Surface roughness interpretation of 730 kg days CRESST-II results

The analysis presented in the recent publication of the CRESST-II results finds a statistically significant excess of registered events over known background contributions in the acceptance region and attributes the excess to a possible Dark Matter signal, caused by scattering of relatively light WIMPs. We propose a mechanism which explains the excess events with ion sputtering caused by 206Pb recoils and alpha particles from 210Po decay, combined with realistic surface roughness effects.Comment: 15 pages, 6 figures. v2: corrected quenching factor discussion. v3: corrected references. v4: added reference

Features of Fast Neutrons in Dark Matter Searches

Diffractive scattering of "fast" or "high energy" neutrons, can give low energy nuclear recoils in the signal region for dark matter searches. We present a discussion using the 'black disc' model. This permits a simple and general, although approximate, description of this possible background. We note a number of its features. In particular there are mass number A dependent aspects which can be studied in setups where events on different nuclei are observable at the same time. These include the recoil energy distributions, and the A behavior of the cross section. We define a parameter $E^o_R$ which characterizes the recoil energy to be expected due to fast neutrons. It ranges from 100 keV on light nuclei to a few keV on heavy nuclei, and a general treatment is possible in terms of it, within the 'black disc' approximation. In addition, the presence of inelastic processes would be characteristic of fast neutrons.Comment: new version with numerous small corrections and clarifications. Improved figures and references. No essential changes in conten

Status of the EDELWEISS-II experiment

EDELWEISS is a direct dark matter search experiment situated in the low radioactivity environment of the Modane Underground Laboratory. The experiment uses Ge detectors at very low temperature in order to identify eventual rare nuclear recoils induced by elastic scattering of WIMPs from our Galactic halo. We present results of the commissioning of the second phase of the experiment, involving more than 7 kg of Ge, that has been completed in 2007. We describe two new types of detectors with active rejection of events due to surface contamination. This active rejection is required in order to achieve the physics goals of 10-8 pb cross-section measurement for the current phase

Das deutsche und französische Klarinettensystem

Die Existenz verschiedener Klarinettensysteme sorgt in der Fachwelt seit Jahren für intensive Diskussionen über Vor- und Nachteile der unterschiedlichen Griffsysteme und ihrer klanglichen Eigenschaften. Vor diesem Hintergrund bietet die vorliegende Studie einen umfassenden Vergleich der deutschen und französischen Klarinette, der sich ausgehend von der historischen Entwicklung über instrumentenbauliche Unterschiede und akustische Eigenschaften bis hin zu klangästhetischen Aspekten erstreckt. Ergänzt wird diese Gegenüberstellung durch eine empirische Untersuchung zur Wahrnehmbarkeit von klanglichen Systemmerkmalen. Im Ergebnis zeigt sich, dass nicht unterschiedliche Instrumente, sondern kulturelle Faktoren und individuelle Ausdrucksintentionen den Klang und die Wirkung des Instrumentalspiels bestimmen. Abschließend werden in einer vertiefenden Analyse von Unterrichtswerken die Auswirkungen der Systemtrennung auf die Instrumentaldidaktik aufgezeigt

Organische Modifizierung von mesoporösen Silicaten unter der Verwendung metallorganischer Reagenzien - Strategie, Variabilität und Anwendungen

Die Arbeit befasst sich mit der Entwicklung einer neuen Methode zur organischen Funktionalisierung mesoporöser Silicate. Zu diesem Zweck werden metallorganische Verbindungen eingesetzt. Die Arbeit gliedert sich in die Bereiche Methodenentwicklung, Einfluß auf die Festkörperstruktur, Variabilität der Reaktion und Anwendung der neu entwickelten Materialien

CdWO4 scintillating bolometer for Double Beta Decay: Light and Heat anticorrelation, light yield and quenching factors

