{"id":{"repo_id":"heid-diss","oai_identifier":"oai:archiv.ub.uni-heidelberg.de:4651"},"canonical_url":"https://search.dev.ndltd.org/etd/heid-diss/oai:archiv.ub.uni-heidelberg.de:4651","repository":{"repo_id":"heid-diss","name":"Universität Heidelberg","base_url":"http://archiv.ub.uni-heidelberg.de/volltextserver/cgi/oai2"},"display":{"title":"A Kaon Trigger for FOPI : Development and Evaluation of a Trigger System for Strange Particles","abstract":"During collisions of heavy ions at high energies at SIS/GSI, nuclear matter can be exposed to high densities and temperatures. The FOPI experiment detects the traces of the charged particles produced in the nuclear reaction. Their analysis, in particular with respect to the strange K mesons, can extend our knowledge about the structure of nuclear matter and the processes during the evolution of neutron stars and black holes. However, kaons are rarely observed, hence the derived physics results suffer from large uncertainties. In order to significantly enhance the kaon yield, a trigger, which is able to prevent the time consuming readout of the complete detector data for uninteresting events, was developed within the scope of this work. For that purpose, a Hough transform based algorithm was created. It reconstructs particle tracks from a small fraction of the data of the drift chamber CDC. A geometrical matching to the information from the new high-precision time-of-flight detector GRPC allows the determination of the found particles' species. In order to fulfill the requirements from the data bandwidth and the computing intensity, special-purpose processors are required. About 5 to 6 of the FPGA based MPRACE boards developed at Mannheim University can provide this performance cost-effectively. The consistent parallelization of the individual program steps makes the exploitation of the full power of MPRACE and thus a processing time of less than 100 us per event possible. Detailed simulations of the trigger systems show, that in experiments with light nuclei like nickel at beam energies of 1.93 GeV/u the K^+ yield can be enhanced by a factor of 6, and the K^- yield by a factor of 11.","abstract_html":"During collisions of heavy ions at high energies at SIS/GSI, nuclear matter can be exposed to high densities and temperatures. The FOPI experiment detects the traces of the charged particles produced in the nuclear reaction. Their analysis, in particular with respect to the strange K mesons, can extend our knowledge about the structure of nuclear matter and the processes during the evolution of neutron stars and black holes. However, kaons are rarely observed, hence the derived physics results suffer from large uncertainties. In order to significantly enhance the kaon yield, a trigger, which is able to prevent the time consuming readout of the complete detector data for uninteresting events, was developed within the scope of this work. For that purpose, a Hough transform based algorithm was created. It reconstructs particle tracks from a small fraction of the data of the drift chamber CDC. A geometrical matching to the information from the new high-precision time-of-flight detector GRPC allows the determination of the found particles' species. In order to fulfill the requirements from the data bandwidth and the computing intensity, special-purpose processors are required. About 5 to 6 of the FPGA based MPRACE boards developed at Mannheim University can provide this performance cost-effectively. The consistent parallelization of the individual program steps makes the exploitation of the full power of MPRACE and thus a processing time of less than 100 us per event possible. Detailed simulations of the trigger systems show, that in experiments with light nuclei like nickel at beam energies of 1.93 GeV/u the K^+ yield can be enhanced by a factor of 6, and the K^- yield by a factor of 11.","abstract_has_math":false,"creators":["Brosch, Oliver"],"institution":"Universität