@article{oai:nipr.repo.nii.ac.jp:00001386,
 author = {Takaoka, Nobuo},
 journal = {Memoirs of National Institute of Polar Research. Special issue},
 month = {Dec},
 note = {P(論文), Concentrations of noble gases and isotopic compositions of He, Ne and Ar were determined for small Yamato chondrites. Five of the ten specimens studied showed high (^<22>(Ne)/^<21>(Ne))_c ratios, suggesting hard cosmic-ray irradiation in small bodies in space or near surfaces of meteoroids. Among them, Y-74447 (H) shows a cosmogenic ^<22>(Ne)/^<21>(Ne) ratio as high as 1.306±0.040,which suggests a very hard cosmic-ray irradiation in a small body. The preatmospheric size of this chondrite may be as small as inferred from its recovered mass (14.3g). No significant difference was found in cosmic-ray irradiation history between antarctic and non-antarctic chondrites. Cosmic-ray irradiation ages and U/Th-He and K-Ar ages are given. While Y-74138(H) was found to contain appreciable amounts of trapped, solar-type gases, Y-74060(H) shows complete loss of radiogenic ^4(He) and radiogenic ^<40>(Ar) as low as found in shocked L chondrites. The Y-74060 chondrite is one of those rare cases in which H chondrites lost radiogenic gases by shock or other metamorphic events. Trapped planetary gases are discussed in relation with petrologic types.},
 pages = {153--161},
 title = {Noble gases in ten, small Yamato chondrites},
 volume = {25},
 year = {1982}
}