New magnets for FAIR tested at CERN


­This text is based on a news by the European research organisation CERN

The very first superconducting magnets for NUSTAR (Nuclear Structure Astrophysics and Reactions) have been tested at the European research center CERN in Switzerland. NUSTAR is one of the four large experiment pillars at the future international accelerator center FAIR (Facility for Antiproton and Ion Research), which is currently being built at GSI.

As part of a collaboration agreement between CERN and GSI/FAIR signed in 2012, 56 magnet assemblies intended for the Super-Fragment Separator (Super-FRS), the central device of the NUSTAR experiment, will be entirely tested and validated at CERN. Thus, 32 multiplets and 24 dipoles will be tested at the Laboratory. The multiplets are manufactured by the Italian company ASG, the dipoles by the Spanish company Elytt. For this purpose, a new test facility has been especially designed and constructed in CERN’s Building #180 to validate no fewer than 30 types of magnets. Three test benches have been created by experts from CERN and GSI to accommodate up to 7-metre-long, 3.5-metre-high magnet assemblies. The heaviest ones weigh up to 70 tons.

“A large and complex cryogenic system has been developed, combining two pre-cooling/warming-up units and a 4.5 K liquid helium refrigerator,” explains Antonio Perin, work package leader for the cryogenic system. “The plant is designed for continuous operation: the validation tests are performed on one bench, while the second bench is cooling down and the third one is warming up; the test sequence lasts about six weeks for each magnet.” During the tests, the magnets are powered to their nominal current and their magnetic field is accurately mapped. The powering and magnetic measurement systems have been adapted to the new test facility, which was made possible thanks to the unique combination of competences existing at CERN.

“We are currently testing the first-of-series magnets; the multiplet series will be delivered next year. All 56 magnet assemblies should be tested by 2026,” says Dr. Germana Riddone, CERN’s technical coordinator of the test facility at CERN. “Many CERN groups and GSI partners have been involved in the successful installation of the new test facility and its commissioning, and still are now for the validation tests. The collaboration with GSI is a very good example of how CERN works hand-in-hand with national infrastructures and how that adds mutual value.” Dr. Antonella Chiuchiolo, GSI work package leader for on-site testing at CERN, agrees: "We are very pleased that our testing activities at CERN can proceed so smoothly and on schedule."

The Project Leader Super-FRS at GSI/FAIR, Dr. Haik Simon, was also very pleased with the start of the tests and explains: “The multiplets will later be used in FAIR's Super-FRS for beam focusing in order to achieve a high-precision particle beam. The dipoles will serve later to specifically deflect a split up the particle beam“. The Super-FRS of the future FAIR accelerator center is an important component of the entire facility with great potential for scientific discovery: This part of the accelerator complex will be used for experiments on the fundamental structure of extremely rare exotic nuclei. “For these experiments, ions of the heaviest elements will be shot at a target, where they will shatter upon impact. The resulting fragments will include exotic nuclei that the Super-FRS can separate and supply for further experiments. With the new separator, nuclei up to uranium can be produced at relativistic energies and can be separated into pure isotopes. Because this entire process lasts for only a few hundred nanoseconds, the Super-FRS provides researchers access to very short-lived nuclei,” says Dr. Haik Simon. (CERN/BP)

Further information

News at the CERN website

Video about the Super-FRS magnet testing