Range- (traveling distance) increasing effect caused by the decrease in interaction cross sections of the incident particles with atoms in a single crystal when a highly collimated particle beam impinges on a crystal along its principal axis or principal plane.
Source:
PAC, 2021, 93, 69. 'Vocabulary of radioanalytical methods (IUPAC Recommendations 2020)' on page 74 (https://doi.org/10.1515/pac-2019-0302)