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