Untersuchungen zu Transport und Speicherung von hohen Ionenstrahlintensitäten

In the framework of this thesis the intense low energy ion beam transport was investigated. Especially, the beam transport in toroidal magnetic field configurations was discussed, as it may allow the accumulation of high intensive beams in the future. One of the specific tasks is to design an injection system that can be used for the proposed low energy accumulator ring. This thesis regarding beam transport investigations is related to the larger research fields, storage rings used in accelerator physics and non-neutral plasmas. The proposal of building a storage ring with longitudinal guiding magnetic fields was made. Due to natural transversal focussing in magnetic fields it is possible to accumulate very intense charged particle beams, a subject of interest within the physics community. A simulation code (TBT) was written to describe the particle motion in curved segments. Particle in Cell techniques were utilized to simulate a multi particle dynamics. This code allows the user to generate different particle distributions as input parameter. A possibility of reading an external data file was made available so that a measured distribution can be used to compare simulation results with measured ones. A second order cloud in cell method was used to calculate charge density and in turn to solve Poisson’s equation. The circular toroidal coordinate system was used. The drift motion and gyrating motion was proved to be consistent with analytical values. Further simulations were performed to study the self field effects on beam transport. The experiments with single toroidal segments find niche in the work. The experiments were performed to compare the simulation results and gain practical experience. The toroidal segment has similar dimensions (major axis R = 1:3 m, minor axis r = 0:1 m, arc angle 30°) as for a full scale ring design. The main difference lies in the magnetic field strength. The available segments can be operated at room temperature producing 0:6T on axis maximum magnetic field, while for the storage ring design this value is in the range of 5T. The preparatory experiments consisted of building and characterization of the ion source in a first step. Along with the momentum spectrometer and emittance scanner the beam properties were studied. Low mass ion beams He+ and mixed p, H2+, H3+ beams were analyzed. The proton beam consisting of a 48% H+ fraction was extracted regularly and used for further experiments. A moderate beam energy of 10 keV was chosen as operational energy for which 3.08 mA proton beam current was measured. In the second stage, beams were transported through a solenoid and the phase space distribution was measured as a function of the magnetic field for different beam energies. The phase-space as distributions measured in a first stage were simulated backward and then again forward transported through the solenoid. The simulated results were then compared with the measured distribution. The LINTRA transport program was used. The phase-space distribution was further simulated for transport experiments in a toroidal magnetic field. The experiments with a single toroidal segment give basic results necessary to compare the results between transport code (TBT) and measurements. The optical diagnostic provides measurements which can be well compared with the simulated results. A digital camera with a magnetic shield was used to record images in jpeg file format. A subroutine was written to analyze an image file to give the intensity distribution of a given image file. The integrated profile in vertical and horizontal direction was used to calculate the vertical drift and the beam size. The simulated values were in good agreement with the measured ones. The injection system needs most care. The transport program that was used to simulate the beam in the toroid was also used to design the injection system. The injection system with its special field configurations was designed to perform experiments with room temperature segments. The main point to tackle was to smoothly bring the charged particles generated outside the trap into the acceptance of the ring. The designed system consists of two sources, one representing a ring beam and the other one the injection beam. While simulations showed a clear way, how to inject the particle beam via a well positioned solenoid and in combination with a transverse electric field element causing an ExB drift into the main ring acceptance. After construction of these injection elements it will be very important to measure the robustness of such a system with respect to the beam stability- especially of the injection channel.Gegenstand der vorliegenden Arbeit war die Untersuchung des Transports intensiver Ionenstrahlen in toroidalen Magnetfeldern und die Injektion von geladenen Teilchenstrahlen in stelleratorähnlichen Ringen. Ein Speicherring mit einem toroidalen Magnetfeld wurde für die Akkumulation von intensiven Ionenstrahlen vorgeschlagen. Die Konfiguration ist ähnlich, wie bei den klassischen Stellaratoren, bei denen Toroidsegmente zu einem Torus angeordnet werden, um geladene Teilchen einzuschließen. Die sich daraus ergebenden longitudinalen Magnetfelder ermöglichen aber auch die Fokussierung eines in solch einer Apparatur eingeschlossenen Ionenstrahls. Für die numerischen Simulationen des Strahltransports wurde ein Computermodell entwickelt, das die Teilchenbewegung in inhomogenen Magnetfeldern berechnet. Dieser "Particle in Cell" - Code (PIC) ermöglicht die Untersuchung einer Multiteilchendynamik. Die Berechnung des Strahltransports kann auf verschiedenen Arten von numerischen Gittern erfolgen, nämlich auf kartesischen, zylindrischen und toroidalen Gittern. Für die Berechnung der Raumladungskräfte wurde die Poisson-Gleichung auf dem toroidalen Gitter diskretisiert und die für die Lösung erforderliche Ladungsträgerdichte mit Hilfe der Cloud in Cell - Methode zweiter Ordnung an jedem Gitterpunkt bestimmt. Zunächst wurde untersucht, welche Methode sich für die Lösung der Poisson-Gleichung hinsichtlich der Rechenzeit und der Flexibilität gegenüber den zu variierenden Randbedingungen eignet. Es erfolgt dann die iterative Lösung einer Matrix, die ein System aus unbekannten linearen Gleichungen beschreibt. Für diese Methode wurden verschiedene iterative Verfahren untersucht und optimiert. Die externen magnetischen Felder, wie zum Beispiel das Feld der Toroidsegmente, wurden mit Hilfe eines Biot-Savart-Solvers bestimmt, mit dem es möglich ist die realen Feldverteilungen inklusive der in dieser Arbeit nicht zu vernachlässigenden Randfelder zu berechnen. Neben den umfangreichen Arbeiten zur numerischen Simulation des Strahltransportes wurden auch Experimente durchgeführt, um das entwickelte Computermodel zu evaluieren und praktische Erfahrungen bei der Konstruktion und dem Aufbau eines toroidalen Speicherringes zu sammeln. Das für die Experimente verwendete Toroidsegment entspricht hinsichtlich seiner Geometrie etwa den Segmenten, die für den geplanten Speichering vorgesehen sind. Während es sich später jedoch um supraleitende Magneten handeln wird, die eine Feldstärke von bis zu 5T erzeugen können, kann das für die Experimente ausgelegte Toroidsegment bei Raumtemperatur betrieben werden und erreicht eine magnetische Feldstärke von 0,6T auf der magnetischen Achse. Durch den Vergleich der experimentellen Befunde mit den Ergebnissen der numerischen Simulation kann eine Skalierung auf die zu erwartenden Strahleigenschaften in dem zukünftigen Speicherring erfolgen. Durch die Vielzahl an Experimenten zum Strahltransport konnte das im Rahmen der Arbeit entwickelte Computerprogramm (TBT) erfolgreich evaluiert werden. Die Messergebnisse konnten durch das numerische Modell mit geringen Abweichungen reproduziert werden, so dass sich das Programm dazu eignen sollte, die Strahldynamik in einem kompletten Ring zu beschreiben und die Auslegung des Injektionssystems zu berechnen. Gerade die Injektion in einen troroidalen Speicherring stellt wegen der geschlossenen magnetischen Flächen eine Herausforderung dar. Da das Injektionssystem zu einem späteren Zeitpunkt mit der im Rahmen dieser Arbeit aufgebauten Experimentieranordnung untersucht werden soll, wurde die Injektion auf die vorhandene Spezifikation der Toroidsegmente angepasst. Der bisherige Aufbau soll zunächst um ein Toroidsegment erweitert werden und ermöglicht damit, den Einfluss des Kickers auf den im Ring zirkulierenden Strahl zu untersuchen. Die Transportrechnungen mit TBT ergaben für das geplante Setup optimale Abmessungen der Ablenkplatten, um bei möglichst großen Driften, die für die Injektion benötigt werden geringe Störungen des Primärstrahles zu erreichen. Für die kommenden Experimente wird eine baugleiche Ionenquelle verwendet, die den Injektionsstrahl erzeugen soll. Die Strahlanpassung erfolgt mit Hilfe eines Solenoiden, während die Ankopplung der Strahltrajektorien an den Feldverlauf im Ringsegment mit Hilfe von Hilfsspulen erfolgen soll, deren sorgfältige Auslegung mit TBT erfolgte. Der Strahltransport durch die Toroidsegmente ist sehr sensitiv auf die Randfelder der Hilfsspulen. Es konnte aber gezeigt werden, dass es Einstellungen gibt, bei denen sich ein Ionenstrahl bei guter Transmission injizieren lässt, während der im Ring zirkulierende Strahl kaum beeinflusst wird. Eine große Variation der Einschlussparameter bei den Simulationen lieferte schließlich die Akzeptanz des Injektionssystems sowie dessen Abbildungseigenschaften

