GEANT -- H2GEANTPHYS100

Steering routine for Cross-section and Energy loss calculation

+-------------+ +----------## | Geant 3.10 | GEANT User's Guide | PHYS100 ## +-------------+ +----------##

Author(s) : R. Brun Submitted: 30.05.86 Origin : same Revised:

                    +--------------------------------+
                    |CALL GPHYSI  |
                    +--------------------------------+

The routine GPHYSI is called at initialisation time from a user routine like UGINIT (see example in BASE 100). The purpose of GPHYSI is twofold:

print the parameters which will define the current run
compute the cross-section and energy loss tables and fill the JMATE data structure [CONS-199].

Print the run definitions

Get from the JRUNG data structure [BASE-299] the GEANT version number and the ZEBRA version number.

Get from the JTMED data structure the tracking and physics parameters which will be valid for the current run. See the description of the JTMED data structure in [CONS-210] and [CONS-299].

A summary table like below will be output by GPHYSI

  **********************************************************
 *                                                          *
 *    G E A N T  Version 3.1061      DATE/TIME 860521/1208  *
 *                                                          *
 *                      R U N      1                        *
 *                                                          *
 ************************************************************
 *                                                          *
 *      Data structure   Date   Time    GVERSN    ZVERSN    *
 *      --------------   ----   ----    ------    ------    *
 *                                                          *
 *           INIT       860521  1208    3.1061     3.41     *
 *                                                          *
 *           KINE       860521  1208    3.1061     3.41     *
 *                                                          *
 *           HITS       860521  1208    3.1061     3.41     *
 *                                                          *
 *           DIGI       860521  1208    3.1061     3.41     *
 *                                                          *
 *----------------------------------------------------------*
 *                                                          *
 *              Standard TPAR for this run are              *
 *              ------------------------------              *
 *                                                          *
 *  CUTGAM=500.00 KEV  CUTELE=500.00 KEV  CUTHAD=  1.00 MEV *
 *  CUTNEU=  1.00 MEV  CUTMUO=  1.00 MEV                    *
 *  BCUTE =500.00 KEV  BCUTM =500.00 KEV                    *
 *  DCUTE = 10.00 TEV  DCUTM = 10.00 TEV  PPCUTM= 10.00 MEV *
 *  IPAIR =        1.  ICOMP =        1.  IPHOT =        1. *
 *  IPFIS =        0.  IDRAY =        0.  IANNI =        1. *
 *  IBREM =        1.  IHADR =        2.  IMUNU =        0. *
 *  IDCAY =        1.  ILOSS =        2.  IMULS =        1. *
 *                                                          *
 *     Special TPAR for TMED   2   LIQ NE213                *
 *     -------------------------                            *
 *  CUTGAM= 50.00 KEV  CUTELE= 50.00 KEV  CUTHAD=  1.00 MEV *
 *  CUTNEU=  1.00 MEV  CUTMUO=  1.00 MEV                    *
 *  BCUTE = 50.00 KEV  BCUTM = 50.00 KEV                    *
 *  DCUTE = 10.00 TEV  DCUTM = 10.00 MEV  PPCUTM= 10.00 MEV *
 *  IPAIR =        1.  ICOMP =        1.  IPHOT =        1. *
 *  IPFIS =        0.  IDRAY =        0.  IANNI =        1. *
 *  IBREM =        1.  IHADR =        2.  IMUNU =        0. *
 *  IDCAY =        1.  ILOSS =        2.  IMULS =        1. *
 *                                                          *
 *                                                          *
 ************************************************************

The meaning of the parameters can be found in the description of the commons: /GCCUTS/ and /GCPHYS/ [BASE-030]. It is important to understand in which ways the default values of the parameters can be overwritten (see example in BASE-100):

a set of global default values for the parameters are defined within the routine GINIT. 'Global' means: default for all tracking media.
These default values can be changed by data cards via the routine GFFGO. A summary of all valid data cards is given in [BASE-040].
After having set-up its tracking media and materials, the user can redefine again the tracking and physics parameters for each medium via the routine GSTPAR [CONS-210].
Alternately, if the data structures are read from an external file ('GET' data card) all the parameters are taken from this file.

Compute cross-section and energy loss tables

GPHYSI is the steering routine to compute the cross-section and energy loss tables for all materials effectively used as tracking media. GPHYSI builds and fills the JMATE data structure as described in CONS-199. Here, we give the flow chart of the calculations. The description of the specialized 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 cut parameters must be the same. If this is not possible, the user must define different materials.
```
PHYSI
-  GCOMPI     Total cross-section of compton collision
-  GPHOTI     Total cross-section of photo electric effect
-  GPFISI     Total cross-section of photo fission
-  GANNII      Total cross-section of $e^+$ annihilation
-  GMUNUI      Total cross-section of Muon Nuclear interaction
-  GBRELA      Energy loss due to Bremsstrahlung
     GBRELE        for electrons
     GBRELM        for muons
-  GDRELA      Energy loss due to Ionisation:
      GDRELE       for electrons
      GDRELP        for protons
 GDRSGA     Total cross-section of Delta rays production
  GPRELA    Energy loss due to ($e^+,e^-$) production:
     GPRELM    by muons
  GPRSGA     Total cross-section for ($e^+,e^-$) production:
     GPRSGG  by gamma
     GPRSGM  by muons
```
Notes:
1. The Muon Nuclear interactions are treated either as a continuous energy loss by the muon (IMUNU=0) or as a discrete process (IMUNU>=1), in an exclusive way i.e.:
  1. If IMUNU=0 , the DE/DX due to the interactions is computed together + - with that coming from direct (e ;e ) pair production in the routine GPRELA.
  2. If IMUNU>= 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 too much dependent of the nature of the projectile. They are computed at tracking time by the FUNCTIONS: FLDIST in case of FLUKA [PHYS-520] GHESIG in case of GHEISHA [PHYS-510]

Steering routine for Cross-section and Energy loss calculation

Print the run definitions

Compute cross-section and energy loss tables