摘要:

In order to study the chemical effects of heavy charged particles, a number of organic compounds—gases, liquids, and solids—have been bombarded with deuterons from the M.I.T.cyclotron. This work, carried out under American Petroleum Institute Project 43c, included paraffins, organic acids, salts, and some complex mixtures. Gas bombardments were made at approximately atmospheric pressure in a water‐cooled gas chamber (volume: 2.54 liters) provided with a 2‐mil copper window for the entry of the external deuteron beam. A thermocouple and a Bourdon gauge connected to a Microtorque potentiometer allowed the gas temperature and pressure to be recorded electrically at the control bench during the bombardment of liquids and solids. Water‐cooled target‐holders provided with 2‐mil copper windows were mounted inside the gas chamber which served to collect the product gases. To prevent chemical reactions of the compounds with the metal parts, chamber and target‐holders were gold‐plated.

ISSN:0034-6748    

DOI:10.1063/1.1740959

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

War time German vacuum tube research led to the development of metal‐ceramic silver‐soldered vacuum seals. It has been found that such seals can be made successfully with ceramic materials available in this country. The procedure is outlined, and some precautions are noted.

ISSN:0034-6748    

DOI:10.1063/1.1740960

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A mass spectrometer suitable for routine isotope analyses of the lighter elements is described. Complete electronic circuits are given. An all metal mass spectrometer tube is employed. A null method of determining relative abundances of the elements carbon, nitrogen, and oxygen is used. Although designed primarily for analyzing elements for which separated isotopes are available as tracers, the instrument may be modified for use over the entire atomic table or for making gas analyses.

ISSN:0034-6748    

DOI:10.1063/1.1740961

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The probability of the occurrence of a time lag in a counter discharge is expressed in terms of the probability of capture of an electron by an oxygen molecule. The capture probability is shown to be independent of the number of electrons produced and to correspond to a value for the capture cross section in agreement with direct determinations.

ISSN:0034-6748    

DOI:10.1063/1.1740962

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The design and construction of a vibrating capacitor‐type electrometer is described. Experimental data are presented to show that this electrometer reaches, within a small factor, the theoretical limit of sensitivity. The principle of the electrometer is a time‐varying capacitor at the input of the device, which inverts the low frequency signal to a relatively high frequency, and raises its energy level, thereby simplifying the amplification of the voltage being measured, permitting the use of ordinary vacuum tubes, and producing an electrometer that is mechanically rugged and free from long period drift. Stabilization is obtained by negative feed‐back. The electrometer was originally developed for radiation well‐surveying in the petroleum industry, but has found other application in general radiation measurements.

ISSN:0034-6748    

DOI:10.1063/1.1740963

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A description of an x‐ray diffraction camera for recording diffraction phenomena from selected microscopic regions of solid materials is presented. Replaceable collimator systems limit beam diameters from 100 to 25 microns. The camera body may be removed from its support and replaced without readjustment.

ISSN:0034-6748    

DOI:10.1063/1.1740964

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A special camera has been designed for the determination of orientation in electro‐deposited metals and its construction is described. An account is also given of a method of computing the numerical value of the fiber‐axis of the orientated crystals from simple linear measurements on the films obtained using this camera.

ISSN:0034-6748    

DOI:10.1063/1.1740965

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

Details are given of the construction of an evaporated nickel bolometer. These bolometers are approximately 200A thick and are evaporated onto a nitrocellulose pellicle approximately 1000A thick. The pellicle is supported on a glass base in which is a sandblasted groove. This groove is immediately below the area of the pellicle which is covered with the bolometer strip. The techniques are described which were used to measure the bolometer characteristics. The sensitivity and frequency response of the bolometer are discussed. A typical bolometer has a time constant of 0.004 second, and a threshold of 3.3×10−8watt for radiation modulated sinusoidally at 30 cycles per second where the band width of the system is 100 cycles.

ISSN:0034-6748    

DOI:10.1063/1.1740966

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The description of the book entitledThe International Control of Atomic Energyreviewed in Rev. Sci. Inst.18,237 (1947) should read as follows:Scientific Information transmitted to the United Nations Atomic Energy Commission, June 14, 1946—October 14, 1946. Pp. 195, 22½×15 cm. United States Department of State, Publication 2661. Superintendent of Documents, U. S. Government Printing Office. Washington 25, D. C. Price $.30.

ISSN:0034-6748    

DOI:10.1063/1.1740967

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

This paper describes an automatic ratio recorder as applied to infra‐red spectroscopy, incorporating special control devices developed and constructed for E. I. du Pont de Nemours and Company. This instrument is designed for recording the ratio of the energies in the two channels of an infra‐red spectrophotometer. It includes two preamplifiers and automatic control equipment for making readjustments periodically in the spectrometer and the preamplifiers. The instrument is provided with an electronic strip‐chart recorder and has an effective span of 0.5 microvolt.

ISSN:0034-6748    

DOI:10.1063/1.1740968

出版商:AIP    

年代:1947

数据来源: AIP