FLUKA: USRYIELD
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USRYIELD
defines a detector to score a double-differential particle yield
around an extended or a point target
See also USRBDX
The full definition of the detector may require two successive cards
(the second card, identified by the character '&' in any column from
71 to 78, must be given unless the corresponding defaults are
acceptable to the user)
First card:
For SDUM
= anything but BEAMDEF:
WHAT(1)
= ie + ia * 100 + i4 * 10000, where ie and ia indicate the
two physical quantities with respect to which the double-
-differential yield is calculated.
If ie > 0, the yield will be analysed in linear intervals
with respect to the first quantity; if < 0, the yield
distribution will be binned logarithmically.
(Note that for rapidity, pseudorapidity and Feynman-x
logarithmic intervals are not available and will be forced
to linear if requested).
For the second quantity, ia, only one interval will be
considered.
|ie| or |ia| = 1 : kinetic energy in GeV
= 2 : total momentum in GeV/c
= 3 : rapidity in the lab frame
(only linear scoring available)
= 4 : rapidity in the c.m.s. frame
(only linear scoring available)
= 5 : pseudorapidity in the lab frame
(only linear scoring available)
= 6 : pseudorapidity in the c.m.s. frame
(only linear scoring available)
= 7 : Feynman-x in the lab frame (E/Ebeam)
(only linear scoring available)
= 8 : Feynman-x in the c.m.s. frame
(only linear scoring available)
= 9 : transverse momentum in GeV/c
= 10 : transverse mass in GeV
= 11 : longitudinal momentum in the lab frame (GeV/c)
= 12 : longitudinal momentum in the c.m.s. frame (GeV/c)
= 13 : total energy in GeV
= 14 : polar angle in the lab frame (see Note 6)
= 15 : polar angle in the c.m.s. frame (see Note 6)
= 16 : square transverse momentum in (GeV/c)**2
= 17 : 1/(2pi sin(theta)) weighted angle
in the lab frame (see Note 6)
= 18 : 1/(2pi p_t) weighted transverse momentum in GeV/c
= 19 : ratio laboratory momentum/beam momentum
= 20 : transverse kinetic energy
= 21 : excitation energy
= 22 : particle charge
= 23 : particle LET
( = 24 : like 14, but with input data given
in degrees rather than in radians ) (see Note 6)
( = 25 : like 15, but with input data given
in degrees rather than in radians ) (see Note 6)
= 26 : laboratory kinetic energy/nucleon
= 27 : laboratory momentum/nucleon
= 28 : particle baryonic charge
= 29 : four-momentum transfer -t
= 30 : c.m.s. longitudinal Feynman-x
(only linear scoring available)
= 31 : excited mass squared
= 32 : excited mass squared / s
= 33 : time (s)
= 34 : sin weighted angle in the lab frame (see Note 6)
= 35 : total momentum (GeV/c) in the c.m.s. frame
= 36 : total energy (GeV) in the c.m.s. frame
( = 37 : like 17, but with input data given
in degrees rather than in radians ) (see Note 6)
( = 38 : like 34, but with input data given
in degrees rather than in radians ) (see Note 6)
i4 = 0 : group-wise scoring for low energy neutrons
=+/-1 : point-wise scoring for low energy neutrons
WHAT(2)
> 0.0: number or name of the (generalised) particle type to be
scored
< -800.0 and WHAT(4)
= -1.0 and WHAT(5)
= -2: the (generalised)
particles of type IJ ENTERING an inelastic hadronic
interaction are scored by setting WHAT(2)
= -1000 -IJ
Default
= 201.0 (all particles)
WHAT(3)
= logical output unit:
> 0.0 : formatted data are written on WHAT(3)
unit
< 0.0 : unformatted data are written on |WHAT(3)
| unit
Values of |WHAT(3)
| < 21.0 should be avoided (with the
exception of +11.0).
Default
= 11.0 (standard output unit)
WHAT(4)
> 0.0: number or name of the first region defining the boundary
(upstream region)
= -1.0 and WHAT(5)
= -2.0: the yield of particles
EMERGING from inelastic hadronic interactions is scored
Default
= -1.0
WHAT(5)
> 0.0: number or name of the second region defining the boundary
(downstream region)
= -2.0 and WHAT(4)
= -1.0: the yield of particles
EMERGING from inelastic hadronic interactions is scored
Default
= -2.0
WHAT(6)
= normalisation factor (the results will be divided by WHAT(6)
)
SDUM
= detector name (max. 10 characters)
Continuation card:
WHAT(1)
= Upper limit of the scoring interval for the first quantity
Default
: beam momentum value in case |ie| = 1 or 2,
no default otherwise!
WHAT(2)
= Lower limit of the scoring interval for the first quantity
Default
: 0.0 if linear binning, 0.001 otherwise. Note that these
values might not be meaningful for all available quantities.
WHAT(3)
= number of scoring intervals for the first quantity
Default
: 50.
