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Mobile xenon polarizer

Especially interesting for
  • basic research
  • biomolecular research
  • biomedical imaging

A mobile apparatus to generate highly nuclear-spin-polarized 129Xe, a naturally abundant xenon noble gas isotope, was set up by PTB and has been used at different laboratories in Berlin for the past year to investigate issues with regard to biomedicine and to basic research in physics.

Highly nuclear-spin-polarized 129Xe gas is being used increasingly in different application areas. This so-called “hyperpolarized” 129Xe, which had originally been developed for basic research in physics and has already been successfully implemented for lung MRI, is now also used in other fields of biomedical research. But also issues having to do with understanding the structure of matter which arise in the search for theories beyond the standard model are to be investigated with hyperpolarized rare gases.

Since even under high-purity conditions, the artificially generated hyperpolarization has a lifetime of a few minutes only, the transport of hyperpolarized 129Xe in the gaseous phase is possible only over short distances and in special glass spheres. If, in addition, highly polarized 129Xe has to be supplied continuously, the nuclear-spin polarization in the xenon gas must be generated on site in a volume flow that is adapted to the respective experiment. The process used to generate it is, however, highly complex. The mobile 129Xe polarizer set up at PTB fulfils all the necessary requirements for this purpose. The device can, in principle, be operated in any laboratory, since it needs no infrastructure other than electrical power and pressurized air supply. It can be shipped and commissioned again within one day. Despite its compact design, the operating mode has been kept variable: depending on the needs, hyperpolarized 129Xe gas can be supplied cyclically or continuously.

After having been successfully tested at PTB's Berlin laboratory last year, the polarizer was brought to Berlin-Buch, to the Leibniz-Institut für molekulare Pharmakologie in order to be operated in connection with a magneticresonance micro-imager. These activities, which are carried out within the scope of BMBF and EMRP projects, aim to develalop methods for molecular imaging with hyperpolarized 129Xe at the cellular level and in small animals.

Furthermore, the polarizer's mobility and flexibility are also exploited at PTB. Here, an experiment is being prepared to search for the electrical dipole moment of xenon's nuclear spin (Xe-EDM Project in collaboration with the Technical University of Munich) for which investigations on the nuclear spin precession in ultralow magnetic fields (nT) are being carried out at PTB's Berlin laboratories. For this purpose, the polarizer was transitorily operated in the direct vicinity of the magnetically shielded room (BSMR-2) to ensure optimum test conditions for this new research project.

Scientific publication

S. E. Korchak, W. Kilian, L. Mitschang: Configuration and performance of a mobile 129Xe polarizer. Appl. Magn. Reson. 44, 65–80 (2013)