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PHOTONUC


     activates gamma interactions with nuclei

     See also LAM-BIAS, MUPHOTON

     For all 
SDUM
's except 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 (or corresponding name) of materials 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
= 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 (or corresponding name) of materials where the indicated photomuon production mechanisms are activated ("From material
WHAT(4)
..."
Default
= 3.0
WHAT(5)
= upper index bound (or corresponding name) of materials 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 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 cross sections are much smaller than photon cross sections for electromagnetic interactions with atoms and electrons, analogue simulations of photonuclear interactions are very inefficient. Generally, it is recommended to use PHOTONUC in combination with LAM-BIAS to increase artificially the frequency of photonuclear interactions. See the Notes 9) and 10) to option LAM-BIAS for more details. 3) High-energy photonuclear interactions are also activated by
WHAT(1)
and
WHAT(4)
in option EMF. However, this is a duplicate that eventually will be removed.
Example 1:
* Giant Resonance and Quasideuteron photonuclear interactions are requested
* in material 18. The photon hadronic interaction length is artificially
* shortened by a factor 0.02 in order to improve statistics
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
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:
* Photonuclear interactions are requested at all energies in materials
* 3, 7, 11 and 15. The photon hadronic interaction length is shortened
* by a factor 0.025
*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
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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