513 research outputs found
Analysing the Control Software of the Compact Muon Solenoid Experiment at the Large Hadron Collider
The control software of the CERN Compact Muon Solenoid experiment contains
over 30,000 finite state machines. These state machines are organised
hierarchically: commands are sent down the hierarchy and state changes are sent
upwards. The sheer size of the system makes it virtually impossible to fully
understand the details of its behaviour at the macro level. This is fuelled by
unclarities that already exist at the micro level. We have solved the latter
problem by formally describing the finite state machines in the mCRL2 process
algebra. The translation has been implemented using the ASF+SDF
meta-environment, and its correctness was assessed by means of simulations and
visualisations of individual finite state machines and through formal
verification of subsystems of the control software. Based on the formalised
semantics of the finite state machines, we have developed dedicated tooling for
checking properties that can be verified on finite state machines in isolation.Comment: To appear in FSEN'11. Extended version with details of the ASF+SDF
translation of SML into mCRL
Commissioning and early physics analysis with the ATLAS and CMS experiments
These lecture notes for graduate students and young postdocs introduce the
commissioning and early physics programme of the high-transverse-momentum
experiments ATLAS and CMS, operating at the Large Hadron Collider (LHC) at
CERN.Comment: Lecture notes from the 5th Latin American School of High-Energy
Physics, Recinto Quirama, Colombia, March 15-28, 2009; 84 pages, 92 Figure
Generating and Solving Symbolic Parity Games
We present a new tool for verification of modal mu-calculus formulae for
process specifications, based on symbolic parity games. It enhances an existing
method, that first encodes the problem to a Parameterised Boolean Equation
System (PBES) and then instantiates the PBES to a parity game. We improved the
translation from specification to PBES to preserve the structure of the
specification in the PBES, we extended LTSmin to instantiate PBESs to symbolic
parity games, and implemented the recursive parity game solving algorithm by
Zielonka for symbolic parity games. We use Multi-valued Decision Diagrams
(MDDs) to represent sets and relations, thus enabling the tools to deal with
very large systems. The transition relation is partitioned based on the
structure of the specification, which allows for efficient manipulation of the
MDDs. We performed two case studies on modular specifications, that demonstrate
that the new method has better time and memory performance than existing PBES
based tools and can be faster (but slightly less memory efficient) than the
symbolic model checker NuSMV.Comment: In Proceedings GRAPHITE 2014, arXiv:1407.767
Mechanical Design of the HGCal Wedges with Thermal Gradient
After the discovery of the Higgs Boson, the purpose of the world's largest and most powerful particle accelerator, the Large Hadron Collider (LHC), seemed to have been achieved. Despite the fact that the Standard Model apparently complies with most experimental data up to this day, the majority of particle physicists feel that it is not a complete framework [1]. Therefore, there are still many unresolved problems in the physics of elementary particles. That is the reason why, in 2013, the European Strategy for Particle Physics announced its update. The High-Luminosity Large Hadron Collider (HL-LHC) project aims to increase luminosity by a factor of 10 beyond the LHC’s design. The higher the luminosity, the more data the experiments can gather to allow scientists to observe rare processes. Its development depends on several technological innovations, like the High-Granularity Calorimeter (HGCal), a major upgrade of the Compact Muon Solenoid (CMS) detector. [2] This project analyses the design and optimisation processes of the supports (wedges) which join the calorimeter (HGCal) to the related parts of the CMS detector. Specifically, the study focuses on the intermediate wedges. The main challenge is to create an optimal configuration for both the operational (vertical) and the assembly (horizontal) position. For this reason, a series of mechanical, magnetic and thermal considerations must be taken into account. This includes withstanding a mass of 200 tons and 50 °� of thermal difference. In order to achieve this goal, it is first necessary to analyse the functionality of the detector. This in-depth research allows a precise problem definition. Later, the preliminary design of the intermediate wedges is studied. By analysing the finite element results, the optimisation steps are established. At the end, the final version, the results of its analyses and some suggestions for the building process are presented. In the final result analyses, a hybrid configuration of fixed and hinged intermediate wedges was presented. In the operational position, stresses and vertical load values were lowered. In addition, a thermal analysis concluded that the heat transfer was sufficient for meeting the given requirements. In the assembly analysis, it was verified that the supports are not buckling or permanently deforming
The International Linear Collider Technical Design Report - Volume 4: Detectors
The International Linear Collider Technical Design Report (TDR) describes in
four volumes the physics case and the design of a 500 GeV centre-of-mass energy
linear electron-positron collider based on superconducting radio-frequency
technology using Niobium cavities as the accelerating structures. The
accelerator can be extended to 1 TeV and also run as a Higgs factory at around
250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator
is give, together with associated uncertainties. It is shown that no
significant technical issues remain to be solved. Once a site is selected and
the necessary site-dependent engineering is carried out, construction can begin
immediately. The TDR also gives baseline documentation for two high-performance
detectors that can share the ILC luminosity by being moved into and out of the
beam line in a "push-pull" configuration. These detectors, ILD and SiD, are
described in detail. They form the basis for a world-class experimental
programme that promises to increase significantly our understanding of the
fundamental processes that govern the evolution of the Universe.Comment: See also http://www.linearcollider.org/ILC/TDR . The full list of
signatories is inside the Repor
A CMS kísérlet Barrel Müon Helyzetmeghatározó Rendszerének kalibrációja, validációja és működtetése
A doktori disszertáció célja a CERN (Európai Nukleáris Kutatási Szervezet, Conseil Européen pour la Recherche Nucléaire) intézet Nagy Hadron Ütköztető (LHC, Large Hadron Collider) gyorsítójánál működő Kompakt Müon Szolenoid (CMS, Compact Muon Solenoid) kísérlet Barrel Muon Spektrométer pozíció meghatározó rendszerének építésevel, validációjával és üzemeltetésével kapcsolatban végezett munkám ismertetése.The aim of the PhD thesis is to describe my work on the construction,
installation, validation and operation
of the position monitoring (called also alignment) system
of the Barrel Muon Spectrometer of the CMS (Compact Muon Solenoid) experiment located in the P5 experimental hall of the Large Hadron Collider (LHC) accelerator at CERN (Conseil Européen pour la Recherche Nucléaire
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Track quality monitoring for the compact muon solenoid silicon strip tracker
ThesisThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The CMS Tracker is an all silicon detector and it is the biggest of its kind to be built. The system consists of over 15,000 individual detector modules giving rise to readout through almost 107 channels. The data generated by the Tracker system is close to 650 MB at 40 MHz. This has created a challenge for the CMS collaborators in terms of data storage for analysis. To store only the interesting physics data the readout rate has to be reduced to 100 Hz where the data has to be ltered through a monitoring system for quality checks. The Tracker being the closest part of the detector to the interaction point of the CMS creates yet another challenge that needs the data quality monitoring system. As it operates in a very hostile environment the silicon detectors used to detect the particles will be degraded. It is very important to monitor the changes in the sensor behaviour with time so that to calibrate the sensors to compensate for the erroneous readings. This thesis discusses the deve..
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