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Re: What do the displays mean ?

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

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

Re: What do the displays mean ?

Posted: Wed Apr 14, 2010 1:37 pm
by LarryS
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"?

Re: What do the displays mean ?

Posted: Wed Apr 14, 2010 1:44 pm
by Bornerdogge
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.

Re: What do the displays mean ?

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

Re: What do the displays mean ?

Posted: Wed Apr 14, 2010 8:59 pm
by mrgumby
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.
:)

Re: What do the displays mean ?

Posted: Wed Apr 14, 2010 10:30 pm
by Harbles
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

Re: What do the displays mean ?

Posted: Thu Apr 15, 2010 9:15 am
by Kasuha
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:

Re: What do the displays mean ?

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

BKGD numbers figured out

Posted: Fri Apr 16, 2010 7:49 am
by Tau
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.

Re: What do the displays mean ?

Posted: Fri Apr 16, 2010 8:01 am
by mrgumby
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.

Re: What do the displays mean ?

Posted: Fri Apr 16, 2010 4:43 pm
by Harbles
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.

Re: What do the displays mean ?

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

Re: What do the displays mean ?

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

is there an explanation about these displays?

Re: What do the displays mean ?

Posted: Sat Apr 17, 2010 9:56 pm
by Harbles
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.

Re: What do the displays mean ?

Posted: Sun Apr 18, 2010 12:20 am
by mrgumby
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: