2015 Fiscal Year Research-status Report
Compact neutron source for water Cherenkov detectors
| Project/Area Number |
26800127
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| Research Institution | Kyoto University |
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Principal Investigator |
ウェンデル ロジャー 京都大学, 理学(系)研究科(研究院), 准教授 (20647656)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | neutron / generator / triggered source |
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| Outline of Annual Research Achievements |
Efforts to produce a pulsed compact neutron source during FY27 have been delayed such that there is essentially no significant progress to report. However, over the last year contact has been made with Super-Kamiokande collaborators in the UK, who are interested in joint development of a neutron source. Since this group has the capacity to manufacture a solid state neutron generator like that from the original proposal, a collaborative effort may enable the research to proceed despite restrictions on the construction of accelerator-based neutron sources in Japan. For this reason the next year will focus on developing a collaborative relationship to realize a triggered neutron source for water Cherenkov detectors.
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| Current Status of Research Progress |
Current Status of Research Progress
4: Progress in research has been delayed.
Reason
Though it is known the construction of a deuterium-tritium based neutron generator within Japan is complicated due to restrictions on the use of tritium, it has become clear over the last year that there are also several legal restrictions on the construction of particle accelerators. Since the original and modified proposal rely on the acceleration of ions for neutron production, these restrictions require designing an acceleration scheme with low instantaneous radioactivity, but sufficient energy for neutron production. This has been a considerably challenging.
In the course of redesigning the proposed neutron source the lead investigator changed institutions from Tokyo University to the University of Kyoto. In addition, as a Super-Kamiokande collaborator, the 2015 Nobel Prize in Physics for neutrino oscillations resulted in a series of celebrations and seminar campaigns, which ultimately took considerable time away from this research. For both of these reasons, progress has been unfortunately delayed
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| Strategy for Future Research Activity |
Over the coming year, this project will focus on the construction of a triggered neutron source in Japan which is within the confines of legal constraints, while at the same time advancing a collaborative effort with overseas collaborators as mentioned above.
For the former there are two possibilities under consideration. The first of which is to continue efforts from last fiscal year to design a vacuum tube-based deuterium-deuterium source with low instantaneous radioactivity but sufficient neutron yield. If this still proves infeasible then an alternative design using standard isotopes is also under consideration. The primary idea is to construct a mechanically triggered neutron source from Am-241, an alpha emitter, and Be-9. While these two isotopes are usually combined to produce a neutron source, physically separating them with a movable mechanical barrier would allow for triggered neutron production. Which of these devices (or both) to construct will be decided by July of H28, to allow for construction and testing over the rest of the year.
At the same advancing an overseas collaborative effort will potentially allow a higher intensity accelerator-based device to be constructed outside of Japan and later imported, as has been done with other sources at Super-Kamiokande.
In all scenarios discussed here, trigger logic and test setups for evaluating neutron production will be developed as described in the original proposal.
This work will begin after the final design is established in the summer of H28.
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| Causes of Carryover |
For the reasons outlined above, no purchases were made to secure equipment for this research. As a result the entirety of the grant has been requested to be rolled over to this fiscal year.
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| Expenditure Plan for Carryover Budget |
In this fiscal year funds will be used to secure isotopes necessary for the neutron source design, as well as circuitry for timing and triggering in addition to power supplies and control hardware as outlined in the original proposal. Further, materials for the production of water proof source container will also be purchased.
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