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Nakamura, Takahiro; Sanada, Hiroyuki; Sugita, Yutaka; Teshima, Minoru*; Kasagi, Toshio*; Kishimoto, Munemaru*; Deguchi, Tomonori*; Makuuchi, Ayumu*
JAEA-Research 2010-006, 68 Pages, 2010/06
The present document is to report the result of geophysical survey by electric survey around a site proposed for the Horonobe Underground Research Laboratory Project at Horonobe-cho, Hokkaido by the Japan Atomic Energy Agency. This Electric survey using pole-pole array in Horonobe Underground Research Laboratory Area was the third survey. Resistivity distribution near surface was about 20 m and it become to about 2 m as the depth increasing. Resistivity distribution was good agreement with existing survey results and existing electrical resistivity log data. By comparing resistivity model with hydrology model, it was confirmed that resistivity reflected the density of salinity. The range and distribution trends of apparent resistivity in this year were similar to the results of last year. It is thought that the data in which reproducibility is high is acquired in this survey. The influence on the underground water flow by construction is not admitted now.
Yoshida, Junya; Ekawa, Hiroyuki; Hayakawa, Shuhei; Kasagi, Ayumi*; Nishimura, Shin*; Nyaw, A. N. L.*; Yoshimoto, Masahiro*; Nakazawa, Kazuma*
no journal, ,
J-PARC E07, an experiment with emulsion technique, is carrying out to detect 10 times higher statistics of double hypernuclei compared to the past experiments. This experiment aims to obtain quantitative data on baryon-baryon interaction, such as - and -nucleon interaction, by the mass measurement of various double hypernuclei. We completed beam exposure and photographic processing of the all emulsion modules as scheduled in 2018. In this presentation, the current status of the experiment, progress of analysis, the detection efficiency, and the schedule are introduced. As of Jan. 2019, we have scanned about 53% of 1300 emulsion sheets at least once. We have detected 22 candidate events of double hypernuclei.
Yoshida, Junya; Hayakawa, Shuhei; Ekawa, Hiroyuki*; Yoshimoto, Masahiro*; Kasagi, Ayumi*; Lin, P. M.*; Nyaw, A. N. L.*; Nakazawa, Kazuma*
no journal, ,
J-PARC E07 is an experiment with the photographic emulsion technique to detect 10 times higher statistics of double hypernuclei compared to the past experiments. This experiment aims to obtain quantitative data on - and -nucleon interaction, by the mass measurement of various double hypernuclei. As of July 2019, we have scanned about 53% of 1300 emulsion sheets at least once and detected about 30 candidate events of double hypernuclei. We start a study of the branching ratio of the decay mode with the accumulating data. However, the detection efficiency is about half of the designed value. It is due to the rugged surface position of emulsion module. We are developing the correction method to reconstruct its original geometry by using proton tracks which punch through SSD and emulsion sheets.
Yoshida, Junya; Hayakawa, Shuhei; Ekawa, Hiroyuki*; Yoshimoto, Masahiro*; Kasagi, Ayumi*; Lin, P. M.*; Nyaw, A. N. L.*; Nakazawa, Kazuma*
no journal, ,
J-PARC E07 is an experiment to detect double hypernuclear events with the largest statistics in the past using photographic emulsion sheets. Experimental data on - and -nucleon interaction, are obtained by mass measurements of various double hypernuclei. The main step in the analysis of this experiment is the tracking of particles in emulsion sheets under optical microscopes. We expect to complete the first period analysis of all the sheets by March 2020. The number of events obtained in the first period is about 40% of the planned yield. The remaining events will be detected in the second search in the near future. It is considered that the cause of missing particles was that the prediction of the incident position of particles was incorrect due to poor flatness of the uppermost stream sheet. Therefore, we are trying to correct the surface position and find the missing particles.