摘要:

An analytical balance is described in which the materials to be weighed are attached to a ferromagnetic body that is freely suspended by the axial magnetic field of a solenoid. The vertical position of the suspended mass is maintained by the automatic regulation of the current through the solenoid by means of an electronic servo‐circuit actuated by a light beam and photomultiplier tube arrangement. The horizontal position of the supported mass is maintained by the symmetrically diverging field of the solenoid. Changes in the nonferromagnetic masses of the suspended bodies are determined by the resulting changes in the current through the solenoid necessary to keep the bodies freely suspended. Masses ranging from 105grams to 2×10−6gram have been suspended. The precision of the balance is limited only by the natural fluctuations in the circuit, the photomultipliers and the support system. This balance is especially useful where it is necessary to weigh materials inside of sealed chambers which contain gases, vapors or liquids, or which are evacuated. A method is described for accurately calibrating the balance.

ISSN:0034-6748    

DOI:10.1063/1.1715217

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

The design is described of several liquid organic scintillation counters which have been used to detect 100‐Mev neutrons and gamma rays with the exclusion of lower‐energy particles and quanta.The neutron counter efficiency is a few percent and is nondirectional, properties not possessed by a more conventional counter telescope system. The gamma‐ray counter has an efficiency of about 50%, with a line width of about 10%.Particular problems arise in the use of these counters; counting rate stability is difficult to achieve; the maximum counting rate is limited by the pileup of individual pulses due to their finite width. These problems are discussed in detail and some solutions mentioned.

ISSN:0034-6748    

DOI:10.1063/1.1715218

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

The timing precision attainable with large liquid scintillation detectors has been studied. Such detectors have slow rise‐times (∼10−8sec) compared with those used in conventional nuclear physics timing experiments. The rise‐time is a result of photon time of flight and transit time in the larger, slower photomultipliers (such as the Dumont 6364) which must be used for good light collection. However, timing errors due to rise‐time may be largely overcome when dealing with large, statistically smooth pulses such as are encountered in cosmic‐ray experiments with unstable particles. A simple correction based on the pulse height is applied to each time measurement. Using this technique a timing error curve is obtained with a standard deviation of 1.6 m&mgr;sec for a large detector using a Dumont 6364.

ISSN:0034-6748    

DOI:10.1063/1.1715219

出版商:AIP    

年代:1955

数据来源: AIP

摘要:

A simple apparatus for producing humidity step‐functions at room temperature, using saturated salt solutions to maintain constant relative humidities, is described. For an air flow of 200 lpm, the time required to change from one relative humidity to another is of the order of 30 to 50 milliseconds. This apparatus is particularly useful for establishing the lag characteristics of hygrometer elements.

ISSN:0034-6748    

DOI:10.1063/1.1715220

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715222

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715224

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715226

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715228

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715230

出版商:AIP    

年代:1955

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1715232

出版商:AIP    

年代:1955

数据来源: AIP