An Upgrade for the 1.4 MeV/u Gas Stripper at the GSI UNILAC

The GSI UNILAC will serve as part of an injector system for the future FAIR facility, currently under construction in Darmstadt, Germany. For this, it has to deliver short-pulsed, high-current, heavy-ion beams with highest beam quality. An upgrade for the 1.4 MeV/u gas stripper is ongoing to increase the yield of uranium ions in the desired charge state. The new setup features a pulsed gas injection synchronized with the beam pulse transit to increase the effective density of the stripper target while keeping the gas load for the differential pumping system low. Systematic measurements of charge state distributions and energy-loss were conducted with 238U-ion beams and different stripper gases, including H2 and He. By using H2 as a stripper gas, the yield into the most populated charge state was increased by over 50%, compared to the current stripper. Furthermore, the high gas density, enabled by the pulsed injection, results in increased mean charge states

A Pulsed Gas Stripper for Stripping of High-Intensity, Heavy-Ion Beams at 1.4 MeV/u at the GSI UNILAC

The GSI UNILAC in combination with SIS18 will serve as a high-current, heavy-ion injector for the future FAIR. It has to meet high demands in terms of beam brilliance at a low duty factor (100 mus beam pulse length, 2.7 Hz repetition rate). An advanced 1.4 MeV/u gas stripper setup has been developed, aiming at an enhanced yield into the required charge states. The setup delivers short, high-density gas pulses in synchronization with the beam pulse. This provides an increased gas density at a reduced gas load for the differential pumping system. In recent measurements, high-intensity, heavy-ion beams of U⁴⁺ were successfully stripped and separated for the desired charge state. The modified stripper setup, as well as major results, are presented, including a comparison to the present gas stripper based on a N₂ gas-jet. The stripping efficiency into the desired 28⁺ charge state was significantly increased by up to 60 % using a hydrogen stripper target while the beam quality remained similar

