On 2011-12-24, 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.
Surveying is done by GPS, as is timing so mountain ranges do not really matter. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions