The influence of wakefields on superconducting TESLA-cavities in FEL-operation

Due to the additional need of very short bunches for the FEL operation with the TESLA-machine strong wakefield effects are expected. One third of the total wakefield energy per bunch is radiated into the frequency region above the energy gap of Cooper pairs in superconducting niobium. The energy of the cooper pairs in superconducting niobium at 2 K corresponds to a frequency of 700 GHz. An analytical and experimental estimation for the overall energy loss of the FEL bunch above energy gap is presented. The analytical method is based on a study from R. B. Palmer [1]. The results of the wakefield estimations are used to calculate possible quality factor reduction of the TESLA cavities during FEL operation. Results are presented

Turn-taking: From perception to speech preparation

Wesselmeier H, Müller HM. Turn-taking: From perception to speech preparation. Neuroscience Letters. 2015;609:147-151.We investigated the preparation of a spoken answer response to interrogative sentences by measuring response time (RT) and the response-related readiness potential (RP). By comparing the RT and RP results we aimed to identify whether the RP-onset is more related to the actual speech preparation process or the pure intention to speak after turn-anticipation. Additionally, we investigated if the RP-onset can be influenced by the syntactic structure (one or two completion points). Therefore, the EEG data were sorted based on two variables: the cognitive load required for the response and the syntactic structure of the stimulus questions. The results of the response utterance preparation associated event-related potential (ERP) and the RT suggest that the RP-onset is more related to the actual speech preparation process rather than the pure intention to speak after turn-anticipation. However, the RP-onset can be influenced by the syntactic structure of the question leading to an early response preparation

Energy Propagation through the TESLA Channel: Measurements with Two Waveguides Modes

A new method for the determination of S-matrices of devices in multimoded waveguides and first experimental experiences are presented. The theoretical foundations are given. The scattering matrix of a TESLA copper cavity at a frequency above the cut-off of the second waveguide mode has been measured

The design of the HOM-damping cells for the S-band linear collider

Damping cells for the higher order modes are necessary for the S-band linear collider to minimize BBU (Beam-Break-Up). The construction of the damper cells has to take into account the different field geometries of the higher order modes. So two different types of dampers have been designed: a wall slotted an an iris slotted cell. In order to optimize the two types of damping cells with respect to damping strength, impedance matching between coupling system and waveguide dampers and between damping cell and undamped cells and the tuning system, damping cells of both types have been built and examinated

The effect of a single HOM-damper cell within a channel of undamped cells

The effect of a single HOM-damper cell within a channel of undamped cells is described theoretically using an equivalent circuit model. From this a simple equation can be derived which relates the Q-value of the single damping-cell, the bandwidth of the passband under consideration, and the additional phase shift which is introduced by the damper cell to provide energy flow into the damper cell. This equation immediately shows the limitations of such single cell damping systems. Comparisons with experimental results are shown

Börsenkooperationen im Labyrinth des Börsenrechts : ILF Symposion

Enthaltene Aufsätze: Reto Francioni : Börsen im internationalen Wettbewerb: Konsolidierung als Teilaspekt einer globalen Wachstumsstrategie, S. 1 Roger Müller : Kooperationen und Zusammenschlüsse von Börsen als Bewährungsprobe für das Börsenrecht, S. 8 Horst Hammen : Verschmelzung von Börsen? S. 1

Tricky Figures: Why the Assessment of Competition in Banking Industries is Rather a Matter of Taste

Economic studies on the degree of competition (DC) in banking systems use various measures which are subsumed under the 1) structure- (e.g. Hirschman-Herfindahl index), 2) conduct- (e.g. Boone indicator) or 3) performance-oriented approach (e.g. Lerner index). Yet, the respective empirical operationalizations of the different DC measures are expected to represent one central construct – the true DC of a banking system. We review 35 studies covering 15 European banking systems from 1998 to 2007. Contrasting the central construct hypothesis, we find substantial differences in the produced DC measures. Thus, the economic validity of derived conclusions regarding the competition intensity is chal-lenged

Mode propagation in an iris type accelerator section loaded with single heavily HOM-damped cells

The wakefield effects in accelerator sections for future linear colliders will be reduced either by damping by detuning or by a combination of both. For the DESY/THD linac [1] it is forseen to employ heavily HOM-damped cells to provide a strong coupling to the TE/TM11-dipole passband as well as to the TM/TE11-dipole passband. For our experiments we have used wall-slotted damping cells. This leads to several problems concerning the propagation of fundamental and HOM-modes. Experimental investigations have been done. Results are presented