Acceleration of the LHC commissioning testsThe quadrupole and main dipole circuits have been powered up to 10,200 amps in Sector 4-5. Sector 5-6 is currently being cooled and will be the next to undergo electrical tests, which will be stepped up over the next few weeks.
The Control Room is a hive of activity while the electrical tests are carried out.
Numerous electrical tests were carried out in Sector 4-5 during the period from November to mid-February. Once the temperature had been stabilised at around 1.9 K (-271°C) at the beginning of December, the circuits were initially powered up to 8,500 amps. The main dipole circuit was then gradually brought up to 10,200 amps during the last week of January, then the main quadrupole circuits to 10,800 amps in February. At this intensity of current the magnets are capable of guiding a 6 TeV proton beam. During this process, for both the dipole and the quadrupole circuits, a number of training quenches occurred.
138 superconducting circuits ramped in unison at an equivalent beam energy of 5.3 TeV.
"Given the limited time at our disposal, we decided to stop at this energy, which is very close to the target, and start to commission the numerous circuits (each sector has 200) before Sector 4-5 was warmed up again. The mechanics have to connect the triplet (the focussing magnet on both sides of each experiment). We have scanned all the circuits to check that they are working properly. Today we know that the electrical circuits in this sector require no major corrective action", says Roberto Saban, responsible for coordinating the commissioning of the LHC technical systems.
The Control Room is a hive of activity while the electrical tests are carried out.
Numerous electrical tests were carried out in Sector 4-5 during the period from November to mid-February. Once the temperature had been stabilised at around 1.9 K (-271°C) at the beginning of December, the circuits were initially powered up to 8,500 amps. The main dipole circuit was then gradually brought up to 10,200 amps during the last week of January, then the main quadrupole circuits to 10,800 amps in February. At this intensity of current the magnets are capable of guiding a 6 TeV proton beam. During this process, for both the dipole and the quadrupole circuits, a number of training quenches occurred.
138 superconducting circuits ramped in unison at an equivalent beam energy of 5.3 TeV.
"Given the limited time at our disposal, we decided to stop at this energy, which is very close to the target, and start to commission the numerous circuits (each sector has 200) before Sector 4-5 was warmed up again. The mechanics have to connect the triplet (the focussing magnet on both sides of each experiment). We have scanned all the circuits to check that they are working properly. Today we know that the electrical circuits in this sector require no major corrective action", says Roberto Saban, responsible for coordinating the commissioning of the LHC technical systems.
"The experience we gained in Sector 7-8 has already allowed us to validate and improve the procedures, the tools and our understanding of the phenomena we encounter. This is invaluable for the sectors to follow, as confirmed by the commissioning of Sector 4-5, which was a lot quicker and more efficient", he continues. The teams who carried out the work and those responsible for the equipment from the AB, AT and TS Departments worked flat out to optimise the tests. Their task was facilitated by the existence of special tools designed to help with carrying out tests and analysing the results.
The commissioning of the LHC began with Sector 7-8 in June 2007. During the summer, the quadrupole circuits in the sector were powered up to 6500 amps . The next sector to cross the 10,000 amp threshold will be Sector 5-6, which is currently being cooled down. It is scheduled to reach 1.9 K by the end of March, when it will be subjected to the same tests as Sector 4-5. Thanks to the experience gained, the commissioning should proceed even faster.
From late April onwards, the LHC commissioning teams will have a new sector cooled to 1.9 K and ready for testing every two weeks.
"We are working on unique and magnificent hi-tech facilities with sophisticated tools. I have every confidence in the professionalism and motivation of the teams involved and think we will be able to meet the challenge of completing the commissioning procedure for the summer", concludes Roberto Saban.
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