J. Ruzicka1, S. Saro1, L. Krupa1, P. V. Zrelov2, V. P. Zrelov2, E. D. Lapchik2, H. Geissel3, H. Irnich3, C. Kozhuharov3, A. Magel3, G. Muenzenberg3, F. Nickel3, C. Scheidenberger3, H.-J. Schott3, W. Schwab3, T. Stoehlker3, B. Voss3
1 Comenius University, Bratislava, Slovakia,
2 Joint Institute for Nuclear Research, Dubna, Russia,
3 Gesellschaft fur Schwerionenforschung, Darmstadt, Germany
In the classical paper by Tamm and Frank on the Vavilov-Cherenkov effect the motion of a particle in transparent infinite medium is supposed to be, rectilinear and with strictly constant velocity. Later Tamm formulated a criterion for tolerable variation of the particle velocity for this effect. For a fast single charged particle moving in a transparent medium, the energy losses are small enough, so the criterion of Tamm is fulfilled for all frequencies corresponding to visible light. However, energy losses of heavy ions moving in a dense medium cannot be considered small. As a result, the decrease in the velocity of heavy ions becomes so large that the Tamm’s criterion is strongly violated. The experimental results on the Vavilov-Cherenkov radiation arising from the motion of relavistic heavy ions of 17979Au in the transparent solids and liquides are presented.