CompCMSbril < TOTEM

TOTEM Web>WebLeftBar>CompOfflineSw>CompCMSbril (2015-11-17, JiriProchazka) (raw view)

BRIL (Beam Radiation Instrumentation and Luminosity) is a new project within CMS introduced after LS1: "it comprises all subdetectors for the measurement of the luminosity, monitoring of the beam conditions, and protection of CMS from serious radiation damage"


There are currently two CMS scripts which provides CMS luminosity calibrated using VDM scans (separation scans):

   1.  lumiCalc2.py for lumi data *before* LS1 (LHC Run1)
   1.  and newer brilcalc (part of brilws) for data *after* LS1 (LHC Run2) which should support also LHC Run1 lumi data at some point

---+ How to download luminosity for runs BEFORE LS1

See users guide of lumiCalc2.py  on CMS Twiki (lumiCalc2.py requires CMSSW + one extra module and provides only HF lumi)

*Example*
<verbatim>
lumiCalc2.py -o fill_2836_lumiCalc2.py_V04-02-10_lumibylsXing.csv -f 2836 lumibylsXing --xingMinLum -1
</verbatim>

---+ How to download luminosity and beam/bunch intensities for runs AFTER LS1

CMS doc to brilws (look at it before continuing): http://cms-service-lumi.web.cern.ch/cms-service-lumi/brilwsdoc.html

brilws release notes: http://cms-service-lumi.web.cern.ch/cms-service-lumi/releaserss.xml



In short in the simplest case  (look to the doc for more details, options and up to date comments):

1) login to lxplus:
<verbatim>
ssh -Y <user>@lxplus.cern.ch
</verbatim>

2) run (adjust to your real running setup accordingly, the following will uninstall current version of brilws and install the latest one)
<verbatim>
export PATH=$HOME/.local/bin:/afs/cern.ch/cms/lumi/brilconda-1.0.3/bin:$PATH
pip uninstall -y brilws
pip install --install-option="--prefix=$HOME/.local" brilws
pip show brilws
</verbatim>


*Examples*

   * _lumi info_ 

     for a given fill number may be downloaded as:
     <verbatim>
     brilcalc lumi -f 4489 --xing -o fill_4489_brilcalc_lumi_xing.csv
     </verbatim>
     which may provide only some BCIDs. To download some lumi values for all BCIDs you may try HF detector (dedicated to mainly online measurement):
     <verbatim>
     brilcalc lumi -f 4489 --xing -o fill_4489_brilcalc_lumi_xing.csv --type hfoc
     </verbatim>
     To select just some BCIDs (e.g., 41,1826,901,932):
     <verbatim>
     lumi -f 4489 --xing --xingId "41,1826,901,932" --xingMin 1e-100 -o fill_4489_brilcalc_lumi_xing_ids.csv  --type hfoc
     </verbatim>

   * _beam/bunch intensities_ 

      may be downloaded as:
      <verbatim>
      brilcalc beam -f 4489 --xing -o fill_4489_brilcalc_beam_xing.csv
      </verbatim>

---+ Important note
The above instructions should help to get fast some lumi data.  For more advanced analyses it is necessary to ask CMS which lumi should be used for given TOTEM runs and what is the corresponding uncertainty etc (some corrections or calibration may require some more time for offline analysis and may come much later). The downloaded file with lumi values includes in header also some meta information (data tag and norm tag - "version") which is very useful for later usage - to keep track of the version, lumi values serving as an input for an physics analysis (=>save and keep the file).

CMS lumi/bril mailing list:
hn-cms-luminosity@cern.ch

---+ Some usefull links
CMS Luminosity - public results
https://twiki.cern.ch/twiki/bin/view/CMSPublic/LumiPublicResults#2015_Proton_Proton_Collisions

Simple lumi calculator:
https://lpc.web.cern.ch/lpc/lumi.html

General information about luminosity calibration at the LHC (mostly outdated but contains links about concept of luminosity etc)
http://lpc.web.cern.ch/lpc/lumicalib.htm

---+ Terminology
BCID/BXID - bunch crossing ID (CMS stars from 1, TOTEM from 0 - check it) 

SBIL - single bunch instantaneous luminosity

LS - lumi section or lumi block (~23.3sec)


---+ Miscalaneous
TOTEM fills without stable beams:
in 2015: 3838, 3844, 3952 (no lumi available), 4489


-- Main.JiriProchazka - 2015-10-28

Topic revision: r5 - 2015-11-17 - JiriProchazka

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