Profil und Äquivalentbreite der Na-D 1-Linie als Funktion von Temperatur und Magnetfeld

Because of the anomalous Zeeman-effect and the Paschen-Back-effect of the hyperfinestructure and theL-S-decoupling, the line profil and also the equivalent width of resonance lines is greatly influenced by an external magnetic field. The decoupling effects in the fine- and the hyperfinestructure of the Na-D ₁-line as an example will be determined quantum-mechanically by a second order perturbation, and it will be shown, how the line contour and the equivalent width are varied by temperature, magnetic induction and optical depth. There are certain regions of temperature and optical depth, where the hyperfinestructure may be accounted for approximately by the so called method of quadratic momentum.     

Messung der Fehlordnungsenergie an abschreckend kondensiertem Kupfer bei tiefer Temperatur

Copper films are produced by quenching condensation on a substrate at low temperature. A stored energy release of 216 cal/mole and a resistivity decrease of 1.8μΩcm are observed during annealing from 20 to 60 °K. In this temperature range the recovery of the films is described by a crystallisation of highly disordered material between small crystallites, which are produced during condensation. About 14 atomic-% of the whole film substance take part in this process. The stored energy-resistivity ratioE/Δ? found is 1.9 cal/g/gm/gWcm in the whole temperature range from 20 to 60 °K. This value is in good agreement with the stored energy measurements on neutron-bombarded copper.     

Messung der Fehlordnungsenergie an abschreckend kondensierten Metallschichten bei tiefer Temperatur

Metal films are produced with a high degree of disorder by quenching condensation. The stored energy release and the resistivity decrease are measured during annealing of Au-, Pb-, and Sn-films from 20 to 60° K and during crystallization of amorphous Sn-films with a 10 atomic-% Cu-content. The results are compared with earlier measurements on Bi-, Ga-, and Cu-films produced by quenching condensation. The energy released during the crystallization of the amorphous films (Bi, Ga, Sn+10 at.-% Cu) amounts to half of the heat of melting. This is in good agreement with calculations ofOriani andLumsden for the disorder part of the entropy of melting. The recovery of the crystalline Cu-, Au-, Pb-, and Sn-films is described by a crystallization of highly disordered atoms to crystallites formed during condensation. About 30% of all atoms of these films are in this highly disordered state.     

Die Messung des komplexen Widerstandes der Fackelentladung

Zusammenfassung In der Arbeit wurde ein Gütefaktormesser zur Messung der elektrischen Parameter der Fackelentladung verwendet. Auf Grund der Änderung des Gütefaktors und der Resonanzfrequenz des Resonanzkreises, die durch die Fackelentladung verursacht wird, läßt sich der komplexe Widerstand der Fackelentladung bestimmen. Nach dieser Methode können auch die der Entladung zugeführte elektrische Leistung und die Strom-Spannungskennlinien ermittelt werden.Ferner werden in der Arbeit die Ergebnisse der Messung des parallelen ErsatzwiderstandesR _p und der KapazitätC _p der Fackelentladung angeführt. Durch das Studium der Strom-Spannungskennlinien wird die Analogie zwischen der Glimmentladung und dem Fackelbogen einerseits und der Fackelentladung und dem Fackelbogen andererseits bestätigt.

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The paper describes a method of measuring the complex resistance of a torch discharge. From the change in resonance frequency and the quality of the resonance circuit, caused by the torch discharge burning on this circuit, one can determine the parallel equivalent resistanceR _p and the capacityC _p of the torch discharge.The complex resistance of a torch discharge burning on a copper electrode was measured. The values obtained for the complex resistance and the h-f voltage on the electrode served to construct the volt-ampere characteristic of the torch discharge, equivalent to the characteristics of two-electrode discharges. The course of this characteristic confirms the transition of a torch discharge into a torch arc.

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Abschließend möchte ich Doz. V. Truneek für die Beurteilung der Ergebnisse und J. Chmela und J. Kratochvíl für die Konstruktion der Meßapparatur danken.     

Messung der Elektronenbeugungsintensitäten polykristalliner Aluminiumschichten bei tiefer Temperatur und Vergleich mit der dynamischen Theorie

By means of a retarding field apparatus the electron diffraction intensities of a polycrystalline Aluminium-foil have been measured for different electron energies between 17 and 50 kev. The specimen was kept at 154 °K and the thickness of the crystallites was about 280 Å. It has been shown that the high index reflections behave kinematically, while the first order reflections [e.g. (111), (200)] are much influenced by dynamical extinction effects which can be explained very well by the dynamical two beam approximation. Also the intensities of the higher orders [e.g. (222), (400)] of the strong reflections show marked deviations from the kinematical values. This intensity deficit can be interpreted by multiple scattering processes due to systematic interactions. The experimental results are compared with the second Bethe approximation (introduction of dynamic potentials) as well as with the second Born approximation where double scattering processes within the crystal are taken into account.     

Lokale Messung von Driftgeschwindigkeit und Temperatur der Ionen einer Argon-Niederdruckentladung mit resonanter Laserstreuung

The radial ion drift velocity and temperature in an argon low-pressure discharge have been measured by a resonant laser scattering method with high spatial resolution. The detection limit for the drift velocities was 2 · 10⁴ cm · s^?1. In the vicinity of the discharge axis the drift velocity grows linear with the distance from the axis. The measurements have shown the existence of a radial dependence of the ion temperature T¹(r). Comparisons of axial ion temperature T_? with T_‖(r = 0) are an experimental demonstration of the anisotropy of the ion velocity distribution in this kind of discharges.     

Messung der Glorienstreuung des totalen Streuquerschnitts von Na-Hg

The velocity dependence of the total cross section of Na-Hg has been measured in the velocity region from 750 to 2700 m/s. The extremaN=5.0 toN=11.0 are well resolved. The glory extrema indexing was performed by counting the number of measured rainbow extrema in the differential cross section at corresponding velocities. The results from the data evaluation method proposed by Bernstein and O'Brien are compared with the results from an inversion procedure for this system. Significant errors can result from the use of the Bernstein-O'Brien method except in the case of the expressiona ₁?r _m .     

Messung der Winkelverteilung und des Wirkungsquerschnittes beim Elementarprozeß der Elektron-Elektron-Bremsstrahlung

By using an electron-photon coincidence technique, we have measured the absolute cross section of electron-electron bremsstrahlung in dependence of the photon emission angle for a definite energy and a definite angle of the outgoing electron. An electron beam of 300 keV was used, incident on a carbon target. Within the experimental errors we find agreement with theoretical calculations. Simultaneously with the electron-electron bremsstrahlung the elementary process of electron-nucleus bremsstrahlung of carbon was measured.     

Zeitliches Abklingen des Szintillationslichts von Anthrazen- undp-Terphenyleinkristallen bei Beschuß mit α-Teilchen als Funktion der Einschußrichtung

Single crystals of anthracene andp-terphenyl have been bombarded with α-particles. The angle of incidence with respect to the crystal axes was varied. The directional intensity of the scintillation light was investigated as function of the decay time of the scintillator. During the first 100 nsec after the excitation of the crystal the anisotropy of the scintillation light yield decreases starting with a value larger than that measured with pulses of 1000 nsec length. For the next 900 nsec the anisotropy remains nearly constant being still higher than 1. Therefore the anisotropy of the fast component of the scintillation light is larger than the anisotropy of the slow component. The results are discussed with reference toBirk's formula.     

Messung der Hyperfeinstruktur-Aufspaltung des metastabilen3 P 2-Zustandes des Kr83 nach der Atomstrahl-Resonanzmethode

The hyperfine structure splitting of the metastable³ P ₂-state of Kr⁸³ has been measured by the atomic beam magnetic resonance method. A glow discharge served as a source of metastable atoms which were detected by surface ejection of electrons from a metal. In order to improve the signal-to-noise-ratio the magnetic C-field was modulated at a frequency of 37 cps. From the measured splittings the following hfs coupling constants were determined:

$$A(^3 P_2 ) = - (243 \cdot 970 \pm 0 \cdot 004)Mc/sec,B(^3 P_2 ) = - (452 \cdot 12 \pm 0 \cdot 08)Mc/sec.$$     

Zur elektronischen Struktur ungeordneter eindimensionaler Systeme. II. Verlauf der Streuparameter als Funktion der Energie

Statements on the energy dependence of the three scattering parameters are made for general energy dependent and non-local potentials used in a preceding paper [1] in a one-dimensional model for the electronic structure of disordered systems. All results are also valid in the relativistic case. The possible types for the behaviour of the wave function within the gaps and the form of the scattering parameters for δ-potentials are discussed.     

Messung der spezifischen Wärme von abschreckend kondensierten Indium-, Blei- und Wismut-Schichten bei tiefer Temperatur

Thin metal films are evaporated onto a cooled Be-foil at 25–32 °K in high vacuum. After condensation the films have a large degree of disorder. The specific heat is measured in the temperature range from 5–8 °K after condensation and after annealing. No differences in the specific heat are found for disordered and annealed In- and Pb-films. The specific heat of amorphous Bi-films, however, is 1.7 times larger than that of crystalline films. The results are discussed together with investigations of disordered films by superconducting tunneling.     

Messung der mittleren Lebensdauern des 748 keV- und des 776 keV-Niveaus in51Cr

Using theγ-radiation of 748 and 28 keV the half-lives of the first two excited states in⁵¹Cr at 748 and 776 keV have been measured by a pulsed beam technique. The interesting states were populated by the reaction⁵¹V(p, nγ)⁵¹Cr at 4 MeV proton energy. The half-lives were found to beT _1/2(⁵¹Cr, 748 keV)=(7.35±0.03) ns andT _1/2(⁵¹Cr, 776 keV)=(5.53±0.07) ns. The influence of the 28 keV transition between the two levels upon the lifetime of the 748 keV state has been investigated. The 776 keV-state populates the 748 keV state only by 8.4%. The lifetime of the 776 keV state, therefore, cannot account for the anomalous long lifetime of the level at 748 keV as has been proposed by Bartholomew et al.