The material of {HEAD ~ construction} of the grid walls of this invention is glass with a high content of {TAIL ~ lead oxide}, or other high atomic number oxide 
The material of { HEAD ~ construction } of the grid walls of this invention is glass with a high content of { TAIL ~ lead oxide } , or other high atomic number oxide
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH