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