. On Mar 30, 2012 10:45 PM, "paul swed" <paulswedb@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 <tvb@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" <paulswedb@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 <tvb@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 03/31/2012 05:52 AM, Sanjeev Gupta wrote: > . > On Mar 30, 2012 10:45 PM, "paul swed"<paulswedb@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 ;) Still is as I gather. Seems like facilities like that should regularly have a connector tightening party. What I reacted on was the slope of the signal. Steeper slopes would not had allowed for such a large effect. Also, the receiving end should have a signal level detector and possibly some additional quality of the signal being monitored to ensure that it is correct. Continuous or flickering detection would then give a hint that there is a problem, and is in fact what we use to indicate that we need to send out a tech on the field to polish fibre and tighten connectors. Cheers, Magnus

		Attila Kinali

On Fri, 30 Mar 2012 10:42:55 -0700 (PDT) "J. Forster" <jfor@quikus.com> wrote: > When doing a complex experiment, you have to be an absolute SOB about > everything. "You cannot inspect in quality". Uhm.. Have you ever visited a site of modern nuclear high energy physics? Have you ever seen what kind of constructions they have to just being able to measure something? I guess not, otherwise you wouldn't talk like this. I guess, Fermilab has also tours like CERN does, go and visit them. Have a look on how complex the aparatus is. Then think again whether it's possible to catch all and every error that might occur. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago?

		Attila Kinali

I think that is why John said that you cannot inspect in quality. Every worker has to do his job right the first time, without relying on others to catch his mistakes. As to your questions about John Forster's competency at complicated tasks: You clearly don't know John! -Chuck Harris Attila Kinali wrote: > On Fri, 30 Mar 2012 10:42:55 -0700 (PDT) > "J. Forster"<jfor@quikus.com> wrote: > >> When doing a complex experiment, you have to be an absolute SOB about >> everything. "You cannot inspect in quality". > > Uhm.. Have you ever visited a site of modern nuclear high energy physics? > Have you ever seen what kind of constructions they have to just being > able to measure something? I guess not, otherwise you wouldn't talk like > this. > > I guess, Fermilab has also tours like CERN does, go and visit them. > Have a look on how complex the aparatus is. Then think again whether > it's possible to catch all and every error that might occur. > > > Attila Kinali

		Attila Kinali

> On Fri, 30 Mar 2012 10:42:55 -0700 (PDT) > "J. Forster" <jfor@quikus.com> wrote: > >> When doing a complex experiment, you have to be an absolute SOB about >> everything. "You cannot inspect in quality". > > Uhm.. Have you ever visited a site of modern nuclear high energy physics? Yes. > Have you ever seen what kind of constructions they have to just being > able to measure something? I guess not, otherwise you wouldn't talk like > this. > I guess, Fermilab has also tours like CERN does, go and visit them. > Have a look on how complex the aparatus is. Then think again whether > it's possible to catch all and every error that might occur. I've been in responsible charge of a couple of spacecraft payloads. You have to instill in everybody to double check everything they do or the thing will likely fail. They have to understand that in all likelihood no human will ever revisit what they are doing at every step. -John ============ > > > Attila Kinali > -- > Why does it take years to find the answers to > the questions one should have asked long ago? > >

On 3/31/12 8:10 AM, J. Forster wrote: >> On Fri, 30 Mar 2012 10:42:55 -0700 (PDT) >> "J. Forster"<jfor@quikus.com> wrote: >> >>> When doing a complex experiment, you have to be an absolute SOB about >>> everything. "You cannot inspect in quality". >> >> Uhm.. Have you ever visited a site of modern nuclear high energy physics? > > Yes. > >> Have you ever seen what kind of constructions they have to just being >> able to measure something? I guess not, otherwise you wouldn't talk like >> this. >> I guess, Fermilab has also tours like CERN does, go and visit them. >> Have a look on how complex the aparatus is. Then think again whether >> it's possible to catch all and every error that might occur. > > I've been in responsible charge of a couple of spacecraft payloads. You > have to instill in everybody to double check everything they do or the > thing will likely fail. They have to understand that in all likelihood no > human will ever revisit what they are doing at every step. > And we do things like stake connectors with epoxy, just in case. Serves two purposes: 1) a second independent look at the connector (after the first guy went through and tightened it with the torque wrench with the QA guy watching) 2) if, for some reason, there was a problem with #1 (maybe the torque wrench had an issue, or the QA guy sneezed and looked away, or...), at least the connector won't back off with vibration.

