In a preferred embodiment, a plurality of woven wire mesh screens are stacked in {TAIL ~ layers} to form the radiation shield, with wires in adjacent layers being offset from one another such that the radiation shield is substantially opaque to infrared radiation while permitting the passage of {HEAD ~ the alkali metal vapor} 
In a preferred embodiment , a plurality of woven wire mesh screens are stacked in { TAIL ~ layers } to form the radiation shield , with wires in adjacent layers being offset from one another such that the radiation shield is substantially opaque to infrared radiation while permitting the passage of { HEAD ~ the alkali metal vapor }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD