Abstract
An elastic recoil detection technique has been developed to depth profile light isotopes (A≲35) in low‐atomic‐mass solids (A≲16). It utilizes the maximum‐scattering‐angle property rather than an absorber to reduce background, with resultant depth precision of about ±2 μg/cm2 (100 Å). The sensitivity is ?5×1016 atoms/cm2 for isotopes lighter than the substrate and ?1015 atoms/cm2 for heavier ones.