10th March 2017 – After spending 15 years scanning patients at an Australian hospital, an unwanted MRI machine has been recycled and given a new lease of life at the world’s biggest science experiment as a scanner of the material that makes up exploding stars.
A team of UK scientists and engineers reclaimed the superconducting magnet from an old MRI scanner, before modifying it for use at CERN to help us better understand how the Universe works. This recycling project cost about £130,000 – whereas producing a bespoke magnet from scratch would have cost £1million or more.
After reaching the end of its life at the Brisbane hospital, the magnet undertook an epic journey round the world as it was shipped to CERN, the home of the Large Hadron Collider, in Switzerland. A small team from the UK’s Science and Technology Facilities Council (STFC), including two young apprentices from STFC’s Daresbury Laboratory, worked to strip and reconfigure the magnet ready for use on the ISOLDE instrument. The pair of apprentices from the UK helped strip the insides from the magnet, making it ready to house state-of-the art particle detectors instead of patients. The work took 2 weeks and 1 apprentice went out to CERN each week.
In early 2017 the magnet was ready for final testing and installation. With help from the CERN cryogenics team, the magnet was cooled using liquid helium before being successfully re-energised to prove that it was ready to work again as a superconducting magnet in its new role. The recommissioned magnet has now been carefully moved to its new home in the ISOLDE hall at CERN.
Ian Lazarus from STFC’s Nuclear Physics Group, who is the Technical Coordinator for the ISOL-SRS project, said “For the technical team at STFC the real challenge has been ensuring firstly that the magnet was going to be fit for purpose, then that we could get the magnet back to Europe in one piece before completely reconfiguring it to make it ready for use in its new role.
“As an organization that offers apprentices opportunities to work on complex engineering tasks this project has enabled two young apprentices from STFC a once in a lifetime chance to be a key part of this project.”
Once fully operational the magnet will perform a vital role at ISOLDE, a nuclear physics facility which provides both low-energy and high energy re-accelerated radioactive beams to observe the properties of atomic nuclei. The high energy beams are provided by the HIE-ISOLDE post-accelerator, a superconducting linear accelerator recently commissioned at ISOLDE.
Professor Robert Page from the Physics department at the University of Liverpool, who leads the international collaboration that will exploit the magnet, explained a little about what the recycled magnet will enable the research team at CERN to achieve, "The ISOL-SRS project is designing and constructing spectrometers to explore subtle features of the forces that bind atomic nuclei and nuclear reactions thought to occur in stellar explosions.”
“This ex-MRI magnet is a vital component of the spectrometer to be exploited at CERN's world-leading HIE-ISOLDE facility and following its successful recommissioning we are now in a position to embark on this new and exciting science programme with our collaborators from institutions across the UK, Europe and Argonne National Laboratory in the USA."
The University of Liverpool and STFC Daresbury Laboratory contributions are quite strongly intertwined. Both the Nuclear Physics Group at Daresbury and the Physics department at Liverpool have an interest in using the final device for physics experiments (along with much of the UK Nuclear Physics community). The mechanical design work was done at Daresbury, the detector design work was done in Liverpool and the readout system comes from Daresbury.
The purchase of the ex-MRI magnet and the cost of reconfiguring it for use on the ISOLDE experiment were co-funded by STFC, the University of Liverpool, the University of Leuven and the University of Manchester. It will contain advanced silicon detectors that are being built by a UK-led team as part of the ISOL-SRS project.
Magnetic resonance imaging (MRI) is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body. After successful testing, the second-hand magnet proved to be more than powerful enough to cope with the experiments soon to be carried out at ISOLDE.
A beam of radioactive ions will be fired at a deuterium-rich target (sited inside the magnet itself) where they will capture extra neutrons and go on to form the exotic nuclei of interest. The strong magnetic field causes the protons left over from the neutron-stripped deuterium to then spiral backwards and land nanoseconds later on the silicon detector. From the position of the proton on the detector and its energy the energy levels of the exotic ions can be determined. In this way scientists will be able to understand how the forces in atomic nuclei having differing numbers of protons and neutrons give rise to their very different properties, and how elements are created by supernovae.
There are already 2 experiments approved to run on ISOLDE using the new spectrometer and we expect them to run in 2018 (prior to CERN’s Long Shutdown 2).
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Notes to Editors
The on-line isotope mass separator ISOLDE is a facility dedicated to the production of a large variety of radioactive ion beams for many different experiments in the fields of nuclear and atomic physics, solid-state physics, materials science and life sciences. The facility is located at the Proton-Synchrotron Booster (PSB) at CERN, the European Organization for Nuclear Research. It is operated by the ISOLDE collaboration, whose present members are Belgium, CERN, Denmark, Finland, France, Germany, Greece, Italy, Norway, Poland, Romania, Slovakia, South Africa, Spain, Sweden and the United Kingdom.
The ISOL-SRS project is a major component of a wider European initiative that will exploit the upgraded radioactive ion beam accelerator HIE-ISOLDE at CERN and, although still currently under discussion, the heavy ion storage ring CRYRING at GSI/FAIR. The UK collaboration is leading the development and construction of advanced, innovative detector systems for experiments at these facilities that will deliver a vast range of isotopes at energies ideal for studies of nuclear phenomena. It will provide unrivalled opportunities for measuring key reactions and properties of nuclei relevant for nuclear astrophysical processes, and measuring single-particle, collective, and ground-state properties of the nucleus essential to the understanding of the interactions between nucleons in exotic nuclei, at both the precision and intensity frontiers. The main goal of the project is to build a spectrometer system for the measurement of charged-particle reaction products both in-ring and external to the ring, each employing high granularity silicon-detector systems.
Department of Physics, University of Liverpool
Department of Physics, University of Manchester