WHAT(4)
= Upper scoring limit for the second quantity
Default
: no default!
WHAT(5)
= Lower scoring limit for the second quantity
Default
: 0.0
WHAT(6)
= ixa + 100 * ixm, where ixa indicates the kind of yield or
cross section desired and ixm the target material (if needed
in order to calculate cross section or particle LET,
otherwise ixm = 0). Cross sections are obtained from yields
multiplying the latter ones by the microscopic inelastic cross
section of the beam particle at beam energy on the selected
material.
ixa = 1 : plain double-differential cross section
d2 sigma / d x1 d x2 where x1, x2 are the first
and second quantity
ixa = 2 : invariant cross section E d3 sigma / dp3
ixa = 3 : plain double differential yield
d2 N / d x1 d x2 where x1, x2 are the first
and second quantity
ixa = 4 : double differential yield
d2 (x2 N) / d x1 d x2 where x1, x2 are the
first and second quantity
ixa = 5 : double differential yield
d2 (x1 N) / d x1 d x2 where x1, x2 are the
first and second quantity
ixa = 6 : double differential fluence yield
1/cos(theta) d2 N / d x1 d x2 where x1, x2 are
the first and second quantity, and theta is
the angle between the particle direction and the
NORMAL TO THE SURFACE. The same theta is
also used for x1 or x2 if the laboratory
polar angle (14 or 24) is requested
ixa = 7 : double differential yield
d2 (x2 x2 N) / d x1 d x2 where x1, x2 are
the first and second quantity
ixa = 8 : double differential yield
d2 (x1 x1 N) / d x1 d x2 where x1, x2 are
the first and second quantity
ixa = 9 : double differential yield
d2 N / (x2 d x1 d x2) where x1, x2 are
the first and second quantity
ixa = 10 : double differential yield
d2 N / (x1 d x1 d x2) where x1, x2 are
the first and second quantity
ixa = 11 : double differential yield
d2 N / d (x1/x2) d x2) where x1, x2 are
the first and second quantity
ixa = 12 : double differential yield
d2 (x1 Sqrt[x1^2-x2^2] N) / d x1 d x2 where x1, x2 are
the first and second quantity
ixa = 13 : double differential yield
d2 ([x1^2+x2^2] N) / d x1 d x2 where x1, x2 are
the first and second quantity
ixa = 14 : double differential yield
d2 ([x1+x2^2] N) / (pi d x1 d x2) where x1, x2 are
the first and second quantity
ixa = 15 : double differential yield
d2 ([x1^2+x2] N) / (pi d x1 d x2) where x1, x2 are
the first and second quantity
ixa = 16 : double differential weighted fluence yield
d2 (x2 N) / d x1 d x2 cos(theta) where x1, x2 are
the first and second quantity, and theta is
the angle between the particle direction and the
NORMAL TO THE SURFACE. The same theta is
also used for x1 or x2 if the laboratory
polar angle (14 or 24) is requested
ixa = 26 : double differential weighted fluence yield
d2 (x1 N) / d x1 d x2 cos(theta) where x1, x2 are
the first and second quantity, and theta is
the angle between the particle direction and the
NORMAL TO THE SURFACE. The same theta is
also used for x1 or x2 if the laboratory
polar angle (14 or 24) is requested
ixa > 52 : as per ixa = (ixa - 50), but
double differential cross section instead of yield,
e.g. ixa = 59 is d2 sigma / (x2 d x1 d x2), while
note that ixa = 53 (i.e. d2 sigma / d x1 d x2)
coincides with ixa = 1
ixm : material number of the target for cross section or LET
calculations (default: HYDROGEN). In case of scoring
as a function of LET, it must be a material actually
assigned to some geometry region (and this way
initialised by the code).
Default
: 1.0 (plain double-differential cross section)
Note that calculating a cross section has little meaning
in case of a thick target.
For SDUM
= BEAMDEF:
WHAT(1)
= projectile particle index, or corresponding name
Default
= IJBEAM (beam particle)
WHAT(2)
= target particle index, or corresponding name (used by the
code to define the c.m.s. frame)
Default
: 1.0 (proton)
WHAT(3)
= projectile momentum
Default
= PBEAM (beam momentum)
WHAT(4,5,6) = projectile direction cosines
Default
= UBEAM, VBEAM, WBEAM (beam direction cosines)
Default
(option USRYIELD not given): no yield estimator detector is defined
Notes:
1) While option USRBDX calculates angular distributions WITH RESPECT TO
THE NORMAL to the boundary at the point of crossing, USRYIELD's
distributions are calculated WITH RESPECT TO A FIXED DIRECTION (the
beam direction, or a different direction specified by the user with
SDUM
= BEAMDEF).
2) When scoring thick-target yields, the angle considered is that
between the direction of the particle at the point where it crosses
the target surface and the beam direction (or a different direction
specified by the user, see previous Note). The target surface is
defined as the boundary between two regions (positive values of
WHAT(4)
and WHAT(5)
of the first USRYIELD card.
