- The determination of lead via 30 MeV4He bombardment to produce the long-lived radioisotope210Po was studied. The validity of the technique was tested by the analysis of a series of NBS glass samples doped with 61 different trace elements at nominal 500 to 1 ppm level concentrations. The measurement sensitivity of alpha counting with surface barrier detectors was evaluated. The detection limit was estimated at 0.1 ppm. The4He-activation technique coupled with -counting features a unique combination of sensitivity and accuracy for the trace determination of lead. 1987 Akadmiai Kiad.