Berechnung von Elektron-Photon-Kaskaden in Blei für eine Primärenergie von 200 MeV

The development of 200 MeV electron-initiated showers has been simulated by the Monte-Carlo method on an electronic digital computer. Bremsstrahlung, ionization-loss, and multiple-scattering for electrons and pair-production, Compton scattering, and photo-effect for photons have been taken into account. The total cross-sections for the various processes have partly been corrected by empirical correction factors to provide the correct energy dependence. Electrons were followed down to 1·5MeV total energy and photons to 0·26 MeV. The results are compared with experimental data and the Monte-Carlo calculations ofMessel et al.     

Schnell-Methode zur Umsetzung von Kohlenwasserstoffen zu Wasserstoff für die Isotopenanalyse

Es wird eine weiterentwickeltes, isotopenanalytisches Verfahren zur probenchemischen Umsetzung von Kohlenwasserstoffen mit Chromium zu Wasserstoff bei 1300 K vorgestellt. Die erzielten Testergebnisse zeigen anhand der gemessenen δD-Werte, daβ Quarzöfen bei diesen Temperaturen noch keine die Isotopenmeβwerte beeinflussende Diffusion von Wasserstoff durch die Wandung zulassen. Auβerdem erfolgte die Reaktion nahezu spontan und vollständig, was die Methode zeitlich sehr effektiv macht.

A modified isotope analytical method is presented for the chemical reaction of hydrocarbons with chromium at 1300 K to form hydrogen. The test results obtained (i.e. the measured δD-values) show that at this temperature quartz heating tubes do not allow hydrogen to diffuse through the wail, which fact would influence the isotopic composition. Furthermore the reaction proceeds nearly spontaneously and quantitatively, which yields an effective method, especially with respect to time.     

Abhängigkeit des Torsionsmoduls von stahl von der Torsionsvorspannung

Ohne Zusammenfassung

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Elektrophotolumineszenz eines Zink-Cadmium-Sulfid-Phosphors in Abhängigkeit von Anregungswellenlänge und Feldimpulsbreite

Luminescence flashes in an excited ZnCdS (Ag) phosphor occur when electric fields are put on or off. Whether these flashes are positive or negative depends on the length of the field pulse, on the exciting wavelength, and on the polarity of the irradiated electrode. There is a critical duration of the field pulses for which no field-off flash appears. At another but related critical time, the flashes with periodic field applications change sign. These times change with the exciting wavelength. The observations are interpreted as being controlled by the gradual filling of surface traps, which in its turn is influenced by the distribution of electron and hole concentrations produced by the incident radiation and the electric field. The critical time is approximately equal to the time needed for completely filling the surface traps.     

Parameterberechnung für die Konzentrationsabhängigkeit der Fluoreszenz in nichtphotoleitenden Kristallinen Leuchtstoffen

There are two formulars for the Luminescence as function of activatorconcentration (Johnson-Williams and Ewles-Lee). From this paper it is possible to calculate the parameters in both formulas for very little activatorconcentration direct in a diagram log Intensity versus log concentration. Our calculation leads to a straight line with the slope 1 and the one parameter follows from extrapolation toc=1. The second parameter is available from the maximum of the curve.On the other hand our calculation allows to decide between both formulas. In the region for great values of concentration the equation of Ewles-Lee gives another straight line for log Intensity versus concentration.Experiments from von Uitert and Soden on CaWO₄ activated with rare earth ions confirm our method.     

Zweiteilchen-Näherung für ein Fermionensystem mit anziehender Wechselwirkung

For a System of fermions with short range attractive interaction, the sequence of differential equations for the Green's functions is broken off by using the Martin-Schwinger approximation for the six point function. The solution for the ground state of the system yields the momentum distribution and the spectrum of bound pairs. The latter is to be interpreted as the spectrum of collective excitations. The limits of applicability of the approximation are discussed.