Frankly, I'm a bit surprised at the connector problem. Much of High Energy instrumentation uses LEMO connectors, which have a definite "click" when mated. They are not like BNCs which can be mated, without locking. ------- As to my point about inspecting in quality, look at the (crummy) attached picture: The leads to CR5 (a photocell) just to the left of the ceramic IC have NEVER been soldered or clipped. Yet, this 5519A Laser Interferometer head was built by HP, inspected by HP, tested by HP, and sold to a ciustomer by HP as part of a >$60,000 system. I rest my case. You simply cannot inspect in quality. -John ================ Jim Lux wrote: > And we do things like stake connectors with epoxy, just in case. Serves > two purposes: > 1) a second independent look at the connector (after the first guy went > through and tightened it with the torque wrench with the QA guy watching) > 2) if, for some reason, there was a problem with #1 (maybe the torque > wrench had an issue, or the QA guy sneezed and looked away, or...), at > least the connector won't back off with vibration. >

On Sat, Mar 31, 2012 at 6:23 PM, J. Forster <jfor@quikus.com> wrote: > Frankly, I'm a bit surprised at the connector problem. Much of High Energy > instrumentation uses LEMO connectors, which have a definite "click" when > mated. They are not like BNCs which can be mated, without locking. It was an optical bayonet-type connector, not an electrical one. Changes in optical power induced by the loose connection resulted in big changes in delay through the mechanism of charging and discharging the capacitance associated with the photodiode. At least that is my crude understanding of the matter, > I rest my case. You simply cannot inspect in quality. It's hard to disagree with this statement. Who doesn't like quality? I was trying to go a bit more concrete and suggest that redundant systems, especially based on alternative technologies, can help catch errors which may have gone undetected using other means, like inspection and other sanity checks. In fact, if you have experience with space electronics I think I don't have to convince you of the benefits of redundancy, as well as of the fact that the probability of making mistakes is never 0. If you think about it, this whole issue was solved thanks to redundancy: there was another experiment in the same lab which detected cosmic muons, and it was through the correlation of the muon detections between the two experiments that the slip between time bases was discovered. I think redundancy is a good complement, not necessarily a substitute, to other quality assurance methods. Cheers, Javier

I agree that you can't inspect quality into a system, but it is far to easy to 'not inspect' quality right out of the system. Some of the new 'buzz-word' systems (TQM,6 sigma, etc.) seem to want everyone to be their own QA inspector to lessen the involvement of independent QA. I find that no matter how careful I inspect my own work, just knowing someone else will be looking over it makes me do a better job. Mike On 3/31/2012 11:23 AM, J. Forster wrote: > Frankly, I'm a bit surprised at the connector problem. Much of High Energy > instrumentation uses LEMO connectors, which have a definite "click" when > mated. They are not like BNCs which can be mated, without locking. > > ------- > > As to my point about inspecting in quality, look at the (crummy) attached > picture: > > The leads to CR5 (a photocell) just to the left of the ceramic IC have > NEVER been soldered or clipped. Yet, this 5519A Laser Interferometer head > was built by HP, inspected by HP, tested by HP, and sold to a ciustomer by > HP as part of a>$60,000 system. > > I rest my case. You simply cannot inspect in quality. > > -John > > ================ > > > > Jim Lux wrote: > >> And we do things like stake connectors with epoxy, just in case. Serves >> two purposes: >> 1) a second independent look at the connector (after the first guy went >> through and tightened it with the torque wrench with the QA guy watching) >> 2) if, for some reason, there was a problem with #1 (maybe the torque >> wrench had an issue, or the QA guy sneezed and looked away, or...), at >> least the connector won't back off with vibration. >> >> >> >> _______________________________________________ >> 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.

		Attila Kinali

Moin, On Sat, 31 Mar 2012 09:19:35 -0400 Chuck Harris <cfharris@erols.com> wrote: > I think that is why John said that you cannot inspect in > quality. Every worker has to do his job right the first > time, without relying on others to catch his mistakes. > > As to your questions about John Forster's competency at > complicated tasks: You clearly don't know John! I didn't questions his competency on complicated tasks. But i questioned his finger pointing at the CERN guys. Yes, you have to teach everyone to do their job right at the first time, but mistakes happen, no matter how diligent you are. Especially if the system is as complex as modern nuclear physics expermients. And i do not like it, if people who are not involved in a complex project do finger pointing. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago?