摘要:

A new type of beam postion monitor has been designed and bench tested. The results agreed well with the expected performance. Tests with the proton beam showed that this monitor was applicable to our accelerator.

ISSN:0034-6748    

DOI:10.1063/1.1135849

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A technique is described which allows the measurement of the thermal conductivity &kgr; of superconductors belowTcwithout the use of a thermometer, ifTcis known. The method is particularly adapted to technical superconductors of poor thermal conductivity. It is convenient to use as sample a superconducting wire or band provided with a high conductivity matrix of a normal metal, which has to be removed from the test length. The stabilized ends of the sample are thermally anchored to a heat sink of variable temperatureT. A currentIflowing through the conductor holds the middle part of the test length in the normal state due to Joule heating. The length of the normal section and hence the voltage appearing on the sample are a functions ofIandF&kgr;dT. The variation of the temperature of the heat sink then allows the determination of &kgr; (T). Results for two NbTi samples are included.

ISSN:0034-6748    

DOI:10.1063/1.1135850

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A new method for the rapid investigation of sedimentation phenomena of fine particles is developed by using the force due to a vibrational acceleration. The small displacement of the particle with respect to the wall of the container, which is produced by the vibration, is measured by the interference between the light scattered by the particle and that of the cell wall. The interference is detected as a beat note in the scattered‐light intensity, and displayed as a time‐autocorrelation of the photocurrent, the analysis of which gives the sedimentation coefficient and the dispersion.

ISSN:0034-6748    

DOI:10.1063/1.1135851

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We present improvements of the previously described command system of a 200‐kA circuit breaker with 10‐&mgr;s current transfer time. It uses the magnetic pressure produced by a high‐current pulse sent through two flat conductors instead of a coaxial circuit. The necessary command current is cut in half and the standoff voltage is higher.

ISSN:0034-6748    

DOI:10.1063/1.1135852

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An improved10B‐loaded liquid scintillator solution has been developed containing trimethylborate, 1‐methylnaphthalene, and 9,10‐diphenylanthracene. Cells up to 5 cm in diameter by 15.2 cm long have been prepared and tested with10B‐loadings up to 7.2% by weight (80% trimethylborate). The solution has excellent light output and pulse‐shape discrimination properties and is stable at temperatures as low as −17°C. Neutron efficiency calculations are also presented.

ISSN:0034-6748    

DOI:10.1063/1.1135853

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Excellent pulse height and pulse shape discrimination performance has been obtained for liquid scintillators containing as much as 10 wt.%6Li‐salicylate dissolved in a toluene‐methanol solvent system using naphthalene and 9,10 diphenylanthracene as intermediate and secondary solutes. This solution has improved performance at higher6Li‐loading than solutions in dioxane‐water solvent systems, and remains stable at temperatures as low as −10°C. Cells as large as 5 cm in diameter and 15.2 deep have been prepared which have a higher light output for slow neutron detection than10B‐loaded liquids. Neutron efficiency calculations are also presented.

ISSN:0034-6748    

DOI:10.1063/1.1135854

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A wide variety of dissolved chemicals can be measured continuously with some specificity by directly interfacing a relatively inexpensive mass spectrometer to a solution. Specifically, we describe the construction and initial use of a membrane interace to a mass spectrometer which allows the continuous measurement of the concentration of dissolved volatile compounds in buffered aqueous solution. In addition to volatile compounds that do not dissociate appreciably atpH7 (e.g., ethanol, ethylene glycol), volatile acids and bases, such as acetic acid or ammonia, can be measured with the interface is operated within the range 1⩽pH⩽12. We also discuss the sensitivity of the system to variations in flow rate and describe a satisfactory method for providing sufficiently constant flow rates.

ISSN:0034-6748    

DOI:10.1063/1.1135855

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We describe the design and operation of the solid hydrogen pellet injection system used in plasma refueling experiments on the ISX tokamak. The gun‐type injector operates on the principle of gas dynamic acceleration of cold pellets confined laterally in a tube. The device is cooled by flowing liquid helium refrigerant, and pellets are formedinsitu. Room temperature helium gas at moderate pressure is used as the propellant. The prototype device injected single hydrogen pellets into the tokamak discharge at a nominal 330 m/s. The tokamak plasma fuel content was observed to increase by (0.5–1.2) ×1019particles subsequent to pellet injection. A simple modification to the existing design has extended the performance to 1000 m/s. At higher propellant operating pressures (28 bars), the muzzle velocity is 20% less than predicted by an idealized constant area expansion process.

ISSN:0034-6748    

DOI:10.1063/1.1135856

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The design, construction, and performance of a 100‐MHz noise spectrometer are described. Basically a 100‐MHz bridge, this system uses the properties of a double balanced mixer to enable the experimenter to determine spectral densities of fluctuations in the real or imaginary parts of a sample impedance, as well as the real part of the cross‐spectral density. Calibration circuits and techniques are described. The results of measurements on commercial 50‐&OHgr; terminators demonstrate fluctuations of both the real and the imaginary parts of the impedance and partial correlation between them.

ISSN:0034-6748    

DOI:10.1063/1.1135857

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An electron spectrometer is described which is designed to measure a variety of electron spectra of solid surfaces in ultrahigh vacuum. The instrument is capable of the high‐energy resolution (10–15 meV) required for vibrational inelastic electron scattering from atoms and molecules on surfaces. It has also been designed to carry out angle‐resolved photoemission measurements, Auger electron spectroscopy, and energy‐loss measurements of electronic excitations. The performance of the instrument in these modes of operation is discussed.

ISSN:0034-6748    

DOI:10.1063/1.1135858

出版商:AIP    

年代:1979

数据来源: AIP