摘要:

A three color, fast response optical pyrometer utilizing the double‐ratio method is described. The temperature of a rapidly heated source is displayed on a cathode ray oscilloscope as a function of time. Direct current sources can also be observed. The basic approach involves a beam splitter, a three‐channel logarithmic photometer, and a summing amplifier. For proper choice of wavelength, the measurement is independent of the emissivity of the source. Results are shown for an exploding wire.

ISSN:0034-6748    

DOI:10.1063/1.1684940

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

We have constructed a stage and measuring microscope servocontrolled by a PDP‐8 computer. The travel of of the stage is 0.5×0.5 m(x,y) and the travel of the microscope objective is 7.5 cm (z). The measuring accuracy is 1 &mgr; in thex‐yplane and 5 &mgr; along thezaxis.

ISSN:0034-6748    

DOI:10.1063/1.1684941

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Weak static magnetic moments have been measured under hydrostatic pressure up to 20 kilobars with the full sensitivity of the Faraday method over a wide temperature range. Only minor modifications of the magnetometer and cryogenic equipment are needed to accommodate a miniature pressure clamp. The method is simple, at least two orders of magnitude more sensitive than previous techniques, and makes Pauli paramagnets and dilute magnetic alloys accessible to magnetic measurements under high pressure.

ISSN:0034-6748    

DOI:10.1063/1.1684942

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

The design and construction of an ion source designed for the MS‐9 mass spectrometer are described. The source is designed to operate at ion chamber pressures up to 2 Torr while the pressure in the remainder of the source housing does not exceed 2×10−4Torr. It is possible with this source to study ion‐molecule reactions, i.e., chemical ionization mass spectrometry. Alternatively, if operated at lower ion chamber pressures, the source provides normal electron impact mass spectra and is thus a dual‐purpose source. Modifications necessary to the MS‐9 are described, as are performance characteristics of the new source.

ISSN:0034-6748    

DOI:10.1063/1.1684943

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

A calorimetric technique has been developed for measuring the ac loss in short, cylindrical thin film superconductors carrying a transport current. Substrates used in the present study were 0.32 cm in diameter by 3.8 cm long. Loss in the range 10−8−10−4W may be determined by measuring the temperature rise at the center of the sample, which causes a decrease in resistance of a carbon resistance thermometer mounted inside the hollow cylindrical substrate on which the superconductor is deposited. By maintaining the current contacts at 4.2 K and heating the center of the sample (in a vacuum can), loss may be determined from 4.2 K up to the transition temperature of the superconductor. Data below 4.2 K are taken by lowering the temperature of the coolant bath. This technique has been used extensively to study the temperature dependent ac properties of Nb3Sn. Typical loss data are shown.

ISSN:0034-6748    

DOI:10.1063/1.1684944

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

A double reflecting plate calorimeter [Rev. Sci. Instrum.41, 1479 (1970)] was used to evaluate the energy components of a pulsed 1.060 &mgr; neodymium laser light beam entering the calorimeter polarized parallel (EH) and perpendicular (EV) to a horizontal plane. The relationship between these components varied fromEH= 0.94EVtoEH= 1.25EV. Estimated error ofEHandEVis 2.3%. As a check on the accuracy of polarization component measurements at 1.060 &mgr;, an intercomparison of data was made between this calorimeter and an NBS liquid cell calorimeter. The agreement was about 0.2%.

ISSN:0034-6748    

DOI:10.1063/1.1684945

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

By taking into account the pulse height distribution, the maximum available information from a photomultiplier is examined in the case of very low light intensities and is compared with that information which is obtained in the conventional photon counting method using an optimized triggering level. Using the proposed method, the relative error is diminished by about a factor 1.4, i.e., nearly a factor of 2 is gained in the measuring time in the case of an EMI photomultiplier 6256.

ISSN:0034-6748    

DOI:10.1063/1.1684946

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

We have developed a sensitive calorimetric method for measuring the absorptivity of metals in the visible and infrared. The short thermal time constant of the system, typically 25 msec, has allowed us to use phase sensitive detection and continuous wavelength scanning. The absolute accuracy of this method was five times better than the best accuracy obtained in reflectivity measurements. The system has also been used to measure the difference between the absorptivities of pure and dilute alloy samples.

ISSN:0034-6748    

DOI:10.1063/1.1684947

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

The properties of the cylindrical mirror analyzer are discussed for the case where its entrance and exit slots are on the surface of the inner electrode. A comparison with the case where the slots are on the axis shows that although the axial arrangement is superior, the surface case is more compact. It seems also that sample alignment in the surface case is not as critical as in the axial arrangement.

ISSN:0034-6748    

DOI:10.1063/1.1684948

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

A new oscillating crucible viscometer, having a torus shaped crucible, is presented. The geometry of the torus allows a rigorous treatment of the fluidodynamical problem for an oscillating viscous liquid. The damping coefficient &dgr; is shown to characterize two possible distinct zones of oscillation: In the first zone, &dgr; rises when the viscosity &eegr; of the liquid rises; in the second one, &dgr; is lowered by an increase of &eegr;. The second zone proves to be much more convenient for fixing the working point of the instrument because here the sensitivity is expected to be twice that of the first zone. Some preliminary experiments have confirmed the results of the theory.

ISSN:0034-6748    

DOI:10.1063/1.1684949

出版商:AIP    

年代:1971

数据来源: AIP