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FLUKA 2023.3.4, April 10th 2024
(last respin 2023.3.4)
flair-2.3-0d 13-Sep-2023

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-- Fluka Release
( 10.04.2024 )
FLUKA 2023.3.4 has been released.


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OPT-PROP

defines optical properties of specified materials

See also OPT-PROD, Chap. (12).

For SDUM = WV-LIMIT: defines wavelength range for optical photon transport

     WHAT(1) > 0.0: minimum wavelength (in cm) for optical photon transport
             = 0.0: ignored
             < 0.0: resets to default
             Default: 2.50E-5 (250 nm)
     WHAT(2) > 0.0: central wavelength (in cm) for optical photon transport
             = 0.0: ignored
             < 0.0: resets to default
             Default: 5.89E-5 ((589 nm, Na D line)
     WHAT(3) > 0.0: maximum wavelength (in cm) for optical photon transport
             = 0.0: ignored
             < 0.0: resets to default
             Default: 6.00E-5 (600 nm)
     WHAT(4-6): assignment to materials, see below
     SDUM    = WV-LIMIT

For SDUM = OM-LIMIT: defines angular frequency range for optical photon transport

     WHAT(1) > 0.0: minimum angular frequency for optical photon transport
               omega = 2pi x frequency (in rad/s)
             = 0.0: ignored
             < 0.0: resets to default
             Default: 3.14E15 rad/s (corresponding to 600 nm)
     WHAT(2) > 0.0: central angular frequency for optical photon transport
               omega = 2pi x frequency (in rad/s)
             = 0.0: ignored
             < 0.0: resets to default
             Default: 3.20E15 rad/s (corresponding to 589 nm, Na D line)
     WHAT(3) > 0.0: maximum angular frequency for optical photon transport
               omega = 2pi x frequency (in rad/s)
             = 0.0: ignored
             < 0.0: resets to default
             Default: 7.53E15 rad/s (corresponding to 250 nm)
     WHAT(4-6): assignment to materials, see below
     SDUM    = OM-LIMIT

For SDUM = RESET: all optical properties are zeroed

     WHAT(1-3) = no meaning
     WHAT(4-6): assignment to materials, see below
     SDUM    = RESET

For SDUM = METAL: flag the material as a metal

     WHAT(1) = 1st optical property (not used at the moment)
     WHAT(2) = 2nd optical property (not used at the moment)
     WHAT(3) = 3rd optical property: (1-r), where r is the reflectivity
               index at the central wavelength (or at the central angular
               frequency, depending on which one of the two quantities has been
               defined). See also Note 2
             Default = 0.0
     WHAT(4-6): assignment to materials, see below
     SDUM    = METAL

For SDUM = blank:

     WHAT(1) = 1st optical property: refraction index at the central
               wavelength (or at the central angular frequency, depending
               on which one of the two quantities has been defined)
             < -99: forces to use user routine RFRNDX (see Note 1)
             Default = 1.0
     WHAT(2) = 2nd optical property: absorption coefficient (cm^-1) at
               the central wavelength (or at the central angular
               frequency, depending on which one of the two quantities has
               been defined)
             < -99: forces to use user routine ABSCFF (see Note 1)
             Default = 0.0
     WHAT(3) = 3rd optical property: diffusion coefficient (cm^-1) at
               the central wavelength (or at the central angular
               frequency, depending on which one of the two quantities has
               been defined)
             < -99: forces to use user routine DFFCFF (see Note 1)
             Default = 0.0
     WHAT(4-6): assignment to materials, see below
     SDUM = blank

For SDUM containing &1 (resp. &2) (resp. &3):

     WHAT(1) = 4th (resp. 7th) (resp. 10th) optical property of the material
               (derivatives of the refraction index, see Note 2 below)
             Default = 0.0
     WHAT(2) = 5th (resp. 8th) (resp. 11th) optical property of the material
               (derivatives of the absorption coefficient, see Note 2 below)
             Default = 0.0
     WHAT(3) = 6th (resp. 9th) (resp. 12th) optical property of the material
               (derivatives of the diffusion coefficient, see Note 2 below)
             Default = 0.0
     WHAT(4-6): assignment to materials, see below
     SDUM = &1, &2 or &3

For all previous SDUM's:

