. On Mar 30, 2012 10:45 PM, "paul swed" <paulsw...@gmail.com> wrote: > > I have to say that in general I have been staying clear of this thread. > But its really a surprise that they are that sloppy and basing the results > on a Vectron OCXO. Not that I have ever had a complaint about those. > It just seems like the stunt I would do in the basement on my surplus > accelerator.
Their accelerator _was_ in their basement ;) > Regards > Paul. > > On Fri, Mar 30, 2012 at 12:57 PM, Tom Van Baak <t...@leapsecond.com> wrote: > > > Hi Javier, > > > > Thanks very much for posting the link to the presentations. > > > > For those of you who just want a summary of the resolution of > > the "neutrino faster than light" problem, here's what happened: > > > > 1) For several years an optical cable connector was loose. I have > > attached photos from pages 7 and 8 of the G._Sirri.pptx where > > you can see the actual connector and waveforms, before/after. > > > > 2) They used a Vectron OCXO to generate timestamps within each > > 0.6 second measurement cycle. This oscillator was found to be high > > in frequency by 0.124 ppm. Thus, depending on where within this > > 0.6 s interval the timestamp was made a timing bias of 0 to 74 ns > > would occur. > > > > Javier -- if you have contacts there, it looks to me like they forgot > > to include OCXO frequency drift effects into their analysis. What > > they did was compensate for linear time drift (which assumes a > > fixed frequency offset). They call the 124.1 ns/s time drift "stable" > > since 2008. What evidence do they have for this? We know that > > OCXO will drift in *frequency* over time; the time drift is quadratic. > > The time drift rate may be 124e-9 today, but it probably wasn't last > > month or last year, etc. > > > > /tvb > > > > There was a meeting in Gran Sasso on Wednesday. You can see some of > >> the slides at http://agenda.infn.it/**materialDisplay.py?materialId=** > >> slides&confId=4896< http://agenda.infn.it/materialDisplay.py?materialId=slides&confId=4896> > >> > >> I found particularly interesting the ones by Maximiliano Sioli, where > >> he explained the two mistakes found in the OPERA data acquisition > >> chain and how, after correcting for their best estimate of their > >> effects, the time of flight is compatible with a speed of c. > >> > >> I saw the webcast of the event. Some people did give the OPERA > >> spokesman a hard time, and he admitted to not having fully checked > >> everything they could have. Ah well, everyone makes mistakes. There > >> will be another run with neutrinos spaced by 100 ns in May. If all > >> four experiments in LNGS give the same result this time, I suppose the > >> case will be closed. It will also be very interesting to see the MINOS > >> results. > >> > >> In any event, from a time-nut point of view this is quite exciting. It > >> is the first time neutrino speed is measured with this precision. I > >> think this will pave the way for future experiments using precision > >> geodesy and time transfer. > >> > >> Cheers, > >> > >> Javier > >> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. On Mar 30, 2012 10:45 PM, "paul swed" <paulsw...@gmail.com> wrote: > I have to say that in general I have been staying clear of this thread. > But its really a surprise that they are that sloppy and basing the results > on a Vectron OCXO. Not that I have ever had a complaint about those. > It just seems like the stunt I would do in the basement on my surplus > accelerator. > Regards > Paul. > > On Fri, Mar 30, 2012 at 12:57 PM, Tom Van Baak <t...@leapsecond.com> wrote: > > > Hi Javier, > > > > Thanks very much for posting the link to the presentations. > > > > For those of you who just want a summary of the resolution of > > the "neutrino faster than light" problem, here's what happened: > > > > 1) For several years an optical cable connector was loose. I have > > attached photos from pages 7 and 8 of the G._Sirri.pptx where > > you can see the actual connector and waveforms, before/after. > > > > 2) They used a Vectron OCXO to generate timestamps within each > > 0.6 second measurement cycle. This oscillator was found to be high > > in frequency by 0.124 ppm. Thus, depending on where within this > > 0.6 s interval the timestamp was made a timing bias of 0 to 74 ns > > would occur. > > > > Javier -- if you have contacts there, it looks to me like they forgot > > to include OCXO frequency drift effects into their analysis. What > > they did was compensate for linear time drift (which assumes a > > fixed frequency offset). They call the 124.1 ns/s time drift "stable" > > since 2008. What evidence do they have for this? We know that > > OCXO will drift in *frequency* over time; the time drift is quadratic. > > The time drift rate may be 124e-9 today, but it probably wasn't last > > month or last year, etc. > > > > /tvb > > > > There was a meeting in Gran Sasso on Wednesday. You can see some of > >> the slides at http://agenda.infn.it/**materialDisplay.py?materialId=** > >> slides&confId=4896< > http://agenda.infn.it/materialDisplay.py?materialId=slides&confId=4896> > >> > >> I found particularly interesting the ones by Maximiliano Sioli, where > >> he explained the two mistakes found in the OPERA data acquisition > >> chain and how, after correcting for their best estimate of their > >> effects, the time of flight is compatible with a speed of c. > >> > >> I saw the webcast of the event. Some people did give the OPERA > >> spokesman a hard time, and he admitted to not having fully checked > >> everything they could have. Ah well, everyone makes mistakes. There > >> will be another run with neutrinos spaced by 100 ns in May. If all > >> four experiments in LNGS give the same result this time, I suppose the > >> case will be closed. It will also be very interesting to see the MINOS > >> results. > >> > >> In any event, from a time-nut point of view this is quite exciting. It > >> is the first time neutrino speed is measured with this precision. I > >> think this will pave the way for future experiments using precision > >> geodesy and time transfer. > >> > >> Cheers, > >> > >> Javier > >> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
