1. |
Pressure Gauge for Corrosive Gases in the Micron and Submicron Region |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1073-1078
J. R. Anderson,
Preview
|
PDF (349KB)
|
|
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
|
2. |
Radiation Attenuation Method of Measuring Density of a Two‐Phase Fluid |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1079-1085
Michael Petrick,
Bernet S. Swanson,
Preview
|
PDF (448KB)
|
|
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
|
3. |
Capillary Viscometer for High‐Temperature Measurements of Polymer Solutions |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1086-1088
Gordon D. Patterson,
Louis H. Rabouin,
Preview
|
PDF (225KB)
|
|
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
|
4. |
Mass Spectrometer Ion Source for Solid Samples |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1089-1092
B. R. F. Kendall,
Preview
|
PDF (292KB)
|
|
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
|
5. |
Compact Microwave Refractometer for Use in Small Aircraft |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1093-1096
M. C. Thompson,
M. J. Vetter,
Preview
|
PDF (303KB)
|
|
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
|
6. |
Dose‐Rate Dependent Dosimeter for Low‐Intensity Gamma‐Ray Fields |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1097-1100
Keran O'Brien,
Leonard R. Solon,
Wayne M. Lowder,
Preview
|
PDF (264KB)
|
|
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
|
7. |
He3Recirculation and Purification System for a Cyclotron Ion Source |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1100-1103
H. E. Wegner,
W. S. Hall,
Preview
|
PDF (297KB)
|
|
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
|
8. |
Efficient Low‐Level Counting System for C11 |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1104-1107
J. B. Cumming,
R. Hoffmann,
Preview
|
PDF (306KB)
|
|
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
|
9. |
Improved Measuring Apparatus for X‐Ray Absorption Spectrometry |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1107-1111
H. P. Hanson,
W. E. Flynt,
J. E. Dowdey,
Preview
|
PDF (393KB)
|
|
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
|
10. |
Cyclotron Beam Intensity Measurements |
|
Review of Scientific Instruments,
Volume 29,
Issue 12,
1958,
Page 1112-1115
Saadia Amiel,
Norbert T. Porile,
Preview
|
PDF (305KB)
|
|
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
|