Channeling in direct dark matter detection I: channeling fraction in NaI (Tl) crystals

Abstract

The channeling of the ion recoiling after a collision with a WIMP changes the\nionization signal in direct detection experiments, producing a larger signal\nthan otherwise expected. We give estimates of the fraction of channeled\nrecoiling ions in NaI (Tl) crystals using analytic models produced since the\n1960's and 70's to describe channeling and blocking effects. We find that the\nchanneling fraction of recoiling lattice nuclei is smaller than that of ions\nthat are injected into the crystal and that it is strongly temperature\ndependent.\n