subroutine get_tracker_acceptance(tvox)
  use precision_def
  use sim_utils
  implicit none
  type tracker_voxel
     real(rp) pVtx
     integer nGen, nVtx
  end type tracker_voxel
  type (tracker_voxel)  tvox(0:180,0:18,0:18)
  character*50 voxel_file,voxel_f(3)
  character*600 long_string
  real(rp) pVtx, value
  real(rp) x,y,z
  integer nGen, nVtx
  logical itexists
  logical first/.true./
  integer  lun
  integer i
  integer ix, ixx,iy,iz,number
  lun=lunget()
  voxel_f(1) = 'TrackerVoxel.txt'
  voxel_f(2) = 'TrackerVoxel_truth.txt'
  voxel_f(3) = 'TrackerVoxel_truthQuality.txt'
  print '(2(a,a3,3x),a3,3x,a,a5,3x,$)', trim(voxel_f(1)),'(1)',trim(voxel_f(2)),'(2)', 'or',trim(voxel_f(3)),'(3)  '
  read(5, *)number
  voxel_file = voxel_f(number)
  print '(a,a)','file = ',trim(voxel_file)
  inquire (file=voxel_file, exist = itexists)
  if(.not. itexists)then
     print *, voxel_file, ' does not exist'
     return
  endif
  open(lun,file=voxel_file)
    do while(.true.)
    read(lun,'(a)',end=99)long_string
    if(long_string(1:3) == '   ' .or. index(long_string,'distance')/= 0)cycle
    
      i=0
      ix=0
      do while(i<12)
         call string_trim(long_string(ix+1:), long_string, ix)
         i=i+1
         if(index(long_string(1:ix),':')/= 0)cycle
         read(long_string(1:ix),*)value
         if(i == 2)then
            z = value
         elseif(i == 4)then
            x=value
         elseif(i == 6)then
            y = value
         elseif(i == 8)then
            nGen=value
         elseif(i == 10)then
            nVtx = value
         elseif  (i == 12)then
            pVtx = value
         endif
      end do
      iz=(z-1700)/10
      ixx = (x+42.5)/5
      iy= (y+42.5)/5
      tvox(iz,ixx,iy)%nGen=nGen
      tvox(iz,ixx,iy)%nVtx=nVtx
      tvox(iz,ixx,iy)%pVtx= pVtx
      
   end do

99 continue
    return
  end subroutine get_tracker_acceptance