The Higgs Boson, better known as “the God particle”, is what holds the basic building blocks of our universe together. For years, scientists have been trying to isolate it with the ‘Large Hadron Collider (LHC)’, a $4 billion particle collider at CERN (Geneva). The LHC machine creates 600,000,000 collisions among 3,000,000,000,000,000 protons every second. In the same time, over 50,000,000,000,000 bytes of data are being analyzed to prove the particle existence. On July 4th 2012, finally scientists announced the discovery of a new particle "consistent with" the Higgs boson -- a subatomic particle also colloquially referred to as the "God particle." After years of design and construction, the LHC first sent protons around its 27 kilometer (17 mile) underground tunnel in 2008. Four years later, the LHC's role in the discovery of the Higgs boson provides a final missing piece for the Standard Model of Particle Physics -- a piece that may explain how otherwise massless subatomic particles can acquire mass. With such a ‘real time system’, as critical as expensive, unique and amazing in all its aspects, it was definitively an extraordinary environment to deploy GTD’s experience and to innovate technologies for such an exclusive machine. WHAT DOES IT TAKE TO CONTROL AND COMMAND SUCH AN IMMENSE MACHINE For more than 10 years, our engineers at GTD have been designing, developing and installing many of the most critical subsystems of LHC, the world’s largest and most powerful particle accelerator. This machine mainly consists of a 27-kilometre ring of superconducting magnets with a number of accelerating structures to boost the energy of the particles along the way. Inside the accelerator, two beams of particles travel at close to the speed of light with very high energies before colliding with one another. The beams travel in opposite directions in separate beam pipes – two tubes kept at ultrahigh vacuum. They are guided around the accelerator ring by a strong magnetic field, achieved using superconducting electromagnets. These are built from coils of special electric cable that operates in a superconducting state, efficiently conducting electricity without resistance or loss of energy. This requires chilling the magnets to about ‑271°C – a temperature colder than outer space. For this reason, much of the accelerator is connected to a distribution system of liquid helium, which cools the magnets, as well as to other supply services. Thousands of magnets of different varieties and sizes are used to direct the beams around the accelerator. These include 1232 dipole magnets of 15m length which are used to bend the beams, and 392 quadrupole magnets, each 5–7m long, to focus the beams. Just prior to collision, another type of magnet is used to "squeeze" the particles closer together to increase the chances of collisions. The particles are so tiny that the task of making them collide is akin to firing needles from two positions 10km apart with such precision that they meet halfway! All the controls for the accelerator, its services and technical infrastructure are housed under one roof at the CERN Control Centre. From here, the beams inside the LHC are made to collide at four locations around the accelerator ring, corresponding to the positions of the particle detectors. CERN’s Control Centre The operating of the new 27 km cryogenic accelerator, LHC, forces to unify four control rooms in one. GTD’s design of the new Operations Centre, baring in mind the integration and unification of human equipment, of material equipment and of pre-existing heterogeneous software applications. The purpose of the CERN Control Centre (CCC) is to combine the control rooms of the Laboratory’s eight accelerators, as well as the piloting of cryogenics and technical infrastructures. The LHC is not an isolated machine: it will be fed by a succession of interconnected accelerators. Protons will be accelerated and formed in beams in four increasingly large machines before being injected with an energy of 450 GeV into the LHC’s 27–km ring. The beams will then be accelerated in the ring until their energy is increased by a factor of 15, to 7000 GeV. When that energy is reached, the beams will collide in the centres of the detectors. Each beam will consist of about 3000 bunches of protons, each bunch containing up to 100 billion protons. The GTD’s design approached physical aspects related to space distribution, job post arrangements and its ergonomics. 24/7, capacity for 36 operators. Cryogenic Control System for the LHC accelerator The LHC design is based on superconducting twin-aperture magnets that operate in a superfluid helium bath at 1.9 K. After a tuff international competition, GTD was selected to buid up the Process Control Systems (PCS) including the control software for the cryogenic equipment of the LHC accelerator and the LHC experimental magnets (ATLAS and CMS). This is to control: • Eight 4.5 K and 1.8 K cryoplants supplying liquid helium (LHe) to the LHC accelerator and its infrastructure distributed over five sites. • The cryogenic equipment in the machine tunnel distributed over 27 km. • The ATLAS & the CMS Detectors Cryoplant and helium external common cryoplant. • The fully deployed system architecture features over more than 20 data servers • more than 300 PLC’s controllers. • A Central SCADA System SCADA that manages several million tags with a maximum refresh rate in the 50ms range. • The software design is an evolution of the “Object Oriented” philosophy used with former control system. In this approach each process component (I/O channel, actuator, set of sensors and actuators constituting a process entity) is modeled in an object. This object integrates the process behavior and the Human Machine Interface (HMI). SPS Accelerator‟s Power Supply & Interlock Controller In the SPS, the particle beam is maintained on a circular path by a magnetic guide field produced by 746 dipole magnets distributed around the synchrotron. 12 power converters are used to feed the dipole magnets. The crosssection of the particle beam is maintained by a system of 216 quadrupole magnets, alternatively focusing and defocusing fed by dedicated power converters. The 14 power converters, together with 3 spare power converters, are fed from an 18 kV substation located in the central electrical building. The power converters together with the 18 kV substations constitute the SPS Main Power Converters. The distribution of the power converters around the SPS accelerator brings with it a considerable risk to personnel and equipment. The control and interlock system detects faults and may stop all the main power converters or, if necessary, switch off all 18 kV circuit breakers. Faults are displayed on the front panel of the individual converter and the information is transmitted to the control room. In addition, the control and interlock system allows the remote control of the power converters from the control room. GTD replaced the obsolete system with a technical infrastructure of Programmable Logic Controllers (PLCs) and specially designed protocols and control/safety architectures to achieve balanced safety/availability.