Heidelberg","degree_name":null,"degree_level":"thesis.doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Männer, Reinhard"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2004,"date_issued":"2004-05-12","date_published":"2004-05-12","updated_at":"2026-07-24T02:29:49Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://www.ub.uni-heidelberg.de/archiv/4651","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Männer, Reinhard"]},{"key":"dc:creator","label":"Author","values":["Brosch, Oliver"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:publisher","label":"Institution","values":["Universitätsbibliothek Heidelberg"]},{"key":"dc:type","label":"Dc Type","values":["doctoralThesis"]},{"key":"thesis:degree_level","label":"Degree Level","values":["thesis.doctoral"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Universität Heidelberg"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["During collisions of heavy ions at high energies at SIS/GSI, nuclear matter can be exposed to high densities and temperatures. The FOPI experiment detects the traces of the charged particles produced in the nuclear reaction. Their analysis, in particular with respect to the strange K mesons, can extend our knowledge about the structure of nuclear matter and the processes during the evolution of neutron stars and black holes. However, kaons are rarely observed, hence the derived physics results suffer from large uncertainties. In order to significantly enhance the kaon yield, a trigger, which is able to prevent the time consuming readout of the complete detector data for uninteresting events, was developed within the scope of this work. For that purpose, a Hough transform based algorithm was created. It reconstructs particle tracks from a small fraction of the data of the drift chamber CDC. A geometrical matching to the information from the new high-precision time-of-flight detector GRPC allows the determination of the found particles' species. In order to fulfill the requirements from the data bandwidth and the computing intensity, special-purpose processors are required. About 5 to 6 of the FPGA based MPRACE boards developed at Mannheim University can provide this performance cost-effectively. The consistent parallelization of the individual program steps makes the exploitation of the full power of MPRACE and thus a processing time of less than 100 us per event possible. Detailed simulations of the trigger systems show, that in experiments with light nuclei like nickel at beam energies of 1.93 GeV/u the K^+ yield can be enhanced by a factor of 6, and the K^- yield by a factor of 11.","In Stößen schwerer Ionen bei hohen Energien am SIS/GSI kann Kernmaterie großer Dichte und Temperatur erzeugt werden. Im FOPI-Experiment werden die Spuren der bei den Kollisionen entstehenden geladenen Teilchen nachgewiesen. Durch deren Analyse, insbesondere im Hinblick auf die seltsamen K-Mesonen, können unsere Kenntnisse über die Struktur der Materie und die Vorgänge beim Entstehen von Neutronensternen und Schwarzen Löchern vertieft werden. Kaonen werden jedoch selten beobachtet, und so sind die erzielbaren physikalischen Ergebnisse meist mit großen Fehlern behaftet. Um die Ausbeute an Kaonen deutlich zu erhöhen, wurde im Rahmen dieser Arbeit ein Trigger entwickelt, der das Zeit raubende Auslesen der kompletten Detektordaten für nicht interessante Ereignisse verhindern kann. Dafür wurde ein auf der Hough-Transformation basierender Algorithmus geschaffen. Dieser rekonstruiert Teilchenspuren aus einem kleinen Teil der Daten der Driftkammer CDC. Die geometrische Verknüpfung mit den Informationen des neuen, hoch auflösenden Flugzeitdetektors GRPC erlaubt die Bestimmung der gefundenen Teilchenarten. Um den Anforderungen durch die Datenbandbreite und die Rechenintensität zu genügen, sind für die Implementierung spezielle Prozessoren nötig. Etwa 5 bis 6 der an der Universität Mannheim entwickelten, FPGA-basierten MPRACE-Karten können diese Leistung kostengünstig erbringen. Die konsequente Parallelisierung der einzelnen Programmschritte ermöglicht das Ausnutzen der vollen Leistungsfähigkeit von MPRACE und damit eine Rechenzeit von weniger als 100 us pro Ereignis. Ausführliche Simulationen des Triggersystems zeigen, dass in Experimenten mit leichten Kernen wie Nickel bei Strahlenergien von 1,93 GeV/u die K^+-Ausbeute etwa um den Faktor 6 und die K^--Ausbeute um den Faktor 11 gesteigert werden kann."