Channeling Effect and Improvement of the Efficiency of Charged Particle Registration with Crystal Scintillators

TL;DR

This paper discusses how channeling effects in crystal scintillators influence the detection efficiency of low-energy recoil ions, potentially explaining observed signals in dark matter experiments by considering massive particles from specific orbital paths.

Contribution

It introduces the significance of channeling effects in low-energy recoil ion detection and proposes their impact on interpreting signals in crystal scintillator experiments.

Findings

Channeling reduces nuclear stopping power for low-energy ions.

Higher light yield occurs for ions in channels compared to outside channels.

Massive particles may cause recoil signals consistent with DAMA/NaI observations.

Abstract

The importance is emphasized of taking into account the channeling along the low index crystallographic axes and planes of a part of low-energy (1-10 keV) recoil ions in measurements of their parameters with crystal scintillators of the type of NaI(Tl) etc. Because the nucleus stopping power in channels is low as compared with electronic stopping power, the light yield of the scintillator must be, accordingly, higher in the given case than that for ions having higher energy (tens keV and more), which lose most part of their energy via nuclear collisions outside channels. Hence, in particular, it follows that the DAMA/NaI observations in Gran Sasso of the annual modulation of the signal frequency in a narrow range of scintillations with an amplitude of 2-6 keV electron equivalent may be due to incidence onto the Earth of exceedingly massive particles (of the type of Planckian objects) from elongated Earth-crossing heliocentric orbits at a velocity of 30-50 km/s. In NaI(Tl), these particles create the iodine recoil ions with just the energy of 2-6 keV.