The UCD
Nuclear Physics Group
FTPC Raw Data Format

Physics Department, University of California, One Shields Avenue, Davis, CA 95616

STAR DAQ Links

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)