Exercise. Submit a short abstract (100-300 words in English) about your research work to the instructor.

[I'm not M2 but M1. So I'm not a member of any laboratories.]
[So, I'll describe an abstract of previous university(Kyoto-University of Education).]

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KOPIO (BNL-E926) experiment is concerned with CP violation, and which is due in 2005 at BrookhavenNational Laboratory. The aim is to measure the branching ratio of K0L->pi0nu~nu(K zero Long meson decays and generates pi zero meson and neutrino-antineutrino pair. ) which is ~10-11 order.
The method, to identify K0L-> pi0nu~nu decay mode, is to detect 2gammas from pi0 ->2gamma and not to veto events which contain gammas from another pi0 or other charged particles. So, it needs to get rid of another decay mode, because of its small branching ratio. The most dangerous background is K0L-> pi0pi0 decay mode. K0L-> pi0pi0 decay creates 4gammas. The trouble is that if 2gammas among 4gammas losts at K0L-> pi0pi0 decay mode, we cannot distinguish between K0L
->pi0nu~nu with K0L-> pi0pi0.
pi0 detector system needs a hole to pass through a secondary neutral particles which are created at K0L production target. So, we must develop the beam catcher which is willing to veto the gamma on beam line. As the requirement of this beam catcher, it has strong efficiency to gammas. But because of it's on the beam line, it needs no efficiency to neutron. As a prototype of this beam catcher, we developed an Aerogel Cherenkov type counter,
and tested. In conclusion, radiation effect to proton was larger than assumed one.
It is considered that the light is influenced by Nitrogen scintillation. The purpose of this study is the confirmation
of provability of Nitrogen scintillation on the Aerogel Cherenkov beam catcher and calibration of the best
suited gas.
We study 3 things.
1. Cabibbo-KOBAYASHI-MASKAWA matrix.
2. the theory of scintillation. Especially, Bethe-Bloch formula and Quenching
mechanism.Bethe-Bloch formula describes the behavior of passage radiation particles from the matter and energy loss.
3. the Experiment of Nitrogen scintillation.
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