EMFRAY¶

Summary

Activates Rayleigh (coherent) scattering, Compton binding corrections and profile function corrections, and acolinearity in annihilation at rest in selected regions. Only meaningful when the EMF option has been requested, explicitly or implicitly via option DEFAULTS.

For all SDUM values except ORTHPOSI or ORTPOSTM¶

WHAT(1) < 0.0:: no Rayleigh scattering and neither binding corrections nor Compton profile function, no acolinearity in annihilation at rest
= 0.0:: ignored
= 1.0:: both Rayleigh scattering and Compton binding corrections are activated, no Compton profile function, no acolinearity in annihilation at rest, no ortho-positronium 3 photon annihilation at rest
= 2.0:: only Rayleigh scattering is activated, naive Compton, no ortho-positronium 3 photon annihilation at rest
= 3.0:: only Compton binding corrections are activated
= 4.0:: all, Rayleigh, binding corrections, and profile function in Compton activated, no acolinearity in annihilation at rest,no ortho-positronium 3 photon annihilation at rest
= 5.0:: only Rayleigh scattering is activated, naive Compton, no acolinearity in annihilation at rest, no ortho-positronium 3 photon annihilation at rest
= 6.0:: only binding corrections and profile function in Compton are activated, no Rayleigh, no acolinearity in annihilation at rest, no ortho-positronium 3 photon annihilation at rest
=100.0:: ignored for Rayleigh and Compton, acolinearity in annihilation at rest activated, no ortho-positronium 3 photon annihilation at rest
=101.0:: both Rayleigh scattering and Compton binding corrections are activated, no Compton profile function, acolinearity in annihilation at rest activated, no ortho-positronium 3 photon annihilation at rest
=102.0:: only Rayleigh scattering and acolinearity in annihilation at rest activated, naive Compton, no ortho-positronium 3 photon annihilation at rest
=103.0:: binding corrections in Compton only and acolinearity in annihilation at rest activated, no Rayleigh, no ortho-positronium 3 photon annihilation at rest
=104.0:: all Rayleigh, binding corrections and profile function in Compton, acolinearity in annihilation at rest activated, no ortho-positronium 3 photon annihilation at rest
=105.0:: Rayleigh and acolinearity in annihilation at rest activated, naive Compton, no ortho-positronium 3 photon annihilation at rest
=106.0:: binding corrections and profile function in Compton are activated, no Rayleigh, acolinearity in annihilation at rest activated, no ortho-positronium 3 photon annihilation at rest
=1000.0:: ignored for Rayleigh, Compton, and acolinearity in annihilation at rest, ortho-positronium 3 photon annihilation at rest activated
=1001.0:: both Rayleigh and binding corrections in Compton activated, no acolinearity in annihilation at rest, ortho-positronium 3 photon annihilation at rest activated
=1002.0:: Rayleigh and ortho-positronium 3 photon annihilation at rest activated
=1003.0:: binding corrections in Compton activated, no Rayleigh, no acolinearity in annihilation at rest, ortho-positronium 3 photon annihilation at rest activated
=1004.0:: all Rayleigh, binding corrections and profile function in Compton activated, no acolinearity in annihilation at rest, ortho-positronium 3 photon annihilation at rest activated
=1005.0:: Rayleigh and ortho-positronium 3 photon annihilation at rest activated
=1006.0:: binding corrections and profile function in Compton activated, no Rayleigh, no acolinearity in annihilation at rest, ortho-positronium 3 photon annihilation at rest activated
=1100.0:: ignored for Rayleigh and Compton, acolinearity in annihilation at rest and ortho-positronium 3 photon annihilation at rest activated
=1101.0:: both Rayleigh and binding corrections in Compton activated, acolinearity in annihilation at rest activated, ortho-positronium 3 photon annihilation at rest activated
=1102.0:: Rayleigh and acolinearity in annihilation at rest activated, naive Compton, ortho-positronium 3 photon annihilation at rest activated
=1103.0:: binding corrections in Compton only and acolinearity in annihilation at rest activated, no Rayleigh, ortho- -positronium 3 photon annihilation at rest activated
=1104.0:: all Rayleigh, binding corrections and profile function function in Compton, acolinearity in annihilation at rest activated, ortho-positronium 3 photon annihilation at rest activated
=1105.0:: Rayleigh and acolinearity in annihilation at rest activated, naive Compton, ortho-positronium 3 photon annihilation at rest activated
=1106.0:: binding corrections and profile function in Compton activated, no Rayleigh, acolinearity in annihilation at rest activated, ortho-positronium 3 photon annihilation at rest activated
Default: : if option DEFAULTS is used with SDUM = CALORIMEtry, EM–CASCAde, ICARUS, HADROTHErapy, PRECISIOn or DAMAGE the default is 1104.0.