     WHAT(4) = lower bound of the indices of materials to which the indicated
               optical properties refer
               From material WHAT(4)...
               Default = 3
     WHAT(5) = upper bound of the indices of materials to which the indicated
               optical properties refer
               ...To material WHAT(5)...
               Default = WHAT(4)
     WHAT(6) = ... in step of WHAT(6)
               Default = 1

For SDUM = SENSITIV: sets up the optical photon detection sensitivity parameters (See also SDUM = WV-SENSI, SDUM = OM-SENSI, Note 3 below and the examples in Chap. (12))

     WHAT(1) = 0th photon sensitivity parameter
             < -99: forces to use user routine QUEFFC (see Note 1)
     WHAT(2) = 1st optical property (not used at the moment)
     WHAT(3) = 2nd optical property (not used at the moment)
     WHAT(4) = 3rd optical property: (1-r), where r is the reflectivity
               index at the central wavelength (or at the central angular
               frequency, depending on which one of the two quantities has been
               defined). See also Note 2
             Default = 0.0
     WHAT(5) = maximum optical photon sensitivity over the allowed range (must be
               consistent with the previous values). It can be overestimated.
               Default = 1.0
     WHAT(6) : not used
     SDUM    = SENSITIV

For SDUM = WV-SENSI: setup the wavelength of the optical photon sensitivity (See also SDUM = SENSITIV, SDUM = OM-SENSI and Note 3 below)

     WHAT(1) > 0.0: minimum wavelength (in cm) for optical photon sensitivity
             = 0.0: ignored
             < 0.0: resets to default
             Default = 2.5 x 1.0E-5 (250 nm)
     WHAT(2) > 0.0: central wavelength (in cm) for optical photon sensitivity
             = 0.0: ignored
             < 0.0: resets to default
             Default = 5.89 x 1.0E-5 (589 nm, Na D line)
     WHAT(3) > 0.0: maximum wavelength (in cm) for optical photon sensitivity
             = 0.0: ignored
             < 0.0: resets to default
             Default = 6.0 x 1.0E-5 (600 nm)
     WHAT(4)-WHAT(6): not used
     SDUM    = WV-SENSI

For SDUM = OM-SENSI: setup the angular frequency of the optical photon sensitivity (See also SDUM = SENSITIV, SDUM = WV-SENSI and Note 3 below)

     WHAT(1) > 0.0: minimum angular frequency for optical photon sensitivity
                    omega = 2 pi x frequency in rad/s
             = 0.0: ignored
             < 0.0: resets to default
             Default = 3.14E15 rad/s (corresponding to 600 nm)
     WHAT(2) > 0.0: central angular frequency for optical photon sensitivity
                    omega = 2 pi x frequency in rad/s
             = 0.0: ignored
             < 0.0: resets to default
             Default = 3.20E15 rad/s (corresponding to 589 nm, Na D line)
     WHAT(3) > 0.0: maximum angular frequency for optical photon sensitivity
                    omega = 2 pi x frequency in rad/s
             Default = 7.53E15 rad/s (corresponding to 250 nm)
     WHAT(4)-WHAT(6): not used
     SDUM    = OM-SENSI

For SDUM = SPEC-BDX: flags special boundary crossings for optical photons At the selected boundary crossings special user defined properties are defined by means of the user routine OPHBDX (see Note 1 below). A maximum of 40 boundaries can be flagged by issuing option OPT-PROP with SDUM = SPEC-BDX as many times as needed.

     WHAT(1) >= 1.0: special boundary treatment activated for the n-th+1 boundary
             =  0.0: ignored
             =< -1.0: special boundary treatment deactivated for the n-th+1 boundary
     WHAT(2) = One of the two regions defining the n-th+1 boundary
     WHAT(3) = The other region defining the n-th+1 boundary
     WHAT(4) >= 1.0: special boundary treatment activated for the n-th+2 boundary
             = 0.0: ignored
             =< -1.0: special boundary treatment deactivated for the n-th+2 boundary
     WHAT(5) = One of the two regions defining the n-th+2 boundary
     WHAT(6) = The other region defining the n-th+2 boundary
     SDUM    = SPEC-BDX


     Default (option OPT-PROP not given): no optical photon transport

Notes:

  • 1) The optional user routines concerning optical photons are:
  • RFRNDX: to specify a refraction index as a function of wavelength,
    frequency or energy. Activated by setting WHAT(1) < -99 when SDUM = blank.
  • ABSCFF: to specify an absorption coefficient as a function of wavelength,
    frequency or energy. This is activated by setting WHAT(2) < -99 when SDUM = blank.
  • DFFCFF: to specify a diffusion coefficient as a function of wavelength,
    frequency or energy. Activated by setting WHAT(3) < -99 when SDUM = blank.
  • RFLCTV: to specify the reflectivity of a material.
    This can be activated with SDUM = METAL and WHAT(3) < -99
  • OPHBDX: to set optical properties of a boundary surface. The call is activated with SDUM = SPEC-BDX
  • FRGHNS: to set a possible degree of surface roughness, in order to have both diffusive and specular reflectivity from a given material surface (NOT YET IMPLEMENTED)
  • QUEFFC: to introduce Quantum efficiency. This is activated by setting the 0-th photon sensitivity parameter to a value < -99 with SDUM = SENSITIV .

  • 2) The 9 material properties input by the user with SDUM = &1, &2 and &3 are derivatives of order 1 to 3 of the three basic quantities which are input with SDUM = blank or SDUM = METAL. The three basic quantities and their derivatives are used to perform three series expansions centreed on the selected central wavelength (if SDUM = WV-LIMIT has been used for the material concerned) or on the selected central angular frequency (if SDUM = OM-LIMIT has been used). The variable x used in the expansion is adimensional: 
              x = ( lambda - lambda_central ) / lambda_central    or
              x = ( omega - omega_central )   / omega_central

  • 3) The three basic quantities are: 
           If SDUM = blank: 1) refraction index n_refr
                            2) absorption coefficient mu_abs
                            3) diffusion coefficient mu_diff
           If SDUM = METAL: 1) (not implemented yet)
                            2) (not implemented yet),
                            3) (1-r) (r = reflectivity index)
           The 4th, 5th, 6th material properties are:
                  d n_refr/ dx, d mu_abs/dx, d mu_diff/dx
           the 7th, 8th, 9th material properties are:
                  d2 n_refr/ dx^2, d2 mu_abs/dx^2, d2 mu_diff/dx^2
           the 10th, 11th, 12th material properties are:
                  d3 n_refr/ dx^3, d3 mu_abs/dx^3, d3 mu_diff/dx^3

  • 4) SDUM = SENSITIV can be used to set the quantum efficiency as a function of photon energy OVERALL through the problem and it is not material/region dependent. The reason is that it is applied ä priori" at photon generation time. If a quantum efficiency curve is to be introduced AT DETECTION, then a weighting user routine should be used, such as FLUSCW or COMSCW. It is advantageous to reduce computer time avoiding to generate and transport a photon which would have a significant probability to remain undetected.

  • 5) The optical photon sensitivity parameters are: epsilon(0), d epsilon/dx, d2 epsilon/dx2, d3 epsilon/dx3 where x is: 
              x = (lambda - lambda_central)/lambda_central
               or
              x = (omega - omega_central)/omega_central

Example 1:

 * Optical photon transport requested between 3.E15 and 7.E15 rad/s
 * (4.77E5 and 1.11E6 GHz, or 314 to 628 nm) for materials 6,9,12,15 and 18
 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 OPT-PROP       3.E15     6.E15     7.E15       6.0      18.0       3. OM-LIMIT
 * User routine USRMED called when an optical photon is going to be transported
 * in materials 6, 12 and 18
 MAT-PROP         1.0       0.0       0.0       6.0      18.0       6. USERDIRE

Example 2:

 * Material 11 has a reflectivity index = 0.32
 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 OPT-PROP         0.0       0.0      0.32      11.0       0.0       0. METAL

Example 3:

 *
 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 * Optical photon transport requested between 300 and 600 nm for water.
 * (material 9). The optical properties are for the Na D line (589 nm)
 MATERIAL         1.0       1.0  .0000899       3.0       0.0       1. HYDROGEN
 MATERIAL         8.0      16.0   0.00143       5.0       0.0       0. OXYGEN
 MATERIAL         0.0       0.0       1.0      21.0       0.0       0. WATER
 COMPOUND         2.0       3.0       1.0       5.0       0.0       0. WATER
 OPT-PROP       3.E-5   5.89E-5     6.E-5      21.0       0.0       0. WV-LIMIT
 * diffusion coefficient of water from Appl.Opt. 17, 3587 (1978)
 OPT-PROP     1.33299    0.0013     1.220      21.0       0.0       0.

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