Performance of the ALICE SPD cooling system Francescon, A; Rinella, G Aglieri; Altini, V ...
Journal of physics. Conference series,
01/2012, Letnik:
395, Številka:
1
Journal Article
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The new generation of silicon detectors for particle physics requires very reduced mass and high resistance to radiations with very limited access to the detector for maintenance. The Silicon Pixel ...Detector (SPD) is one of the 18 detectors of the ALICE (A Large Io Collider Experiment) experiment at the Large Hadron Collider (LHC) at CERN. It constitute the two innermost layers of the Inner Tracking System (ITS) and it is the closest detector to th interaction point. An evaporative cooling system, based on C4F10 evaporation at 1.9 bar, was chosen to extrac the 1.35 kW power dissipated by the on-detector electronics. The whole system wa extensively tested and commissioned before its installation inside the ALICE experimenta area. Since then we had to deal with a decrease of the flow in some lines of the system tha imposed severe restrictions on the detector operation. Recently, a test bench has been built in order to carry out a series of tests to reproduce the misbehaviour of the system and investigat proper actions to cure the problem. The performance of the systems and the most interesting results of the above mentioned test will be presented.
The future opportunities for high-density QCD studies with ion and proton beams at the LHC are presented. Four major scientific goals are identified: the characterisation of the macroscopic long ...wavelength Quark-Gluon Plasma (QGP) properties with unprecedented precision, the investigation of the microscopic parton dynamics underlying QGP properties, the development of a unified picture of particle production and QCD dynamics from small (pp) to large (nucleus--nucleus) systems, the exploration of parton densities in nuclei in a broad (\(x\), \(Q^2\)) kinematic range and the search for the possible onset of parton saturation. In order to address these scientific goals, high-luminosity Pb-Pb and p-Pb programmes are considered as priorities for Runs 3 and 4, complemented by high-multiplicity studies in pp collisions and a short run with oxygen ions. High-luminosity runs with intermediate-mass nuclei, for example Ar or Kr, are considered as an appealing case for extending the heavy-ion programme at the LHC beyond Run 4. The potential of the High-Energy LHC to probe QCD matter with newly-available observables, at twice larger center-of-mass energies than the LHC, is investigated.
This document was prepared by the community that is active in Italy, within INFN (Istituto Nazionale di Fisica Nucleare), in the field of ultra-relativistic heavy-ion collisions. The experimental ...study of the phase diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP) deconfined state will proceed, in the next 10-15 years, along two directions: the high-energy regime at RHIC and at the LHC, and the low-energy regime at FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the present and future programme of the ALICE experiment, the upgrade of which will open, in the 2020s, a new phase of high-precision characterisation of the QGP properties at the LHC. As a complement of this main activity, there is a growing interest in a possible future experiment at the SPS, which would target the search for the onset of deconfinement using dimuon measurements. On a longer timescale, the community looks with interest at the ongoing studies and discussions on a possible fixed-target programme using the LHC ion beams and on the Future Circular Collider.
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