With any other value of SDUM or if option DEFAULTS is not used, the default is 3.0.
WHAT(2) =: lower bound (or corresponding name) of the region indices where Rayleigh scattering and/or Compton binding corrections and/or Compton profile function and/or acolinearity in annihilation at rest are requested.

(“From region ``WHAT(2)``…”)
Default: = 2.0
WHAT(3) =: upper bound (or corresponding name) of the region indices where Rayleigh scattering and/or Compton binding corrections and/or Compton profile function and/or acolinearity in annihilation at rest are requested.

(“…to region ``WHAT(3)``…”)
Default: = WHAT(2)
WHAT(4) =: step length in assigning indices.

(”…in steps of ``WHAT(4)`` ”)
Default: = 1.0
WHAT(5): = ratio of para- and orto-positronium annihilation at rest, meaningful only when orto-positronium 3 photon annihilation at rest is activated (def. 378)
WHAT(6): = Z0 + 1000 x Z1, where [Z0,Z1] is the interval of atomic numbers to which apply what(5)
Default: (option EMFRAY not requested): if option DEFAULTS is used with SDUM = CALORIMEtry, EM-CASCAde, ICARUS, HADROTHErapy, PRECISIOn, or DAMAGE, Rayleigh scattering, binding corrections and profile function in Compton, and acolinearity in annihilation at rest are activated.

With any other value of SDUM or if option DEFAULTS is not used, only binding corrections in Compton scattering are activated.

See also Table 7.1 at.

For SDUM = ORTHPOSI:¶

WHAT(1): < 0.0 : resets the default (1.)

= 0.0 : ignored

> 0.0 : ortho-positronium 3 photon annihilation correction factor (relative to the region one) for the n_th Fluka medium
WHAT(2): < 0.0 : resets the default (1.)

= 0.0 : ignored

> 0.0 : fraction of “normal” ortho-positronium 3 photon annihilation for the n_th Fluka medium
WHAT(3): : not used
WHAT(4): = lower bound (or corresponding name) of the material indices in which the previous parameters must be applied (“From material WHAT(4)…”) Default = 3.
WHAT(5): = upper bound (or corresponding name) of the material indices in which the previous parameters must be applied (”… to material WHAT(5)…”) Default = WHAT(4)
WHAT(6): = step length in assigning indices (”…in steps of WHAT(6)”) Default = 1.

For SDUM = ORTPOSTM:¶

WHAT(1): < 0.0 : resets the default (def. 1.42 x10^-7 s)

= 0.0 : ignored

> 0.0 : ortho-positronium 3 photon annihilation normal component time constant (s) for the n_th Fluka medium
WHAT(2): < 0.0 : resets the default (def. 1.42 x10^-7 s)

= 0.0 : ignored

> 0.0 : ortho-positronium 3 photon annihilation anomalous component time constant (s) for the n_th Fluka medium
WHAT(3): < 0.0 : resets the default (oo s)

= 0.0 : ignored

> 0.0 : ortho-positronium to para-positronium transition time constant (s) for the n_th Fluka medium
WHAT(4): = lower bound (or corresponding name) of the material indices in which the previous parameters must be applied (“From material WHAT(4)…”) Default = 3.
WHAT(5): = upper bound (or corresponding name) of the material indices in which the previous parameters must be applied (”… to material WHAT(5)…”) Default = WHAT(4)
WHAT(6): = step length in assigning indices (”…in steps of WHAT(6)”) Default = 1.

Notes

The treatment of Rayleigh scattering is rather poor for non monoatomic materials (it assumes additivity and does not take into account important molecular effects). However, Rayleigh scattering, in general, has little effect on energy deposition and on particle transport.
The full treatment of electron binding and motion in Compton scattering (referred above as “binding corrections and profile function”) is now available. It is particular important for low energies and/or heavy materials, and in general for all problems where the best accuracy for photon transport is requested.

Example (number based):

*...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
EMF
EMFRAY           1.0       8.0      12.0       4.0
EMFRAY           3.0       9.0      15.0       2.0
*   In the above example, Compton binding corrections are requested in
*   regions 8 to 15, excluding regions 10 and 14.
*   Rayleigh scattering is requested only in regions 8 and 12

The same example, name-based:

EMF
EMFRAY           1.0  EightReg  TwelvReg       4.0
EMFRAY           3.0   NineReg  FifteenR       2.0