FLUKA: ASSIGNMAt
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ASSIGNMAt
defines the correspondence between region indices (or names) and material
indices (or names). It defines also regions with magnetic and/or electric
fields. There is the possibility of selectively changing region material to
vacuum/blackhole (and/or switching on/off possible fields) when transporting
radioactive decay products. Radioactive decay products originating from
regions switched to vacuum/blackhole are ignored. This is helpful for
situations where the emissions of an activated object in a complex
environment have to be evaluated standalone.
See also MATERIAL, MGNFIELD
WHAT(1)
> 0 : material index, or material name.
<=0 : resets the default
Default
= 1.0 (blackhole)
WHAT(2)
= lower bound (or name corresponding to it) of the region indices
with material index equal or name corresponding to WHAT(1)
.
("From region WHAT(2)
...")
Default
= 2.0
WHAT(3)
= upper bound (or name corresponding to it) of the region indices
with material index equal or name corresponding to WHAT(1)
.
("...to region WHAT(3)
...")
Default
= WHAT(2)
WHAT(4)
= step length in assigning indices
("...in steps of WHAT(4)
")
Default
= 1.0
WHAT(5)
= 1.0 : a magnetic field is present (no electric field) in the
region(s) defined by WHAT(2)
, (3), and (4), for both prompt
and radioactive decay products
= 2.0 : an electric field is present (no magnetic field) in the
region(s) defined by WHAT(2)
, (3), and (4), for both prompt
and radioactive decay products
= 3.0 : both magnetic and electric fields are present in the
region(s) defined by WHAT(2)
, (3), and (4), for both prompt
and radioactive decay products
= 4.0 : a magnetic field is present (no electric field) in the
region(s) defined by WHAT(2)
, (3), and (4), for prompt
products only
= 5.0 : an electric field is present (no magnetic field) in the
region(s) defined by WHAT(2)
, (3), and (4), for prompt
products only
= 6.0 : both magnetic and electric fields are present in the
region(s) defined by WHAT(2)
, (3), and (4), for prompt
products only
= 7.0 : a magnetic field is present (no electric field) in the
region(s) defined by WHAT(2)
, (3), and (4), for radioactive
decay products only
= 8.0 : an electric field is present (no magnetic field) in the
region(s) defined by WHAT(2)
, (3), and (4), for radioactive
decay products only
= 9.0 : both magnetic and electric fields are present in the
region(s) defined by WHAT(2)
, (3), and (4), for radioactive
decay products only
= 0.0 : ignored
< 0.0 : resets the default (no field) in the region(s) defined by
WHAT(2)
, (3), and (4)
Default
= 0.0 (ignored)
WHAT(6)
= material index, or material name, for a possible alternate
material for radioactive decay product transport.
(See Note 5 below).
Default
= 0.0 : same material as for prompt products
SDUM
: not used
Default
(option ASSIGNMAt not requested): not allowed! Each region must be
explicitely assigned a material, or vacuum or blackhole (see
Note 3).
No magnetic and no electric field is the default for all regions.
Notes:
1) Several ASSIGNMAt definitions are generally necessary to assign a
material to all regions. Standard material names and their numbers
are listed in 5}. They may be redefined and others may be added
(see Note 5 to command MATERIAL)
2) Overlapping region indices can be given in several ASSIGNMAt
definitions, each definition overriding the earlier ones. This makes
the assigning of materials very convenient (see Example below).
The same can be done even if region names are used instead of indices:
the region numbers correspond to the order in which they appear in the
geometry input. Anyway, the name-index correspondence can be found on
standard output after a short test run.
3) Option ASSIGNMAt must always be present. If a region has not been
assigned a material, the program stops at initialisation time.
Notice that this was different in previous versions of FLUKA, where
blackhole was assigned by default.
4) Magnetic field tracking is performed only in regions defined as
magnetic field regions by WHAT(5)
= 1.0, 3.0, 4.0, 6.0, 7.0, 9.0.
It is strongly recommended to define as such only regions where a
magnetic field actually exists, due to the less efficient and less
accurate tracking algorithm used in magnetic fields. To define a
region as one with magnetic field and to return systematically
B = 0.0 in that region via the user subroutine MAGFLD must be
absolutely avoided (see MGNFIELD)
5) There is the possibility of selectively changing regions to
a different material (and/or switching on/off possible fields) when
transporting radioactive decay products. Radioactive decay products
originating from regions switched to a new material are ignored.
This is helpful for situations where the emissions of an activated
object in a complex environment have to be evaluated standalone.
Example (for an input number-based):
MATERIAL 13.0 0.0 2.7 10.0 0.0 0.0 ALUMINUM
ASSIGNMA 10.0 1.0 15.0 0.0 1.0 0.0
ASSIGNMA 2.0 5.0 17.0 6.0 -1.0 0.0
ASSIGNMA 2.0 16.0 18.0 2.0 0.0 0.0
The corresponding name-based input cards could be (using arbitrary names):
ASSIGNMA ALUMINUM FirstReg Reg15 0.0 1.0 0.0
ASSIGNMA VACUUM FifthReg Reg17 6.0 -1.0 0.0
ASSIGNMA VACUUM Reg16 Reg18 2.0 0.0 0.0
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