After eight and a half years, scientists and engineers from STFC, many of them based at the Cockcroft Institute, successfully completed the supply of high beta cavities (HBC) to the European Spallation Source (ESS) in Lund, Sweden. This achievement marks the conclusion of the organisation’s work on the project at Daresbury Laboratory and the beginning of an exciting new phase in the accelerator’s beam commissioning.
Teams from STFC were responsible for delivering 86 high beta cavities in line with ESS specifications. The project began in 2016 with the initial development and procurement processes.
When the ESS is operating, it will use these cavities as part of the particle accelerator which accelerates sub-atomic particles called protons to around 95% of the speed of light. To operate efficiently, these cavities must be exceptionally clean, and a suite of facilities were built to enable qualification testing and specialist cleaning of individual HBC cavities. This facility at Daresbury is known as the Superconducting Radiofrequency Laboratory, or SuRF Lab.
Inside its available cleanrooms, there must be fewer than 10,000 particles greater than 0.00001 cm in size, per cubic metre of air. Normal air by comparison would have many tens of millions of such particles in the same volume.
Two cavity support inserts were created so that each could hold three jacketed cavities for testing. These mobile structures moved between the loading/preparation area and a deep testing bunker via a ceiling crane system. The bunker is a concrete enclosure which was built for the project, with a large cryostat located within it. A liquid helium cryogenic plant facility allows the cavities to be cooled down to two Kelvin temperature (or -271oC), before being powered by a radio frequency amplifier to check that they can produce the electric fields needed to accelerate the ESS proton beam.
In total, the 86 cavities were tested along with the team working with ESS partners DESY to compliment testing at their site in Germany.
Once verified, the cavities were shipped to CEA Saclay in France, another in-kind partner on the project, where they were inserted into the cryomodules before making their final journey to the ESS in Lund, Sweden.
Throughout the entire process, quality and performance remained at the forefront of STFC’s work. In addition to procuring, building infrastructure, and conducting tests, STFC experts implemented rigorous workflow management processes and reporting systems, ensuring that data could be efficiently shared with ESS and other partners whenever required.
HBC Project Sponsor and Deputy ASTeC Director Peter McIntosh reflects:
“Over the past eight years, the STFC team has gone above and beyond to meet the demanding requirement for delivering the high beta cavities for ESS, which has been outstanding. Thanks to the dedication, skill and commitment of everyone involved, we’ve now firmly positioned ourselves among the world’s leading laboratories in SRF technology development and delivery. This is a huge milestone, and it wouldn’t have been possible without the incredible teamwork across ASTeC, Technology, Digital Infrastructure and Finance, spanning both Daresbury and Rutherford Labs. Delivering this capability for ESS is a true reflection of the strength of our multi-disciplinary STFC teams.”
This article is based on https://www.linkedin.com/pulse/cavity-teams-celebrate-ess-success-stfc-magte/