An excellent performance for the non-LHC programme

With the LHC firmly in the public eye, the rest of CERN’s accelerator complex and experimental programme isn’t getting the attention it richly deserves, so I’ve decided to address that in my message this week. After all, even the LHC relies on the machines that deliver its beams day after day with little or no fanfare. It’s time for the people involved with those machines and the experiments that use them, to step forward and take their share of the limelight.


The first link in the CERN accelerator chain is Linac 2, a machine first switched on in 1978 and scheduled to be replaced by Linac 4 in 2016. It is here that most of CERN's beams are born. From there, the beams move into the booster, which combines bunches from the linac in order to boost intensity. From the booster, it’s onto the PS, and then to the SPS. All of these machines have been in service for over 30 years.

Along the way, beams are farmed out to a range of experimental facilities. ISOLDE takes its beams from the booster. The PS supplies n-ToF, the East Hall and the AD, while the SPS provides beams for the North Area, CNGS and the LHC. It all adds up to a remarkably diverse and rich research programme.

So far, 2010 has been a good year all round, with excellent performances for the non-LHC physics programme. ISOLDE, for example, is a remarkable facility with a repertoire of over 700 different isotope beams. In 2010, some 40 experiments are using those beams for research, ranging from nuclear structure to nuclear astrophysics and biophysics. At CNGS, some 3.2×1019 protons have been delivered on target: 10% more than was expected at this point in the year. The performance of the PS in delivering beam to the n-ToF facility is also significantly exceeding expectations. At the beginning of the year, n-ToF’s request for 1.6×1019 protons on target seemed wildly optimistic, but the PS’s 92% up-time, coupled with technical improvements, means that the actual total delivered will come very close to that figure. Last but not least, the SPS has been reliably delivering beams to the COMPASS experiment in North Area, with an up-time of 87%.

Our research programme can only be as good as the accelerators that feed it, so it’s encouraging that the full accelerator complex is performing so well. An upgrade programme has long been planned, and its implementation began with civil engineering for the new Linac 4 building in 2008. We had originally intended to hook up Linac 4 in 2015, but due to current austerity measures, that will not now happen until 2016. The risk we take in delaying a year is in having to rely on ageing machinery for one more year. However, with overall reliability figures of over 80% so far in 2010, I think it’s safe to say that the risk is a small one.

Rolf Heuer