The Silicon Vertex Tracker (SVT) of the BABAR experiment at the PEP-II asymmetric B factory is a five layers double sided, AC coupled silicon microstrip detector. It represents a crucial element to ...measure with precision the decay position of B mesons, satisfying the severe constraints imposed by the accelerator design, in terms of geometry of the interaction region and conditions of operation. In the following paper the SVT performances are described. Radiation issues are discussed and the results of different tests aimed to study the SVT degeneration in performance due to the radiation damage are presented. The alignment procedure is described and a few BaBar physics results are presented as examples of the SVT capabilities to reconstruct decay vertices with good resolution and efficiency.
Performance of the upgraded small angle tile calorimeter at LEP Alvsvaag, S.J.; Bari, M.; Barreira, G. ...
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255),
1998, Letnik:
1
Conference Proceeding
The small angle tile calorimeter (STIC) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with ...so-called "shashlik" technique, allows the insertion of tracking detectors within the sampling structure, in order to make it possible to determine the direction of the showering particle. Presented here are some results demonstrating the performance of the calorimeter and of these tracking detectors at LEP.
The authors describe in detail the basic concepts of the design, the composition of the data flow, and the tools developed to monitor the trigger in real time. The results of the trigger performance ...in terms of efficiencies achieved during the first two and a half years of operation in the LEP (Large Electron Positron Collider) machine are also shown. So far, a total of approximately 10/sup 6/ hadronic Z/sup 0/s have been collected from 21 million recorded events. The DELPHI trigger system provides an efficiency nearly 100% over the covered solid angle for all particles and physical channels. The system has also proved to be stable despite very different beam conditions. This is a consequence of the high redundancy provided by the different detectors for all e/sup +/e/sup -/ final state processes, which also ensures a method for calculating the absolute trigger efficiencies using data only.< >
The new luminosity monitor of the DELPHI detector, STIC (Small angle TIle Calorimeter), was built using a Shashlik technique. This technique does not provide longitudinal sampling of the showers, ...which limits the measurement of the direction of the incident particles and the
e —
π separation. For these reasons STIC was equipped with a Silicon Pad Shower Maximum Detector (SPSMD). In order to match the silicon detectors to the Shashlik read out by wavelength shifter (WLS) fibers, the silicon wafers had to be drilled with a precision better than 10
μm without damaging the active area of the detectors. This paper describes the SPSMD with emphasis on the fabrication techniques and on the components used. Some preliminary results of the detector performance from data taken with a 45 GeV electron beam at CERN are presented.
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