3Helium spin filters provide an elegant means of polarising neutron beams. 3He gas has been polarised employing metastability-exchange optical pumping technique (MEOP) for more than a decade at ILL. Thus, since 2002, the MEOP filling station Tyrex has successfully produced more than 1000 litre bar of polarised 3He gas allowing numerous neutron experiments to be performed.
Based on this success, two new filling stations with similar performances have been developed and constructed at ILL. More compact, the new stations adopt a vertical design in order to maximise the lifetime of the electric piston compressor. Among many advances, a new release of the control software has been developed to ease the operation and improve further the reliability. We expect to reach 75% of 3He polarisation at a rate of at least 1bar-litre per hour.

In April 2012, the first station was successfully completed and installed at ISIS. Neutron tests on the performances of 3He spin filters produced by the new station have been carried out. Preliminary results are very promising and show that in the near future, the ISIS instruments can be provided with “in-house” high quality 3He spin filters every day!

The installation of the second machine is also on the right tracks: it has been sent by ship to Australia and it is expected to be installed at ANSTO by the end of September 2012.

The exceptional work of the ILL 3Helium team combined with the ILL recognised expertise in the field of polarised neutrons have made such a tremendous achievement possible. Many thanks to all people who have contributed to this success story that started several years ago with the construction of Tyrex!

P. Courtois, D. Jullien, S. Marty and P. Mouveau