documentation

FTPC PadMonitor Project

Welcome! You have found the webpage dedicated to providing information and documentation on the FTPC PadMonitor. The FTPCs (Forward Time Projection Chamber) are a key sub-system of the STAR Experiment at RHIC. The PadMonitor is a software program designed to allow for monitoring of FTPC performance. The program can be separated into two basic parts: the GUI (Graphical User Interface) and the data I/O interface. The GUI has been designed using Java with the data I/O interface provided by the Java Native Interface to C and C++ code. This choice of languages reflects the desire to marry cross-platform transportability with legacy code already written for STAR DAQ data. In addition, we hope to be able to run the PadMonitor as a Servlet or Javascript from the Web, allowing collaborators access to view detector performance or issue trigger commands from a distance.

The following pages provide code, a description of the code and its development, and links to useful sites, as well as information about the STAR data acquisition and the FTPC prospective raw data format.

Raw Data Format This page provides background on the STAR DAQ Raw Data Format and the proposed FTPC version of the DAQ RDF.

FTPC PadMonitor Code Information includes a Java Class Library description, links to STAR DAQ Documentation and an explanation of Herb Ward's "Mock Data" writer code.

Source Code The most recent updates of the code can be found here. Please note that DAQ Format Reader code may be modified and older than what is available from the STAR CVS Repository.

Current Status/Immediate Future Informational page; also contains screenshots of the current program.

Links Various resources for this project as well as links to STAR information may be found here.

Raw Data Format

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)

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.