The radio frequency transition unit (RFT) is a useful component to produce nuclear-polarized hydrogen/deuterium atoms for both the atomic-beam source and for the laser-driven source. In the laser-driven source, atoms exiting out from a spin-exchange cell undergo a number of wall collision in the RF transition region in a transport tube. Experiments were conducted to evaluate deterioration of the transition efficiency for tubes wall-coated with different materials. The atomic beam source was utilized for these experiments instead of laser-driven one. The transition efficiency for hydrogen atoms were derived from ratios of beam intensities, which were measured by switching on and off the weakfield RFT installed into the atomic-beam source. The transport tubes in three geometries were set to give rise to different numbers of wall collisions and several wall materials were tested. It was confirmed that coating of organosilicon compounds both preserves polarization of the hydrogen atoms and prevents the atoms from recombination into molecules during wall collisions in the transport tubes. A simple calculation on RF transition is presented which considers the trajectories of the hydrogen atoms.
|ジャーナル||Memoirs of the Faculty of Engineering, Kyushu University|
|出版ステータス||出版済み - 3 1 2001|
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