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Subroutines

CALL GBRELA GBRELA fills the tables for the energy loss of electrons, positrons and muons due to bremsstrahlung at initialisation time for different materials. The energy binning is set within the array ELOW (common /CGMULO/) in the routine GPHYSI. In the tables, the dE/dx due to bremsstrahlung is summed with that due to the ionisation. For energy loss of electrons and positrons, GBRELA calls the function GBRELE. Following pointers are used:

JMA = LQ(JMATE-I): pointer to the $I$ ^th material;
JEL1 = LQ(JMA-1): pointer to $dE/dx$ for $e$ ^- ;
JEL1+NEK1: pointer to $dE/dx$ for $e$ ⁺ .

GBRELA is called at initialisation time by GPHYSI. GBRELEVALUE = GBRELE(ZZ,T,BCUT) GBRELE calculates the energy loss due to bremsstrahlung of an electron with kinetic energy T in material with atomic number ZZ. It is called by GBRELA and for energies below the cut BCUT it adds the contribution of bremsstrahlung to. Above this cut, the bremsstrahlung process is simulated explicitly (see [PHYS341]) and tabulation of these continuous losses is not needed. GBRELE is called by GBRELA. GBFLOSVALUE = GBFLOS(T,C) GBFLOS calculates a weight factor for the positron continuous bremsstrahlung energy loss. T is the kinetic energy in GeV of the positron and C is the energy cut for bremsstrahlung ( BCUTE). The value is the ratio of the energy loss due to bremsstrahlung of the positron to that of the electron so that: < positron loss> = GBFLOS

x

< electron loss>. GBFLOS is called by GBRELA. CALL GBRSGA GBRSGA calculates the total cross-section for bremsstrahlung in all materials. It tabulates the mean free path,

λ= {1 Σ}

(in cm) as a function of medium and energy. The energy binning is set within the array ELOW (common /CGMULO/) in the routine GPHYSI. The following pointers are used:

JMA = LQ(JMATE-I): pointer to the $I$ ^th material
JBREM = LQ(JMA-9): pointer to bremsstrahlung cross-sections
JBREM: pointer for $e$ ^-
JBREM+NEK1: pointer for $e$ ⁺
JBREM+2*NEK1: pointer for $μ$ ⁺/μ^-

GBRSGA is called at initialisation time by GPHYSI. GBRSGEVALUE = GBRSGE(ZZ,T,BCUT) GBRSGE calculates the total cross-section of bremsstrahlung of an electron with kinetic energy T in material with atomic number ZZ. It is called by GBRSGA. For kinetic energies which are below the cut BCUT or for which bremsstrahlung process is not simulated explicitly (see [PHYS341]) it returns 0. GBFSIGVALUE = GBFSIG(T,C) GBFSIG calculates a weight factor for the positron discrete (hard) bremsstrahlung cross section. T is the kinetic energy in GeV of the positron and C is the energy cut for bremsstrahlung ( BCUTE). The value returned is the ratio of the positron bremsstrahlung cross-section to that of the electron so that: < positron cross-section> = GBFSIG

x

< electron cross-section>. GBFSIG is called by GBRSGA.

Next: Method Up: PHYS340 Total cross-section Previous: PHYS340 Total cross-section

Janne Saarela
Mon Apr 3 12:46:29 METDST 1995