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Relaxation Behavior of Laser-Polarized Xe Gas: Size Dependency and Wall Effect of the T1 Relaxation Time in Glass and Gelatin Bulbs |
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| Authors: | Hideaki Fujiwara Atsuomi Kimura Yasuhiro Yanagawa Takashi Kamiya Mineyuki Hattori Takashi Hiraga |
| Affiliation: | a School of Allied Health Sciences, Faculty of Medicine, Osaka University, 1-7 Yamada-Oka, Suita, Osaka, 565-0871, Japan;b Supermolecular Science Division, Electrotechnical Laboratory, 1-1-4 Umezono, Tsukuba, Ibaraki, 305-8568, Japan;c Department of Material Physics, Osaka National Research Institute, 1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577, Japan |
| Abstract: | Size dependency of the relaxation time T1 was measured for laser-polarized 129Xe gas encapsulated in different sized cavities made by glass bulbs or gelatin capsules. The use of laser-polarized gas enhances the sensitivity a great deal, making it possible to measure the longer 129Xe relaxation time in quite a short time. The size dependency is analyzed on the basis of the kinetic theory of gases and a relationship is derived in which the relaxation rate is connected with the square inverse of the diameter of the cavity. Such an analysis provides a novel parameter which denotes the wall effect on the relaxation rate when a gas molecule collides with the surface once in a second. The relaxation time of 129Xe gas is also dependent on the material which forms the cavity. This dependency is large and the relaxation study using polarized 129Xe gas is expected to offer important information about the state of the matter of the cavity wall. |
| Keywords: | Abbreviations: laser-polarized noble gasAbbreviations: size dependency of relaxation timeAbbreviations: wall effect in relaxation timeAbbreviations: gelatin capsuleAbbreviations: glass materials |
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