A Siberian delivery

On Friday, 14 September, a truck transporting the parts for two new components of Linac4, the linear accelerator that will replace Linac2 in a couple of years' time, arrived at CERN from Siberia.


Preparation of the seal used to obtain a vacuum between the half-cells making up the module elements.

Linac4 will be the new first link in the proton acceleration chain for the LHC. Its four accelerating structures will successively increase the beam energy from 3 MeV to 50 MeV, 102 MeV and finally 160 MeV. These structures include the cell-coupled drift tube linac (CCDTL) which itself comprises 7 modules and will increase the beam energy from 50 to 102 MeV. The first two components of the CCDTL arrived at CERN on 14 September after a journey by truck of over 13,000 km.

The two modules, each weighing 2 tonnes, were disassembled to make them easier to transport. Once the acceptance procedure has been completed, the modules will be assembled and tested in SM18. "The modules will be assembled by a Russian team, who will spend the month of October at CERN," explains Frank Gerigk, the engineer in charge of the accelerating structures of Linac4. "While they are here we will repeat the vacuum tests that were performed before the modules started off on their journey. We will then check the radiofrequency properties and the alignment of the modules on their supports before beginning the first tests at high energy." These will be crucial and are eagerly awaited since it was not possible to perform them before they left Siberia.

Due to traffic authorisation problems in Switzerland, it was not a Russian truck but a Swiss one that delivered the modules to CERN.

"The CCDTL is the only Linac4 component to be entirely produced by a team outside CERN," explains Frank Gerigk. "It's been a remarkable success, and a real pleasure to work with the Russian scientists." The project is the fruit of 6 years of close collaboration with two Russian research institutes: the All-Russian Institute of Technical Physics (VNIITF) and the Budker Institute of Nuclear Physics (BINP), which specialises in nuclear physics among other things and was the project leader. The collaboration was made possible by support from the International Science and Technology Centre (ISTC), an intergovernmental organisation set up in 1992 to help former weapons scientists redirect their skills to peaceful activities.  

The seven modules of the CCDTL took two and a half years to produce. Two further modules are due to be delivered to CERN in December this year, and the final three will follow early next year. Just a few more thousands of kilometres to be covered before we can raise a vodka toast to the CCDTL!

by Caroline Duc