New CERN Control Centre On The Way

CERN is to build a control center that will handle all its accelerators.

In a development crucial for the success of the LHC, CERN will build a Control Centre (CCC) for the operation of all its beams and accelerators. The CCC will be an extension of the existing PCR building at Prévessin and is due to be operational by 1 February 2006. Allocated a budget of MCHF 8.1, costs are being kept down by using as much existing infrastructure as possible.
At present, five accelerator operators work in two control rooms at Prévessin and Meyrin, and the LHC will add another two full time operators. In addition there are already two operators in the TCR for the CERN technical services and it will be necessary to have yet another Operations team for the LHC cryogenics.
Bringing these personnel together is an important step in streamlining operations because the performance of the LHC will depend critically on the rest of the CERN accelerator complex, as well as its technical and cryogenic services.
Starting in the LINAC (linear accelerator), protons for the LHC go to the PSB (Proton Synchrotron Booster) which defines the cross section of the beam: this must be small enough to fit into the LHC and to ensure that a sufficient number of collisions will be generated in the experiments. From there, the beam passes to the PS (Proton Synchrotron) which defines the length and separation of each bunch of protons. The PS then passes the beam to the SPS (Super Proton Synchrotron) which defines the filling pattern and brings beam energy up to 450GeV for injection into the LHC.
The LHC will accelerate these protons up to energy of 7TeV before colliding them in the experiments. However, if any preceding accelerator has delivered an imperfect beam, it will not be possible to correct the error once the beam is in the LHC. This was different in LEP: radiation damping of the electrons and positrons ensured that small 'errors' in the beam preparation in the injector chain had little or no influence on the LEP performance. However, protons behave differently. They have a very long 'memory' and any small errors in the injector chain will, unfortunately, be preserved in the LHC. With the CCC coordinating the process, beam quality will be assured.
The CCC will also have to handle all CERN's other beams, such as the n-TOF (the neutron time-of-flight at the PS); the AD (Antiproton Decelerator) and its experimental area; the Low Energy Ion Ring (LEIR); ISOLDE (On-line Isotope Mass Separator) at the PS Booster; the North and East experimental areas, and the CNGS facility, which is due to come on-line in 2006.
With the ongoing construction of the LHC, the next two years will see many more changes. In 2005 the PS and SPS machines will be stopped to free more resources for LHC related tasks. In 2003 a number of Accelerator Operators were seconded to work on LHC magnet test program in SM18. When that task is complete, the new CCC will be in operation, ready to ensure the LHC can operate at peak efficiency.

Beam Operators don't just push buttons

'It is a strange job because the Operators are in the front line but people don't really know what we do,' says Simon Baird, AB Operations Group Leader.
Accelerator Operators ensure that CERN's research can happen. The biggest challenge is to keep the beams at top performance while reducing downtime, the time that a scheduled beam is not available to the users with the correct characteristics. Working round the clock, at nights and weekends is all part of the job.
Each accelerator carries several beams at the same time, and can tailor every beam to a particular experiment. It is this exceptional ability to support many different facilities simultaneously that makes CERN unique in its range of research.
'We multitask the accelerators,' says Simon Baird. 'It's a little like a railway network that uses the same set of infrastructure to carry many different passengers to many different places.'
In CERN's most powerful accelerators these passengers are particles (protons, ions, antiprotons etc.), and every experiment requires them to be organised differently, at different energy levels, and in different quantities. The Operators must make sure that all the passengers (particles) arrive at the right places at the right time and in the right quantities. Operators must also organise the timetable, conduct experiments aimed at improving efficiency and quality, and help to repair the system in case of breakdowns.
'We encourage people to push the machines to enhance beam performance,' says Simon Baird. 'It's certainly much more than just keeping things running.' Indeed operating the LHC and the new CNGS beam, at the same time as maintaining and improving all the existing beams and facilities, will stretch CERN's accelerators beyond their present limits.
And the strangest part of the job? Although most of the accelerators are underground, thunderstorms can cause big problems by affecting the electricity supply to the delicate accelerator hardware. Beam operators even have to check the weather forecast!