DAQ and Analysis-Software

Main DABC/DAQ features concerning TRB3/TDC:

  1. Data readout from several TRBs and events building.
  2. If necessary, sort incoming UDP packets according trigger number. Enables usage of TRB3 with two Ethernet links.
  3. Store data in HLD files (including RFIO support)
  4. Deliver data for arbitrary online analysis via GSI-standard socket connection (so-called MBS stream server)
  5. Provides very simple API to access offline (HLD files) and online (MBS-like server) data
  6. Such API used in hldprint utility - powerful tool to printout HLD data, especially for TRB3/TDC setups.

Analysis code for TRB3/TDC implemented in 'stream' framework and has following features:

  1. It is pure C++ code, independent from ROOT or DABC (http://dabc.gsi.de) or Go4 (http://go4.gsi.de).
  2. Developed code very well integrated with ROOT, with DABC and with Go4.
  3. It can run offline (reading HLD files) or online (taking data directly from DAQ)
  4. It dedicated for unpacking and calibration of TRB/TDC data, means producing correct time stamps out of fine-counter values.
  5. Calibration also includes compensation of time-over-threshold (TOT) shifts, measured with internal pulser, produced with trigger type 0xD.
  6. Produced calibrated data can be stored in ROOT TTree, supporting two major formats: with absolute time stamps as double values, and with relative (to channel 0) time stamps as float values.
  7. Framework optionally provides number of histograms useful for online monitoring.
  8. If required, custom user code can be easily append to running application and access all produced data directly.

Use of analysis code with Go4 framework:

  1. Go4 is used as "run engine", providing environment for running TRB/TDC calibration code online/offline
  2. When used online, produced histograms can be monitored with few seconds delay in Go4 GUI application with standard ROOT graphics.

Use of analysis code in DABC:

  1. If configured, TDC data can be calibrated on-the-fly, including TOT-shift compensation
  2. Produce calibration data can be stored in modified HLD files. Either replacing original TDC messages (same size, but lost of raw data), or inserting additional messages with calibrated values (~25% of file size increase)
  3. Calibrated data can be stored directly in ROOT format out of DABC together with (or instead of) normal HLD files.
  4. Histograms, produced by calibration and analysis code, running in DABC, can be monitored via http protocol in normal web browser (using JavaScript ROOT interface, http://root.cern.ch/js/)
  5. Same histograms can be accessed via http channel from Go4 GUI and displayed with normal ROOT graphics.
  6. DABC also provides specialized web-interface to control DAQ and calibration process.
  7. All together - DABC can directly produce calibrated TDC data in both HLD and ROOT formats and provides all necessary tools for monitoring and control of DAQ and analysis code.

Planned features:

  1. Provide measured calibration curves for specific FPGA TDC designs. One expects about 100 ps precision (leading edge) without need of complex calibration procedures.
  2. Take into account FPGA temperature changes for such simplified setup. Hopefully one could achieve 30 ps for leading and about 60 ps for trailing edge.
  3. Use of temperature information in normal calibration procedure.