A.P. de Haas

Alignment of the ALICE inner tracking system with cosmic-ray tracks

ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 mu m in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10(5) charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 μm in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton– proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 105 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.

Precision and mass fractionation in 14C analysis with AMS

Modifications of the Utrecht AMS set-up have resulted in 14C analysis with a routine 0.4% analytical precision and a detection limit of 2.0 × 10−15. In analysis with 10Be, 26Al and 36Cl the precision is a few percent and the detection limit 10−14. Measurements on small carbon samples (< 0.4 mg) revealed a sample-mass dependent isotope fractionation effect, which together with the background limits the precision for the smallest samples (0.02 mg) to a few percent.

Energy dependence of hyperon production in nucleus–nucleus collisions at SPS

A measurement of strange baryon and antibaryon production in Pb-Pb collisions has been carried out by the NA57 experiment at the CERN SPS, with 40 and 158 A GeV/c beam momentum. Results on

Study of the transverse mass spectra of strange particles in Pb–Pb collisions at 158 A GeV/c

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Determination of the event centrality in the WA97 and NA57 experiments

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Results on hyperon production from NA57

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Silicon pixel detectors for tracking in NA57

and

Front-end modules for ALICE SSD

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A time projection chamber with microstrip read-out

hyperon yields at mid-rapidity in the most central 53% of Pb-Pb collisions at 40 A GeV/c are presented and compared with those obtained at higher energy, in the same collision centrality range. The

Multiplicity of charged particles in Pb–Pb collisions at SPS energies

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