We report the performances of a 0.51 kg CdWO4 scintillating bolometer to be used for future Double Beta Decay Experiments. The simultaneous read-out of the heat and the scintillation light allows to discriminate between different interacting particles aiming at the disentanglement and the reduction of background contribution, key issue for next generation experiments. We will describe the observed anticorrelation between the heat and the light signal and we will show how this feature can be used in order to increase the energy resolution of the bolometer over the entire energy spectrum, improving up to a factor 2.6 on the 2615 keV line of 208Tl. The detector was tested in a 433 h background measurement that permitted to estimate extremely low internal trace contaminations of 232Th and 238U. The light yield of gamma/beta, alpha and neutrons is presented. Furthermore we developed a method in order to correctly evaluate the absolute thermal quenching factor of alpha particles in scintillating bolometers.Comment: 8 pages 7 figure

An evaluation of leadership characteristics required to meet the demands of a strategic change process in the automative cluster in the Eastern Cape region

Against a backdrop of increasing globalisation, deregulation, the rapid pace of technological innovation, a growing knowledge workforce, and shifting social and demographic trends, the primary task of management today is the leadership of organisational change (Graetz, 2000:550). In the words of Lussier and Achua Abstract v (2001:9): “The companies that will survive in the new global competitiveness environment are those that can attract and maintain leaders”. The above emphasises the important role of managers during times when change take place in the organisation. Yet employees are often managed inappropriately in a period of change. There are two reasons for this: (1) managers managing change are under pressure which undermines their own performance, (2) organisations often do not possess managers who are skilful at handling change. It is this second reason that will form the focus of this study. Carnall (1999:105) states that managing change effectively requires an understanding of both what is and seems likely to happen and of how people react to change, and a skilful management performance. Leaders must take on more facilitative roles, as competencies in change management become critical to creating and sustaining effective organisations. The major technological advances of today rely heavily on leaders to facilitate change. Leaders need to encourage people to “collaborate, take risks, take responsibility and be accountable for the change process the organisation must continually undergo to maintain a leadership position in its industry”, according to Moran and Brightman (2000:3). They furthermore argue that “change leaders recognise that they are always trying to balance stability and change. It is a delicate balance to accomplish since employees desire order and stability, while organisations must be ready to adapt to changing conditions quickly”. In this rapidly changing world, organisations must become more flexible, more responsive, and more willing to change and adapt. They must create and assimilate new knowledge at an increasing pace, encourage innovation, and learn to compete in new ways. Dess and Picken (2000:30) argue that the leaders of these organisations must be proactive in facilitating organisational learning and encouraging positive adaptation to external changes. The above shows what an important role leaders/managers have to play in the strategic change process. They need to possess the requisite skills in leadership, problem solving, continuous improvement, team effectiveness, and customer service in order to ensure the long-term growth and stability in the organisation which change can bring about. This research project will identify the various skills needed to successfully manage a change initiative

Low energy neutron propagation in MCNPX and GEANT4

Simulations of neutron background from rock for underground experiments are presented. Neutron propagation through two types of rock, lead and hydrocarbon material is discussed. The results show a reasonably good agreement between GEANT4, MCNPX and GEANT3 in transporting low-energy neutrons.Comment: 9 Figure

Interpretation of Light-Quenching Factor Measurements

We observe that the pattern of the quenching factors for scintillation light from various ions, recently studied in $CaWO_4$ in connection with dark matter detectors, can be understood as a saturation phenomenon in which the light output is simply proportional to track length, independent of the ion and its energy. This observation is in accord with the high dE/dx limit of Birks' law. It suggests a simple model for the intrinsic resolution of light detectors for low energy ions, which we briefly discuss.Comment: Seven pages, seven figures, some with colo

Composite Inelastic Dark Matter

Peaking consistently in June for nearly eleven years, the annual modulation signal reported by DAMA/NaI and DAMA/LIBRA offers strong evidence for the identity of dark matter. DAMA's signal strongly suggest that dark matter inelastically scatters into an excited state split by O(100 keV). We propose that DAMA is observing hyperfine transitions of a composite dark matter particle. As an example, we consider a meson of a QCD-like sector, built out of constituent fermions whose spin-spin interactions break the degeneracy of the ground state. An axially coupled U(1) gauge boson that mixes kinetically with hypercharge induces inelastic hyperfine transitions of the meson dark matter that can explain the DAMA signal.Comment: 5 pages (two-column), 1 figure, revised version, references adde