Performance of the ALICE luminosity levelling software architecture in the Pb-Pb physics run

Luminosity leveling is performed in the ALICE experi-ment of the Large Hadron Collider (LHC) in order to limitthe event pile-up probability, and ensure a safe operation forthe detectors. It will be even more important during Run3 when 50 KHz Pb ion-Pb ion (Pb-Pb) collisions will bedelivered in IP2. On the ALICE side, it is handled by theALICE-LHC Interface project, which also ensures an onlinedata exchange between ALICE and the LHC. An automated luminosity leveling algorithm was developed for the proton-proton physics run, and was also deployed for the Pb-Pb run with some minor changes following experience gained. The algorithm is implemented in the SIMATIC WinCC SCADA environment, and determines the leveling step from measured beam parameters received from the LHC, and the luminosity recorded by ALICE. In this paper, the softwarearchitecture of the luminosity leveling software is presented,and the performance achieved during the Pb-Pb run and Vander Meer scans is discussed.peer-reviewe

Long-Term Clinical Consequences of Intense, Uninterrupted Endurance Training in Olympic Athletes

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Proposal for a new ALICE CPV-HMPID front-end electronics topology

This paper presents the proposal of a new front-end readout electronics (RO) architecture for the ALICE Charged-particle Veto detector (CPV) located in PHOton Spectrometer (PHOS), and for the High Momentum particle IDentification detector (HMPID). With the upgrades in hardware typology and proposed new readout scheme in FPGA design, the RO system shall achieve at least five times the speed of the present front-end readout electronics. Design choices such as using the ALTERA Cyclone V GX FPGA, the topology for parallel readout of Dilogic cards and an upgrade in FPGA design interfaces will enable the RO electronics to reach an approximate interaction rate of 50 kHz. This paper presents the new system hardware as well as the preliminary prototype measurement results. This paper concludes with recommendations for other future planned updates in hardware schema

Design of a Quasi-Linear Rail-to-Rail Delay Element with an Extended Programmable Range

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On the Design of a Linear Delay Element for the Triggering Module at CERN LHC

This paper presents an analytical model of a linear delay element circuit to be employed in the triggering module for the High Momentum Particle Identification Detector (HMPID) at the CERN Large Hadron Collider (LHC). The aim of the analytical model is to facilitate the design of the linear delay element circuit, while maximizing its linearity and delay range. The analytical model avoids the need of time consuming parametric sweeps on the aspect ratios of the various transistors of the delay element in order to optimize it. In addition, the analytical model can be used to predict the variation of the delay with the input tuning voltage. The proposed analytical model is verified via the simulation of the delay element circuit using the 0.18 μm X-FAB technology

Particle Swarm Optimization of a Rail-to-Rail Delay Element for Maximum Linearity

This paper illustrates the use of the Particle Swarm Optimization (PSO) algorithm to maximize the linearity of a rail-to-rail delay element. Previous approaches relied on approximating the piecewise time-delay model of the delay element through either the Newton Polynomial or the Lagrange Polynomial methods. While adequate linearity was achieved in both cases, this could be further improved. This work successfully employed the PSO algorithm to improve the linearity by reducing the mean square error such that the delay element exhibits a spurious-free dynamic range of 29.62 dB, with a delay range of 170.4 ns. The results were verified in Cadence using the X-FAB 0.18 μm technology

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe