Experimental evidence of independence of nuclear de-channeling length on the particle charge sign

Abstract

Under coherent interactions, particles undergo correlated collisions with the crystal lattice and their motion result in confinement in the fields of atomic planes, i.e. particle channeling. Other than coherently interacting with the lattice, particles also suffer incoherent interactions with individual nuclei and may leave their bounded motion, i.e., they de-channel. The latter is the main limiting factor for applications of coherent interactions in crystal-assisted particle steering. We experimentally investigated the nature of de-channeling of 120 GeV/c e- and e+ in a bent silicon crystal at H4-SPS external line at CERN. We found that while channeling efficiency differs significantly for e- (2 ± 2 %) and e+ (54 ± 2 %), their nuclear de-channeling length is comparable, (0.6 ± 0.1) mm for e- and (0.7 ± 0.3) mm for e+. The experimental proof of the equality of the nuclear de-channeling length for positrons and electrons is interpreted in terms of similar dynamics undergone by the channeled particles in the field of nuclei irrespective of their charge.