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:

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The Large Hadron Collider (LHC) is the most complex instrument ever built for particle physics research. It will, for the first time, provide access to the TeV-energy scale. Numerous technological innovations are necessary to achieve this goal. For example, two counterrotating proton beams are guided and focused by superconducting magnets whose novel two-in-one structure saves cost and allowed the machine to be installed in an existing tunnel. The very high (>8-T) field in the dipoles can be achieved only by cooling them below the transition temperature of liquid helium to the superfluid state. More than 80 tons of superfluid helium are needed to cool the whole machine. So far, the LHC has behaved reliably and predictably. Single-bunch currents 30% above the design value have been achieved, and the luminosity has increased by five orders of magnitude. In this review, I briefly describe the design principles of the major systems and discuss some initial results.

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