Compute cross-section and energy loss tables

GPHYSI is the steering routine to compute the cross-section and energy loss tables for all materials used as tracking media. GPHYSI builds and fills the JMATE data structure described in [CONS199]. Here, we give the flow chart of this process. The description of the specialised routines can be found in the rest of the section PHYS.

Note: if several tracking media are using the same material (for instance a calorimeter and a chamber support can be both in steel) the energy cuts must be the same. If this is not possible, the user must define materials with different numbers.

 
GPHYSI     		 		 		 		 Initialisation of physics
processes. This routine should be called by the user before the tracking
starts, but after all the material,  mechanism flags and energy
cuts have been defined. GPHYSI should also be called whenever
a new initialisation data structure is read from disk.

 		  GRNDMQ   		 		 		 
Initialises the value of the
seeds of the random number generator. See  [BASE420] for more 
information

 		  GEVKEV   		 		 		 
Routine to format energy
values for printout. See  [BASE410] for more details.

 		  GPHINI   		 		 		 
Initialisation of the
constants for photoelectric effect (see  [PHYS230]).

 Loop on tracking media

 		  GPHXSI   		 		 		 Initialisation of the cross
section coefficients for the photoelectric effect in a tracking medium, see
 [PHYS230].

 		  GPROBI   		 		 		 Initialisation
of constants for various physical effects.

 		 		  GMOLI    		 		 Initialises constants for
Molière scattering, see  [PHYS325].

 Loop on energy bins

 		  GDRELA   		 		 		 Initialises the ionisation
energy loss tables
$dE/dx$
 for protons, $\mu$
 and , , see  [PHYS430].

 		 		  GDRELP   		 		 Calculates ionisation
energy loss for protons, see  [PHYS430].

 		 		  GDRELM   		 		 Calculates ionisation
energy loss for $\mu$
, see  [PHYS430].

 		 		  GDRELE   		 		 Calculates ionisation
energy loss for /, see  [PHYS330].

 		  GBRELA   		 		 		 Adds the contribution of
bremsstrahlung to continuous energy loss tables for protons, $\mu$

and /, see  [PHYS440].

 		  GPRELA   		 		 		 Adds the contribution
of direct pair production and $\mu$
-nucleus interactions to the
$\mu$
 continuous energy loss tables, see  [PHYS450].

 		  GPHOTI   		 		 		 Calculates the
cross section for photoelectric effect, see  [PHYS230].

 		  GRAYLI   		 		 		 Initialises the tables
of cross sections for the Rayleigh effect, see  [PHYS250].

 		  GANNII   		 		 		 Initialises the cross 
section for positron annihilation, see  [PHYS350].

 		  GCOMPI   		 		 		 Initialises the cross section 
tables for Compton effect, see  [PHYS220].

 		  GBRSGA   		 		 		 Initialises the cross
section tables for discrete bremsstrahlung of / and
$\mu$
, see  [PHYS340],  [PHYS440].

 		  GPRSGA   		 		 		 Initialises cross
section tables for pair production by photons and direct
pair production by muons, see  [PHYS210],  [PHYS450].

 		  GDRSGA   		 		 		 Initialises the
cross section tables for delta rays production by $\mu$
 and
electrons, see  [PHYS330],  [PHYS430].

 		  GMUNUI   		 		 		 Initialises the cross section
tables for $\mu$
-nucleus interactions, see  [PHYS460].

 		  GPFISI   		 		 		 Initialises the cross section
tables for photo-fission and photo-absorption, see  [PHYS240].

 End of loop on energy bins

 		  GRANGI   		 		 		 Calculates the stopping
range integrating the $dE/dx$
 tables, see  [PHYS010].

 		  GCOEFF   		 		 		 Calculation of the coefficients
of the interpolating parabolas for the range tables, see  [PHYS010].

 		  GSTINI   		 		 		 Initialisation of the
energy loss tables for the thin layers, see  [PHYS334].

 		 		  GFCNRM   		 		 Calculation of
mean ionisation potentials and normalisation factors for
oscillator functions.

 		 		  GSREE0   		 		 Calculation of the real
part of the refractive index.

 		 		  GSDNDX   		 		 Calculation of number of
collisions for a given value of $\beta$
.

 		  GMULOF   		 		 		 Calculation of the
 STMIN tables, see  [PHYS325].

 		 		  GMOLIO   		 		 Calculation of the
constants of Molière scattering to estimate the step limitation
due to multiple scattering simulation, see  [PHYS325].

 End of loop on tracking media

1. The $\mu$ -nucleus interactions are treated either as a continuous energy loss by the muon ( IMUNU=0) or as a discrete process ( IMUNU$\ge$ 1), in an exclusive way i.e.:
   • If IMUNU=0, the $dE/dx$ due to the interactions is added to that coming from direct ($e+/e-$ ) pair production in the routine GPRELA.
   • If IMUNU$\ge 1$ , the total cross section is computed in GMUNUI.
2. The total cross sections for hadronic interactions cannot be tabulated at initialisation time, as they are dependent on the nature of the incident particle. They are computed at tracking time by the function FLDIST in case of FLUKA [PHYS520], GHESIG in case of GHEISHA [PHYS510] or FMDIST in case of MICAP [PHYS530].

PHYS210