BAIKAL DUMAND : Extremely High Energy Neutrino Astrophysics

在这个项目中，我们计划对迄今为止从未作为科学分支存在的极高能中微子天体物理学进行各种基础研究。我们认为，极高能中微子天体物理学的最大特点之一就是观测宇宙，而宇宙的存在从来不是光所能观测到的，只能通过中微子来观测。本项目的目的是发展观测这种宇宙的技术和理论概念，我们正在发展基于半导体技术的新型高性能光子计数器，即局域反馈型和超晶格型计数器（参考文献14），因为传统的照片类型-在超级神冈实验中广泛使用的倍增器在极高能中微子天体物理中失去了效力。极高能量的中微子是通过测量电子（在电子中微子的情况下）和μ子（在μ中微子的情况下）发出的切伦科夫辐射来探测的。对于电子，我们研究了等离子体状态下的电子簇射（Re.No.1）、强磁场中的电子簇射（Re.No.3）和LPM效应问题（Re.No.8，9）。对于μ介子，研究了重原子对轫致辐射（Re.No.13）和大气μ介子问题（Re.No.18）的影响。此外，时空结构的知识，要求检测中微子（Re.No.10）。另一方面，获得了对于理解极高能中微子行为绝对重要的高能中微子的实验知识（Re.No.5，6，7）。

In this program, we have planned to study various fundamental researches for extremely high energy neutrino astrophysics which has never existed as the brancn of science up to now. In our opinion, one of the biggest characteristics of extremely high energy neutrino astrophysics lies in to observe the universe, the existence of which is never observed by light1 but only by neutrino. The purpose of this program is to develop techniques and theoretical concepts by which such universe could be observed.We are developing new types of high performance of photon counters based the semiconductor technique, namely counters with both local feed back type and superlattice types (Reference No.14), because the conventional type of photo-multipliers which have been extensively utilized in the Superkamiokande experiment have lost effectiveness in the extremely high energy neutrino astrophysics. Extremely high energy neutrino is detected by the measurement of the emitted Cherenkov radiation from both electron (in the case of electron neutrino) and muon (in the case of muonneutrino). As for electron, we investigated such electron showers in the plasma state (Re.No.1) these in strong magnetic field(Re.No.3) and the LPM effect problems (Re.No.8,9). As for muon, the influence of the heavy atom on the bremsstralilung (Re.no.13) and atmospheric muon problem (Re.No.18) are investigated. Also, the knowledge on the space-temporal structure is requested to detect neutrino(Re.No.10). On the other hand, experimental knowledge on high energy neutrino which is absolutely important for the understanding of behavior of extremely high energy neutrino is obtained (Re.No.5,6,7).