On 2011-12-24, j...@specsol.spam.sux.com <j...@specsol.spam.sux.com> wrote: > John Hasler <jhas...@newsguy.com> wrote: >> unruh writes: >>> They require ns accuracy in the timing and m accuracy in the >>> distance. And the timing is not simply gps ( although they could have >>> gotten that wrong) but then that timing has to be brought down into >>> the mine a km or so below ground and horizontally and that also has to >>> be surveyed for the distance. >> >> The NOvA detector is not in a mine so it should be possible to site the >> GPS receiver directly above it and drop a cable straight down. The same >> should be possible at the Fermi end. You could set up both timing >> chains at Fermilab (using indentical components including cable lengths >> if you want to be fanatical), calibrate them against each other for >> delay from antenna to output, and then pack one up and ship it up north >> (of course there may be good reasons not to do it this way). The >> surveying should be easier than in Europe: there's no mountain range in >> the way. > > That's the common misconception of the geology. > > Basically the lab is in a tunnel in the side of a mountain and is no more > a km underground than is the lobby of a 20 story hotel 20 stories > underground.
But it is a few km inside the mountain. Is a mine in Denver not underground just because Denver is 1600 m above sea level? > > _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
