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 Post Posted: Wed Apr 14, 2010 10:05 am 
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Anybody some idea about what the displays in CMSTV mean??

I particularly wonder why the number of stored events regularly goes back to zero...


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 Post Posted: Wed Apr 14, 2010 1:37 pm 
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Have a question on the "CERN BE - OP" eLog display:

I see: "Preparing IP8 squeeze where I know "IP8" is Injection Point 8

Followed by: "IP8 down to 8 m." OR "Started step to 5 m. in IP8"

Question is: What is "m"?


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 Post Posted: Wed Apr 14, 2010 1:44 pm 
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it's the value, in meters, of the beta* parameter. I think there's a good explanation about this in the forum, I don't remember where... It has something to do with the diameter and stability of the beam.


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 Post Posted: Wed Apr 14, 2010 1:47 pm 
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Thanks, I suspected it was a longitudinal parameter in meters.


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 Post Posted: Wed Apr 14, 2010 8:59 pm 
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If I remember rightly...its the distance in meters the beam takes to double in diameter after the squeeze point. Low numbers mean a tighter squeeze but it also means the beam spreads out again more quickly and is more difficult to control.
:)


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 Post Posted: Wed Apr 14, 2010 10:30 pm 
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And New OP Vistar LHC_Coordination turns out to be the operational plan of the week. http://op-webtools.web.cern.ch/op-webto ... r=LHCCOORD


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 Post Posted: Thu Apr 15, 2010 9:15 am 
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Harbles wrote:
And New OP Vistar LHC_Coordination turns out to be the operational plan of the week. http://op-webtools.web.cern.ch/op-webto ... r=LHCCOORD

Mon beam
Tue beam
Wed beam
Thu beam
Fri beam

hmmm not many details there. :lol:


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 Post Posted: Thu Apr 15, 2010 10:08 pm 
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If I may paraphrase "The Everly Brothers"...
Beeaam, Beam Beam Beeaam.... :lol:


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 Post subject: BKGD numbers figured out
 Post Posted: Fri Apr 16, 2010 7:49 am 
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We found info on the BKGD information at the OPERATION page: http://op-webtools.web.cern.ch/op-webto ... p?usr=LHC3
Basically BKGD stands for "background events", of course. It is expressed in percent.
The number signifies how many "false" events there are, as measured by various detectors outside the main detector. The kind of detector varies.
  • Value 0 means: everything OK
  • Value >0 means: there is some noise, but we can handle it.
  • Value 100 means: danger for detectors, dump beam.

_________________
- Tau


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 Post Posted: Fri Apr 16, 2010 8:01 am 
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I think...BKGD is like "Hiss" in a stereo system...... the less the better....we are always going to have some but keep it as low as possible, so it doesn't screw up the experiments.


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 Post Posted: Fri Apr 16, 2010 4:43 pm 
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The Cern bulletin has finally weighed in on describing event displays. http://cdsweb.cern.ch/journal/CERNBulle ... 8907?ln=en
Nothing new and we have more detailed descriptions on the forum here but nice of them to finally speak up.


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 Post Posted: Sat Apr 17, 2010 5:00 am 
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No sign yet of CMS live I suppose? :Big Smile2:


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 Post Posted: Sat Apr 17, 2010 1:49 pm 
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not more than this one: http://cmsdoc.cern.ch/cmscc/cmstv/cmstv ... frames=yes

is there an explanation about these displays?


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 Post Posted: Sat Apr 17, 2010 9:56 pm 
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CMSTV is here http://cmsdoc.cern.ch/cmscc/cmstv/cmstv ... frames=yes
You can click the green items near the top to see other things but some require a pw.
On the Daq status page shown in the earlier message, the LHC_page1 screen is upper left and the data flow column on the right.
The data flow is interesting with my guess the #Lv1 (GT) is the number of events going into the level 1 trigger, Lv1RATE is the number of events passed by the level one trigger, then much interesting stuff I think has to do with level 2 trigger processing, and near the bottom Acc,Rate which I believe to be the actual number of interesting events that are stored the quantity of which is shown in the stored box, for this run.
I hope someone who knows for sure will correct me if I'm wrong about the above, and fill in details as there is a lot of stuff there.


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 Post Posted: Sun Apr 18, 2010 12:20 am 
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Thanks for that...those displays have a huge amount of information on them.
What I'm really hoping for is real time collision displays like we have for Atlas/Alice/LHCb.

:pray:


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