OLDER 2/15/10 ** current events and discussion **

The place to discuss the LHC. Commissioning, operation, issues, events ....
Danny252
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Re: ** current events and discussion **

Post by Danny252 » Mon Dec 14, 2009 8:00 pm

16x16 + Pilots now.

1.50E11 B1, 1.70E11 B2.

Image

dh2va
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Re: ** current events and discussion **

Post by dh2va » Mon Dec 14, 2009 8:10 pm

Keep in mind, that in full operations later, ONE bunch will have 1E11 p...

... and SPS will fill 72 bunches in one go!

I like the meticulous approach.. one small step at a time. Good job CCC!

Harbles
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Re: ** current events and discussion **

Post by Harbles » Tue Dec 15, 2009 12:05 am

Aw They Broke Page one again It's saying 22:59 and it really 01:04 now.

Elog messages say they tried to restart it no joy.

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Xymox
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Re: ** current events and discussion **

Post by Xymox » Tue Dec 15, 2009 8:53 am

Nice job Danny.. As usual..

Danny252
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Re: ** current events and discussion **

Post by Danny252 » Tue Dec 15, 2009 3:07 pm

Today's schedule implies a Ramp to 1.18TeV, squeezing and then collisions ("measurements"). These could well be 16x16 as well, just to be more exciting!

Last night, the LHC reached what we believe is the highest intensity it has ever reached - 1.55/1.75e11 for the respective beams. They were colliding the 16x16 beams as well - so the highest intensity and bunch count collisions the LHC has seen to date.

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islandofmind
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Re: ** current events and discussion **

Post by islandofmind » Tue Dec 15, 2009 7:16 pm

I'm curious about the cryo conditions in sector 78. As I've been following along for the past month or so, authorization is usually lifted when the average temperature exceeds about 1.94 or so. The Arch magnets in 78 have been running 1.98 - 1.99 over the last few days but authorization has remained in place. Obviously the temperature average is not the crucial determinant but it's still odd to me that it is allowed to be that far (3-4%) above specs.

josch222
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Re: ** current events and discussion **

Post by josch222 » Tue Dec 15, 2009 9:26 pm

islandofmind wrote:I'm curious about the cryo conditions in sector 78. As I've been following along for the past month or so, authorization is usually lifted when the average temperature exceeds about 1.94 or so. The Arch magnets in 78 have been running 1.98 - 1.99 over the last few days but authorization has remained in place. Obviously the temperature average is not the crucial determinant but it's still odd to me that it is allowed to be that far (3-4%) above specs.
At this site:
http://lhc.web.cern.ch/lhc/Cooldown_status.htm
You can see some sensor readings of several magnets that appear to be far above
the allowed temperature. I think that is due to some defective sensors (or channels in
the electronics), maybe they are masked out for the decision "too hot" but not
in the calculation of the more informal average.
But this is just a guess and in fact there is sector 1-2 with one sensor reading
at 20K what should give a higher average than 7-8.
Where do you saw the average temperatures?

Joerg.

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islandofmind
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Re: ** current events and discussion **

Post by islandofmind » Wed Dec 16, 2009 1:54 am

Joerg,

I'm looking at the LHC2 screen (bottom half). Current reading for 78 is 2.00K so it's generally trending slowly upward.

I've seen what you refer to at the site you linked to - there have been persistent "outliers" like that in several of the magnets over the past month and I started assuming they were bad sensors - but they didn't seem to deflect the overall average by very much.

Oh well, as long as it doesn't interrupt the "Physics Phun" :) I can live with it.

Danny252
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Re: ** current events and discussion **

Post by Danny252 » Fri Dec 18, 2009 3:33 pm

Christmas isn't completely silent in CERN - today a fire alarm was set off in the LHC.

However, not to worry - after an investigation by a pair of firemen, it turns out that someone forgot they were doing welding down there!

Glacialis
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Re: ** current events and discussion **

Post by Glacialis » Fri Dec 18, 2009 3:42 pm

To demonstrate how frazzled someone can get by the end of the week, for a second I read it as someone left their welding torch on. Like you forgot you had a cake in the oven.

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