RE:RE:Hoping for helium production very soonI was just referring to 6 standard deviations. Not the whole system as deployed by Jack Welch and dumper by Larry Culp for Lean (of Toyota game).
Anyway, 6 sd is 3.4 deviations per million. Or 99.99966 pure. So 99.9999 is just a twitch better at 1 deviation per million.
With helium, 6 digit gas (grade six, the highest commercial grade) is actually 6 sigma gas. I do not know where you got the 1/500,000,000 number.