For the purposes of x-ray absorption, I'm trying to discover the average chemical composition of a typical PCB.
My research so far has indicated that the most common type of PCB is designated FR-4. It is composed of fiberglass and epoxy resin. The resin often contain Bromine to add fire resistance. Let's ignore any printed copper for the mean time. So we are looking at H, C, O, Si, Br, and probably some other bits and pieces. But what are the percentage of these elements?