S. I. Klimushin

MUM: flexible precise Monte Carlo algorithm for muon propagation through thick layers of matter

We present a new Monte Carlo muon propagation algorithm MUM (MUons+Medium) which possesses some advantages over analogous algorithms presently in use. The most important features of algorithm are described. Results on the test for accuracy of treatment the muon energy loss with MUM are presented and analyzed. It is evaluated to be of 0.002 or better, depending upon simulation parameters. Contributions of different simplifications which are applied at Monte Carlo muon transportation to the resulting error are considered and ranked. It is shown that when simulating muon propagation through medium it is quite enough to account only for fluctuations in radiative energy loss with fraction of energy lost being as large as 0.05 -- 0.1. Selected results obtained with MUM are given and compared with ones from other algorithms.

Parametrization of atmospheric muon angular flux underwater

The analytical expression for angular integral flux of atmospheric muons in matter with the explicit relation of its parameters with those of the sea level spectrum is obtained. The fitting formula for the sea level muon spectrum at different zenith angles for spherical atmosphere is proposed. The concrete calculations for pure water are presented. Fluctuations of muon energy losses are taken into account by means of parametrized correction factor calculated using survival probabilities resulted from Monte Carlo simulations. Parametrizations of all continuous energy losses are obtained with using the most recent expressions for muon interaction cross-sections. The corresponding parametrization errors and field of method application are comprehensively discussed. The proposed formulae could be useful primarily for experimentalists processing data of arrays located deep under water or under ice.

The Lake Baikal experiment

Abstract We review the present status of the Baikal Neutrino Project. The construction and performance of the large deep underwater Cherenkov detector NT-200 with 192 PMTs [1], which is currently taking data in Lake Baikal, are described. Some results from intermediate detector stages are presented.

The Lake Baikal Neutrino Telescope NT-200: Status, results, future

The Baikal Neutrino Telescope NT-200 has been put into operation on April 6th, 1998. We describe the parameters and structure of NT-200 and present results with various stages of the stepwise increasing detector: from NT-36 to NT-96. Results cover atmospheric muons, neutrino events, search for neutrino events from WIMPS annihilation, search for magnetic monopoles. We also give preliminary results of the combined operation of the underwater array and a Cherenkov EAS array, placed on the ice surface.

Status of the Lake Baikal experiment

Abstract We review the present status of the Baikal Underwater Neutrino Experiment and report on neutrino events recorded with the detector states NT-36 and NT-96 .We review the present status of the Baikal Underwater Neutrino Experiment and report on neutrino events recorded with the detector stages NT-36 and NT-96.

The Baikal Neutrino Project: Status and Perspectives

We review the present status of the Baikal Neutrino Project and present results of a search for upward going atmospheric neutrinos, WIMPs and magnetic monopoles obtained with the detector NT-200. Also, the results of a search for very high energy neutrinos are presented. An upper limit on the v e+v μ+v T neutrino diffuse flux of E 2 · F(E) < 1.3 · 10 -6 cm-2 s-1 sr-1 GeV within a neutrino energy range 104 ÷ 107 GeV is obtained, assuming an E -2 behaviour of the neutrino spectrum and flavor ratio v e+v μ+v T = 1: 1: 1- We describe the moderate upgrade of NT-200 planned for the next years and discuss a possible detector on the Gigaton scale.