Raw Data Format



STAR DAQ Home Page This is the local working home page for the DAQ Group. Specific links of interest on this site include:

  • Software Documentation This page contains the Format Reader Specification for the DAQ RDF Format Reader written by M. Levine, M. Schulz and J. Landgraf as well as other DAQ documentation.
  • Raw Data Format Document describes the structure of data files written out by DAQ. Information in this document details the general pointer structure and the specific pointer structure for the main TPC. Space has been provided to include documentation from sub-system groups.


    FTPC Raw Data Format

    The FTPC data format resembles that of the main TPC in many ways. Both systems utilize the same basic readout electronics, however certain physical differences between the two detectors call for different handling. These differences are outlined here:

    Main TPC

    24 Sectors-each one handled by a single VME crate
    Each VME crate contains 6 receiver boards and one "Sector Broker" (to handle global sector characteristics and communication)
    Each receiver board contains 3 mezzanine boards which buffer the data and host the STAR Cluster Finding ASICs (pedestal subtraction,gain correction, 10bit->8bit data conversion, 2D cluster finding)

    To reconstruct a single sector's data, one must gather:
    From each of six receiver boards, the contributions from all three mezzanine boards

    24 sectors in the main TPC
    384 pads per sector
    45 padrows per sector
    Number of pads per padrow variable (due to wedge-shape of sectors)
    512 timebins per pad

    Forward TPCs

    2 Chambers-each one handled by a single VME Crate
    Each crate contains 10 receiver boards and one "Chamber Broker" (performs the same functions as the Sector Broker but for a single FTPC Chamber)
    Each receiver board handles three FTPC Sectors (30 sectors per chamber)
    Each receiver board has 3 mezzanine boards. The simplest sector->mezzanine mapping is 1:1, but may not necessarily be so. In order to be general, the pointer structure is set up such that from the receiver board, one points to a sector and from the sector one points to the mezzanine board.

    To reconstruct a single sector's data, one must gather:
    From one receiver board, the sector via contribution from one mezzanine board

    2 chambers in the FTPC sub-system
    30 sectors per chamber
    320 pads per sector
    2 padrows per sector
    160 pads per padrow
    512 timebins per pad

    Ideally, one would like to hide this heirarchy behind a simpler user interface. This has been done by making the FTPC Format Reader very similar to the main TPC. Users request data from a specific sector, numbered 1 to 60 (1-30 for West FTPC, 31-60 for East FTPC). The user numbering scheme follows the FTPC Cabling design drawings. The mapping to correct receiver board and mezzanine contributions for a given sector is provided by a header file included with the Format Reader.

    FTPC Raw Data Format Document (postscript)

    DAQ/Data Schematics

    View some schematic pictures of the DAQ design and the current Raw Data Format:

  • Schematic of DAQ Design
  • Schematic of Data Format

  • The following is a diagramatical sketch of the information path explained in the DAQ Raw Data Format Document.

  • STAR Data Model...1
  • STAR Data Model...2
  • STAR Data Model...3
  • STAR Data Model...4
  • STAR Data Model...5
  • STAR Data Model...6