摘要:

Recent developments in instrumentation for low‐energy electron diffraction (LEED) are reviewed. After a summary of the major types of measurements in LEED, the properties of LEED instruments that are important in performing these measurements are described. A detailed discussion is presented on the major components of a LEED diffractometer. LEED is compared briefly to some other techniques that are sensitive to surface structure.

ISSN:0034-6748    

DOI:10.1063/1.1137259

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Microbeam Auger elemental mapping of surfaces is both time consuming and, for topographically rough surfaces, difficult to interpret. Backscattered electron imaging can provide maps where intensity is a function of atomic numberZ. Using a coaxial detector, and moderate primary beam energy, qualitative elemental maps are easily obtained. These maps are used to identify regions for point quantitative analysis by Auger electron spectroscopy. The analysis of heavy‐metal defects in metallurgical‐grade silicon is presented to demonstrate the application of this potentially powerful technique.

ISSN:0034-6748    

DOI:10.1063/1.1137260

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We have measured the ultraviolet dispersion of several microscope objectives and we find that all of them are limited by axial chromatic aberration when used for polychromatic exposure of photoresist. We show how to measure and correct for the ultraviolet focus shift, and estimate the corrected resolution. Certain lenses are able to produce micron features over millimeter fields.

ISSN:0034-6748    

DOI:10.1063/1.1137239

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

It is possible to filter out the primary ionizing electrons from the ion extraction region of a multicusp source by installing the filament inside the dipole fields of the permanent magnets and thereby enhance the H+ion species in the extracted beam. An optimum position of the filament has been determined such that a quiescent plasma together with a uniform plasma density profile across the extraction plane can be obtained.

ISSN:0034-6748    

DOI:10.1063/1.1137261

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A module of an induction Linac is developed, being aimed at application to ion acceleration. A proton beam of 30 mA is extracted from a reflex discharge ion source and accelerated up to 20 keV, directly by the applied inductive field in a 0.5–1.0 &mgr;s pulse.

ISSN:0034-6748    

DOI:10.1063/1.1137262

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A directional velocity analyzer has been developed for measuring electron distribution functions in plasmas. It contains a collimating aperture which selects particles from a narrow cone in velocity space and a retarding potential analyzer. The distribution functionf(v, &thgr;, &fgr;) is obtained from a large number of analyzer traces taken at different angles &thgr;, &fgr;. In addition, the small analyzer can be moved in space and the measurements are time resolved so as to obtain the complete phase space informationf (v,r,t). The large data flow of this seven‐variable function is processed with a high‐speed digital data‐acquisition system. The new electron velocity analyzer is applicable over a wide parameter range in electron energies and densities. Various cases of anisotropic distributions such as beams, shells, tails, and drifts have been successfully investigated.

ISSN:0034-6748    

DOI:10.1063/1.1137263

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The general characteristics are compared for the plane, convex, and concave fixed crystal analyzers which may be applied to the spectrometry of concentrated, intense plasma sources of x radiation involved, for example, in fusion energy and x‐ray laser research. The unique advantages of the elliptical analyzer for precise and absolute spectral measurements are noted and detailed descriptions of its geometrical and physical optics are presented. With a source point at one of the foci of the elliptical analyzer profile, the spectrum is Bragg reflected (45°<2&thgr;<135°) at normal incidence upon a detection circle with its center at the second focal point, at which an effective scatter aperture and filter window is located. A primary monochromator consisting of a cylindrical, grazing‐incidence mirror is placed between the source and the analyzer to provide an efficient cutoff for high‐order diffracted background radiation and to focus the divergent rays so as to obtain an adjustable spectral line length at the detection circle. Photographic film may be transported along the detection circle. Linear position‐sensitive electronic detection arrays or a streak camera slit window may be placed along a chord of the detection circle. Calibration procedures for absolute line and continuum intensity measurement are described and examples of calibrating spectra are presented as measured with elliptical analyzers of LiF, PET, KAP, and molecular multilayers for the 80–8000‐eV photon energy region. The instrumental effects that contribute to the spectral line shape as measured by the elliptical analyzer spectrograph are defined and a simple line‐shape analysis procedure is presented for the determination of the line‐broadening contributions of the source. The effects of an off‐axis positioning of a source point and of an extended source are analyzed and the application of the elliptical analyzer spectrograph for one‐ and two‐dimensional imaging or an extended source at a given photon energy is discussed. Finally, methods and materials for the construction of the elliptical analyzers are described.

ISSN:0034-6748    

DOI:10.1063/1.1137264

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We describe the adaptation of an image dissecting detector to a visible/near‐ultraviolet radiation spectrometer used in laboratory plasma diagnostics. The detector has advantages in terms of sensitivity, fast scanning capability, and versatility over other detectors. We demonstrate several plasma diagnostics applications for the system.

ISSN:0034-6748    

DOI:10.1063/1.1137265

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We show that a commercial dye laser can be modified to allow rapid wavelength tuning via an applied voltage. By controlling the laser with a minicomputer, an arbitrarily specified continuous or discrete spectral output can be obtained.

ISSN:0034-6748    

DOI:10.1063/1.1137240

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Design, construction, and operational details of a simple and efficient axial flow compressor, suitable for large closed‐cycle gas transport laser applications is described. These compact and high performance devices are easily assembled from standard low‐cost industrially available components. Performance achieved is as good as that of commercial units, but at an order of magnitude lower cost.

ISSN:0034-6748    

DOI:10.1063/1.1137241

出版商:AIP    

年代:1983

数据来源: AIP