LHC Machine

Abstract

2008 JINST 3 S08001 9.3.1 The VME and PC Front End Computers 9.3.2 The PLCs 9.3.3 The supported fieldbuses 9.3.4 The WorldFIP fieldbus 9.3.5 The Profibus fieldbus 9.4 Servers and operator consoles 9.5 Machine timing and UTC 9.5.1 Central beam and cycle management 9.5.2 Timing generation, transmission and reception 9.5.3 UTC for LHC time stamping 9.5.4 UTC generation, transmission and reception 9.5.5 NTP time protocol 9.6 Data management 9.6.1 Offline and online data repositories 9.6.2 Electrical circuits 9.6.3 Control system configuration 9.7 Communication and software frameworks 9.7.1 FEC software framework 9.7.2 Controls Middleware 9.7.3 Device access model 9.7.4 Messaging model 9.7.5 The J2EE framework for machine control 9.7.6 The UNICOS framework for industrial controls 9.7.7 The UNICOS object model 9.8 Control room software 9.8.1 Software for LHC beam operation 9.8.2 Software requirements 9.8.3 The software development process 9.8.4 Software for LHC Industrial Systems 9.9 Services for operations 9.9.1 Analogue signals transmission 9.9.2 Alarms 9.9.3 Logging 9.9.4 Post mortem 10 Beam dumping 10.1 System and main parameters 13 LHC as an ion collider 13.1 LHC parameters for lead ions 13.1.1 Nominal ion scheme 13.1.2 Early ion scheme 13.2 Orbits and optical configurations for heavy ions 13.3 Longitudinal dynamics 13.4 Effects of nuclear interactions on the LHC and its beams 13.5 Intra-beam scattering 13.6 Synchrotron radiation from lead ions LHC machine acronyms Bibliography-vi-2008 JINST 3 S08001 Chapter 1 2008 JINST 3 S08001 2.2.7 Collective beam instabilities The interaction of the charged particles in each beam with each other via electromagnetic fields and the conducting boundaries of the vacuum system can result in collective beam instabilities. Generally speaking, the collective effects are a function of the vacuum system geometry and its surface properties. They are usually proportional to the beam currents and can therefore limit the maximum attainable beam intensities. 2.2.8 Luminosity lifetime The luminosity in the LHC is not constant over a physics run, but decays due to the degradation of intensities and emittances of the circulating beams. The main cause of the luminosity decay during nominal LHC operation is the beam loss from collisions. The initial decay time of the bunch intensity, due to this effect, is:

Readiness of the ATLAS Tile Calorimeter for LHC collisions

“…The cosmic trigger configuration during this run period consisted of L1 triggers from the muon spectrometer 3 (both the Resistive Plate Chamber (RPC) and the Thin Gap Chambers (TGC)), the L1 calorimeter trigger and the MBTS. For much of the cosmic ray analysis discussed in Sect.…”

Performance of the CMS precision electromagnetic calorimeter at the LHC Run II and prospects for high-luminosity LHC

“…The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid (CMS) experiment [1] is a high-resolution, hermetic, homogeneous and compact detector made of 75848 lead tungstate (PbWO 4 ) scintillating crystals arranged in a cylindrical structure around the LHC [2] interaction point. The lead tungstate crystals are radiation tolerant, have fast scintillation (∼ 75% in 25 ns), density ρ = 8.28 g/cm 3 , short radiation length (X 0 = 0.89 cm) and small Moliere radius (R M = 2.2 cm).…”

LHC signatures of a Z ′ mediator between dark matter and the SU(3) sector

“…In such framework, dimension six operators are suppressed by a factor M 2 (M being the mass of heavy fermions integrated out) and the dark matter sector, charged under U(1) X , couples with the weak or coloured sector of the Standard Model. An interaction with the weak SM sector was shown to have possible astrophysical signatures [48,49], while a coupling to the coloured SM sector was constrained [11] using mono-jets events at the LHC [52], as well as indirect detection constraints arising from astrophysical measurements. Such couplings had been studied, together with couplings to the top quarks in [53] but only in the context JHEP03(2016)006 Figure 1.…”