Cubic dispersion relation for a relativistic backward-waveoscillator

The cubic approximation to the dispersion relation for a relativistic backward-wave oscillator is obtained, and the utility and limits of the approximation are presented. The approximation is obtained by Taylor series expansion of the wave admittance in the dispersion relation for the transverse-magnetic and free-streaming modes of a relativistic, thin, hollow, cylindrical electron beam moving along the axis of a disc-loaded waveguide in a strong axial magnetic field. The resulting cubic dispersion relation yields instability growth rates and frequencies which fall off beyond their maximum more sharply with increasing wavenumber than for the complete dispersion relation. The approximation is found to be quite good near the operating points of contemporary high-power relativistic backward-wave oscillators, namely, for relatively long wavelength and small ratio of Budker's parameter to the relativistic gamma factor of the beam     

Determination of organic group parameters (AOCl, AOBr, AOs) in water by means of ion-chromatographic detection

Summary The control of water quality is often performed by analysis of organic group parameters, e.g., Adsorbable Organic Halogen (AOX). The differentiation of the group parameter AOX and the determination of the parameter Adsorbable Organic Sulfur Compounds (AOS) can be performed by ion-chromatography for detection of the anions obtained after pyrohydrolysis of the organic adsorbed compounds. Investigations concerning pyrohydrolysis of organic solutes and enrichment on a nearly chlorine- and sulfur-free active charcoal have been performed. By means of this charcoal the determination of organic sulfur solutes in the g/l range can be realized.

---

Bestimmung der organischen Gruppenparameter (AOCl, AOBr, AOS) in Wässern mit ion-chromatographischer Detektion

     

Experimental results on diffractive one-pion production at the CERN ISR

New experimental results are reported on diffractive dissociation of protons into (nπ⁺) in proton-proton collisions at a centre-of-mass energy of $\text{s}\text{= 45}\text{GeV}$. The data were obtained using the Split-Field-Magnet detector at the CERN Intersecting Storage Rings. We have searched for resonance contributions and found peaks at mass values of 1.5 GeV, 1.65 GeV, and 2.1 GeV. A dip in $\text{d}\text{σ}\text{d}\text{t}$ is observed at low t and low mass; it is most pronounced for events with neutrons emitted at 90° in the Gottfried-Jackson frame. The correlation between mass and slope depends strongly on θ_J. The cross section of the channel pp → pnπ⁺ is 400 ± 110 μb at $\text{s}\text{= 45}\text{GeV}$, giving an energy dependence of s^?0.30±0.07 for isospin exchange zero in this channel.     

On the distribution of the number of packets in the fluid flow approximation of packet arrival streams

Fluid flow approximations are widely used for approximating models of communication systems where packet arrival streams are generated in a regular manner over certain intervals (constant rate). The appropriate mathematical model for describing those bursty arrival streams in the fluid flow framework are the well-known Markov modulated rate processes (MMRP). The paper deals with the distribution of the numberN(t) of packets in the interval [0,t] of MMRP. For two-state MMRPs and their superpositions we derive formulas for the distribution ofN(t) and its density. Further we give asymptotic results. The presented numerical results and simulation studies illustrate the goodness of the fluid flow approximation and show that the proposed numerical algorithms work well even in the case of multiplexing a large number of burst silence sources.This work was partially supported by a grant from the Deutsche Bundespost TELEKOM.     

Über die Frequenzabhängigkeit der Schallabsorption im Aerosol

Zusammenfassung Es werden die verschiedenen Ursachen für die Schallabsorption in Nebeln untersucht. Ein wesentlicher Intensitätsverlust der Schallstrahlen kann, wie schon durch frühere Untersuchungen bekannt ist, durch die Reibung in den das Partikel periodisch umströmenden Gasschichten bewirkt werden. Diese Reibungsverluste sind zunächst von der mehr oder weniger vollständigen Teilnahme der Schwebeteilchen an der Schwingung abhängig. Der Grad der Teilnahme und damit auch der Absorptionskoeffizient lassen sich als Funktion von Teilchenradius und Schallfrequenz elementar berechnen. Je feinteiliger der Nebel ist, bei um so höheren Frequenzen beginnt der Anstieg der Absorption. Es erklärt sich daraus zum Teil die geringe Reichweite kurzwelliger Schallstrahlen in Nebeln.Herrn Doz. Dr. E. Hiedemann bin ich für anregende Erörterungen zu Dank verpflichtet.     

Search for spontaneous fission emitters in Atlantis II (Part I)

No evidence for spontaneous fission decay (and the implied presence of superheavy nuclides) has been found in a several kilogram precipitate gathered at the Atlantis-II site in the Red Sea. The sample was investigated with a neutron multiplicity counternon-destructively so that no chemical losses should have been sustained. Upper limits have been determined for possible superheavy element concentrations in the sample.     

Weak self-consistent approximation scheme in many-body systems

In this paper we show a possibility of restricting the usual self-consistency conditions in approximations to many-body systems. Instead of requiring thermodynamic consistency for even non-physical one-particle quantities, we impose it for the physically relevant quantities only. As a consequence of this less severe requirement, one does not lose any physically relevant information, but one can construct new types of approximations. As an example a parametric approximation scheme is given.     

Magnetooptical studies on thin iron films

Magnetooptical measurements on Fe-films in the layer system ZnS-Fe-MgF₂-Ag showed a decrease of the Kerr-intensity values with Fe-film thicknesses below 15nm, not predicted by theoretical calculations. Magnetization curves obtained magnetooptically indicate a significant influence of the layer system on the magnetic properties of Fe-films.     

A study of the charge-exchange reaction pp → nΔ++(1232) at ISR energies

We report on a study of the charge-exchange reaction pp → nΔ⁺⁺(1232) at the CERN intersecting storage rings (ISR) in the energy range √s = 23 to 53 GeV. From our analysis of the energy dependence of the total cross-section, of the differential cross-section dσ/dt and of the decay angular distributions we find evidence that pion exchange is dominant up to √s = 23 GeV and that (?+A₂) exchange dominates the reaction for √s ? 30 GeV, as described by simple Regge-pole models.