Data Acquisition Software for CMS HCAL Testbeams

1
Data Acquisition Software for CMS HCAL Testbeams

• Jeremiah Mans
• Princeton University
• CHEP2003 San Diego, CA

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Quick Review of the CMS HCAL

• Sampling calorimeter using brass absorber and
  plastic scintillator panels
• Light is collected using wavelength-shifting
  fibers and carried to a hybrid photodiode.
• Segmentation
• 4 5 phi slices/wedge
• 18 eta slices/wedge
• 17 depth layers
• added optically do not count towards channel
  count
• Readout
• QIE digitization at 40 MHz (33 MHz for 2002 test
  beam)
• Optical link to HCAL Trigger/Readout (HTR)
• HTR sends 20 time slices/channel to Data
  Concentrator (DCC) on L1Accept.

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HCAL Readout Chain
CCA
Hybrid Photodiode
QIE
QIE
QIE
Front End (on detector) Readout crates (in
blockhouse)
Trigger
HCAL Trigger Readout (HTR) 8/16 inputs 24/48
channels
Data Concentrator (DCC) 18 inputs Up to 432
channels
S-LINK
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Subdetectors

• Wire chambers for particle position detection
  (TDC)
• Trigger scintillators between wire chambers (TDC)
• 7x7 crystal ECAL mockup (QDC)
• HCAL wedge (HCAL DAQ chain)
• Muon identification scintillator

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Testbeam Area
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DAQ Hardware

• HCAL is read out using SLINK-32 from the DCC into
  DMA memory on a Linux PC.
• All other subdetectors are read out over VME,
  using SBS VME ? PCI fiber bridge.
• Second SBS link used for HCAL crate
  configuration.
• Linux PC is a dual processor 1.2 GHz Pentium III
  in a custom rackmount case.
• Windows PC used for DCS and configuration/communic
  ation with front-end electronics. (DIM interface
  to DAQ PC)

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2002 Testbeam Software

• Modular design
• Each module is a separate pthread thread.
• Inter-Module Communication
• Broadcast commands of fixed meaning
• INIT, RUN, STOP, LOAD, READOUT, etc
• Exported module parameters
• Module can make variables available for other
  modules to read or modify.
• Each subdetector has its own readout module,
  which produces one or more data blocks, which are
  sent an EventBuilder module.

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Data Storage

• The EventBuilder distributes the completed events
  to various consumers, including the Writer.
• The Writer formats and stores events in ROOT
  files.
• Other consumers are responsible for monitoring
  the data
• Runs Database
• XML database of basic run parameters (streams
  configured, events taken, table position, etc)
• Published in searchable form on the web

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Run Control via Java GUI

• Connects to DAQ through IP port
• a crash in the GUI doesnt bring down the DAQ
• Capabilities
• Send broadcast messages
• Access/change the values of all exported
  parameters

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Data quality monitoring

• Within the DAQ, various plots are prepared using
  the data stream and made available over an IP
  port.
• The GUI contains a separate window for data
  quality monitoring.

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2002 Testbeam Performance

• 7/1/02 9/20/02
• Runs 3302 SPS Spills
  54,849
• Events 105,380,936
• Average DAQ rate 350 Hz (peak 960 Hz)
• Beam data event size 6kB
• Total data stored in CASTOR 291 GB (compressed)

Run 3328 ECALHCAL 100 GeV ? Multiple hits in
one 600 ns time slice
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Testbeam Resolution
Pions (MIP in ECAL)
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2003 Testbeam Changes

• In 2002, the final HCAL electronics was used only
  to read out the barrel and outer parts of the
  detector. In 2003, the final electronics will be
  used for the barrel (HB), endcap (HE), and
  forward (HF) calorimeters.
• HBHE one partition
• HF one partition
• Additionally, the 2003 HCAL Testbeam DAQ will be
  built using the xDAQ toolkit provided by the
  central CMS DAQ group.
• See other talks in this session for full details
  on xDAQ

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Configuration/Firmware Databases

• The 2003 HCAL testbeam DAQ will be set up using
  configuration information stored in an XML
  database. This database will contain hardware
  configuration values, trigger setup information,
  and firmware version information.
• The mapping between firmware revisions and actual
  firmware files will be handled by a separate
  database.
• These databases will accessed with xDAQ using a
  modified version of the standard dstore module
  which supports simple SQL-style queries.

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Additional improvements/Extensions

• Examine-type monitoring
• Allow sampling of event data through an IP port
• Online access to partial data sample in a ROOT
  session easier development of data quality
  monitoring scripts

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Goals for 2003

• HB/HE
• Large scale testing of HB/HE DAQ electronics
• Testing of phase-dependent information
• Investigating mysteries from the 2002 data
• HF
• Complete calibration of 18 wedges
• 1000 electrons for each EM fiber
• Sustained average rate of 3kHz
• Overall get hardware (and software) to as near a
  final form as possible.