{HEAD ~ The soft emission} of {TAIL ~ electrons} from the beta emitting gas can not penetrate the glass wall of the microspheres, thereby constituting no radiation hazard 
of
{ HEAD ~ The soft emission } of { TAIL ~ electrons } from the beta emitting gas can not penetrate the glass wall of the microspheres , thereby constituting no radiation hazard
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH