The Alice inner tracking system Antinori, F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2003, Volume:
511, Issue:
1
Journal Article
Peer reviewed
The paper provides a short description of the inner tracking system under preparation for the Alice experiment, together with an illustration of its expected physics performance.
A realistic simulation of the trigger system in a complex HEP experiment is essential for performing detailed trigger efficiency studies. The ALICE trigger simulation is evolving towards a framework ...capable of replaying the full trigger chain starting from the input to the individual trigger processors and ending with the decision mechanisms of the ALICE central trigger processor. This paper describes the new ALICE trigger simulation framework that is being tested and deployed. The framework handles details like trigger levels, signal delays and busy signals, implementing the trigger logic via customizable trigger device objects managed by a robust scheduling mechanism. A big advantage is the high flexibility of the framework, which is able to mix together components described with very different levels of detail. The framework is being gradually integrated within the ALICE simulation and reconstruction frameworks.
The WA97 experiment has measured the transverse mass \(({m_{\mathrm T}})\) spectra for negative hadrons (\(\mathrm{h}^-\)) and strange particles produced at mid–rapidity in Pb–Pb collisions. The ...increased statistics of analysed data samples allowed us to perform a study of the spectra of \({\rm K_S^0}\), \(\mathrm{\Lambda}\), \(\mathrm{\Xi}\), \(\mathrm{\Omega}\) and \(\mathrm{h}^-\) as a function of the collision centrality. The data, which correspond to the most central 40% of the total inelastic cross section, have been divided into four centrality classes according to the estimated number of nucleons taking part in the collision. The \(m_{\mathrm T}\) spectra, analysed separately for each centrality bin, exhibit only weak (\(\leq\) 15%) centrality dependence. The deviation of the \(\mathrm{\Omega}\) inverse slope from the linear dependence on the particle mass is confirmed even for the most central Pb–Pb collisions.
A pixel detector system for ALICE Antinori, F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/1997, Volume:
395, Issue:
3
Journal Article
Peer reviewed
Two layers of Si pixel detectors are foressen in the proposed layout of the ALICE experiment at LHC. Their main task is to provide secondary vertex detection capability for the study of flavour ...production in nucleus-nucleus collisions at LHC. We illustrate the requirements for the ALICE pixel system, present a concept for its implementation and discuss the expected performance for the detection of charm and strange decay vertices.
The measurement of the production of charm jets, identified by the presence of a D$^{0}$ meson in the jet constituents, is presented in proton–proton collisions at centre-of-mass energies of $ ...\sqrt{s} $ = 5.02 and 13 TeV with the ALICE detector at the CERN LHC. The D$^{0}$ mesons were reconstructed from their hadronic decay D$^{0}$ → K$^{−}$π$^{+}$ and the respective charge conjugate. Jets were reconstructed from D$^{0}$-meson candidates and charged particles using the anti-k$_{T}$ algorithm, in the jet transverse momentum range 5 < p$_{T,chjet}$< 50 GeV/c, pseudorapidity |η$_{jet}$| < 0.9 − R, and with the jet resolution parameters R = 0.2, 0.4, 0.6. The distribution of the jet momentum fraction carried by a D$^{0}$ meson along the jet axis $ \left({z}_{\Big\Vert}^{\textrm{ch}}\right) $ was measured in the range 0.4 <$ {z}_{\Big\Vert}^{\textrm{ch}} $< 1.0 in four ranges of the jet transverse momentum. Comparisons of results for different collision energies and jet resolution parameters are also presented. The measurements are compared to predictions from Monte Carlo event generators based on leading-order and next-to-leading-order perturbative quantum chromodynamics calculations. A generally good description of the main features of the data is obtained in spite of a few discrepancies at low p$_{T,chjet}$. Measurements were also done for R = 0.3 at $ \sqrt{s} $ = 5.02 and are shown along with their comparisons to theoretical predictions in an appendix to this paper.graphic not available: see fulltext
We present a performance study for the detection of open beauty hadrons decaying in the semi-electronic channels in Pb-Pb collisions at the LHC with the ALICE detector.
Recent test results of the ALICE silicon pixel detector Riedler, P.; Anelli, G.; Antinori, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2005, Volume:
549, Issue:
1
Journal Article
Peer reviewed
The ALICE SPD (Silicon Pixel Detector) forms the two innermost layers of the Inner Tracking System (ITS) of the ALICE experiment at LHC. After several years of development the production of the ...modules is starting. The present article provides an overview of the different elements that will be used in the SPD with special emphasis given to testing of wafers and bump-bonded ladders.
First results from the ALICE silicon pixel detector prototype Riedler, P; Anelli, G; Antinori, F ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Volume:
501, Issue:
1
Journal Article
Peer reviewed
System prototyping of the ALICE silicon pixel detector (SPD) is well underway. The ALICE SPD consists of two barrel layers with 9.83 million channels in total. These are read out by the ALICE1LHCb ...pixel chip, which has been developed in a commercial
0.25
μm
process with radiation hardening by design layout. The readout chip contains 8192 pixel cells each with a fast analog preamplifier and shaper followed by a discriminator and digital delay lines. Test results show a pixel cell noise of about 110 electrons rms and a mean minimum threshold of about 1000 electrons rms before threshold fine tuning. Several readout chips have been flip-chip bonded to detectors using two different bump-bonding techniques (solder, indium). Results of radioactive source measurements of these assemblies are presented for
90
Sr
and
55
Fe
sources. Several chip-detector assemblies have been tested in a
150
GeV/
c
pion beam at CERN where an online efficiency of about 99% across a wide range of detector bias and threshold settings was observed. All preliminary investigations confirm the functionality of the chip and the chip-detector assemblies for the ALICE experiment.
The first measurement of the production of pions, kaons, (anti-)protons and ϕ mesons at midrapidity in Xe–Xe collisions at $\sqrt{s_{NN}}$ = 5.44 TeV is presented. Transverse momentum ...(pT) spectra and pT-integrated yields are extracted in several centrality intervals bridging from p–Pb to mid-central Pb–Pb collisions in terms of final-state multiplicity. The study of Xe–Xe and Pb–Pb collisions allows systems at similar charged-particle multiplicities but with different initial geometrical eccentricities to be investigated. A detailed comparison of the spectral shapes in the two systems reveals an opposite behaviour for radial and elliptic flow. In particular, this study shows that the radial flow does not depend on the colliding system when compared at similar charged-particle multiplicity. In terms of hadron chemistry, the previously observed smooth evolution of particle ratios with multiplicity from small to large collision systems is also found to hold in Xe–Xe. In addition, our results confirm that two remarkable features of particle production at LHC energies are also valid in the collision of medium-sized nuclei: the lower proton-to-pion ratio with respect to the thermal model expectations and the increase of the ϕ-to-pion ratio with increasing final-state multiplicity.
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