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Seßlestalbrücke - Verbundbrücke mit einteiligem Querschnitt / Wanzek, Thorsten; Gossla, Ulrich
(2003)
Within the Crystal Clear Collaboration four centres are developing 2nd generation high performance small animal PET scanners for different kinds of animals and medical applications. The first prototypes are PMT-based systems including depth of interaction (DOI) detection by using a phoswich layer of LSO and LuYAP. The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in FOVs caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN) was used. The simulations have shown that all PMT designs with one-to-one coupling of crystals have a very nonlinear axial sensitivity profile. By shifting every other PMT 1/4 of a PMT length in axial direction the sampling of the FOVs became more homogeneous. At an energy threshold of 350keV the regression coefficient increases from 0.818 for the non-shifted to 0.993 for the shifted design. Simulations of a point source centred in the FOV (threshold: 350keV) resulted in sensitivities of 4.2% for a 4×20PMT (LSO/LuYAP a 10mm) and 3.8% for a 4×16PMT (LSO/LuYAP a 8mm) ring design. The 3D-MLEM reconstruction of a point source shows the enormous improvement of resolution using a crystal double layer with DOI (3.1mm at 40mm from CFOV) instead of a 20mm single layer (11.9mm).
Within the Crystal Clear Collaboration (CCC), four centers are developing second generation high performance small animal positron emission tomography (PET) scanners for different kinds of animals and medical applications. The first prototypes are photomultiplier tube (PMT)-based systems including depth of interaction (DOI) detection by using a phoswich layer of lutetium oxyorthosilicate (LSO) and lutetium yttrium aluminum perovskite (LuYAP). The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in fields of view (FOVs) caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN, Geneva, Switzerland) was used.
Untersuchung eines hybriden EMV-Simulationsverfahrens anhand eines virtuellen Komponententests
(2003)
Ein vorausschauendes Risikomanagement beinhaltet, Risiken zu kalkulieren. Es liefert Entscheidungsgrundlagen, um diese Risiken zu begrenzen und es macht transparent,welche Risiken sinnvoll über Versicherungen abgedeckt werden sollten. Bei Unternehmen, die mit umfangreichen elektronischenEinrichtungen produzieren oder Dienstleistungen erbringen (und das sind heutzutage wohl die meisten), muss auch das Risiko durch Blitzeinwirkungen besondere Berücksichtigung finden. Dabei ist zu beachten, dass der Schaden aufgrund der Nichtverfügbarkeit der elektronischen Einrichtungen und damit derProduktion bzw. der Dienstleistung und ggf. der Verlust von Daten den Hardwareschaden an der betroffenen Anlage oft bei weitem übersteigt.
Dem Blitzschutz von Anlagen der regenerativen Energien kommt in Zukunft eine steigende Bedeutung zu. Dabei ist es notwendig zu berücksichtigen, dass die Schutzmaßnahmen technisch/wirtschaftlich ausgewogen sind. Erbauer, Besitzer oder Benutzer von netzautarken Hybridanlagen haben zu entscheiden, ob die Anlage einen Schutz braucht oder nicht. Um diese Entscheidung zu fällen, ist eine Risikoanalyse als erster Schritt sinnvoll. Diese muss dabei die für die Hybridanlage relevanten Schadenarten und spezifischen Parameter, Werte und Randbedingungen mit einbeziehen. Dazu ist die Hilfe eines Blitzschutzexperten sehr hilfreich.
Sonderbilanz und Status
(2003)
The Virtual Clean Room - a new tool in teaching MST process technologies University education in high-technology fields like MST is not complete without intensive laboratory sessions. Students cannot fully grasp the complexity and the special problems related to the manufacturing of microsystems without a thorough hands-on experience in a MST clean room.
Application of a (bio-)chemical sensor (ISFET) for the detection of physical parameters in liquids
(2003)
Mobile CRM-Systeme : Customer Relationship Management zur Unterstützung des Vertriebsaußendienstes
(2003)
Strategies of miniaturised reference electrodes integrated in a silicon-based „one chip“ pH sensor
(2003)
Härtebegriff im Zusammenhang mit Vernetzung, Bruchdehnung und Dauerfestigkeit eines Elastomers
(2003)
Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis.
Pulse shape discrimination of LSO and LuYAP scintillators for depth of interaction detection in PET
(2003)
A feasible way to gain the depth of interaction information in a PET scanner is the use of phoswich detectors. In general the layer of interaction is identified front the pulse shape of the corresponding scintillator material. In this work pulses from LSO and LuYAP crystals were investigated in order to find a practical method of distinguishing. It turned out that such a pulse processing could he kept simple due to an additional slow component in the light decay of the LuYAP pulse. At the same time the short decay time guarantees that the major amount of the light output is still collected within a short pulse recording time.
Pulse shape discrimination of LSO and LuYAP scintillators for depth of interaction detection in PET
(2003)
A feasible way to gain the depth of interaction information in a positron emission tomography scanner is the use of phoswich detectors. In general, the layer of interaction is identified from the pulse shape of the corresponding scintillator material. In this work, pulses from LSO and LuYAP crystals were investigated in order to find a practical method of distinguishing. It turned out that such a pulse processing could be kept simple because of an additional slow component in the light decay of the LuYAP pulse. At the same time, the short decay time guarantees that the major amount of the light output is still collected within a short pulse recording time.