Time-dependent measurement of pion-muon channelling

Abstract

The paper introduces the concept of the “pion age” (=the time spent by a positive pion in a crystal before decaying) and shows that the dependence ofπ ⁺/μ ⁺ lattice steering on pion age may be measured in the so-called 17 MHz mode of the Swiss Institute of Nuclear Research (SIN). By means of this new technique it is demonstrated thatπ ⁺ implanted into Ta single crystals at 80 K take up their final lattice positions (tetrahedral interstices) in less than 4 ns. Further potential applications of the technique are discussed.