Comptes Rendus
Transfer of para-hydrogen spin order into polarization by diabatic field cycling
[Transfert de cohérence de spin de para hydrogène à polarisation par changement diabatique du champ magnétique]
Comptes Rendus. Physique, Volume 5 (2004) no. 3, pp. 315-324.

Dans une expérience de polarisation induite par para hydrogène (PHIP), il est possible d'obtenir une polarisation substantielle sur un hétéronoyau par l'utilisation d'une technique de changement diabatique du champ magnétique. Cela est démontré expérimentalement dans le cas du propionate d'hydroxyethyle. Le champ ambiant est réduit avec plusieurs cylindres concentriques de mu-métal. La variation du champ magnétique est modélisée comme une transition abrupte d'un champ intermédiaire vers un champ très faible suivie par une réaimantation adiabatique. Une expression analytique de la polarisation en fonction des couplages scalaires est dérivée pour un système de spins AA′X en considérant un profil de champ magnétique idéalisé. Il est aussi démontré que l'entitée hyperpolarisée peut être utilisée pour l'imagerie par résonance magnétique (IRM).

In a para-hydrogen induced polarization (PHIP) experiment, it is possible to obtain a substantial net polarization of a hetero nucleus using a diabatic field cycling scheme. This is experimentally demonstrated for hydroxyethyl propionate. The screening of the ambient magnetic field was accomplished by using several concentric mu-metal cylinders. The field cycling is modeled as a sudden decrease from intermediate field to low field, followed by an adiabatic remagnetization. An analytical expression for the polarization as a function of the constituent scalar couplings, using an idealized field cycling profile, is derived for an AA′X spin system. It is also demonstrated that the hyperpolarized compound can be used for magnetic resonance imaging (MRI).

Publié le :
DOI : 10.1016/j.crhy.2004.02.001
Keywords: Para-hydrogen induced polarization, Diabatic, Field cycling
Mot clés : Polarisation induite par para hydrogène, diabatique, champ magnétique cyclé

Haukur Jóhannesson 1 ; Oskar Axelsson 1 ; Magnus Karlsson 1

1 Amersham Health R&D AB, Medeon, 205 12 Malmö, Sweden
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     title = {Transfer of para-hydrogen spin order into polarization by diabatic field cycling},
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Haukur Jóhannesson; Oskar Axelsson; Magnus Karlsson. Transfer of para-hydrogen spin order into polarization by diabatic field cycling. Comptes Rendus. Physique, Volume 5 (2004) no. 3, pp. 315-324. doi : 10.1016/j.crhy.2004.02.001. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2004.02.001/

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