On Fri, 19 Oct 2007 23:13:29 -0500, Jon Elson wrote:
Dave Hinz wrote:

x-ray tubes use tungsten for the electrode/target. Nearly always round,
as the modern ones spin. I know that GE Medical Systems scraps out the
field returns, because a friend of mine runs the operation.

They have a lot of tubes fail for various reasons. If you can
get a tube that has cracked, then there's no vacuum hazard to
worry about. Also, the dental X-rays have smaller, non-spinning
anodes. Many of these get dumped in the trash when they go bad.
Those probably are no more than a pound, though.

GE really does a remarkable job of salvage operations on returned parts
and so on. Some of it is cost-avoidance (recycle it at a loss so you
don't have to landfill it at a higher loss), some of it is profitable,
and some of it is just because that's the right thing to do. So, the
CRTs come apart - the copper yokes go into one bin, the Mu-metal in the
neck of the tube goes into another, the lead glass face of the tube goes
into another, the rest of the glass, the plastic, the steel chassis, and
all that gets put with more of the same. Any gold edge connectors on
circuit boards get sheared off and put into one bin, the rest of the
board into another. Amazing how fast those guys can take stuff apart.

And, yup, no radiation in an xray tube unless you're feeding it tens of
thousands of volts at the moment. I've got an older xray tube on my
desk; it's amazing that even within the company and division that made
it, so many people have no idea what it is or how it works.