Quality of the CMS tracker end cap silicon strip modules

Der Large Hadron Collider (LHC) am CERN soll 2007 in Betrieb genommen und 10 Jahre lang für Experimente verwendet werden. Der Compact Muon Solenoid (CMS), ein so genanntes ”multi purpose” Experiment, ist eines der vier großen Experimente am LHC. Der Bau des Siliziumdetektors von CMS benötigte mehr als 15.000 Detektormodule mit ungefähr 24.000 grossflächigen Silizium Sensoren. Diese Diplomarbeit wurde am Institut für Hochenergiephysik (HEPHY) in Wien verfasst und beschäftigt sich mit der Qualitätssicherung wärend der Produktion der 6.400 Detektor Endkappen (TEC) Module des CMS Siliziumdetektors. Die wichtigsten Schritte bei der Produktion dieser Module, bei der unser Institut einen wichtigen Beitrag geleistet hat, sind Eingangstests der industriell hergestellten Einzelteile, deren präziser Zusammenbau, Bonden der elektrischen Verbindungen und die abschließenden Funktionalitätstests der fertigen Module. Nach einem Überblick über den LHC und das CMS Experiment werden die Eigenschaften von Silizium-Streifen Sensoren und die Bestandteile der Detektormodule beschrieben. Abschließend wird die Qualitätssicherung wärend der Modulproduktion und deren Ergebnisse präsentiert. Am HEPHY wurden alle Ring 2 Detektormodule der beiden Detektor Endkappen produziert. Meine Arbeit begann mit einem Genauigkeitsproblem beim Modulzusammenbau, das gelöst werden konnte. Zeitgleich übernahm ich die Verantwortung für die Tests der Rahmen, der Front End Hybride und der fertigen Module. Dabei half ich die Feineinstellungen des Fehleranalyse-Algorithmus der Testsoftware für die Hybrid- und Modultests zu verbessern. Kaputte Hybride und Module wurden, wenn möglich, von mir repariert. Weiters habe ich die Probleme mit dem Leitkleber an der Sensorrückseite untersucht und eine Lösung entwickelt. Später fing ich an die Qualität der gesamten TEC Modulproduktion zu überwachen und mir die kaputten Module genauer anzusehen. Das HEPHY entwickelte sich zum ”TEC Module Repair Center” und zerlegte außerdem alle Module bei denen nur noch der Sensor gerettet werden konnte. Gemeinsam mit Marko Dragicevic und Thomas Bergauer wurden alle kaputten Module charakterisiert und mithilfe einer speziell erzeugten Datenbank eine Statistik produziert. Schlussendlich wurde die Aufgabe der Charakterisierung und Reparatur von Ersatzmodulen von mir übernommen.The Large Hadron Collider (LHC) at CERN, a 27 TeV proton-proton collider, is planned to be operable in 2007 and will run for at least 10 years. The Compact Muon Solenoid (CMS), a huge multipurpose detector, is one of the four major experiments at the LHC. The construction of the Inner Tracker of CMS required more than 15.000 silicon micro-strip detector modules including about 24.000 large area silicon strip sensors. This diploma thesis has been composed at the Institute for High Energy Physics (HEPHY) of the Austrian Academy of Sciences [1]. It reviews the quality assurance for the 6.400 silicon micro-strip detector modules, built of one or two silicon strip sensors, in the Tracker End Caps (TEC), one out of four subsystems of the Inner Tracker. In the production laboratories, including our institute, the main steps during the fabrication of these modules are reception tests of the industrially produced module parts, their precise mechanical assembly, application of thin wire micro-bond connections and electrical functionality tests of the finalised modules. This diploma thesis begins with a short overview of the Large Hadron Collider taking a deeper look at the CMS experiment. Then an overview of silicon sensors and the basic elements of the TEC silicon strip modules are provided. Afterward the quality assurance program during the module production and its results are presented. At HEPHY Vienna the complete production of the Tracker End Cap Ring 2 modules was performed. My first task was to review the module assembly precision at our institute, where some problems had to be solved. At the same time I became responsible for the testing of the frames and front-end hybrids before the module assembly and the tests of the finalised modules. This included the fine-tuning of the cuts for the fault finding algorithm of the automated setup for the hybrid and module tests and the repair of different faults. I investigated the problem of the conductive glue on the sensor backplane and developed a solution. Later on I started to monitor the quality of the whole TEC module production and to supervise the repairs and the sensor recuperation of the faulty modules together with Marko Dragicevic and Thomas Bergauer. We characterised every faulty module and with the help of a specially created data base we could produce a statistic on them. Finally I became responsible for characterising and repairing of the TEC spare modules.Stephan HänselZsfassung in dt. SpracheWien, Techn. Univ., Dipl.-Arb., 2007OeBB(VLID)182968

High Performance Computing in Science and Engineering '99 : Transactions of the High Performance Computing Center

The book contains reports about the most significant projects from science and engineering of the Federal High Performance Computing Center Stuttgart (HLRS). They were carefully selected in a peer-review process and are showcases of an innovative combination of state-of-the-art modeling, novel algorithms and the use of leading-edge parallel computer technology. The projects of HLRS are using supercomputer systems operated jointly by university and industry and therefore a special emphasis has been put on the industrial relevance of results and methods

High Performance Computing in Science and Engineering '02 : Transactions of the High Performance Computing Center

This book presents the state-of-the-art in modeling and simulation on supercomputers. Leading German research groups present their results achieved on high-end systems of the High Performance Computing Center Stuttgart (HLRS) for the year 2002. Reports cover all fields of supercomputing simulation ranging from computational fluid dynamics to computer science. Special emphasis is given to industrially relevant applications. Moreover, by presenting results for both vector sytems and micro-processor based systems the book allows to compare performance levels and usability of a variety of supercomputer architectures. It therefore becomes an indispensable guidebook to assess the impact of the Japanese Earth Simulator project on supercomputing in the years to come

High Performance Computing in Science and Engineering '98 : Transactions of the High Performance Computing Center

The book contains reports about the most significant projects from science and industry that are using the supercomputers of the Federal High Performance Computing Center Stuttgart (HLRS). These projects are from different scientific disciplines, with a focus on engineering, physics and chemistry. They were carefully selected in a peer-review process and are showcases for an innovative combination of state-of-the-art physical modeling, novel algorithms and the use of leading-edge parallel computer technology. As HLRS is in close cooperation with industrial companies, special emphasis has been put on the industrial relevance of results and methods