The trigger and data acquisition system of the SAPHIR detector
Description
At present SAPHIR, a new experimental facility for medium energy physics is under construction at the Bonn electron accelerator ELSA (energy ≤ 3.5 GeV, duty cycle ≅ 100%). SAPHIR combines a large solid angle coverage with a tagging system and is therefore suited to investigate reactions with multi-particle final states. Structure and function of the multi-stage trigger system, which is used to select such processes, are described in this paper. With this system the trigger decision can be based on the number of charged particles as well as on the number of neutral particle detected. Several VMEbus modules have been developed, using memory look-up tables to make fast trigger decisions possible. In order to determine the number of neutral particles from the cluster distribution in the electromagnetic calorimeter some ideas of cellular had to be added. The system has a modular structure, so it can easily be extended. In the second part of this thesis the SAPHIR data acquisition system is discussed. It consists of a multiprocessor system with the VIP microcomputer as central element. The VIP is a VMEbus modul optimized for a multiprocessor environment. Its description as well as that of the other VMEbus boards developed for the SAPHIR online system can be found in this paper. As a basis for software development the operating system SOS is supplied. With SOS it is possible to write programs independent of the actual hardware configuration and so the complicated multiprocessor environment is hidden. To the user the system looks like a simple multi-tasking system. SOS is not restricted to the VIPs but can also be installed on computers of the VAX family, so that efficient mixed configurations are possible. The SAPHIR online system, based on the VIP microcomputer and the SOS operating system, is presented in the last part of this paper. This includes the read-out system, the monitoring of the different components etc. (orig./HSI)
Availability note (English)
MF available from INIS under the Report Number.Abstract (German)
Weltweit wird derzeit an einer neuen Generation von Teilchenbeschleunigern mit hohem Tastverhaeltnis gearbeitet. Als erste Anlage dieser Art wurde im Oktober 1987 ELSA am physikalischen Institut der Universitaet Bonn in Betrieb genommen. Das hohe Tastverhaeltnis gestattet den Einsatz von Grossraumspektrometern und Tagging Systemen, und ermoeglicht so zum Beispiel die Untersuchung von Photoproduktionsprozessen mit Mehrteilchenendzustaenden. Fuer solche Messungen wird an ELSA der SAPHIR Detektor aufgebaut. In dieser Arbeit wurden mit dem Trigger- und dem Datenerfassungssystem zwei Komponenten von SAPHIR vorgestellt. Aufgabe des Triggers ist es, moeglichst schnell anhand der von den verschiedenen Detektorkomponenten bereitgestellten Informationen physikalisch interessante Ereignisse vom Untergrund zu unterscheiden. Zu diesem Zweck wurde fuer SAPHIR ein mehrstufiges Triggersystem entworfen und aufgebaut. Arbeitsweise und elektronischer Aufbau des Triggersystems, insbesondere der zweiten Triggerstufe, werden im dritten Kapitel dieser Doktorarbeit vorgestellt. Hier sollen die wesentlichen Punkte nur noch einmal aufgelistet werden. (orig./HSI)
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Additional details
Additional titles
- Original title (German)
- Das Trigger- und Datenerfassungssystem des SAPHIR-Detektors
Publishing Information
- Imprint Pagination
- 142 p.
- Report number
- BONN-IR--88-61
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 20080103
- Subject category
- S46: INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- BONN SYNCHROTRON; CALORIMETERS; CHARGED PARTICLE DETECTION; COMPUTER NETWORKS; DATA ACQUISITION; DATA ACQUISITION SYSTEMS; DATA PROCESSING; DEAD TIME; DEC COMPUTERS; DRIFT CHAMBERS; GAMMA DETECTION; HODOSCOPES; LOGIC CIRCUITS; MICROPROCESSORS; MODULAR STRUCTURES; MULTIPLE PRODUCTION; MULTIPLICITY; ON-LINE MEASUREMENT SYSTEMS; OPTIMIZATION; PHOTOPRODUCTION; PROCESS COMPUTERS; PROGRAMMING; READOUT SYSTEMS; TIME-OF-FLIGHT METHOD; TRIGGER CIRCUITS
- Descriptors DEC
- ACCELERATORS; BASIC INTERACTIONS; COMPUTERS; CYCLIC ACCELERATORS; DETECTION; ELECTROMAGNETIC INTERACTIONS; ELECTRONIC CIRCUITS; INTERACTIONS; MEASURING INSTRUMENTS; MICROELECTRONIC CIRCUITS; MULTIWIRE PROPORTIONAL CHAMBER; ON-LINE SYSTEMS; PARTICLE INTERACTIONS; PARTICLE PRODUCTION; PROPORTIONAL COUNTERS; PULSE CIRCUITS; RADIATION DETECTION; RADIATION DETECTORS; SYNCHROTRONS; TIMING PROPERTIES