1. Data Quality Monitoring of the CMS Tracker
Laura Borrello
Scuola Normale Superiore and INFN Pisa, Italy
on behalf of the CMS Tracker collaboration

2. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Outline
DQM architecture in CMS
Tracker DQM
Graphical User Interface
CMS GUI
Tracker GUI
Historic DQM: long term monitoring
Data Certification
Summary
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

3. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Introduction
The Data Quality Monitoring (DQM) is an important tool to ensure
high quality data taking throughout the lifetime of the experiment.
It is partitioned in:
Online
Evaluate data integrity and sub-system operation
Check any problem and take a prompt action to solve it
Offline
Identify problems in calibration constants and reconstruction
Check the quality of each run
Data Certification
Define good runs for physics analysis
The DQM system in CMS is
- implemented using the CMS software framework (C++ code) and ROOT
- centralized across sub-detectors, DAQ, trigger
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

4. Prompt reconstruction
DQM overview
On-line
Off-line
Prompt reconstruction
DATA
Online
DQM
Express
Stream
Off-line
Condition DB
Data
Certification
Alignment and
calibration
constant
Visualisation
DQM Online
- Real time
Fraction of data
(10-15 Hz)
Full granularity
DQM Express Stream
- Within 1-2 h
Fraction of data
Full granularity
DQM Prompt Reco
- Within 48 h
Full statistics
Reduced granularity
Best alignment and
calibration constants
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

5. L. Borrello – The Data Quality Monitoring of the CMS Tracker
The CMS DQM workflow
The DQM application of all CMS sub-systems based on same workflow
DQM Producer
– books/fills histograms
DQM Consumer
– Accesses histograms from source
and performs further analysis,
including quality tests
– Write DQM output ROOT file
(accessible with GUI and stored on disk)
GUI
– Visualisation of the information
CMS GUI: common tool
Tracker GUI: optimised for Tracker
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

6. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Quality Test
Tool developed to produce automatic qualification of histograms
Comparison with reference histograms using statistical tests to detect unexpected behavior
Application of cuts to spot outliers
Different type of results:
OK Warning Error
Quality tests configured through XML files
Histogram qualification by attaching a label
with the result of the test
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

7. L. Borrello – The Data Quality Monitoring of the CMS Tracker
The CMS Tracker consists of:
15148 micro-strip detector modules  ~10 million channels
1440 pixel detector modules  ~67 million channels
Tracker DQM requirements
Check single module
operation
Check global performance
(track reconstruction)
High granularity results in a large number of histograms produced: ~300k
- Need of specific tool to identify and debug problems
Common tools for Pixel and Strip
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

8. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Tracker DQM
Tracker DQM Producers book and fill histograms with information from different levels
of reconstruction
Raw data: readout and unpacking errors
Local reconstruction: Digi, Cluster, on/off track Clusters
Global reconstruction: Track parameters (h, j, pT, … )
Alignment: Residuals of hits
The Tracker DQM Consumer use information from single module to
- Create summary histograms
- Perform Quality Test
- Produce global DQM flags
Histograms are arranged in tree like folder structure (mirroring the geometrical layout)
Full Detector
layers/disks....
Detector modules
Any problem identified from summary information can be investigated at module level
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

9. Graphical User Interface (GUI)
The Graphical User Interfaces used in DQM are web based
- Easily accessible from everywhere  no software installation is needed
Asynchronous Javascript and XML (Ajax) is used
More responsive  asynchronous communication minimizes dead time in browser
Native “desktop-like” look and feel
CMS GUI
– Widely used to visualize DQM
histograms for both Online and Offline
– Very robust
Capable of handing all
histograms in ~100 ms
– Used also for file archival
Tracker Expert GUI
– Developed for Tracker experts and shifters
– Used only during data taking (Online)
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

10. L. Borrello – The Data Quality Monitoring of the CMS Tracker
CMS GUI: Summary Page
Report from each sub-system
2D map with Quality Test results
Quality Alarm: %, 85-95%, < 85%
elements in a subsystem
PIXEL
STRIP
TRACKING
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

