JRA3 Electromagnetic Calorimeter Technical Design Report

This report describes the design of the prototype for an Silicon Tungsten electromagnetic calorimeter with unprecedented high granularity to be operated in a detector at the International Linear Collider (ILC). The R&D for the prototype is co-funded by the European Union in the FP6 framework within the so called EUDET project in the years 2006-2010. The dimensions of the prototype are similar to those envisaged for the final detector. Already at this stage the prototype features a highly compact design. The sensitive layers, the Very Front End Electronics serving 64 channels per ASIC and copper plates for heat draining are integrated within 2000 μm

Planare Graphen und ihre Dualgraphen auf Zylinderoberflächen

In this thesis, we investigates plane drawings of undirected and directed graphs on cylinder surfaces. In the case of undirected graphs, the vertices are positioned on a line that is parallel to the cylinder’s axis and the edge curves must not intersect this line. We show that a plane drawing is possible if and only if the graph is a double-ended queue (deque) graph, i. e., the vertices of the graph can be processed according to a linear order and the edges correspond to items in the deque inserted and removed at their end vertices. A surprising consequence resulting from these observations is that the deque characterizes planar graphs with a Hamiltonian path. This result extends the known characterization of planar graphs with a Hamiltonian cycle by two stacks. By these insights, we also obtain a new characterization of queue graphs and their duals. We also consider the complexity of deciding whether a graph is a deque graph and prove that it is NP-complete. By introducing a split operation, we obtain the splittable deque and show that it characterizes planarity. For the proof, we devise an algorithm that uses the splittable deque to test whether a rotation system is planar. In the case of directed graphs, we study upward plane drawings where the edge curves follow the direction of the cylinder’s axis (standing upward planarity; SUP) or they wind around the axis (rolling upward planarity; RUP). We characterize RUP graphs by means of their duals and show that RUP and SUP swap their roles when considering a graph and its dual. There is a physical interpretation underlying this characterization: A SUP graph is to its RUP dual graph as electric current passing through a conductor to the magnetic field surrounding the conductor. Whereas testing whether a graph is RUP is NP-hard in general [Bra14], for directed graphs without sources and sink, we develop a linear-time recognition algorithm that is based on our dual graph characterization of RUP graphs.Die Arbeit beschäftigt sich mit planaren Zeichnungen ungerichteter und gerichteter Graphen auf Zylinderoberflächen. Im ungerichteten Fall werden Zeichnungen betrachtet, bei denen die Knoten auf einer Linie parallel zur Zylinderachse positioniert werden und die Kanten diese Linie nicht schneiden dürfen. Es kann gezeigt werden, dass eine planare Zeichnung genau dann möglich ist, wenn die Kanten des Graphen in einer double-ended queue (Deque) verarbeitet werden können. Ebenso lassen sich dadurch Queue, Stack und Doppelstack charakterisieren. Eine überraschende Konsequenz aus diesen Erkenntnissen ist, dass die Deque genau die planaren Graphen mit Hamiltonpfad charakterisiert. Dies erweitert die bereits bekannte Charakterisierung planarer Graphen mit Hamiltonkreis durch den Doppelstack. Im gerichteten Fall müssen die Kantenkurven entweder in Richtung der Zylinderachse verlaufen (SUP-Graphen) oder sich um die Achse herumbewegen (RUP-Graphen). Die Arbeit charakterisiert RUP-Graphen und zeigt, dass RUP und SUP ihre Rollen tauschen, wenn man Graph und Dualgraph betrachtet. Der SUP-Graph verhält sich dabei zum RUP-Graphen wie elektrischer Strom durch einen Leiter zum induzierten Magnetfeld. Ausgehend von dieser Charakterisierung ist es möglich einen Linearzeit-Algorithmus zu entwickeln, der entscheidet ob ein gerichteter Graph ohne Quellen und Senken ein RUP-Graph ist, während der allgemeine Fall NP-hart ist [Bra14]

Zyklische Levelzeichnungen gerichteter Graphen

The Sugiyama framework proposed in the seminal paper of 1981 is one of the most important algorithms in graph drawing and is widely used for visualizing directed graphs. In its common version, it draws graphs hierarchically and, hence, maps the topological direction to a geometric direction. However, such a hierarchical layout is not possible if the graph contains cycles, which have to be destroyed in a preceding step. In certain application and problem settings, e.g., bio sciences or periodic scheduling problems, it is important that the cyclic structure of the input graph is preserved and clearly visible in drawings. Sugiyama et al. also suggested apart from the nowadays standard horizontal algorithm a cyclic version they called recurrent hierarchies. However, this cyclic drawing style has not received much attention since. In this thesis we consider such cyclic drawings and investigate the Sugiyama framework for this new scenario. As our goal is to visualize cycles directly, the first phase of the Sugiyama framework, which is concerned with removing such cycles, can be neglected. The cyclic structure of the graph leads to new problems in the remaining phases, however, for which solutions are proposed in this thesis. The aim is a complete adaption of the Sugiyama framework for cyclic drawings. To complement our adaption of the Sugiyama framework, we also treat the problem of cyclic level planarity and present a linear time cyclic level planarity testing and embedding algorithm for strongly connected graphs

n-Alkyl Methacrylate Polymeric Memristors for Synaptic Response Modeling: Organic and Biologically Relevant Thin Films

There is a strong interest in organic materials for electrical devices due to several advantages that organic systems have over their inorganic counterparts including ease of processability and lower toxicity. Many of these organic materials can be utilized in the creation of thin-film devices that can be formed in high-throughput processes and with a very small profile. One such device that has emerged in recent years is the memristor which can be used in new computational concept or as a synaptic model. This work studies the alternating current (AC) and direct current (DC) electrical response of a number n-alkyl methacrylate polymers with a charge transporting pendant carbazole ring. The electrical properties of the polymers were studied as a function of n-alkyl length with n ranging from 2 to 11. The DC current (I)-voltage (V) response of the polymers was characterized by an erratic and bistable response, while their AC I-V response was a pinched hysteresis loop when measured between 1-100 Hz. For polymers with n \u3c 9, their pinched hysteresis loop is characterized by jump transitions indicative of bistability, while polymers with n ≥ 9 had a pinched hysteresis loop that is smooth in appearance. Dielectric spectroscopy on the polymers indicates that as the n-alkyl length is increased, the rotation flexibility of the carbazole moiety is enhanced. The n-alkyl methacrylate polymers with a pendant carbazole ring spaced n ≥ 9 exhibited a lower activation energy and temperature for the onset of ring motion and resulted in polymer-based memristors that exhibit electrical characteristics, such as incrementally adjustable conductivity, that are potential candidates for mimicking synaptic plasticity. Further characterization was done on similar methacrylate systems with oxygen-substituted side chains and the addition of bulky phenyl groups to the carbazole moieties. From this work, the most promising candidate for synaptic modeling behavior was taken and further examined. It was shown that this polymer could be pulsed through a multitude of conductivity states and demonstrated behavior consistent with the Hebbian Learning Rule upon the application of pre- and post-synaptic pulses. The system was further characterized for the effects of different spike rates and voltages before being utilized in a flexible device. Other thin-film devices as well as novel processing methods were also demonstrated in this work including a biologically based reserve battery and a printed diode utilizing pentacene. The battery utilized standard alkaline chemistry where the zinc and manganese oxide electrodes are formed using stencil printing. Fish eggs are used to sequester the electrolyte out of the system until the application of force to the device. This application of force bursts the fish eggs and allows the battery to function by introducing the electrolyte into the system. A printed diode is also demonstrated through the use of a miniemulsion process that allows for the dispersion of the material into aqueous solution. This pentacene emulsion in water can then be used as the basis for the formation of diodes in a variety of fabrication processes

InSb charge coupled infrared imaging device: The 20 element linear imager

The design and fabrication of the 8585 InSb charge coupled infrared imaging device (CCIRID) chip are reported. The InSb material characteristics are described along with mask and process modifications. Test results for the 2- and 20-element CCIRID's are discussed, including gate oxide characteristics, charge transfer efficiency, optical mode of operation, and development of the surface potential diagram

AlGaAs heterojunction lasers

The characterization of 8300 A lasers was broadened, especially in the area of beam quality. Modulation rates up to 2 Gbit/sec at output powers of 20 mW were observed, waveform fidelity was fully adequate for low BER data transmission, and wavefront measurements showed that phase aberrations were less than lamda/50. Also, individually addressable arrays of up to ten contiguous diode lasers were fabricated and tested. Each laser operates at powers up to 30 mW CW in single spatial mode. Shifting the operating wavelength of the basic CSP laser from 8300 A to 8650 A was accomplished by the addition of Si to the active region. Output power has reached 100 mW single mode, with excellent far field wave front properties. Operating life is currently approx. 1000 hrs at 35 mW CW. In addition, laser reliability, for operation at both 8300 A and 8650 A, has profited significantly from several developments in the processing procedures

End-to-end numerical modeling of the Roman Space Telescope coronagraph

The Roman Space Telescope will have the first advanced coronagraph in space, with deformable mirrors for wavefront control, low-order wavefront sensing and maintenance, and a photon-counting detector. It is expected to be able to detect and characterize mature, giant exoplanets in reflected visible light. Over the past decade the performance of the coronagraph in its flight environment has been simulated with increasingly detailed diffraction and structural/thermal finite element modeling. With the instrument now being integrated in preparation for launch within the next few years, the present state of the end-to-end modeling is described, including the measured flight components such as deformable mirrors. The coronagraphic modes are thoroughly described, including characteristics most readily derived from modeling. The methods for diffraction propagation, wavefront control, and structural and thermal finite-element modeling are detailed. The techniques and procedures developed for the instrument will serve as a foundation for future coronagraphic missions such as the Habitable Worlds Observatory.Comment: 113 pages, 85 figures, to be published in SPIE Journal of Astronomical Telescopes, Instruments, and System

Foraging strategies of an aerial-hawking insectivore, the common noctule bat Nyctalus noctula

Movement is a key signature of life. Yet, the integration of movement ecology and biodiversity concepts was only recently formalize. In this framework, an individual’s movement path and the underlying drivers are used to explain interactions between individuals and eventually species coexistence. Interactions influence the individual’s environment including species assemblage, and thereby feed back on the individual’s movement path. Foraging represents one of the most common movements of many animals, and thus has been of interest for ecologists ever since. Yet, classical foraging ecology predominantly focused on optimality models to explain the behaviour of single foragers, but rarely took into account the interactions between moving individuals. The overarching question of the three studies in this thesis thus was “How can different foraging strategies support coexistence?”. Being highly mobile and showing a large niche overlap with several other species, the insectivorous Common noctule bat Nyctalus noctula (Schreber, 1774) is an ideal model species to study intra- and interspecific interactions during foraging movements. I therefore investigated movement behaviour and space use of N. noctula during aerial foraging, and evaluated the potential role of different foraging strategies for the coexistence of competing bat species in the light of different competitor densities and prey distributions. In chapter one, I asked whether foraging N. noctula adjust their space use to abiotic factors (i.e. moonlight) which might be linked to prey distribution. I used GPS (global positioning system) loggers to investigate the habitat use of nine N. noctula during high and low moonlight intensities. During moonlit nights, N. noctula hunted preferentially over open fields, whereas they avoided open fields in dark nights. I suppose that foraging activity followed changes in insect activity triggered by the lunar cycle. The results suggest that N. noctula might be able to predict cyclic changes in prey distribution. The exploitation of prey aggregations in lit habitats might be an advantage towards competing bat species that are less light tolerant. In chapter two, I asked whether the use of social foraging by N. noctula depends on season, possibly as a response to changes in insect availability. I quantified N. noctula activity at foraging sites in early and late summer during acoustic playbacks of either hunting conspecifics or heterospecifics. N. noctula activity increased during heterospecific playbacks in early summer, but decreased in late summer. There was no clear reaction towards conspecific playbacks, irrespective of the season. The results suggest that external factors determine the strengths of intraspecific and interspecific competition, but that insectivorous bats mitigate different competitive pressures through flexibility in foraging strategy and fine scale space use. I argue that conspecific might impair each other by acoustic interference of echolocation calls and competition for flight space. However, niche segregation might make social foraging with heterospecifics beneficial, given that there is low competition for prey items. In chapter three, I asked whether the foraging strategy of N. noctula depends on the combination of conspecifics density and landscape features that might determine prey distribution. I used combined GPS-ultrasound loggers to record the nightly foraging movements and hunting activity of 27 N. noctula above farmland and forested landscape. Acoustic records also allowed quantification of nearby conspecifics. I deduced two movement states - area restricted movement and directed movement - from the GPS tracks. Above farmland, N. noctula switched to area restricted movements after encounters with conspecifics, and foraging activity was highest during those movements. Above forested landscape, encounters with conspecifics had little influence on the movement behaviour of N. noctula, and foraging activity occurred during directed and area restricted movements alike. N. noctula encountered more conspecifics above the forested landscape than above farmland. I argue that N. noctula was able to integrate prey distribution and competitive pressure when deciding whether or not to pursue a social foraging strategy. The use of a social foraging strategy might be a prerequisite for survival in agricultural landscapes where prey is patchily distributed and ephemeral. In contrast, solitary foraging might be the optimal strategy in forested landscapes that offer evenly distributed prey and support larger populations. In conclusion, the results showed that N. noctula integrated environmental factors that probably influenced prey distribution, adverse effects from intra- and interspecific competition, and public information about prey availability provided by hunting con- and heterospecifics. N. noctula used this compiled information to decide where to forage and whether to forage solitary or socially. The studies highlighted that N. noctula can adjust its foraging strategy context dependently. This flexibility was achieved through dynamic feedbacks between the movement paths and the perceived environment. These dynamic feedbacks may play a pivotal role in promoting the coexistence of competing species. In particular, the similarity of movement behaviours and resulting foraging strategies among conspecifics might stabilize species assemblages through intraspecific competition, while slight differences in the movement behaviour among heterospecifics might allow fine-scale niche segregation and thereby equalize the fitness of coexisting species. I propose that dynamic foraging behaviour might act stabilizing and equalizing not only in insectivorous bats but on assemblages of highly mobile predators in general