DOUBLE SCREENING PROBLEM IN DECHANNELING BY POINT-DEFECTS

A simple double screening model is used to calculate the interaction p otential between an energetic channeled mu(+) and an impurity (O) in a n otherwise perfect single crystal (Ta). The twofold screening of the nuclear charge of the impurity is first due to the atomic electrons an d second due to conduction electrons of the host crystal (Ta). Using t his potential the dechanneling cross-section of muons due to the oxyge n impurity in the lattice of Ta along various planes is evaluated. Thr ee charge states of the oxygen impurity are considered and the corresp onding dechanneling cross-sections are predicted.