COSMOS v7.655  COSMOSv7655
(AirShowerMC)
Functions/Subroutines
cpairLPMXsec.f File Reference

Go to the source code of this file.

Functions/Subroutines

subroutine cpairlpmxsec (eg, rhoin, xs)
 

Function/Subroutine Documentation

◆ cpairlpmxsec()

subroutine cpairlpmxsec ( real*8  eg,
real*8  rhoin,
real*8  xs 
)

Definition at line 16 of file cpairLPMXsec.f.

References e, and e10.

Referenced by csampgintl().

16  implicit none
17 ! compute pair creation probability of very high energy
18 ! gamma rays in air. Landau effect is taken into account
19 ! eg. input. gamma energy in gev. 5.e8 < eg < 1.e13
20 ! rhoin.input. air density in kg/m**3
21 ! xs. output. probability /r.l
22 !
23 ! input outside of this range will be accepted
24 ! properly.
25 !
26 !
27  real*8 eg, rhoin, xs
28 !
29 ! Since the probability of pair creation f(v, Eg, rho)dv
30 ! (v = Ee/Eg) scales as f(v, Eg*rho)dv,
31 ! we made an approximate formula for f(v, x)dv for x
32 ! =1 to 10^10 GeV*gm/cm3
33 !
34  real*8 x, xlog
35  integer i
36  real*8 xxx(6)
37  data ( xxx(i), i= 1, 6)/
38  1 59.363582 , -19.567178 , 2.4813214 ,
39  2 -0.15128851 , 0.44302046e-02, -0.50465366e-04
40  * /
41 
42  x = eg* rhoin * 1.e-3 ! GeV g/cm3
43  if(x .lt. 1.e5) then
44  xs = 0.777
45  elseif(x .lt. 1.e10) then
46  xlog = log(x)
47  xs = 0.
48  do i =6, 2, -1
49  xs =(xs + xxx(i))* xlog
50  enddo
51  xs = xs + xxx(1)
52  xs = exp(xs)
53  else
54  xs = 2.12e-2 * (x/1.e10)**(-0.5)
55  endif
56 
e
dE dx *! Nuc Int sampling table e
Definition: cblkMuInt.h:130
i
nodes i
Definition: cstdatmos0.fNew2.h:93
xs
! constants thru Cosmos real ! if multiplied to deg radian Torad ! light velocity m sec ! infinty ! kg m2 *Togpcm2 g cm2 ! g cm2 *Tokgpm2 kg m2 ! cm *Tom m ! m *Tocm cm ! g cm3 *Tokgpm3 kg m3 ! kg m3 *Togpcm3 g cm3 ! sec *Tonsec nsec ! Tesla m ! Avogadro *A2deninv ! mfp *n * xs
Definition: Zglobalc.h:18
e10
*************************block data cblkTracking *************************implicit none data *ExactThick *Freec *RatioToE0 *MagChgDist *TimeStructure *Truncn *Truncx data *IncMuonPolari *KEminObs *ThinSampling *EthinRatio *Generate *LpmEffect *MagPairEmin e10
Definition: cblkTracking.h:9
x
! structure defining a particle at production ! Basic idea of what is to be contained in ! the particle structue is that dynamical ones should be included those derivable from the particle code ! is not included ******************************************************type fmom momentum sequence union map real e endmap map real * x
Definition: Zptcl.h:21
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