Electromagnetic cascades in oriented crystals of garnet and tungstate

We present experimental data on characteristics of peculiar electromagnetic cascades initialed by 26 GeV electrons in transparent oriented crystals of artificial garnet and lead tungstate. The mean energy deposition in the crystals and its orientation dependence as a function of the crystal thickness are determined. A measurement of the transversal development of the cascades is performed. Implications for the functioning of crystalline electromagnetic calorimeters are discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved.