//==========================================
// Garfield V8.1 Input file for:  
//
// Vertical Drift Chamber (VDC) Simulation
// for the Qweak experiment at JLab
//
// => Generated the gas definition file
//
//=================================================================
// 
// Author: Klaus Grimm
//         Department of Physics
//         The College of William and Mary
//         Williamsburg, VA 23185 
//
//  email: grimm@jlab.org
//
//==========================================
// Last Change: 06/29/2004
//==========================================

// gas related globals
GLOBAL pbar       =  1.0           // relative gas pressure 
GLOBAL gasmbar    =  pbar*1013.25  // absolute gas pressure in MILLI-BAR
GLOBAL gastemp    =  300           // gas temperature = 300 KELVIN 


//----------------------------------------------------------------------*
//Gas composition                                                       *
//----------------------------------------------------------------------*
Global ar   90
Global coo  10

//Global gas_file `Ar-CO2_`/string(ar)/`-`/string(coo)

Global gas_file="Ar-CO2_90-10.gas"

//----------------------------------------------------------------------*
// Magnetique Field (Tesla)                                              *
//----------------------------------------------------------------------*
Global Bx 0.0
Global By 0.0
Global Bz 0.0


// Delete some result files, otherwise results from different settings/simulations
// will be saved in the same file ...   

//=============================================
& MAGNETIC
//=============================================

 // at present: no B fieed here
 // whats about the earth B field ?!
 COMPONENTS  {Bx} {By} {Bz} GAUSS

//=============================================
& GAS
//=============================================


//======================================================================

// Load or generate gas_file, which contains all
// the gas properties needed for tracking

Call inquire_file(gas_file,exist)
 
If exist Then
   get {gas_file}
 Else
   WRITE {gas_file}	

  // temp + pressure def before Heed
  TEMPERATURE {gastemp} KELVIN
  PRESSURE {gasmbar} MILLI-BAR

  // Compute for electrons: drift velocity, diffusion coefficient etc
  // time comsuming: several hours on a 2.4GHz Xeon !!!
  MAGBOLTZ ARGON {ar} CO2 {coo}

 Endif

 // (Tong put it outside if-else-endif ?!)
  // Prepares cluster generation by Heed
  Heed ARGON {ar} CO2 {coo}


//---------------------
// Open Postscript file
//---------------------
!add meta type PostScript file-name "gas_co2.ps"
!open meta
!act meta


// Plot some gas properties
plot-options drift-velocity nodiffusion notownsend
opt gas-plot nogas-print


//-------------------------------------------------------------------------*
//  Extract the tables from Magboltz.                                      *
//-------------------------------------------------------------------------*
Call get_gas_data(p,t,gasid)
Call get_E/p_table(ep)
Call drift_velocity(0,0,ep*p,drift)

//----------------------
// Close Postscript file
//----------------------
!deact meta
!close meta
!del   meta