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