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. -- John Hasler [email protected] Dancing Horse Hill Elmwood, WI USA _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
