BAIKAL DUMAND[HIGH ENERGY NEUTRINO AND GAMMA-RAY ASTROPHYSICS]

本项目的主要目的是发展实现贝加尔湖极高能中微子天体物理的基础技术。我们认为，极高能中微子天体物理学的最终目标是理解只有中微子才能解释的宇宙。另一方面，能量低于极高能中微子天体物理的高能中微子天体物理学的目标是通过中微子来理解宇宙，即高能γ射线照射下的宇宙图像。大家都知道，目前国际上有四个高能中微子天体物理项目。即DUMAND（夏威夷）、NT-200（贝加尔湖）、阿曼达（南极）和NESTOR（地中海中部）。其中，只有[NT-200]成功地重建了高能μ子径迹，这对高能宇宙μ子-中微子的探测是至关重要的，但仍有严重的问题需要解决 ...更多信息 在高能中微子天体物理学的实验和计算中仍然存在。其中之一是μ介子-中微子的能量测定。在这个问题中，涨落起着重要的作用。严格考虑了涨落效应，计算了μ子能量与产生的切伦科夫光的关系，并考察了高能μ子在水中的行为，发现轫致辐射引起的能量灾难性损失对μ子能量的确定起着决定性的作用.在高能γ射线天体物理方面，我们考察了与NT-200相联系的高能γ射线实验中需要改进的俄制光电倍增管的性能。得到了极高能μ介子产生韧致辐射和直接电子对的截面。该截面可望用于极高能μ子的能量测定。少

The Main puropose of our project is to develope the fudamental techniques by which we could realize the extremely high energy neutrino astrophysics in the lake Baikal. In our opinion, the ultimate aim of the extremely high energy neutrino astrophysics is to understand the Universe which could be elucidated by neutrino only. On the other hand, the aim of the high energy neutrino astrophysics whose enery is lower than that of extremely high energy neutrino astrophysics is to understand the Universe by neurtino, reffering to the image of the Universe enlighted by high energy gamma-ray. As you know well, there are four projects on the high energy neutrino astrophysics in the world. Namely, DUMAND (Hawaii), NT-200 (the Baikal), AMANDA (south pole) and NESTOR(the Me diterranean). Among them, only [NT-200] has succeeded in the reconstructions of high energy muon tracks which are absolutely important for thedetection of the high energy cosmic muon-neutrino.There are serious problems to be over … More come in both experiments and the calculations in high energy neutrino astrophysics still now. One of them is the energy determination of muon-neutrino. In this problem, the fluctuation play an important role. We have calculated the relation between the muon energy and the Cherenkov light produced, taking into account the fluctuation effect rigorously.Also, we have examined the behavior of hig energy muon in water, taking into account the fluctuation correctly and have found that the catastrophic energy loss due to the bremsstrahlung play the decisively important role for the energy determination of the muon. As for the high energy gamma-ray astrophysics, we have examined the performances of Russian made photomultiplier which is expected to be improved for the high energy gamma-rsay experiment linked with NT-200.Some techniques have been developed in this project for the extremely high energy neutrino astrophysics. The cross sections for the extremely high energy muon to cause the bremsstrahlung and direct electron pair production have been obtained. The cross section is expected to be utilized the energy determination of the muon in extremaly high energies. Less