11. CMS GUI: Sub-detector Layout
Layouts for sub-detector shifters/experts
Histogram Image Size
Flexible options
Short description and Link to Documentation Page
Histogram failed in Qtest with red border and comment
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

12. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Tracker Expert GUI
Tracker Expert GUI
- Attached to the DQM client and can interact with it
Complementary to the CMS GUI
- allows for efficient debugging: easy switch between global overview plots and
detailed histogram
 Spot a problem on overview plots
 Navigate through detector
 Plot single module distributions on demand using easy click buttons
Main feature is one page overview in form of
TrackerMap (synoptic view of the full detector)
Summary histograms (monitor one variable for all modules simultaneously)
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

13. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Tracker Expert GUI
STRIP
Button to interact with client
PIXEL
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

14. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Tracker Map: Strip
Synoptic view of the Strip detector
TrackerMap interactive  SVG (Scalable Vector Graphic) format
Different Views:
Geometric and Read-out
Mouse hover enables
detailed description
Zoom to a layer
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

15. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Historic DQM
Extract summary information from DQM root files & store them in the offline DB
• Extract quantities from DB to create trends
• Visualization of trends: automatically available in a web page
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

16. Historic DQM: few examples
STRIP
MPV of StoN for
On-Track clusters vs Run number
PEAK
Strip sub-detectors
DECO
New calib constant
PIXEL
Mean raw charge
in Barrel vs Run number
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

17. Data Certification in CMS
Manual data certification
based on DQM shifters evaluation of results from Online and Offline DQM
Automated data certification
Done in DQM application (Online and Offline) and based on DQM, power supply and DAQ information
Apply defined cuts to some histograms
An algorithm is combining results to define an overall flag (good or bad) for each subsystem (STRIP and PIXEL)
Results of this process are stored in DQM root files and accessible through the DQM GUI
Final review of flags done by sub-system experts (Sign-off)
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

18. Data Certification: Tracker
Run Registry:
Database to store information
and manage the creation of
certification results
DBS:
Dataset Bookkeeping System
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

19. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Certification: Strip
Combine the module and layer level results per sub-system
Module level certification
- FED errors
- #Digis
- #Clusters
Layer level certification
- S/N of each layer
(per sub-system
TIB/TOB/TID/TEC)
Global performance
Performance in terms of sub-detector
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

20. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Certification: Pixel
Check the fraction of all Barrel or Endcap modules which pass certain cuts based on:
- Any FED errors
- #Digis
- Digi charge (raw charge in ADC)
- Cluster size, #Clusters, cluster
charge (OnTrack and OffTrack)
- Mean and RMS for X and Y residuals
- RecHit errors in X and Y
All information is then combined to define the final flag (good/bad)
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

21. Certification: Tracking
Tracking certification based on
Track Rate, # of Reconstructed Hits per track, Chi2 per degrees of freedom
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

22. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Performance
DQM tool extensively used during cosmic data taking in CMS
DQM system was stressed and tested deeply
It operated stably even for runs lasted more than h on line, and always stable in the offline processing
About 480M events processed and used to
monitor performance
data certification
Resources usage
Online, with full granularity, together with the reconstruction ~2GB of RAM
Offline, with a reduced granularity in order to share resources with the other processes, ~0.5 GB of RAM
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

23. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Summary
Tracker DQM successfully working in common CMS framework
Sub-system specific tool: Tracker Expert GUI available to improve identification and debugging of problems
Proved functionality and reliability in cosmic data taking: both in online and offline processing
DQM is ready for proton-proton collision
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

24. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Back-up slide
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

25. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Ajax model
Asynchronous communication minimizes dead time in browser
Only modified parts of browser updated
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

26. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Traditional Web Model
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

27. L. Borrello – The Data Quality Monitoring of the CMS Tracker
Tracker Expert GUI
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

28. Strip Expert GUI: Alarm View
Layer Selection
Get AlarmTree
Follow Alarm structure to find Faulty Modules and plot histograms
Qtest Result
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker

29. Strip Expert GUI: Module View
Layer Selection
Get Module list
List of Modules
Select One or Multiple histograms
Draw Selected Histograms
7 October 2009 – ICATTP09
L. Borrello – The Data Quality Monitoring of the CMS Tracker