The pad monitor we use was developed by Andreas Schuettauf. It is referred to as the Munich Pad Monitor. (The FTPC pad monitor development was started by Jennifer Klay in Davis. Her documentation contains alot of useful information. Unfortunately, Jennifer left STAR before she finished the pad monitor.)
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.
STAR DAQ Home Page This is the local working home page for the DAQ Group. Specific links of interest on this site include:
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
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
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)
View some schematic pictures of the DAQ design and the current Raw Data Format:
The following is a diagramatical sketch of the information path explained in the DAQ Raw Data Format Document.
