Expected Reconstruction Error of Arrival Direction in Observation by Water Cerenkov Detector

[Abstract] Reconstruction error of emitted direction of electrons observed in water cerenkov detector is estimated assuming gaussian approximation for multiple scattering process and exponential decrease with increasing mean square angle for detecting efficiency of cerenkov photon. After correcting geometrical limitation by Mott formula we got reasonable result explaining experimental data of wide energy range. Similar estimation by Kamioka group seems unable to explain those data because of inadequate cut of large angle scattering used in EGS simulation code

Scattering Angle of Cosmic Ray Muons with Energy Loss Deep Underground

[Abstract] The root mean square scattering angle and the scattering behaviors of the cosmic ray muous after traversing deep underground are extensively studied by considering various energy loss modes; ionization loss, electron pair production, bremsstrahlung, and nuclear interaction. The rms angular dependences are studied as functions of incident muon energies a.t sea level and observed muon energies in underground detector at various depths. As the extreme case of the calculations, we can get Rossi & Greisen expression and Eyges expression which have been very familiar to cosmic ray field. The rms angle of scatterings of muons is almost determined by the minimum energy of muons which is able to penetrate rock overburden an underground detector. The calculated results are compared with the broad deflected angular spreads of muons from Cygnus X-3 which have been observed by Soudan detector at a depth of 1800 hg/cm^2 and Nusex detector at a depth of 5000 hg/cm2. Also, we compare and discuss our calculated root mean square angles of (θ^2)^ scatterings of low energy electrons with the measured values of electrons in the energy region of 5 MeV-40 MeV from the neutrino burst of SN 1987A which have been done by Kamiokande and IMB groups