LIPAc accelerator prepares for beam operation

Radio Frequency injection trials in the LIPAc accelerator carried out for the first time from the central control room. Rokkasho, March 2021.

One year after the outbreak of the COVID-19 pandemic, the team of engineers from Europe and Japan working on LIPAc, the Linear IFMIF Prototype Accelerator, have got used to a combination of on-site and remote working to carry out their activities. This facility located in Rokkasho (Japan) will allow scientists to validate the engineering design of the particle accelerator used in the neutron source facility to test materials for DEMO, the fusion machine that will follow ITER

One of the main activities performed in the last few months was the global alignment survey of the entire LIPAc accelerator. For the first time engineers performed the survey for all the components along the line, from ion source to beam dump cartridge. Consequently, the complexity of the task increased because the visibility and accessibility of the so-called fiducial markers (i.e. the points of reference for the measurements) was limited. The alignment survey served to check that all accelerator components were positioned within permissible limits. As a result, the key elements for the forthcoming beam operation campaign have been realigned and detailed procedures will be prepared to make corrections between some of the accelerator components –the Radio Frequency Quadrupole (RFQ) cavity and the Medium Energy Beam Transport (MEBT) line.

“The alignment survey and the realignment carried out by the LIPAc team on Rokkasho site is of primary importance for the beam operation phase. Any position imperfections of the accelerator components like the magnets, and accelerating structures beyond the allowed limits, may affect the particle motion and severely limit the performance of the accelerator,” explains Hervé Dzitko, F4E Project Manager for IFMIF/EVEDA.

Realignment of a magnet in the Low Energy Beam Transport (LEBT) line.
Realignment of a magnet in the Low Energy Beam Transport (LEBT) line. Rokkasho, March 2021.

The opening of the new central control room has been another of the recent highlights. Experts have already used this room to perform some trials with the injector, the part of the machine that creates and injects the particles into the RFQ cavity. This cavity, which shapes and accelerates the beam of particles received from the injector, has also been controlled from the new room, as well as the Radio Frequency Power Sources, which deliver energy to other LIPAc components. Conditioning of the RFQ cavity will continue towards higher duty cycle with the remote support of INFN.

CIEMAT is also providing remote support to the team in Rokkasho. They are participating in the checkout tests performed in the High Energy Beam Transport magnets and in the Beam Dump skid. As the beam carries a lot of energy, the Beam Dump must be cooled down with water to avoid overheating and melting. The skid is a part designed to cool the Beam Dump, the 90-tonne component where the beam ends.

David Jimenez-Rey, Researcher at Fusion Technologies Department in LNF, CIEMAT, explains the details of this collaboration. “For CIEMAT, the LIPAc accelerator is a highly relevant cutting-edge project, therefore, meeting these milestones is a priority. We have been working closely with the team in Machine and Personnel Protection systems (MPS & PPS), tests of great importance so as to ensure the safe operation of the accelerator. Recently, the Beam Dump cooling skid automatic control system was completed thanks to this new remote working way, which is proving to be really helpful.”