A Critical Review on Balachaturbhadra Churna: An Effective Ayurveda Formulation for the Pediatric Age

Balachaturbhadra Churna offers a multitude of health benefits for which it has become so poapular prescription by Kaumarbhritya practioners of Ayurveda. It is a combination of four drugs Musta, Pippali, Ativisha and Karkatashringi. This combination was first mentioned in Chakradatta and has been in practice since a millennium. Many queries have been raised on the usage of Aconite species of drugs recently, thus doubting the safety and efficacy of Balachaturbhadra Churna. Very few works have been published on Balachaturbhadra Churna till now. The aim of the present study was to compile and review such available references from classics and research works published on Balachaturbhadra Churna. Total five studies are published on Balachaturbhadra Churna, which revalidated the impact of classical guidelines. The research papers revealed standards of Quality Control and pharmacological efficacy of the drug. All the experimental studies revealed that Balachaturbhadra Churna is having no toxic hazards at very higher Dose levels, proving it safe for therapeutic use. Though certain limitations were observed in these researches, the results can be considered as a lead for further well stratified clinical studies

5th International and 26th All India Manufacturing Technology, Design and Research Conference

This book presents selected research papers of the AIMTDR 2014 conference on application of laser technology for various manufacturing processes such as cutting, forming, welding, sintering, cladding and micro-machining. State-of-the-art of these technologies in terms of numerical modeling, experimental studies and industrial case studies are presented. This book will enrich the knowledge of budding technocrats, graduate students of mechanical and manufacturing engineering, and researchers working in this area.

