Older Events and discussion 3/22/10

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Xymox
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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 5:01 am

I saw that !

What does that mean ?

I will send a email...

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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 5:21 am

Its cooling again...

But wow, to stop all work on the whole ring ?

Hmmmm.......

Not good...

But keep in mind, delays ARE EXPECTED.. Its been 10+ years in the making, slight delays are no big deal...

Actually I hope this delay is just enough so I can get back from out of town work and be there for the start up...

Hmmmmmmmmmmmmmmmmm im worried..

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Re: ** Current Events and discussion **

Post by Shadowdraxx » Thu Feb 25, 2010 5:33 am

a standard quench should only have a knock on affect for like 4hours, but its not understood why this happened, so im guessing they wanna do all the checks to why how when etc before giving the go ahead for beams

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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 5:39 am

I would bet ALOT of people are in there right now working the problem...

I dont know if it was a quench.... Maybe the quench protection system had some hicup. The QPS was a bit unstable during the last run...

Many experts were called up im sure !

I wonder what "non standard" events were..

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Re: ** Current Events and discussion **

Post by jmayes » Thu Feb 25, 2010 5:48 am

More from eLog;

22:49> major problem in sector 78. heaters of more than 50 magnets were fired when opening the swithes to accelerate the current decay on RB.A78. following an abort of the ramp using an IDDLE command. in equip state..More info available in the MP3 logbook.
As a consequence of the event. no more tests on RB in any sector till further notice.

06:34> We got back sector 81 .sector 78 event had produced some perturbations on 81. since thay are sharing the same cold box.... and we start the pyramid on RQD/F.A81 on boards B.

-------------------------------------------
Fingers crossed 78 comes back too;
J

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Xymox
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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 7:50 am

On the highest authority, its nothing at all. Software glitch. A unknown "feature".

Good to discover these things now rather then later.

-might- cause a day or so delay.

Houston, we are almost go for launch.

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Re: ** Current Events and discussion **

Post by DCWhitworth » Thu Feb 25, 2010 8:12 am

Info in the MPP log suggests that there isn't any damage. I guess that they need to stop to make sure they understand *why* this happened and how to stop it in future.

From MPP log -

50 dipoles quenched in RB.A78 at 19h08m23 after openeing the EE during a SPA. As Jens explained in the meeting afterwards the following happened.
- The sunglass filter triggered during the start of the SPA because the trigger threshold of -1.6 V was reached. The sunglass filters up to 1.3 V and 900 ms.
- The sunglass filter stayed activated because the condition for reactivating was not met. Reactivating starts when the voltage over the 4 magnets of the SymQ are positive. but during discharge the voltages remain negative.
- By the time the EE was put in. the sunglass was no longer filtering and the travelling wave coming from the EE caused multiple quenches.

Heater firing looks fine in all magnets and at first look no damage to any of the magnets. but the quench signals of all 50 magnets should be looked at in more detail.

Voltages of the EE look also fine. Current decay time constant is about 33 s. in line with quenching of 50 out of 154 magnets. .104/154*50=34 s.
DC

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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 1:03 pm

Well after they have thought about it, they have decided to go with beams friday as planned.

Drats, I was hoping for some delay to get back into town to enjoy the start up, but NooOOoo the CERN guys are just too quick.

So back to the original schedule for the weeks ahead.

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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 1:04 pm

Oh and I was wrong, it was not a software bug.

DC's log quotes were a tad,,, ummmm,,, technical !

I am sure tho I have not idea exactly what happened..

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Re: ** Current Events and discussion **

Post by DCWhitworth » Thu Feb 25, 2010 1:05 pm

Xymox wrote:Oh and I was wrong, it was not a software bug.

DC's log quotes were a tad,,, ummmm,,, technical !
I'm not pretending I know what they mean either ! :geek:
DC

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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 1:35 pm


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Re: ** Current Events and discussion **

Post by Stephen » Thu Feb 25, 2010 1:53 pm

Just usual technical difficulties. I love that The Register mentions the possibility of visitors from other dimensions in all of their articles about the LHC.

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Re: ** Current Events and discussion **

Post by Xymox » Thu Feb 25, 2010 2:36 pm

I LOVE ElReg.. Lewis writes some great stories. I love the drama in his stories and the sensationality of it all..

Yes I know its not a word..

Its SOOOO boring reading most LHC stories,,, But not when Lewis writes them. I like ElReg and have been reading ElReg for, jeeze,, A really really long time... Its my favorite news site.

They also have great reporting. I have seen many stories first in ElReg. Hardware reviews are great. Stuff like BOFH. I read it everyday.

You MUST give Lew important credit.. HE was very much a inspiration to make this site. WHen he covered the Baguette dropping shutdown that I spotted it was so much fun I had to do more with my links. I needed to share them,, and the LHCPortal was born. In a hour or so that same day.

Honestly... I loved reading about the crazy loons who were running for cover to escape the end of the world caused by the LHC.. It was so fun and so ridiculous.. I was inspired that maybe I could attract loons and tin-foil hatters so I had fun humor everyday to watch and that other could also enjoy.. I liked the idea of having a really great outreach site with awesome technical depth and fun science people along with a "comics" section where we could relax and enjoy a loony or 2..

Sure enough. Ivan and Beast so far.. Ivan's thread is viewed more by repeat visitors then ANY other thread. SO others also enjoy this kind of public display of a loon. Well maybe "enjoy" is the wrong word. "Entertained" ? "Enraged" ? That whole you-just-wanna-slap-him thing ? :violence-smack:

SOooo.... Looks like I will not be able to be in fun chat when first beam goes around. SO much fun... It seems really quiet on the forum and chat... I think the public has no idea things are really restarting.. After the restarting occurs and all the press cover it tho.. Hang on, lots more people will appear..

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Re: ** Current Events and discussion **

Post by CharmQuark » Thu Feb 25, 2010 3:02 pm

Big Thumbs up to Lewis :thumbup: :D

Chris I hope your not working to hard :D
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.

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Re: ** Current Events and discussion **

Post by jmayes » Thu Feb 25, 2010 3:21 pm

Still Looking good for tomorrow!

From Log;
Thursday 25th February

Following yesterday 50 magnet quench incident which reveal a feature in the Quench Protection logic, the main bend current has been limited to 2 kA until a full analysis has been performed and compensatory measures implemented. (The quenching is not so dangerous in itself but it does unecessarily stress the system).

We will carry on the beam commissioning program as planned with the above limitation in place for the moment. Still hope to put beam in tomorrow.

J

PS, thats the problem with Burglar alarms, they tend to be a nuisance!

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