Material dependence of 2

Calculations of the material dependence of 2H(d,p)3H cross section and neutron-to-proton branching ratio of d+d reactions have been performed including a concept of the 0+ threshold single particle resonance. The resonance has been assumed to explain the enhanced electron screening effect observed in the d+d reaction for different metallic targets. Here, we have included interference effects between the flat and resonance part of the cross section, which allowed us to enlighten observed suppression of the neutron channel in some metals such as Sr and Li. Since the position of the resonance depends on the screening energy that strongly depends on the local electron density. The resonance width, observed for the d+d reactions in the very hygroscopic metals (Sr and Li) and therefore probably contaminated by oxides, should be much larger than for other metals. Thus, the interference term of the cross section depending on the total resonance width provides the material dependences

The Deuteron-Fusion-Reactions in metals

Der Einfluß der Elektronenfreiheitsgrade auf Kernreaktionen ist die übergeordnete Thematik dieser Arbeit zu deren Behandlung verschiedene physikalische Forschungsgebiete beitragen. Zu diesem Zweck wurden die d+d Fusionsreaktionen durch Autoimplantation in polykristallinen Metallen der reinen Elemente Lithium, Strontium, Natrium, Aluminium, Zirkonium, Tantal und Palladium untersucht. Durch eine neu entwickelte automatische on-line Analysemethode wurde es erstmals möglich Deuteriumdichten während des Meßvorgangs zu überwachen und dadurch wirkungsquerschnittsbezogene Resultate in metallischer Umgebung zu erhalten. Die Anwesenheit der Elektronen führt zu einer Abschirmung der abstoßenden Kernladungen. Es wurden dazugehörige Abschirmenergien zwischen 190 und 320 eV gemessen, die den Wert für gasförmiges, molekulares Deuterium (25 eV aus Gastartgetexperimenten) um eine Größenordnung überschreiten. Die Verwendung von 4 Detektoren erlaubte die Messung der Winkelverteilung für die Reaktionen 2H(d,p)3H und 2H(d,n)3He zu noch kleineren Energien und Bestätigung der Anisotropie. Für Lithium, Natrium und Strontium konnte eine signifikante Asymmetrie im Verzweigungsverhältnis der beiden Reaktionskanäle zu niedrigen Energien hin beobachtet werden mit einer starken Unterdrückung des Neutronenkanals, die so zuvor noch nicht bekannt war. Damit einher geht auch eine Veränderung der Winkelanisotropie. Die Untersuchung des Metall-Wasserstoff-Systems führt in Verbindung mit der Restgaszusammensetzung der Vakuumanlage zu spezifischen aus der Oberflächenphysik resultierenden Problemen, die in dieser Form bei kernphysikalischen Experimenten bisher unbedeutend waren; deren Nichtbeachtung führt jedoch zu folgenschweren Meßfehlern. Es konnte demonstriert werden, wie die Restgaszusammensetzung einer Hochvakuumanlage unter Einwirkung des Ionenstrahls zum Aufbau einer Metalloxid- oder Kohlenstoffschicht auf der Targetoberfläche führt und welche Bedingungen herrschen müssen, damit der Abschirmeffekt beobachtet werden kann, da beide Arten von Oberflächenschichten sein Verschwinden bewirken. Neben dem Experiment wurden quantenmechanische Simulationsrechnungen durchgeführt, um den Abschirmeffekt quantitativ zu beschreiben. Für die anomale Asymmetrie konnte ein Erklärungsansatz aufgestellt werden

Recovery of Rare Earth Elements from NdFeB Magnets by Chlorination and Distillation

A sustainable separation concept for large-scale recycling of NdFeB magnets under atmospheric pressure was developed by utilizing a combination of two separation concepts known from the literature: (I) selective pre-separation by in situ chlorination and evaporation of ground oxidized NdFeB material and (II) subsequent distillation for high-purity recovery of all recyclable chlorinated material components, especially its Rare Earth Elements (REEs). Theoretically, simplified estimations of the time conversion curves at 1173 K, 1273 K, and 2000 K of a single particle resulted in the idea of realizing chlorination in some kind of combustion chamber, fluidized bed, or continuous combustion chamber. After chlorination, all non-volatile components, such as REE chlorides, are condensed out of the vapor phase in a single-stage phase separator. For subsequent fine separation by distillation (1292–1982 K for Rare Earth Chlorides and 418–867 K at 2500 kPa for boron and zirconium chloride recovery), simplified simulations were performed in a total-reflux column under ideal phase equilibrium conditions to show the estimated minimum separation effort. Using two composition examples from the literature, high-purity separation of the major Rare Earth Chlorides within a twelve-stage distillation column as a residual heavy boiling product has been demonstrated to be potentially technically feasible

Material dependence of

Calculations of the material dependence of 2H(d,p)3H cross section and neutron-to-proton branching ratio of d+d reactions have been performed including a concept of the 0+ threshold single particle resonance. The resonance has been assumed to explain the enhanced electron screening effect observed in the d+d reaction for different metallic targets. Here, we have included interference effects between the flat and resonance part of the cross section, which allowed us to enlighten observed suppression of the neutron channel in some metals such as Sr and Li. Since the position of the resonance depends on the screening energy that strongly depends on the local electron density. The resonance width, observed for the d+d reactions in the very hygroscopic metals (Sr and Li) and therefore probably contaminated by oxides, should be much larger than for other metals. Thus, the interference term of the cross section depending on the total resonance width provides the material dependences

Material dependence of 2H(d,p)3H cross section at the very low energies

Calculations of the material dependence of 2H(d,p)3H cross section and neutron-to-proton branching ratio of d+d reactions have been performed including a concept of the 0+ threshold single particle resonance. The resonance has been assumed to explain the enhanced electron screening effect observed in the d+d reaction for different metallic targets. Here, we have included interference effects between the flat and resonance part of the cross section, which allowed us to enlighten observed suppression of the neutron channel in some metals such as Sr and Li. Since the position of the resonance depends on the screening energy that strongly depends on the local electron density. The resonance width, observed for the d+d reactions in the very hygroscopic metals (Sr and Li) and therefore probably contaminated by oxides, should be much larger than for other metals. Thus, the interference term of the cross section depending on the total resonance width provides the material dependences