摘要:

For use with corrosive gases in the range 10−2to 10−5mm Hg, a gauge is described in which the pressure is indicated by the rate of damping of a hinged silica fiber pendulum, the amplitude of which is measured photo‐electrically. The gauge exposes only glass and silica to the gas, may be baked to 450°C, and gives an accuracy of pressure measurement of better than 5%.

ISSN:0034-6748    

DOI:10.1063/1.1716080

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A gamma‐ray attenuation technique is presented for measuring density and phase distribution in a two‐phase fluid. A comparison is made between a ``one‐shot'' and traverse method. The technique was evaluated on Lucite mock‐ups of simulated flow patterns encountered in two‐phase flow and by a series of tests on an air‐water system at atmospheric pressure.

ISSN:0034-6748    

DOI:10.1063/1.1716081

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

An all‐glass capillary viscometer is described which permits dissolving polymers at high temperatures, filtering, and measuring the solvent and solution efflux flow times without removal from a vapor bath. The advantages include safe handling of liquids at high temperatures without the precipitation or oxidative‐degradation difficulties normally encountered in other methods of measuring polymer solution viscosities at elevated temperatures.

ISSN:0034-6748    

DOI:10.1063/1.1716082

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A single‐filament positive ion source for solid samples is described. The source is simple and compact. Heat dissipation is low. Isotopic fractionation effects are very much smaller than is the case with conventional single‐filament surface ionization sources. The main ionization process occurring in the source is considered to be the surface ionization of the sample vapor on the tungsten filament. The sample vapor is maintained at a comparatively high pressure inside the source assembly. Investigations are described which indicate that other possible emission processes do not contribute any significant proportion of the emitted ion beam. Variations in the measured relative isotopic abundance ratio K39/K41during a run to exhaustion of the sample are discussed. There is no significant ratio trend with time and the random fluctuations of the measured ratio are such that more than half of the values are within 0.2% of their mean. The mean values can be repeated with a probable error which is less than about 0.3%.

ISSN:0034-6748    

DOI:10.1063/1.1716083

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A microwave refractometer has been developed for use in a Type L‐20 ``Beaver'' single‐engine light aircraft. A two‐channel recording system is used providing simultaneous profile and turbulence records with rms noise levels of approximately 0.05 and 0.01Nunit, respectively. Power requirement is 25 amperes at 28 volts dc, and installation requires one‐half hour for two men. No structural modification of the aircraft is required. The results of flight tests are presented.

ISSN:0034-6748    

DOI:10.1063/1.1716084

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

It has been suggested that a NaI(Tl) phosphor be used to amplify densities enough to make a film dosimeter practicable for the low gamma‐ray dose rates produced by background radiation. This use is complicated by the dependence of film density on dose rate as well as dose. An analysis of the process provides a correction for the doserate dependence when the dose rate is constant. The magnitude of the error involved in assuming the dose‐rate constant when it is a function of time is evaluated.

ISSN:0034-6748    

DOI:10.1063/1.1716085

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A He3circulation system for a cyclotron has been built which will recover the gas and purify it continuously. This is accomplished by modifying a mechanical vacuum pump to meet the following special requirements: intake and exhaust sealed for both pressure and vacuum; small volume on the exhaust side; minimum oil volume. This pump, which is used instead of the cyclotron forevac pump during He3operation, recovers the gas and forces it through a liquid nitrogen‐cooled charcoal trap and on to the ion source. The system is completely interlocked to ensure He3safety in the event of operator or electrical failure. With a flow rate of 6 cc per minute, the normal He3loss over a period of 200 hours operation was less than 3 cc per hour after an initial charge of 1000 cc NTP. With trap reactivation periods of 50 hours, no change in ion yield was observed. External beams of approximately 100 &mgr;a of doubly charged particles were obtained.

ISSN:0034-6748    

DOI:10.1063/1.1716086

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A low‐level counting system used in absolute measurements of the C12(p,pn)C11cross section is described. In this system small activities of C11produced in polystyrene‐based plastic scintillators by irradiation with high‐energy protons are detected with high efficiency by 4&pgr; scintillation counting. Background reduction is achieved by counting in a shield consisting of 12 in. of iron and 1 in. of mercury and by the use of a ring of Geiger counters in anti‐coincidence with the scintillation counter. A background of 8 counts per min was obtained for a 1.5‐in. diam, 1‐in. thick scintillator in which the over‐all detection efficiency for C11is 90%. Determination of the counting efficiency by a positron‐annihilation coincidence method is described and the results of experiments to reduce the background still further are reported. Application of this system to monitoring fluxes of energetic protons and neutrons is discussed.

ISSN:0034-6748    

DOI:10.1063/1.1716087

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

Two techniques for simplifying data taking and for eliminating the requirement of a carefully stabilized x‐ray power supply in x‐ray absorption spectrometry have been developed. Method I oscillates the sample in and out of the beam with a period that is small compared to drift and the usual x‐ray tube instabilities. The correspondingIandI0are channeled to two ratemeters, and by analog techniques a quantity proportional to the absorption coefficient is electronically calculated and plotted. In method II, two counters are arranged in tandem with the sample between, yieldingIandI0simultaneously. The proper apportionment of counts in both arrangements is considered.

ISSN:0034-6748    

DOI:10.1063/1.1716088

出版商:AIP    

年代:1958

数据来源: AIP

摘要:

A Faraday cup and target assembly for the determination of cross sections for nuclear reactions induced by charged particles from a 60‐in. cyclotron is described. Independent checks and calibrations on the performance of the assembly were carried out. The conditions affecting the operation of this assembly are discussed. Cross sections for two standard alpha‐induced reactions are given.

ISSN:0034-6748    

DOI:10.1063/1.1716089

出版商:AIP    

年代:1958

数据来源: AIP