Beam Spot Monitoring

Introduction

This twiki describes the ongoing development of implementing beam spot monitoring to Online/Offline DQM and how to use it.

How to use it

cmsrel CMSSW_2_2_5
cd CMSSW_2_2_5/src
cmsenv
cmscvsroot CMSSW
cvs co -d UserCode/BeamSpotMonitoring UserCode/Jeng/BeamSpotMonitoring
scramv1 b
cd UserCode/BeamSpotMonitoring/test/

2) Start DQM Gui Server:

• To test the codes with DQM gui. You have to install DQMGui server on a local machine first. You can follow the instruction under the section of "Specific details" in this page: https://twiki.cern.ch/twiki/bin/view/CMS/DQMTest

• Follow the instruction under the section of "Starting the GUI server"
• Remember to stop GUI server and collector when you are done with the test. See "Stopping the GUI server and the collector"

3) Edit dqmStandalone_cfg.py (or dqmReadFromRAW_cfg), change <DQM Gui Server Host> to the machine that runs gui service

process.ep = cms.EndPath(process.outP)
process.p = cms.Path(process.dqmSource+process.dqmClient+process.dqmEnv+process.dqmSaver)

process.DQMStore.verbose = 0
process.DQMStore.collateHistograms = False

process.DQM.collectorHost = "<DQM Gui Server Host>"
process.DQM.collectorPort = 9190

process.dqmSaver.convention = 'Online'
process.dqmSaver.dirName = '/tmp'
process.dqmSaver.producer = 'DQM'

process.dqmEnv.subSystemFolder = 'BeamSpotMonitor'

4) Run:

cmsRun dqmStandalone_cfg.py

5) Open web browser to check histograms:

http://<DQM Gui Server Host>:8888/dqm/devtest

Histograms

Histogram Name	Type	Description	Note for shifter
	1D	d0 of tracks calculated with respect to (0,0).	Double peak seen for displaced beam line. This already exists in tracker DQM. Shown here for comparison only.
	1D	d0 calculated w.r.t. beam spot (from offlineBeamSpot, which is a collection of beam spot objects from DB. Constant at the moment).	Should see only one peak centers at 0 for good beam fitting results.
	Profile	Track d0-phi0 correlation.	Sinusoidal for displaced beam line
	Profile	Track d0(beam spot)-phi0 correlation where beam spot info is used to calculate d0.	Should be relatively straighter than d0_phi histogram
	Profile	Beam slope: dx/dz.	Should see horizontal if no crossing angle
	Profile	Beam slope:dy/dz.	Should be horizontal if no crossing angle
	Profile	Trending of x coordinate of fitted beam position w.r.t. event number. Beam position is fitted at the end of every lumisection. Input track collection is reset if it has more than 15k tracks.	TBD.
	Profile	Trending of y coordinate of fitted beam position w.r.t. event number. Beam position is fitted at the end of every lumisection. Input track collection is reset if it has more than 15k tracks.	TBD.

Plan

• Add z0, sigma z0
• Add error plots from the beam fit. ex. x0Err, y0Err, dxdzErr, dydzErr, z0Err, sigmaz0Err

-- GengyuanJeng - 30 Mar 2009