摘要:

The first U. S. satellite, 1958 Alpha (Explorer I) carried instrumentation to measure cosmic‐ray intensity, micrometeorite impacts, and temperatures within the satellite. The instrumentation was designed with emphasis on conservation of electrical power, on stable and reliable operation, on operation over a wide range of temperatures, and on compactness and mechanical ruggedness.The cosmic‐ray instrumentation in 1958 Alpha operated according to expectations, providing several hundred recordings of data received during transits over ground stations. These data led to the discovery of a belt of high‐intensity radiation around the earth.

ISSN:0034-6748    

DOI:10.1063/1.1716522

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A large volume expansion chamber (25‐cm diameter, 25 cm deep) was constructed to investigate prebreakdown ionization processes in gaseous discharge. A homogeneous field electrode system was mounted within the chamber and provision was made for irradiation of the cathode. The chamber could be operated automatically at pressures from 40 to 68 cm Hg with a recycling time of about 5 min. Associated circuits for the production of millimicrosecond pulses up to 70 kvp are described. Some preliminary photographs of point‐plane breakdown and of electron avalanches in a homogeneous field electrode system are shown.

ISSN:0034-6748    

DOI:10.1063/1.1716523

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A field‐plotting and ray‐tracing technique based on electron‐optical methods is developed for first‐order ion optics of slit lenses and is applied to a Nier‐type thick lens. A resistance paper analog gives the distribution of electrostatic potential. Maxwellian velocities of ions emitted from the filament and lens thickness affect ion trajectories, which are calculated to a few percent accuracy by a simple approximation technique. Paraxial ray paths are shown and the ion‐focusing action of the single filament is described. Optimum detectability, 100 counts of the smallest isotope, is 5×10−15g for uranium and 2×10−15g for plutonium. Ionization at moderate temperatures improves transmission and avoids background impurities which appear at temperatures above 2000°C. Independent electrostatic focusing in thezdirection improves transmission through the analyzer.

ISSN:0034-6748    

DOI:10.1063/1.1716524

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A random number generator which uses two 2000‐Mc subharmonic oscillators is described. This generator can produce random binary digits at a maximum rate of approximately 3×107digits per second. Statistical tests performed on over a quarter‐million digits produced by this generator indicate that they were at least as random as digits produced by other slower contemporary means.

ISSN:0034-6748    

DOI:10.1063/1.1716525

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A method has been devised for introducing reference marks in stacks of nuclear emulsion pellicles by the use of single‐strand threads. The reference marks are then used for accurate lining‐up of the stack after development. Details of the thread insertion and lining‐up processes are described.

ISSN:0034-6748    

DOI:10.1063/1.1716526

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A method is presented for the determination of the coefficient of thermal expansion of solids, particularly in the low‐temperature region. The method is based on the measurement of the resonant frequency of one or more modes of a microwave cavity made of the material for which the coefficient of expansion is required. A change in length of 5 parts in 106can be detected. This accuracy is primarily determined by theQof the resonant cavity. Measurements of the thermal expansion of copper and barium titanate are presented over the temperature range of −200 to +100°C and the former is compared with observations made by other techniques.

ISSN:0034-6748    

DOI:10.1063/1.1716527

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The focusing properties of a quadrupole lens pair have been studied, and the results of thick‐lens calculations are presented in the form of graphs showing the field strength parameters and magnifications as functions of object and image distances.

ISSN:0034-6748    

DOI:10.1063/1.1716528

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A recording pyrometer which measures the brightness temperature at 0.65 &mgr; of a small incandescent sample in the range 1300°C to above 3000°C with a time constant of a few milliseconds is described. The instrument, designed to be used in studies of materials exposed to the plasma jet of a high‐intensity electric arc, is reliable to within ±20°C, and is suitable for measuring transient high‐temperature fluctuations or for applications where use of a standard optical pyrometer might be hazardous to personnel.

ISSN:0034-6748    

DOI:10.1063/1.1716529

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A general expression for the solid angle subtended by a circular disk is derived in terms of complete elliptic integrals of the first and third kind. The elliptic integral of the third kind is reduced in terms of Heuman's lambda function, which has been tabulated. By transformation of the double integral &OHgr; = ∫ ∫ sin&thgr;d&thgr;d&bgr; into a single line integral, the solid angle can be conveniently determined. Since the solution involves only tabulated functions, it is well suited for desk calculation.

ISSN:0034-6748    

DOI:10.1063/1.1716590

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A vacuum‐type gas‐flow calibrator was designed and constructed for making accurate calibrations of flowmeters needed for the investigation of high‐pressure flames. This calibrator operates by automatically measuring the time required to pressurize a known volume from a near vacuum to 1 atmosphere pressure. The gas volume flow rate is obtained by dividing the calibration volume by the pressurization time and applying corrections from PVT data. This apparatus has been successfully used to calibrate flowmeters for use with hydrogen, oxygen, nitrogen, air, methane, nitric oxide, carbon monoxide, and various homogeneous nonexplosive gas mixtures.

ISSN:0034-6748    

DOI:10.1063/1.1716591

出版商:AIP    

年代:1959

数据来源: AIP