摘要:

A scanning Auger microprobe (SAM) has been modified to detect and process electron beam induced currents (EBIC). The EBIC mode is incorporated as an integral part of the analytical instrument and operates in conjunction with secondary electron detection (SED) and Auger electron spectroscopy (AES) modes. A minicomputer scans the electron beam and acquires the EBIC data. Using the built‐in software designed for Auger data analysis, the data are processed, displayed on a graphics terminal, and plotted on a graphics plotter. The technique has been applied to the study of a grain boundary region of a polycrystalline Si solar cell by extracting a noise‐free signal and obtaining cell parameters such as diffusion length and surface recombination velocity in the vicinity of the grain boundary has been demonstrated.

ISSN:0034-6748    

DOI:10.1063/1.1137905

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A magnetic suspension densimeter is described that has been built for measuring the density of compressed liquids at pressures up to 15 MPa in the temperature range 20°–200°C with an uncertainty of 0.1%. The densimeter combines the principle of magnetic levitation of a buoy with that of liquid density determination by hydrostatic weighing. To accomplish this, the support coil is suspended from an electronic balance, and the balance readings are recorded (1) with the buoy at rest, and (2) with the buoy in magnetic suspension. Details are given of the construction of the cell, coil, buoy, and thermostat. The procedure is described by which cell and buoy are aligned so that the suspended buoy does not touch the cell wall. Test data on the densities of seven different liquids were obtained at room temperature. They agree with reliable literature values to within 0.1%. In a separate experiment, the bulk thermal expansion coefficient of the buoy material was determined. This experiment and its results are also given here.

ISSN:0034-6748    

DOI:10.1063/1.1137906

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A small superconducting magnet with a large highly confined field has been designed for ultralow‐temperature cryostats. The magnet provides a central field of 3 T, with a homogeneity of 0.1% over 7.3 mm and negligible hysteresis, while the field at a radial distance of 2 cm is zero. The confinement is accomplished by using the magnet wire itself to simulate the current distribution of a perfect type I superconducting shield.

ISSN:0034-6748    

DOI:10.1063/1.1137907

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

This paper describes a method of maintaining a constant level of liquid helium in a container over a 5‐day period by continuously transferring liquid from a supply tank. The technique uses no valves and minimizes vibration and disturbances of the temperature distribution.

ISSN:0034-6748    

DOI:10.1063/1.1137908

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

This work describes an innovation of traditional systems used inC–VandG–Vcurve measurements. Although this system has been specifically developed to be used in the characterization of hydrogenated amorphous silicon (a‐Si:H), it is useful when information about conductance (G) or capacitance (C) frequency dependence is needed. The highlights of the new system are signal heterodination and microprocessor‐based digital control over current range and modulation frequency. The outstanding advantages of this system are significant reduction of operation time and more reliable measurements. Additionally, there is no waste of computer time in the control of data‐acquisition operations. The system has an excellent signal‐to‐noise ratio, a nearly infinite line signal rejection, and a broad frequency range of operation (20 to 105Hz).

ISSN:0034-6748    

DOI:10.1063/1.1137909

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A procedure for selecting, for a previously chosen value of the time constant of the lock‐in amplifier, the value of the dwell time at a new measurement location so as to reduce the total time required to complete the sequence of measurements is presented. Results of an application to profile measurements in flames are included.

ISSN:0034-6748    

DOI:10.1063/1.1137884

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The implementation of a compact, inexpensive, programmable stepping motor controller and data‐acquisition system based on the Zilog Z‐80 microprocessor is described, including its basic hardware and software configurations. While originally designed to facilitate data acquisition from scanning x‐ray diffractometers, the units have proven to be quite versatile and have been applied to a variety of instrumentation requiring automatic data acquisition and mechanical control.

ISSN:0034-6748    

DOI:10.1063/1.1137910

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

An inverted bellows‐sealed vacuum valve was modified by replacing the Teflon pad on its stem by a stainless‐steel dish with a knife‐edge circumference and a capillary attached through its center. A Teflon cup for containing liquid air was threaded on top into the valve outlet. With the dish down, condensable gases could be frozen on a small surface area on the bottom of the cup. By pushing the dish upwards so the knife edge pushed into the Teflon, the gas was quantitatively transferred into the capillary upon warming.

ISSN:0034-6748    

DOI:10.1063/1.1137911

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Digital control of a mercury battery low‐noise dc power supply for an electron tunneling spectrometer is described. Advantages are reduced data accumulation time, fully automated spectrometer operation, and signal processing flexibility. Results are illustrated with an inelastic electron tunneling spectroscopic (IETS) study ofn‐propyltrichlorosilane [CH3–(CH2)2–Si–Cl3] adsorbed from vapor on a thin dc plasma‐grown aluminum oxide film.

ISSN:0034-6748    

DOI:10.1063/1.1137874

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The thermistor consisted of a rf‐sputtered SiC film deposited on one surface of an alumina ceramic plate. The thermistor element was brazed to the inner surface of a cylindrical metal housing at the closed end. The thermistor can detect temperatures with a thermal time constant of about 0.6 s.

ISSN:0034-6748    

DOI:10.1063/1.1137875

出版商:AIP    

年代:1984

数据来源: AIP