Linde provides Jülich Research Centre with successful cool-down service and helium recovery for world’s largest MRI magnet

The 5-day cool down, which took place in September was part of a project named 9komma4 after the giant magnet’s field intensity of 9.4 Tesla. The magnet will allow researchers to produce images of the human body of an unparalleled quality and will be used to develop a better understanding of major neurodegenerative diseases such as Multiple Sclerosis, Alzheimer’s and Parkinson’s Disease.

The 9 komma4 project was a collaboration between Siemens in Germany and Magnex Scientific in the UK. Siemens acted as system integrator for the project which it designed and installed. The magnet, approximately 4 metres in length and weighing 57 metric tons, was developed and manufactured by Magnex Scientific. Linde provided the 22,000 litres of liquid helium – almost ten times the amount used to cool conventional sized MRI magnets. Additionally, Linde provided a unique mobile helium recovery system, and specialised equipment to perform the cool-down.

A key aspect of the project was the inclusion of Linde’s first helium recovery unit which captures the rare helium used to cool the magnet as the gas boils off. The captured helium retains its quality as an industrial gas and can therefore be compressed into cylinders and re-marketed for industrial usage. This highly efficient re-capturing of the helium means a reduction in net consumption of the gas by Jülich, resulting in significant cost savings. While helium recovery has been undertaken previously at magnet production facilities like those run by Magnex and Siemens, Linde is the first supplier to offer mobile helium recovery in the field.

“This is a milestone in Linde’s efforts to improve on-site magnet cooling and it will change the economic efficiency of all future projects of this kind” says Matthias Bohn, Market Development Manager and applications expert of the Global Helium team at Linde Gases Division.

“It was a great experience to work with Linde on such an exciting project, commented Mr Ralf Hotzky, Siemens’s project manager.

About The Linde Group

The Linde Gases Division, part of the Linde Group, is a leader in the international industrial and healthcare gases markets, providing compressed, bulk, specialty and medical gases, as well as chemicals to virtually all fields of industry globally. The company adds value to its customers’ businesses through the provision of state-of-the art application technology, process know-how, services and equipment.

The Linde Group is a world leading gases and engineering company with more than 50,000 employees working in over 100 countries worldwide. In the 2007 financial year it achieved sales of EUR 12.3 billion. The strategy of The Linde Group is geared towards earnings-based and sustainable growth and focuses on the expansion of its international business with forward-looking products and services.

Linde acts responsibly towards its shareholders, business partners, employees, society and the environment – in every one of its business areas, regions and locations across the globe. Linde is committed to technologies and products that unite the goals of customer value and sustainable development.

About MRI Magnets

The biggest and most important component in an MRI system is the magnet. The strength of the magnet is rated using a unit of measure known as a tesla. The magnets used in MRI scanners for normal medical imaging today are in the 0.5 to 3.0 tesla range. Magnetic fields greater than 2 tesla have not been approved for use in medical imaging, though much more powerful magnets – like the one tested in Jülich– are used in research.

The magnets are electromagnetic and use superconducting coils or windings. These must be cooled to incredibly low, cyrogenic temperatures in order to lower electrical resistance to almost zero, allowing relatively small amounts of power to create the large magnetic field and making the scanner much more economical to operate.

The 22,000 litres of Linde-supplied helium used in the 9komma4 project at Jülich was cooled to an icy temperature of 4.2 Kelvin (-269 C) which allowed the superconducting coils, made from an alloy of niobium and titanium, to have almost no electrical resistance.