Transcript From 2011 to 2012 - Indico

CMS Pixel General
meeting
Intro, news
G. Bolla
[email protected]
3/27/2016
1
A short recap of 2011
In 2011 we collected 100 times the luminosity (and the radiation damage) of 2010.
The detector and the team operating it performed very well.
This did not come for free.
I take the occasion to thx all the people that made it happen.
3/27/2016
G. Bolla, CMS Week
2
Radiation damage from 2011 to 2012
On radiation damage:
There will be a presentation tomorrow at the tracker general meeting on this
topic. It should include a forecast on what to expect during this year.
In 2011 we just kept taking data watching the performance of the detector.
We did not apply any special correction to counter-balance the effects of
radiation damage.
Would this approach be sufficient for 2012 ?
We expect 3 times more luminosity.
We do not expect to change the Bias voltage applied to the sensors
Will we need to measure/tune gain and threshold at regular intervals?
Later presentation (calibration and offline) should be interesting.
Let’s see at the end of the meeting today if we can already answer these
questions.
3/27/2016
G. Bolla, CMS Week
3
From 2011 to 2012: Beam-Pixel misalignement
I think we are all familiar with the picture below.
The consequences of this misalignment are in multiple direction:
• Different lifetime versus phi
• Different data rate versus phi
• There are consequences also for the offline
3/27/2016
G. Bolla, CMS Week
4
From 2011 to 2012: Beam-Pixel misalignement
I think we are all familiar with the picture below.
The consequences of this misalignment are in multiple direction:
• Different lifetime versus phi
• Different data rate versus phi
• There are consequences also for the offline.
Information has been piped to the LHC operation group back in Novemeber.
The LHC is considering
starting 2012 operation
with a new orbit that will
reduce the misalignment.
Likely we are going to get
1-2 mm better than we
have been so far.
See:
https://winservices.web.cern.ch/winser
vices/Services/DFS/DFSBrowser.aspx/
Users/j/jwenning/Public/LBOC/LBOC.C
MS-IP-shift.Jan12.pptx
3/27/2016
G. Bolla, CMS Week
5
From 2011 to 2012: SEUs
In 2011 we collected strong evidences that the system suffer of Single Event
Upset (SEU).
We developed on the fly some mitigation procedures.
Re-download critical parameters at PAUSE/RESUME
In late 2011 we agreed within CMS on some common action (Pixel is not the
only subsystem suffering this disease).
Ongoing effort within the pixel group that will imply some testing of the new
code in the next couple of months.
3/27/2016
G. Bolla, CMS Week
6
The last few days of 2011
During the last 2 days of operation (Heavy Ion) we had to exclude 6 FPIX
panels (3 blades out of 96 that is ~3% of the detector).
After re-powering up in 2012 these components are not showing any problem.
While this might sound as good news we do not know if the problem (or other
problems) will come up in the future.
I picked this example to remind ourselves that we need to have the tools ready
for debugging single point failures in the detector.
This was not the case last December. We ended up running calibrations
that were producing empty plots and so giving little information on what
was wrong with the hardware.
The ongoing calibration process is tackling all this issues.
See later presentation from Ben.
3/27/2016
G. Bolla, CMS Week
7
Infrastructure
The CAEN power system keep performing well.
Still there are several hickups here and there (one also last week).
We need to keep a person on call 24/7 for power supplies issues.
The cooling system performed very well during 2011.
There has been several tests ongoing during the last few weeks on
determining the limitation of the whole C6F14 CMS system.
While we are still waiting for the official results the first impressions are:
• There is work to be done during LS1 in order to be able to run the tracker at
nominal temperature (-20 -25 deg C).
• For the pixel cooling plan the present installation seems to be compatible
with the long term goal without any major work on the hardware itself.
3/27/2016
G. Bolla, CMS Week
8
The first few weeks of 2012
At P5
We have changed the operation temperature of the pixel system by setting it
colder than 2011 by 7.4 deg C.
The set point of the cooling plant is now at 0 deg C.
The lengthy process of recalibrating the detector is ongoing.
There are several other developments ongoing:
• Upgrade of the OS: SLC4  SLC5
• Other software upgrades.
Offline
Several plots showing the trends of various parameters during 2011.
We will see them during the various presentations.
Try to collect your thoughts for the final part of the meeting were we should
discuss the various things for which we do not yet have an explanation.
Enjoy the meeting
3/27/2016
G. Bolla, CMS Week
9