FLUKA: PHOTONUC
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PHOTONUC
activates gamma, electron and positron interactions with nuclei
See also LAM-BIAS, MUPHOTON
For all SDUM
's except ELECTNUC/MUMUPAIR/MUMUPRIM:
WHAT(1)
: flag to switch on nuclear interactions of photons:
=< -1.0 : resets to default (no photonuclear interactions)
= 0.0 : ignored
= 1.0 : photonuclear interactions are activated at all
energies
= 2.0 : photonuclear interactions are activated only in
the high energy range (above 0.7 GeV)
= 3.0 : photonuclear interactions are activated only in
the energy region of the Delta resonance
= 4.0 : only quasi-deuteron interactions are activated
= 5.0 : only Giant Dipole Resonance interactions are
activated
>= 10.0 : interpreted as ih + id * 10 + iq * 100 + ig * 1000
where ih = 1 to activate High-energy interactions
id = 1 to activate Delta Resonance
iq = 1 to activate Quasi-deuteron
ig = 1 to activate Giant Dipole Resonance
and each is = 0.0 otherwise
Default
= 0.0 (no photonuclear interaction)
WHAT(2)
, WHAT(3)
: not used
WHAT(4)
= lower index bound (or corresponding name) of materials where the
indicated photonuclear interactions are activated
("From material WHAT(4)
..."
Default
= 3.0
WHAT(5)
= upper index bound of materials (or corresponding name) where the
indicated photonuclear interactions are activated
("...To material WHAT(5)
..."
Default
= WHAT(4)
WHAT(6)
= step length in assigning indices ("...in steps of
WHAT(6)
").
Default
= 1.0.
For SDUM
= ELECTNUC:
WHAT(1)
: flag to switch on electronuclear interactions:
<= -1.0 : resets to default (no electronuclear interactions)
= 0.0 : ignored
= 1.0 : electronuclear interactions are activated at all
energies
= 2.0 : electronuclear interactions are activated only in
the high energy range (above 0.7 GeV)
= 3.0 : electronuclear interactions are activated only in
the energy region of the Delta resonance
= 4.0 : electronuclear interactions are activated only in the
Quasi-deuteron energy region
= 5.0 : electronuclear interactions are activated only in the
Giant Dipole Resonance energy region
>= 10.0 : interpreted as = ih + id * 10 + iq * 100 + ig * 1000
where ih = 1 to activate High-energy interactions
id = 1 to activate Delta Resonance
iq = 1 to activate Quasi-deuteron
ig = 1 to activate Giant Dipole Resonance
and each is = 0.0 otherwise
WHAT(2)
, WHAT(3)
: not used
WHAT(4)
= lower index bound (or corresponding name) of materials where the
indicated electronuclear interactions are activated
("From material WHAT(4)
..."
Default
= 3.0
WHAT(5)
= upper index bound (or corresponding name) of materials where the
indicated electronuclear interactions are activated
("...To material WHAT(5)
..."
Default
= WHAT(4)
WHAT(6)
= step length in assigning indices ("...in steps of
WHAT(6)
").
Default
= 1.0
SDUM
= ELECTNUC
For SDUM
= MUMUPAIR/MUMUPRIM:
WHAT(1)
: flag to switch on muon pair production by photons:
= -1: resets to default (no muon pair production)
= 0: ignored
> 0: interpreted as ich + iqe * 10 + iin * 100 + ids * 1000
where ich = 1 to activate muon pair coherent production
iqe = 1 to activate muon pair incoherent quasielastic production
iin = 1 to activate muon pair incoherent inelastic production
ids = 1 to activate muon pair deep inelastic production
and each is = 0.0 otherwise
Default
: no muon pair production by photons
WHAT(2)
= interaction length biasing factor
= 0: ignored
0 < |WHAT(2)
| < 1: the interaction length of the photon is reduced
by a factor |WHAT(2)
|
1 =< |WHAT (2)|: a possible previous biasing factor is reset to the
default value (no biasing)
0< WHAT(2)
< 1: the primary particle always survives with reduced
weight
-1 < WHAT(2)
< 0: Russian Roulette is played to decide if the
primary particle will be killed, or survive with its original
weight
Default
: no biasing
WHAT(3)
: not used
WHAT(4)
= lower index bound of materials (or corresponding name) where the
indicated photomuon production mechanisms are activated
("From material WHAT(4)
..."
Default
= 3.0
WHAT(5)
= upper index bound of materials (or corresponding name) where the
indicated photomuon production mechanisms are activated
("...To material WHAT(5)
..."
Default
= WHAT(4)
WHAT(6)
= step length in assigning indices ("...in steps of
WHAT(6)
").
Default
= 1.0.
SDUM
= MUMUPAIR: photomuon production biasing applied to all photons
MUMUPRIM: photomuon production biasing applied to primaries only
Default
(option PHOTONUC not given): photon or electron interactions with nuclei as
well as photomuon production are not simulated
Notes:
1) Muon photonuclear interactions (via virtual photons) are not handled
by PHOTONUC but by MUPHOTON.
2) Because photonuclear and electronuclear cross sections are much
smaller than photon cross sections for electromagnetic interactions
with atoms and electrons, analogue simulations of photonuclear and
electronuclear interactions are very inefficient.
Generally, it is recommended to use PHOTONUC in combination
with LAM-BIAS to increase artificially the frequency of
photonuclear and electronuclear interactions. See the Notes 9) and
10) to option LAM-BIAS for more details.
3) Also photomuon production cross sections are much smaller than
photon cross sections for electromagnetic interactions with atoms
and electrons, as discussed in Note 2). But in this case, the
artificial increase of interactions can be performed directly with
the PHOTONUC command (see WHAT(2)
with SDUM
= MUMUPAIR or MUMUPRIM)
Example 1:
PHOTONUC 1100.0 0.0 0.0 18.0 0.0 0.0
LAM-BIAS 0.0 0.02 18.0 7.0 0.0 0.0
Example 2:
PHOTONUC 1.0 0.0 0.0 3.0 15.0 4.0
LAM-BIAS 0.0 0.025 0.0 7.0 0.0 0.0
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