Der Modal-Split im Personenfernverkehr Analyse und Berechnung des menschlichen Wahlverhaltens

Available from TIB Hannover: RA2508(47) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Der Modal-Split im Personenfernverkehr Analyse und Berechnung des menschlichen Wahlverhaltens

Available from TIB Hannover: RA2508(47) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Ein Segmentierungsalgorithmus auf einem Parallelrechner

SIGLEAvailable from TIB Hannover: RN 3147(127) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

New methods of improving the orbit determination and stability at LEP

The orbit quality is of particular importance for a good performance of an accelerator. Beam parameters like the interaction rate of a collider or the level of spin polarization strongly depend on the orbit. Two new methods to improve the orbit measurement and stability are demonstrated. The beam position monitors in an accelerator are carefully aligned to the centres of the quadrupole magnets. A residual mechanical but also electronic offset can persist. This offset is measured by a beam based alignment method developed at LEP. The method and its installation are described. Measurement procedures as well as results for different magnet types and BPM electronics are shown. The impact of the BPM offsets on the achievable spin polarization level is outlined. The vertical orbit has shown large variations during LEP operation. Frequent orbit corrections were required to avoid a decrease of the interaction rate. Low-beta insertion quadrupoles were suspected to be the origin of the drifts. The positions of these magnets have been monitored by different systems. The movements are compared to the orbit variations and the correlation is shown. An orbit feedback based on the mechanical measurements has been put into operation to keep the LEP orbit stable. (orig.)SIGLEAvailable from TIB Hannover: RN 6945(1998,5) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Investigation of Microstrip Gas Chambers and their application in the CMS experiment

SIGLEAvailable from TIB Hannover: RN 6945(1998,25) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

GaAs strip and pixel detectors for applications in high energy physics

At the beginning of the next century the Large Hadron Collider (LHC) will start generating pp collisions with a centre of mass energy of 14 TeV, allowing the search for new particles and important tests of the Standard Model of elementary particle physics. The high luminosity and the small bunch spacing in the LHC lead to design constraints for the experiments, which demand central trackers with a large channel density. Thus semiconductor detectors form the core of the tracking systems of the two experiments ATLAS and CMS. The high total reaction rate results in radiation loads much higher than the existing and widely used detector technologies are able to withstand. In view of the radiation environment a research and development program was set up to find alterantives to the commonly used Silicon detectors. Since GaAs electronics is known to be radiation resistant, the I Physics Institute of the RWTH Aachen started a research program on GaAs as a detector material. In the framework of this program GaAs detectors were developed and tested for their radiation resistance and applicability as strip or pixel detectors. This thesis concentrates on the design of GaAs stirp and pixel detectors and on the study of their properties in view of signal behaviour and spatial resolution. After a short description of the Standard Model and the experimental conditions at LHC and CMS in chapter 1, the principles of particle detection using semiconductors and the special properties of GaAs detectors are the subject of chapter 2. Here the formation of the electric field, the magnitude of the leakage currents and the modelling of the signal behaviour are described. A study of the design of GaAs stirp and pixel detectors follows in chapter 3, including the description of integrated elements like coupling capacitors and bias structures. In chapter 4 a presentation of the behaviour of multi-channel GaAs detectors is given, while the next two chapters report on the measurements performed with GaAs strip and pixel detectors, respectively. Here signal response, charge spread, detection efficiency and spatial resolution of the detectors are measured and compared to a Monte Carlo simulation, which particularly includes the position dependent charge collection efficiency of the GaAs detectors. Finally the results of GaAs detectors are confronted with the demands of high energy physics applications. (orig.)SIGLEAvailable from TIB Hannover: RN 6945(1999,11) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Suche nach dem Zerfall des Axions in zwei Photonen

TIB Hannover: RN 6945(1986,19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Messung der Reaktion e"+e"- #-># #gamma##gamma#(#gamma#) mit dem L3-Detektor bei LEP

Available from TIB Hannover: RN 6945(1998,33) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman