摘要:

A peak voltmeter circuit is described which will record, on an Esterline‐Angus chart, the amplitudes of microsecond pulses generated at random in ionization chambers or similar counters. Slow response of the recording pen prohibits the resolution of pulses less than one second apart. Provision is made for selecting pulses coincident with some triggering event as the low counting rates suitable for the circuit are most often encountered in coincidence experiments. Coincidence resolving times as low as five microseconds may be attained, and the linearity is such that input pulse amplitudes from 2 to 100 volts are reproduced on the chart to within ±1 volt.

ISSN:0034-6748    

DOI:10.1063/1.1745437

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An apparatus for determining the thermal conductivity of metals based upon the comparison of flux of heat in a conductor in the usual form of a bar consisting of three parts of different materials has been developed. This method enables one to measure the temperature gradients by only one differential thermocouple sliding in an axial boring of the bar. In this way usually difficult measurements of thermal conductivity can be carried out very easily with sufficient accuracy for industrial purposes.

ISSN:0034-6748    

DOI:10.1063/1.1745438

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An instrument is described which allows the determination of the ellipticity, angle of tilt, and sense of rotation of low frequency radio waves returned from the ionosphere.

ISSN:0034-6748    

DOI:10.1063/1.1745439

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A discussion is given of ion chambers in which a series of electrodes carry layers of solid detecting material. Counters of this type require low operating voltages, and can easily be miniaturized. Formulas are given for the correct layer thicknesses and for the neutron counting efficiency. The equations are applied to boron 10, and it is shown that there is a permissible tolerance of about 50 percent on the thickness of a boron layer, and a very considerable tolerance on the assumed values of the disintegration product ranges. Curves are given relating the optimum boron layer thicknesses and the efficiency to the number of layers. A miniature instrument is described having a sensitive volume of 0.4 cm3. It operates at a thermal neutron efficiency of 24 percent with a collecting voltage of 70.

ISSN:0034-6748    

DOI:10.1063/1.1745440

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A plant for the collection and purification of radon has been constructed. In order to reduce the gamma‐radiation level, the plant was designed to be operated entirely by remote control except for the final sealing of the radon capsule. This plant compares favorably with other collection systems both with regard to the time required for a collection and to the yield of radon obtained.

ISSN:0034-6748    

DOI:10.1063/1.1745441

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A precision thermostat has been developed, based upon that of Roberts, for the control of high temperatures (1000°—1550°C). With the instrument described, temperatures are readily maintained constant within ±0.1°C for several hours, and within ±1.0°C for several days.In this method of control a thyratron is used in conjunction with an a.c. bridge and high gain amplifier. The phase angle of the unbalanced bridge regulates the firing of the thyratron. The control is highly sensitive and independent of normal fluctuations in line voltage. The thermostat is convenient to operate, easy to adjust for any temperature, and reliable for periods of continuous operation from a few minutes to several days.

ISSN:0034-6748    

DOI:10.1063/1.1745442

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A double‐focusing magnetic spectrometer for detecting and analyzing charged particles from nuclear reactions is described. The magnetic field, varying asr−½near an average radius of 10.5 in., extends over a semicircle yielding object and anastigmatic image positions some distance outside of the region of strong field. The acceptance solid angle is &OHgr;=0.0061 sterad. and the momentum resolution with an 8‐mm slit at the detector isR=128. The ultimate resolution determined by spherical aberration and some residual astigmatism is about 1000. Applications to the study of the energy and yield of nuclear reaction products are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1745443

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745444

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745446

出版商:AIP    

年代:1950

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1745447

出版商:AIP    

年代:1950

数据来源: AIP