Experimental investigation and optimization of wall deflection and material removal rate in milling thin-wall parts

The selection of optimal process parameters is essential while machining thin-wall parts since it influences the quality of the product and affects productivity. Dimensional accuracy affects the product quality, whereas the material removal rate alters the process productivity. Therefore, the study investigated the effect of tool diameter, feed per tooth, axial and radial depth of cut on wall deflection, and material removal rate. The selected process parameters were found to significantly influence the in-process deflection and thickness deviation due to the generation of unfavorable cutting forces. Further, an increase in the material removal rate resulted in chatter, thus adversely affecting the surface quality during the final stages of machining. Considering the conflicting nature of the two performance measures, Non-dominated Sorting Genetic Algorithm-II was adopted to solve the multi-objective optimization problem. The developed model could predict the optimal combination of process variables needed to lower the in-process wall deflection and maintain a superior surface finish while maintaining a steady material removal rate

Interactions of Gold and Silver Nanoparticles with Bacterial Biofilms: Molecular Interactions behind Inhibition and Resistance

Many bacteria have the capability to form a three-dimensional, strongly adherent network called ‘biofilm’. Biofilms provide adherence, resourcing nutrients and offer protection to bacterial cells. They are involved in pathogenesis, disease progression and resistance to almost all classical antibiotics. The need for new antimicrobial therapies has led to exploring applications of gold and silver nanoparticles against bacterial biofilms. These nanoparticles and their respective ions exert antimicrobial action by damaging the biofilm structure, biofilm components and hampering bacterial metabolism via various mechanisms. While exerting the antimicrobial activity, these nanoparticles approach the biofilm, penetrate it, migrate internally and interact with key components of biofilm such as polysaccharides, proteins, nucleic acids and lipids via electrostatic, hydrophobic, hydrogen-bonding, Van der Waals and ionic interactions. Few bacterial biofilms also show resistance to these nanoparticles through similar interactions. The nature of these interactions and overall antimicrobial effect depend on the physicochemical properties of biofilm and nanoparticles. Hence, study of these interactions and participating molecular players is of prime importance, with which one can modulate properties of nanoparticles to get maximal antibacterial effects against a wide spectrum of bacterial pathogens. This article provides a comprehensive review of research specifically directed to understand the molecular interactions of gold and silver nanoparticles with various bacterial biofilms

Analytical Validation of an ATR-FTIR Based Method for Quantifying the Amount of Polysorbate 80 Adsorbed on the PLGA Nanoparticles

Nanomedicine is envisioned to have a tremendous impact on targeted drug delivery in future. Coating of nanoparticles with non-ionic surfactants has been often employed for enhancing targeting in drug delivery systems. Polysorbate 80 is one of the non-ionic surfactants used often as a coating agent for receptor-mediated endocytosis into the brain. However, very few studies have been done to investigate the actual amount of the surfactant adsorbed or the mechanism of adsorption onto the nanoparticles. We had developed an assay using an ATR-FTIR method for quantiation and adsorption mechanism of polysorbate 80 on PLGA nanoparticles. Here we show the analytical validation of this method, for exploring its suitability for its intended purpose in industries. To comply with regulatory bodies and for standardization, we have followed the ICH and FDA guidelines for analytical validation and investigated the required criteria i.e. accuracy, precision, linearity, range ,limit of detection and quantitation. The method successfully complied with all regulatory criteria and is therefore suitable for successful use in industry, academia and by regulatory bodies.</p

Evaluation of immunomodulatory activity of Balachaturbhadra Churna- An Ayurvedic formulation

Balachaturbhadra churna (BCBC) is an extensively used poly-herbal formulation of Ayurveda for pediatrics disorders.It is indicated for respiratory disorders, fever, diarrhoea, and vomiting. It is practiced as a potent immune enhancer in children. The present study was undertaken to evaluate immunomodulatory activity of BCBC to validate the classical claims of therapeutic efficacy made on it. The cell-mediated immune response was evaluated against triple antigen induced immunological paw edema in pre-sensitized rats. The humoral immune response against cyclophosphamide induced immunosuppression in sheep red blood cells (SRBC) pre-sensitized rats was evaluated by hemagglutination titer, ponderal changes, and histopathological studies. BCBC produced significant increase (P&lt;0.05) in immunological paw edema in triple antigen pre-sensitized rats and significant increase (P&lt;0.05) in hemagglutination titer value in humoral immune response compared to control and vehicle control groups. The drug had significant effect in reversal of cyclophosphamide induced immune suppression in thymus, spleen, and lymph nodes. The results indicate a significant effect of the BCBC on cell-mediated immune response and humoral immune response. The reversal of cyclophosphamide induced immune suppression of organs indicates cytoprotective activity of BCBC in rats