cpairPath.f

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      subroutine cpairpath(Eg, path)
!        pair below LPM region
      implicit none
#include "ZbpCnst.h"
!      entry  cPrSampP(Eg, prob, path)


      real*8 Eg            ! input. Gamma energy in GeV

      real*8 path          ! output. sampled path in r%l

      real*8 prob          ! output. pair prob. per r%l
      real*8 u


      if( eg .lt. prscre ) then
!          partial screeinig region
         call cprlsampp( eg,  prob)
      elseif(eg .lt. pairegmaxl) then
!            complete screeing region
         call cprcsampp( eg, prob)

      else
!            LPM region
!         call cPrHSampP( Eg, prob); this cannot be used due to rho change
!      branch to LPM routine is at outside.  See cbremsPath for more 
!      detail 

!          use  complete screeing
         call cprcsampp( eg, prob)
      endif
      call rndc(u)
      path = -log(u)/prob
      end
!     *********************************** 
      subroutine cpairenergy( Eg, Ee)
      implicit none
#include "ZbpCnst.h"

      real*8 Eg            ! input. gamma energy in GeV
      real*8 Ee            ! output. sampled Ee in GeV. higher energy of pair


      if(eg .le. pairnonsc + 2.d-3) then
!          table in cPrLSampE is  used >  PairNonSc + 2 MeV
!          because of a glitch  around PairNonSc
!         (for Nelson's case, there is no glitch; glitch
!          comes from diff.  of dsigma/dx at x~xmax.
!
         call cprtsampe(eg, ee)  

      elseif(eg .le. prscre) then
!           partial screeinig region
         call cprlsampe(eg,  ee)

      elseif(eg .le. pairegmaxl) then
!            complete screeing region
         call cprcsampe( eg, ee)

      else
!            LPM region; same as path routine; should not come
!         call cPrHSampE( Eg, Ee)
!
        call cprcsampe( eg, ee)
      endif
      end