@article{oai:repo.qst.go.jp:00045384,
 author = {Kodaira, Satoshi and Doke, Tadayoshi and Hasebe, Nobuyuki and Ogura, Kouichi and Yasuda, Nakahiro and Tsuruta, Takao and et.al and 小平 聡 and 道家 忠義 and 安田 仲宏 and 鶴田 隆雄},
 issue = {Suppl.1},
 journal = {Radiation Measurements},
 month = {Aug},
 note = {Observation of trans-iron nuclei in galactic cosmic rays (Z>30) requires a high performance cosmic ray detector telescope with a large exposure area because of their extremely low fluxes. A solid-state track detector such as CR-39 has the advantage of easy extension of exposure area, but it is necessary to raise the Z/beta detection threshold in order to suppress background tracks produced by galactic cosmic rays with Z/beta<30. The track registration sensitivity and detection threshold for heavy ions with various Z*/beta were verified by using track detectors of copolymers of CR-39 and DAP (diallyl phthalate) with various DAP concentration. We found that it is possible to control the Z*/beta detection
threshold of copolymers by changing DAP concentration. In order to detect heavy ions with Z*/beta > 30, the optimum DAP concentration was
found to be approximately 50%.},
 pages = {S52--S55},
 title = {Track detector of CR-39-DAP-copolymer with variable threshold to detect trans-iron nuclei in galactic cosmic rays},
 volume = {43},
 year = {2008}
}