摘要:

A majority of nuclear measurements involve digital pulse counting so that the associated instruments have many common functions. Further investigation reveals that these counting systems fall into two broad classes: Those in which all pulses exceeding a certain threshold are summed, and a more complex analyzing procedure wherein pulses must be classified according to amplitude or temporal distribution.In the former class are found the orthodox scalers, while the latter defines the pulse amplitude analyzers and other machines capable of yielding spectral distributions.It is found that such instruments may be synthesized from a common group of sub units, and these are outlined and listed on a functional basis.While the utility of the sub units is evidently determined by their versatility, they are in addition required to have high reliability in order that complex assemblies may give satisfactory service. Design for long life follows naturally from the latter consideration.The next section of the paper shows the manner in which the simpler instruments can be synthesized according to the proposed scheme and outlines the more complex automatic counting and analyzing systems to follow in later parts of the paper. In particular the construction of a range of scalers is illustrated and their performance specifications and photographs are shown.

ISSN:0034-6748    

DOI:10.1063/1.1745971

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

An annular Geiger‐Mu¨ller counter with six anodes has been built as a replacement for the usual six‐tube charged particle shielding ring in a cosmic‐ray anticoincidence bundle. Experiments show that the multiple‐anode counter has uniform pulse heights and starting voltages on all anodes, and a slightly higher shielding efficiency than the six‐tube ring.

ISSN:0034-6748    

DOI:10.1063/1.1745972

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

The general linear voltage stabilizer is specified by four independent performance parameters which are necessary and sufficient to determine its performance and an equivalent circuit of four elements is derived to represent it. Corresponding parameters for a stabilizer associated with a load are evaluated in terms of parameters of the stabilizer itself and the load resistance by means of this equivalent circuit. In the case of a stabilizer associated with a load and power supply, corresponding over‐all parameters are defined, and the general solution of the problem of expressing the over‐all performance parameters in terms of parameters of the stabilizer itself and the load and supply resistances is obtained. Prior results are based on three explicit performance parameters, and the case of the general stabilizer is tractable only by the use of a supplementary procedure to include a fourth parameter. The present results yield an analytical criterion for the case where the three‐parameter analysis applies directly and permit direct evaluation of over‐all performance parameters in the general case without reference to the internal configuration of the stabilizer. Confirmatory experimental results are presented.

ISSN:0034-6748    

DOI:10.1063/1.1745973

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

In order to measure the effects of gross changes in the design of the pole and yoke for a large synchrocyclotron cheaply and conveniently, a model half‐magnet having a two‐inch diameter pole was constructed. From data on the fields produced by poles of various lengths using a fixed amount of copper in the coil, the pole length for which the cost of power and magnet steel was a minimum could be determined. Measurements of the efficiencies of poles of various shapes indicated that it would be possible to design a shimmed pole to have an efficiency of 70 to 75 percent at a field of 20,000 gauss. Finally data on over‐all magnet efficiency as a function of the ratio of the cross‐sectional areas of the yoke and pole permitted calculation of the ratio for which the cost of steel, copper, and power would be a minimum.

ISSN:0034-6748    

DOI:10.1063/1.1745974

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

A high intensity cobalt gamma‐ray source for use in radiation chemistry studies is described. The lead shield was designed to provide safety, convenience, and reproducibility in irradiating samples under a variety of conditions.

ISSN:0034-6748    

DOI:10.1063/1.1745975

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

A bar‐magnet velocity meter for vibratory and shock motions has been investigated both theoretically and experimentally. There has resulted a set of characteristics which constitute a marked improvement over the characteristics of previous velocity meters, in important respects. The instrument consists of a long bar magnet which moves relative to a long coil. It is shown that Alnico V combines all the best features required of the magnet material, when compared experimentally with a magnet made of hardened tool steel and theoretically with other grades of Alnico, Cunife, and tungsten steel. Different methods are discussed for installing the velocity meter.

ISSN:0034-6748    

DOI:10.1063/1.1745976

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

The optimum length of an end‐window counter for the measurement of weak C14activities is found to be about 1 cm.

ISSN:0034-6748    

DOI:10.1063/1.1745977

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

An electronic power source for use in selective electrolysis or as a low voltage regulated supply is described. Its output is dc continuously controllable from zero to five volts at two amperes. Among its features are ripple content of 0.1 percent, and an output resistance of 0.01 ohm. The input impedance of the regulator circuit itself is in the order of 10 megohms, permitting control from high resistance electrodes.The instrument uses a variable‐amplitude two‐kilocycle carrier which is amplified by a power stage and fed to a dry‐disk rectifier. The output is then automatically controlled for equality to a self‐contained adjustable reference voltage. With modifications in the high level stages, the circuit is adaptable to a wide range of output capabilities.

ISSN:0034-6748    

DOI:10.1063/1.1745978

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

A discussion is given of the design considerations, operational procedures, safety devices, and performance of a small homogeneous reactor using enriched uranium in a water solution and beryllium oxide and graphite for the neutron reflector. A high power and a low power phase of this reactor are described.

ISSN:0034-6748    

DOI:10.1063/1.1745979

出版商:AIP    

年代:1951

数据来源: AIP

摘要:

Methods are described in which microwave techniques are used to measure the electron density during the period following a discharge. By measuring the detuning of a resonant cavity containing electrons, it is possible to measure electron densities between 1010and 106electrons/cc in gases whose pressure may be varied over a wide range. Design criteria are given to permit proper operation of the method under the conditions encountered in a given experiment.

ISSN:0034-6748    

DOI:10.1063/1.1745980

出版商:AIP    

年代:1951

数据来源: AIP