Qweak R1 Software

Slow Control GUI

MEDM

use EPICS se set HV channels and alarms

Lab View

rotation control.

VFAT setup

The VFAT setup is done through a web interface.

GEM data processing

The GEM detector contains 6 VFAT cards which are used to digitize the charge from an ionization event. Each channel of the VFAT is associated with a charge collection strip within the GEM ionization chamber. Once triggered the VFAT card will transfer 192 bits (Defined in Figure 8 of the VFAT manual V2.0) from each VFAT card to separate I/O channels on a CAEN V1495 module.

CODA file to Tracking data structure

A ROC will transfer GEM data from a CAEN V1495 to the host DAQ computer. At the local institution there will only be one element of the Qweak tracking software. Once the ROC is writeing data to a CODA file from the V1495 we will need to write software which will take the raw data and create a data structure for tracking. The data structure for tracking, in the case of R1, will contain the distance of the elastic scattering event from the beam pipe center ([math]R[/math]) and [math]\phi[/math] representing the local polar angle in which [math]\phi=0[/math] at the center of the detector.

The SVN repository for the Qweak Analysis and tracking software is at

https://qweaksvn.jlab.org/repos/QwAnalysis/trunk/Analysis

Qweak wiki describing the software is at

https://qweak.jlab.org/wiki/index.php/Installation_and_compilation

GEM data header file is located in

QwAnalysis/ Tracking/include/QwGasElectronMultiplier.h

The above defines the processed data structure, it includes a ProcessEventBuffer function to strip data out of the raw CODA data buffer, defines the function to create a QwHit for each r and phi strip hit

Int_t ProcessConfigurationBuffer(const UInt_t roc_id, const UInt_t bank_id, UInt_t* buffer, UInt_t num_words){return 0;};  /* contains IPreamp info if needed occurs during Prestart*/

 Int_t ProcessEvBuffer(UInt_t roc_id, UInt_t bank_id, UInt_t* buffer, UInt_t num_words){return 0;};/* filters out VFAT data from CODA bank*/

 void  ProcessEvent() /* fills hit list */

QwGasElectronMultiplier->fHits

create a tracking source file in the subdirectory which contains the actual code to do the above

QwAnalysis/Tracking/src/QwGasElectronMultiplier.cc

The above *.cc file also needs a LoadMap function to read a prminput file (located in Tracking/prminput/)

an example of which is shown in

Tracking/src/QwDriftChamber.cc

Int_t QwDriftChamber::LoadChannelMap(TString mapfile){
  TString varname, varvalue;
  UInt_t  chan, package, plane, wire, direction, DIRMODE;
  DIRMODE=0;
  

  fDirectionData.resize(2);//currently we have 2  package - Rakitha (10/23/2008)
  fDirectionData.at(0).resize(12); //currently we have 12 wire planes in each package - Rakitha (10/23/2008)
  fDirectionData.at(1).resize(12); //currently we have 12 wire planes in each package - Rakitha (10/23/2008)

  QwParameterFile mapstr(mapfile.Data());  //Open the file

  while (mapstr.ReadNextLine()){
    mapstr.TrimComment('!');   // Remove everything after a '!' character.
    mapstr.TrimWhitespace();   // Get rid of leading and trailing spaces.
    if (mapstr.LineIsEmpty())  continue;

Another simpler eaxample is in

Tracking/src/QwMainDetector.cc

Int_t QwMainDetector::LoadChannelMap(TString mapfile){
  TString varname, varvalue;
  TString modtype, dettype, name;
  Int_t modnum, channum;

  QwParameterFile mapstr(mapfile.Data());  //Open the file
  while (mapstr.ReadNextLine()){
    mapstr.TrimComment('!');   // Remove everything after a '!' character.
    mapstr.TrimWhitespace();   // Get rid of leading and trailing spaces.
    if (mapstr.LineIsEmpty())  continue;

    if (mapstr.HasVariablePair("=",varname,varvalue)){
      //  This is a declaration line.  Decode it.
      varname.ToLower();
      UInt_t value = atol(varvalue.Data());
      if (varname=="roc"){
        RegisterROCNumber(value);
      } else if (varname=="bank"){
        RegisterSubbank(value);
      } else if (varname=="slot"){

References

VFAT manual

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