Reporting from the tunnel: the LHC is under maintenance

Hundreds of people invited, celebrated the world's largest particle accelerator on October the 21st 2008 official opening at the European laboratory for particle physics, CERN. However deep in the depths there was no sign of any concerts, speeches nor any molecular buffets. It is being a 'heads down' silent work towards rebooting the system after the incident a month ago in which parts where damaged. Due to this unscheduled halt we managed to gain access into the Large Hadron Collider's tunnel.

(The report was published originally on 21st October, 2008.)

This is really enormous - it was my the first thought when I stepped out from the elevator after the hundred-metre fast descent, and eventually looked upon the gigantic CMS detector - which had only been seen many times before in pictures and films - in all its glory. Twenty-one metres long, with a diameter of fifteen metres, a 12,500 tons barrel, with countless numbers of sensors, cables and a gigantic solenoid magnet. Well this is one of the humanity's 'top equipment' which along with another detector known as ATLAS will to be used to search for the Higgs particle, the 'Holy Grail' of the physics.

The six-storey-high CMS detector has already been closed but yet so fascinating

The protons arrive here into the detector

Searching for Higgs we need collisions of sufficient energized proton beams in the centre of the detectors. However after the LHC's successful activation in September we instantly became distant from doing so. The latest information indicates that the worlds largest particle accelerator will only be restarted in late spring of 2009. On September the 19th part of the incredibly complex system, consisting of millions of components was seriously damaged by a simple error, a faulty electrical connection caused by bad soldering. The system is currently not working, therefore the proton-proton collisions which were planned for the opening ceremony on the 21st of October were not able to excite the members of the official delegations - instead they could closely look at the tunnel and enjoy the high technology.

A junction in the tunnel: people left, protons right towards the CMS detector

This is an unusual warning sign for the average person

This is something most of us have only seen in sci-fi movies: a retina scanner in the tunnel

The eruption of the liquid helium

CERN on 16 October published the latest results of the tests on the incident. The accelerator ring with a 27 kilometer circumference consisting of nearly ten thousand superconducting magnets is divided into 8 sectors, which are cooling and powering independently to each other. The power tests for each sector - during which the magnets were supplied with 9300 amps - went according to plan until September the 19th during the testing of the last sectors 3 and 4. At this moment occurred what a lot of people were afraid of: a faulty electrical connection between two of the accelerator's magnets 'went off'. Due to this incident within one second an electrical arc developed, and this resulted in mechanical damage. Damage was caused to the insulation vacuum, the cooling system, and six tonnes of liquid helium erupted out to the tunnel. If someone was there they would have instantly frozen (or suffocated while the helium evaporates and forces out the air). Fortunately, nobody was in danger.

A look inside the system showing the connection between two dipole magnets: a similar section to where the fault occurred, due to faulty electrical connection

Helium producers must be glad: six tonnes of helium lost in the incident

The deterioration of vacuum caused severe mechanical damage in the surrounding parts. The faulty magnets are being replaced with spare magnets, and the actual preparation for the experimental work can be continued in the spring of 2009 following the previously planned winter checking period. However during this period physicists continue to work on, the calibration of the detectors, as well as on data acquisition tests.

The situation is rather difficult from the psychological point of view

The damaged magnets reached temperatures below 2 Kelvin. Dezso Horvath (right), the physicist of KFKI RMKI explained to [origo]: 'Despite the fact that the cooling of course, immediately stopped, the heating of the magnets took a period of three weeks. This is because opening the magnets in a cold state would immediately precipitate all the moisture and dirt, and it would be difficult to free the magnets from this. The damaged magnets must be released now, which means a lot of welding, and then they can be brought up to surface for replacement or repairing. According to the most recent report, 24 dipole and 5 quadrupole magnets were ruined, and we have sufficient reserves of them both. This work will take several months. During which time a number of other tasks can also be done which would otherwise have been scheduled for spring.'

Even though many invited guests such as Europe's leading politicians did not attend the official opening ceremony, work is still being carried out intensively. Physicist György Vesztergombi from KFKI RMKI (left) said: 'The situation is really not an easy one in psychological aspects. The increased possibility of failure is inherent in such a complex system. Complex accelerators like those in the United States have ultimately proven the functionality of the technology. Of course most of the problems appear at the launch time, but problems can occur later as well. The operational time of particle accelerators is only 50% of their lifetime. This error did not cause problems in areas where it was expected to, but now modifications of operating process will be carried out according to this. In theory there are no problems as these systems are programmable'.

We could look at the internal structure of the magnets closely. Protons will race through the two smaller middle beam pipes ( in opposite directions ), the other pipes conceal electrical wiring and the cooling system

Originally, the first proton-proton collisions would have provided the sensation of the day, however instead masterpieces of a 'molecular buffet' were competing for this which were created by an exciting combination of physics and gastronomy : for example, ice cream made with liquid nitrogen

The celebration has just ended, work is currently ongoing, launch will hopefully be by next spring