15,000 line per inch grating previously used, and by the installation of a simpler and much more rapid pumping system. The previous range of 2000 to 1000A has been extended so that the instrument can be used from 6000 to 300A, and orders up to and including the sixth have been photographed, giving dispersions ranging between 2.72A/mm and 0.22A/mm with the advantages of an almost normal spectrum. When a constant value for the dispersion is used over a 16 inch plate the correction factor seldom exceeds 0.3A. The errors introduced when Rowland's method of coincidences is used with these Wood gratings appear to be much less than 0.01A. Wave‐lengths of numerous lines of the hot‐spark spectra of copper and nickel, and of the high frequency discharge spectra of argon and neon, have been measured with the instrument, and the accuracy of many of the measurements appears to be in the neighborhood of ±0.005A. The resolving power thus far attained, while still below the theoretical limit of the gratings, is far above that previously claimed for this region. Instead of the four four‐stage mercury condensation pumps previously used, a single steel oil condensation pump of eight inch internal diameter is used, together with a trap in which either solid CO2or circulating tap water can be used as refrigerant. All high vacuum connections are of 8 inch steel tubing, and a satisfactory stopcock of this bore has been constructed. A new type of vacuum gate for installation between the main spectrograph body and the camera box is described. A vacuum of about 2×10−4mm is found sufficient to photograph the complete spectrum covered by the instrument without appreciable absorption in the optical path of 42 feet; a higher vacuum can be obtained in the tube quite readily.

ISSN:0034-6748    

DOI:10.1063/1.1749052

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

A simple crystal growing apparatus is described which allows the production of very uniform single crystalline rods of low melting point metals. The crystals may be produced in any desired gas atmosphere or in a vacuum. Any orientation of crystal to rod may be obtained by a simple seeding procedure.

ISSN:0034-6748    

DOI:10.1063/1.1749053

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

In order to utilize even 25 percent of the theoretical amplification factor of high mu tubes, it is necessary to use a plate load resistance and plate potential too high to be practical. By the use of a dummy tube in the plate circuit, however, one can obtain a resistance characteristic which makes it possible to attain the full amplification of 1500–2500 per stage for the ``57'' tube using only 300–600 volts plate supply. Output voltages as great as 450 volts are attainable with negligible distortion.

ISSN:0034-6748    

DOI:10.1063/1.1749054

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

Three different circuits for use with a single vacuum tube in order to balance out effects of fluctuations of the e.m.f. of the plate battery are described. The theory of the circuits is worked out and the expressions for the galvanometer current given. The circuit in which the stability of balance depends upon the constancy of the amplification factor, &mgr;, is found to be the most stable. A modified two tube circuit operating on this principle is suggested.

ISSN:0034-6748    

DOI:10.1063/1.1749055

出版商:AIP    

年代:1933

数据来源: AIP

摘要:

A new vacuum‐tube voltmeter which has a response proportional to the logarithm of the input voltage is described. The operation of the device is based upon the distortion of the plate‐current wave form occurring in a tube of the ``variable‐mu'' type, and upon the use of a diode rectifier to select only that portion of the wave which has been ``compressed'' by the curvature of the tube characteristic. The elementary circuit may be cascaded for extension of the range of input voltage over which the response is logarithmic. The speed of response of the device to changes in signal intensity is practically unlimited, and the frequency fidelity is only slightly inferior to that of a comparable impedance‐coupled amplifier designed for the same frequency band. Commercially available tubes are used throughout.

ISSN:0034-6748    

DOI:10.1063/1.1749056

出版商:AIP    

年代:1933

数据来源: AIP