This installation, built in collaboration with ICN2, is unique in Catalonia and allows recycling 80% of the liquid helium consumed in ALBA for operating the superconducting magnets and for experiments at ultra-low temperatures.

Cerdanyola del Vallès, 29th January 2018. Despite being the second most abundant element in the universe, helium is very scarce on Earth and it is expected to be completely exhausted in a few decades. This inert gas, which is generated by fusing hydrogen atoms, is hidden in the subsoil of some natural gas reserves and its extraction is expensive and difficult to obtain. This is why different systems are being explored to recover helium and thus facilitate its application in the wide range of equipment in which it is used (beyond the popular balloons).

Liquid helium is basic for the operation of medical equipment such as magnetoencephalography (MEG) to cool down the superconducting magnets they contain to almost 270 ºC. It is also necessary for carrying out different scientific experiments; at the ALBA Synchrotron there are currently two superconducting magnets: one for producing synchrotron light in one of the beamlines and the other one for the sample area of another beamline, needing both a considerable amount of helium. Besides, four of the eight beamlines use it to keep cold the samples that must be analysed when they are irradiated with synchrotron light.

In order to guarantee the availability of this limited substance (it is foreseen that its cost will double in the near future), ALBA has built a plant to liquefy the helium gas and reuse it again once liquefied.

"With the new plant we can recycle 80% of the helium that we consume in our experiments and save more than € 10 per litre nowadays", says Joan Casas, Head of the Engineering division of the ALBA Synchrotron.

A circuit to recycle helium

When liquid helium is used in the experiments at the ALBA Synchrotron, helium goes from liquid to gaseous state. The new plant recovers helium in a gaseous state, purifies it and returns it to liquid state to be used again. The process is the following.

Helium reaches the plant through a recovery ring and is stored in a 20 m3 balloon at ambient pressure. Afterwards, it is compressed in bottles at 200 bar until it is needed to liquefy. The next step, just before liquefaction, is to purify it from the pollutants that could have been introduced throughout the process until they reach 99.999% purity. Finally the purified gas is even more compressed until it cools below -269 °C, when part of the gas becomes liquid. The liquid part is stored in a 1000 litres tank to be distributed again to the needed equipment. The gas part is supplemented with more purified gas, and it continues to be compressed and cooled, to produce more liquid helium.

This plant is unique in Catalonia and allows recycling up to 25,000 litres of helium per year. It has been developed with the collaboration of the Catalan Institute of Nanoscience and Nanotechnology (ICN2), who will also benefit from a part of the production. The plant has been built in a space adjacent to the main building with the collaboration of local companies; it has been fully installed with internal resources of the ALBA Synchrotron and has already completed its legalization.

Apart from the economic savings, the plant favours the sustainability of the equipment, being less dependent on a market with little availability and fluctuating prices and ensuring from now on enough liquid helium for 2 weeks without any new supply.


General view of the new liquefaction helium plant, located at the experimental hall of the ALBA Synchrotron. Photograph: Yuri Nikitin. 

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