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OPT-PROD

requests and controls production of Cherenkov, Transition and Scintillation Radiation in specified materials

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

For SDUM = CERE-OFF: switches off Cherenkov production

     WHAT(1-3): not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = CERE-OFF

For SDUM = TRD-OFF: switches off Transition Radiation production

     WHAT(1-3): not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = TRD-OFF

For SDUM = SCIN-OFF: switches off Scintillation light production

     WHAT(1-3): not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = SCIN-OFF

For SDUM = CERENKOV: switches on Cherenkov production and defines photon energy range

     WHAT(1)  = minimum Cherenkov photon emission energy in GeV
                Default: 2.07E-9 GeV (2.07 eV, corresponding to 600 nm)
     WHAT(2)  = maximum Cherenkov photon emission energy in GeV
                Default: 4.96E-9 GeV (4.96 eV, corresponding to 250 nm)
     WHAT(3) :  not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = CERENKOV

For SDUM = CEREN-WV: switches on Cherenkov production and defines photon wavelength range

     WHAT(1)  = minimum Cherenkov photon emission wavelength in cm
                Default: 2.50E-5 cm (250 nm, or 1.2E6 GHz)
     WHAT(2)  = maximum Cherenkov photon emission wavelength in cm
                Default: 6.00E-5 cm (600 nm, or 5.E5 GHz)
     WHAT(3) :  not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = CEREN-WV

For SDUM = CEREN-OM: switches on Cherenkov production and defines photon angular frequency range

     WHAT(1)  = minimum Cherenkov photon angular frequency omega
                = 2 x pi x frequency (in rad/s)
                Default: 3.14E15 rad/s (corresponding to 600 nm)
     WHAT(2)  = maximum Cherenkov photon angular frequency omega
                = 2 x pi x frequency (in rad/s)
                Default: 7.53E15 rad/s (corresponding to 250 nm)
     WHAT(3) :  not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = CEREN-OM

For SDUM = TR-RADIA: switches on Transition Radiation production and defines its energy range

     WHAT(1)  = minimum TRD photon emission energy
     WHAT(2)  = maximum TRD photon emission energy
     WHAT(3) :  not used
     WHAT(4-6): assignment to materials, see below
     SDUM     = TR-RADIA

For SDUM = SCINTILL: switches on Scintillation Light production and defines photon energy

     WHAT(1)  = i-th scintillation photon emission energy in GeV (i_max =3,
                see Note 4)
     WHAT(2)  > 0: fraction of deposited energy going into i-th scintillation
                   photon emission
          =< -100: forces to use a user routine (NOT YET IMPLEMENTED)
          >= -99.0 and =< 0.0: ignored
     WHAT(3) :  time constant of scintillation light in seconds
     WHAT(4-6): assignment to materials, see below
     SDUM     = SCINTILL

For SDUM = SCINT-WV: switches on Scintillation Light production and defines photon wavelength

     WHAT(1)  = i-th scintillation photon emission wavelength in cm (i_max =3,
                see Note 4)
                Default: 2.50E-5 cm (250 nm, or 1.2E6 GHz)
     WHAT(2)  > 0: fraction of deposited energy going into i-th scintillation
                   photon emission
          =< -100: forces to use a user routine (NOT YET IMPLEMENTED)
          >= -99.0 and =< 0.0: ignored
     WHAT(3) :  time constant of scintillation light in seconds
     WHAT(4-6): assignment to materials, see below
     SDUM     = SCINT-WV

For SDUM = SCINT-OM: switches on Scintillation Light production and defines photon angular frequency range

     WHAT(1)  = i-th scintillation photon emission angular frequency omega =
                2 x pi x frequency (in rad/s), (i_max =3, see Note 4)
                Default: 3.14E15 rad/s (corresponding to 600 nm)
     WHAT(2)  > 0: fraction of deposited energy going into i-th scintillation
                   photon emission
          =< -100: forces to use a user routine (NOT YET IMPLEMENTED)
          >= -99.0 and =< 0.0: ignored
     WHAT(3) :  time constant of scintillation light in seconds
     WHAT(4-6): assignment to materials, see below
     SDUM     = SCINT-OM

For all previous SDUM's:

     WHAT(4) = lower bound of the indices of materials in which the indicated
               Cherenkov, Scintillation or TRD photon emission range is defined
               From material WHAT(4)...
               Default = 3
     WHAT(5) = upper bound of the indices of materials in which the indicated
               Cherenkov or TRD photon emission range is defined
               ...To material WHAT(5)...
               Default = WHAT(4)
     WHAT(6) = step length in assigning indices
               ...in step of WHAT(6)
               Default = 1

     Default: (option OPT-PROD not given): no Cherenkov, scintillation or TRD
              photon production

Notes:

• 1) Optical photons such as those produced by Cherenkov effect are distinguished by their FLUKA name (OPTIPHOT) and by their FLUKA id number (-1), as shown in (5).

• 2) To transport optical photons, it is necessary to define the optical properties of the relevant materials by means of option OPT-PROP. Users can also write their own routines USRMED (which is called at every step and at boundary crossings when activated with MAT-PROP) and FRGHNS (which defines surface roughness).

• 3) The energy/wavelength/frequency range as defined by OPT-PROD for Cherenkov photon production is not necessarily the same as that defined for transport by means of OPT-PROP. The default values, however, are the same.

• 4) In case of scintillation light, only monochromatic photons are considered for the moment, with a maximum of 3 different lines. The lines can be defined repeating i times the OPT-PROD card with SDUM = SCINTILL

Example:

 * Request production of Cherenkov photons with energies between 2 and 3 eV in
 * materials 16, 17, 19 and 20, with wavelengths between 300 and 600 nm in
 * materials 18, 20 and 22, and with frequencies between 0.5 and 1 million GHz
 * in material 21
 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 OPT-PROD       2.E-9     3.E-9       0.0      16.0      17.0       0. CERENKOV
 OPT-PROD       2.E-9     3.E-9       0.0      19.0      20.0       0. CERENKOV
 OPT-PROD       3.E-5     6.E-5       0.0      18.0      22.0       2. CEREN-WV
 OPT-PROD     3.14E15   6.28E15       0.0      21.0       0.0       0. CEREN-OM
 * Optical photon transport requested between 300 and 500 nm for all materials
 * with number between 16 and 21
 OPT-PROP       3.E-5     5.E-5     6.E-5      16.0      22.0       0. WV-LIMIT
 * User routine USRMED called when an optical photon is going to be transported
 * in materials 17 and 21
 MAT-PROP         1.0       0.0       0.0       17.       21.       4. USERDIRE