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["A Kaon Trigger for FOPI : Development and Evaluation of a Trigger System for Strange Particles","Ein Kaon-Trigger für FOPI : Entwicklung und Bewertung eines Triggersystems für seltsame Teilchen"]}]}],"canonical_facts":{"dc:contributor":["Männer, Reinhard"],"dc:creator":["Brosch, Oliver"],"dc:description.abstract":["During collisions of heavy ions at high energies at SIS/GSI, nuclear matter can be exposed to high densities and temperatures. The FOPI experiment detects the traces of the charged particles produced in the nuclear reaction. Their analysis, in particular with respect to the strange K mesons, can extend our knowledge about the structure of nuclear matter and the processes during the evolution of neutron stars and black holes. However, kaons are rarely observed, hence the derived physics results suffer from large uncertainties. In order to significantly enhance the kaon yield, a trigger, which is able to prevent the time consuming readout of the complete detector data for uninteresting events, was developed within the scope of this work. For that purpose, a Hough transform based algorithm was created. It reconstructs particle tracks from a small fraction of the data of the drift chamber CDC. A geometrical matching to the information from the new high-precision time-of-flight detector GRPC allows the determination of the found particles' species. In order to fulfill the requirements from the data bandwidth and the computing intensity, special-purpose processors are required. About 5 to 6 of the FPGA based MPRACE boards developed at Mannheim University can provide this performance cost-effectively. The consistent parallelization of the individual program steps makes the exploitation of the full power of MPRACE and thus a processing time of less than 100 us per event possible. Detailed simulations of the trigger systems show, that in experiments with light nuclei like nickel at beam energies of 1.93 GeV/u the K^+ yield can be enhanced by a factor of 6, and the K^- yield by a factor of 11.","In Stößen schwerer Ionen bei hohen Energien am SIS/GSI kann Kernmaterie großer Dichte und Temperatur erzeugt werden. Im FOPI-Experiment werden die Spuren der bei den Kollisionen entstehenden geladenen Teilchen nachgewiesen. Durch deren Analyse, insbesondere im Hinblick auf die seltsamen K-Mesonen, können unsere Kenntnisse über die Struktur der Materie und die Vorgänge beim Entstehen von Neutronensternen und Schwarzen Löchern vertieft werden. Kaonen werden jedoch selten beobachtet, und so sind die erzielbaren physikalischen Ergebnisse meist mit großen Fehlern behaftet. Um die Ausbeute an Kaonen deutlich zu erhöhen, wurde im Rahmen dieser Arbeit ein Trigger entwickelt, der das Zeit raubende Auslesen der kompletten Detektordaten für nicht interessante Ereignisse verhindern kann. Dafür wurde ein auf der Hough-Transformation basierender Algorithmus geschaffen. Dieser rekonstruiert Teilchenspuren aus einem kleinen Teil der Daten der Driftkammer CDC. Die geometrische Verknüpfung mit den Informationen des neuen, hoch auflösenden Flugzeitdetektors GRPC erlaubt die Bestimmung der gefundenen Teilchenarten. Um den Anforderungen durch die Datenbandbreite und die Rechenintensität zu genügen, sind für die Implementierung spezielle Prozessoren nötig. Etwa 5 bis 6 der an der Universität Mannheim entwickelten, FPGA-basierten MPRACE-Karten können diese Leistung kostengünstig erbringen. Die konsequente Parallelisierung der einzelnen Programmschritte ermöglicht das Ausnutzen der vollen Leistungsfähigkeit von MPRACE und damit eine Rechenzeit von weniger als 100 us pro Ereignis. Ausführliche Simulationen des Triggersystems zeigen, dass in Experimenten mit leichten Kernen wie Nickel bei Strahlenergien von 1,93 GeV/u die K^+-Ausbeute etwa um den Faktor 6 und die K^--Ausbeute um den Faktor 11 gesteigert werden kann."],"dc:format.medium":["application/pdf"],"dc:publisher":["Universitätsbibliothek Heidelberg"],"dc:title":["A Kaon Trigger for FOPI : Development and Evaluation of a Trigger System for Strange Particles","Ein Kaon-Trigger für FOPI : Entwicklung und Bewertung eines Triggersystems für seltsame Teilchen"],"dc:type":["doctoralThesis"],"thesis:degree_level":["thesis.doctoral"],"thesis:institution_name":["Universität Heidelberg"]},"updated_at":"2026-07-24T02:29:49Z"}