in fact if you want to track something as you know, that's hard to find yutaka something radioactive. >> but we don't do that. [laughter] because of safety issues. but yes, radiation stands up and wants to be counted as i like to say it. >> the one way we do do it is you know. >> very small amounts very small amounts brickwork's trivial amounts? >> before we have the question, fusion. i have ad good friend who is a physicist. he finished up his phd in fusion, he was asked by his advisor, this would be probably 75, how many fusion reactors he thought, my friend, would be in the world in 20 or 30 years by the year 2000. his answer was a couple. [laughter] and he was overly optimistic because we so don't have a couple. i have my opinionsni on how fusion is, of the shipping port reactor, is it fusion reactor for. >> let's step back and ask what is going on, the world is focused on in a being built in the south of france. i think they expect to see the first fusing pods and about 15 years if i am not mistaken. from there you got to do demonstration and from there it starts to get more comm