Orientation effects for passage of a relativistic positronium atom through crystals

We examine the passage of a relativistic positronium atom through a crystal for a small entrance angle with respect to the crystallographic axes. We show that the probability for an elastic interaction of the positronium atom with the crystal has orientation dependence. The probability of breakup of a positronium atom in a crystal is significantly greater than in an amorphous target.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 78–82, March, 1989.The author wishes to express his gratitude to S. A. Vorob'ev for his interest in the work and to Yu. L. Pivovarov, L. L. Nemenov, and M. I. Podgoretskii for useful discussions.