[time-nuts] Neutrino timing

ed breya eb at telight.com
Mon Oct 24 22:07:28 UTC 2011

I am not familiar with the experiment, so I have to ask some dumb questions:

First, I wonder how the "beam" is generated at the source, and then 
detected at the receiving end, and how the launch and arrival events 
are determined with high certainty in the first place. I assume the 
neutrinos come from a nuclear or particle accelerator reaction, and 
are produced either randomly or on demand. If they are random, then 
their existence and direction must be detected as the start event, 
but if produced on demand, then the start time is known and 
controlled. If the latter is true, then maybe the beam itself can be 
modulated somehow to carry some of the desired time and frequency 
information, or otherwise help to improve the measurement. I assume 
that it must already be controlled to some extent in time and 
amplitude in order to see an effect above the background level at the detector.

The next question is whether that 60 nSec or so measurement is 
"sharp," or is it the mean value of a large, wide distribution of 
measured arrival times, averaged over some long period of time. If 
so, then the long term stability and tracking of the references 
becomes more important, so it seems to me that GPSDO references would 
ultimately tend to track each other and work better than independent 
Cs references.

The final question for now is how big is the detector? As I 
understand, previous neutrino detectors were huge vessels of water 
(like abandoned salt mines) shielded from all other particle types, 
monitored for faint light pulses from the occasional neutrino 
interactions. If the detector must be on this kind of scale, then its 
dimensions would not allow for that kind of time resolution unless 
lots of light detectors are used to get the spatial information too - 
another time measurement issue.


More information about the time-nuts mailing list