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

Data Quality Monitoring Data Quality Monitoring of the CMS Tracker of the CMS Tracker

Laura BorrelloScuola Normale Superiore and INFN Pisa, Italy

on behalf of the CMS Tracker collaboration

7 October 2009 – ICATTP09

L. Borrello – The Data Quality Monitoring of the CMS Tracker

OutlineOutline

• DQM architecture in CMS• Tracker DQM• Graphical User Interface

• CMS GUI• Tracker GUI

• Historic DQM: long term monitoring• Data Certification• Summary



IntroductionIntroductionThe 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



DQM overviewDQM overview

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 andcalibration constants

DATA

Online DQM

On-line Off-line

Express Stream

Prompt reconstruction

Off-line Condition DB

Alignment andcalibration constant

Visualisation

Data Certification



The CMS DQM workflowThe 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 informationCMS GUI: common toolTracker GUI: optimised for Tracker



Quality TestQuality 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



The CMS Tracker consists of: 15148 micro-strip detector modules ~10 million channels 1440 pixel detector modules ~67 million channels

The CMS TrackerThe CMS Tracker

Tracker DQM requirements- Check single moduleoperation- 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



Tracker DQMTracker DQMTracker 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 (, , 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



Graphical User Interface (GUI)Graphical User Interface (GUI)

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)

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: Summary PageCMS GUI: Summary Page

PIXEL STRIP TRACKING

•Report from each sub-system•2D map with Quality Test results•Quality Alarm:

95-100%, 85-95%, < 85%elements in a subsystem



CMS GUI: Sub-detector Layout CMS GUI: Sub-detector Layout Layouts for sub-detector shifters/experts

Histogram failed in Qtest with red border and comment

Short description and Link to Documentation Page

Histogram Image Size

Flexible options



Tracker Expert GUITracker Expert GUITracker 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)



Tracker Expert GUITracker Expert GUI

STRIP

PIXEL

Button to interact with client



Tracker Map: StripTracker Map: Strip

Different Views:Geometric and Read-out

Zoom to a layer

Mouse hover enables detailed description

Synoptic view of the Strip detectorTrackerMap interactive SVG (Scalable Vector Graphic) format



Historic DQMHistoric 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



Historic DQM: few examplesHistoric DQM: few examples

STRIPMPV of StoN for

On-Track clusters vs Run number

PEAK

DECO

PIXELMean raw charge

in Barrel vs Run number

New calib constant

Strip sub-detectors



Data Certification in CMSData 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)



Data Certification: TrackerData Certification: Tracker

Run Registry:Database to store informationand manage the creation of certification resultsDBS:Dataset Bookkeeping System



Certification: StripCertification: StripCombine the module and layer level results per sub-systemModule 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



Certification: PixelCertification: PixelCheck 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)



Certification: TrackingCertification: TrackingTracking certification based onTrack Rate, # of Reconstructed Hits per track, Chi2 per degrees of freedom



PerformancePerformance• 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 17-18 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



SummarySummary

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



Back-up slideBack-up slide



• Asynchronous communication minimizes dead time in browser • Only modified parts of browser updated

Ajax modelAjax model



Traditional Web ModelTraditional Web Model



Tracker Expert GUITracker Expert GUI



Strip Expert GUI: Alarm ViewStrip Expert GUI: Alarm View

Layer Selection Get AlarmTree

Follow Alarm structure to find Faulty Modules and plot histograms

Qtest Result



Strip Expert GUI: Module ViewStrip Expert GUI: Module View

Layer Selection

List of Modules

Get Module list

Select One or Multiple histograms

Draw Selected Histograms

Documents

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