The silicon multiplicity detector for the NA50 experiment at CERN

The design, operation and performance of the silicon strip Multiplicity Detector for the heavy-ion experiment NA50 at CERN are presented. The main features of the detector are high speed (50 MHz sampling frequency), high granularity (more than 13,000 strips), and good radiation resistance. The detector provided a measurement ofevent centrality in Pb–Pb collisions, as well as target identification and the measurement ofcharged particle pseudorapidity distributions as a function of centrality. r 2002 Elsevier Science B.V. All rights reserved. PACS: 29.4

The silicon Multiplicity Detector for the NA50 experiment

Abstract The operation and performance of the silicon strip Multiplicity Detector in the heavy-ion experiment NA50 at CERN are presented together with a selection of physics results. The main features of the detector are high speed (50 MHz sampling frequency), high granularity (more than 13,000 strips), and good radiation resistance. The detector provided a measurement of event centrality in Pb–Pb collisions, as well as target identification and the measurement of charged particle pseudorapidity distributions as a function of centrality

Real time compensation of the path spread in large time-of-flight systems

The operating principle of an electric system able to compensate in real time the differences in time-of-flight due to the path-length spread occurring in large devices with pointlike geometries is described. Experimental tests with a particle beam have provided very good results, opening the possibility of triggering with very long scintillators with time resolutions of the order of 1 ns. It is concluded the system completely fills the requirements of the OBELIX experiment, extending the range of π/k separation from ≈300 to ≈600 MeV/

Charge injectors of ALICE silicon drift detector

Large area, 7.25 x 8.76 cm(2), Silicon Drift Detector (SDD) has been developed for the ALICE experiment at CERN [A. Vacchi, et al., Nuel. Instr. and Meth. A 306 (1991) 187; A. Rashevsky, et al., Nucl. Instr. and Meth. A 461 (2001) 133-138; A. Rashevsky, et al., Nucl. Instr. and Meth. A 485 (2002) 54; P. Burger, C. Piemonte, A. Rashevsky, A. Roncastri, A. Vacchi, INFN/TC-02/07; C. Piemonte, A. Rashevsky, INFN/TC-02/08; C. Piemonte, A. Rashevsky, D. Nouais, INFN/TC-00/04. C. Piemonte, A. Rashevsky, A. Vacchi, ALICEINT-2002-15, 2002; Inner Tracking System, CERN/LHCC, June 1999]. SDDs form two out of six cylindrical layers of the ALICE inner tracking system. The 260 high-quality SDDs needed to equip these two layers have been selected. One of the detector design elements devoted to allow controlled operating conditions is the on-board arrays of point-like charge injectors [D. Nouais, et al., CERN-ALICEPUB-99-31; V. Bonvicini, et al., 11 Nuovo Cimento 112AN (1-2) (1999) 137-146]. In the case of an SDD they are essential to trace, with the required frequency and precision, the changes in drift velocity induced by temperature variations. In order to ensure operating stability during the 10 years of the ALICE experiment the bias scheme of the charge injectors exploits the electrical properties not only of a detector itself, but also those of the cables mounted onto it, thus constituting a module. Computer simulations of the equivalent circuit revealed a significant improvement of the injection efficiency. Subsequent experimental tests of the first assembled modules confirmed the predicted performances. We report the layout of the charge injectors integrated in the ALICE SDD, as well as test results. (c) 2006 Elsevier B.V. All rights reserved