Stage step reached: Half of the dipole magnets for the large FAIR ring accelerator tested


It is an important step: Half of over 100 superconducting dipole magnets required for the large FAIR accelerator ring SIS100 have been successfully tested. The measurement results of the tests carried out in the Series Test Facility (STF) at GSI: The tested magnets have excellent properties throughout which indicates a high production quality. This decisive moment – the testing of the 55th magnet- was honoured with a ceremony on GSI and FAIR campus.

The testing of the superconducting dipole magnets at the test facility at GSI is ongoing since September 2017, when the first magnet was delivered. Subsequently, series production had been launched at Bilfinger Noell in Würzburg. In total 110 dipole magnets will be produced, 108 will be installed in the ring accelerator tunnel and two more are spare ones. The dipoles, that will mainly be needed for deflecting the particle beam, make up more than a quarter of all 415 fast ramped superconducting magnets utilized in the SIS100.

Each of the dipole magnets, which weight about three tons and are three meter long, is subjected to a comprehensive test program: The quality control of the production as well as the factory acceptance test at normal ambient conditions are performed in Würzburg, while an extended test program, at both ambient and cryogenic conditions (Site Acceptance Test, SAT), is being conducted at the GSI test facility.

The almost 700 square meter test facility, which was especially built at GSI, is equipped with a cryogenic plant with a local liquid helium distribution system to cool the magnets on the operational temperature of 4.5K (i.e. 4.5 degrees Celsius above absolute zero, which is about -273 degrees Celsius). In addition, two 20-kiloampere power supply units enable to perform functionality tests on the magnets. The duration of the regular SAT program for a single magnet is approximately four weeks. The successful testing campaign is the result of the joint work of more than 30 colleagues from various GSI departments.

The goal of the acceptance and functionality tests is to verify the production quality regarding the specified parameters, qualifying the magnets for the operation in the SIS100 accelerator and acquire the data required for machine control. (BP)