3) Point-target yields, i.e. yields of particles emerging from
inelastic hadronic interactions with single nuclei (including
hadronic interactions by ions and real or virtual photons), are
scored by setting WHAT(4)
= -1.0 and WHAT(5)
= -2.0 in the first
USRYIELD card. As an alternative, the corresponding cross sections
can be calculated, depending on the value of WHAT(6)
in the
continuation card.
In addition, if WHAT(2)
in the same card is < -800.0, the
distributions of particles ENTERING the inelastic hadronic
interactions can be scored.
4) Calculating a cross section has little meaning in case of a thick
target. Cross sections are obtained from yields multiplying the
latter ones by the microscopic inelastic cross section of the beam
particle at beam energy on the selected material.
5) Differential yields (or cross sections) are scored over any
desired number of intervals for what concerns the first quantity,
but over only one interval for the second quantity. However, the
results are always expressed as second derivatives (or third
derivatives in the case of invariant cross sections), and NOT as
interval-integrated yields.
In order to obtain more intervals for the second quantity, the
user must define further USRYIELD detectors.
6) In the case of polar angle quantities (|ie| or |ia| = 14,15,17,24,
25,34,37,38) the differential yield is always referred to solid
angle in steradian, although input is specified in radian or
degrees.
7) When scoring yields as a function of LET, the intervals will be in
keV/(micrometer g/cm3), and the histogram will be normalized,
as usual, to the unit interval of the first and second quantities.
8) A USRYIELD card with SDUM
= BEAMDEF, if given, does not refer to a
particular detector, but modifies the reference projectile or target
parameters for all USRYIELD detectors of the current run. No
continuation card has to be given after one with SDUM
= BEAMDEF.
9) The logical output unit for the estimator results (WHAT(3)
of the
first USRYIELD card) can be any one of the following:
- the standard output unit 11: estimator results will be written on
the same file as the standard FLUKA output
- a pre-connected unit (via a symbolic link on most UNIX systems,
ASSIGN under VMS, or equivalent commands on other systems)
- a file opened with the FLUKA command OPEN
- a file opened with a Fortran OPEN statement in a user-written
initialisation routine such as USRINI, USRGLO or SOURCE (see 13})
- a dynamically opened file, with a default name assigned by the
Fortran compiler (typically fort.xx or ftn.xx, with xx equal to
the chosen logical output unit number).
The results of several USRYIELD detectors in a same FLUKA run can be
written on the same file, but of course only if they are all in the
same mode (all formatted, or all unformatted). It is also possible
in principle to write on the same file the results of different
kinds of estimators (USRBDX, USRBIN, etc.) but this is not
recommended, especially in the case of an unformatted file, because
it would make very difficult any reading and analysis.
10) Not all 38x38 combinations of quantities are accepted by the code,
nor are they all meaningful (for instance one could run successfully
by setting WHAT(1)
with ia = ie, but the result would have no
physical meaning).
11) When scoring neutron yield with energy as the first quantity, and
the requested energy interval structure overlaps with that of the
low energy neutron groups, interval boundaries are forced to
coincide with group boundaries and no interval can be smaller than
the corresponding group. Actually, the program uses the requested
energy limits and number of intervals to estimate the desired
interval width. The number of intervals above the upper limit of the
first low-energy neutron group is recalculated according to such
width. To preserve the requested upper energy limit, the width of
the first interval above the low energy groups may be smaller than
that of the others. Note that the lowest energy limit of the last
neutron group is 1.E-14 GeV (1.E-5 eV) for the 260-group data set.
All group energy boundaries are listed in Table 10.4.1.1}.
12) If the scored yield with energy as the first quantity is that of a
generalised particle which includes neutrons (e.g. ALL-PART,
ALL-NEUT, NUCLEONS, NUC&PI+-, HAD-NEUT, and even ENERGY), the
spectrum is presented in two separate tables. One table refers to
all non-neutron particles and to neutrons with energies > 20 MeV.
The second table refers only to neutrons with energy < 20 MeV, and
its interval structure is that of the neutron energy groups. In case
an interval crosses 20 MeV, it will include the contribution of
neutrons with energy > 20 MeV and not that of neutrons with
energy < 20 MeV.
13) A program USYSUW is available with the normal FLUKA code
distribution in directory $FLUPRO/flutil. USYSUW reads USRYIELD
results in binary form from several runs and allows to compute
standard deviations. It returns differential and cumulative fluence,
with the corresponding percent errors, in a file, and differential
fluence in another file formatted for easy plotting. It also returns
a binary file that can be read out in turn by USYSUW. The content of
this file is statistically equivalent to that of the sum of the
files used to obtain it, and it can replace them to be combined with
further output files if desired (the USYSUW program takes care of
giving it the appropriate weight).
14) The maximum number of yield detectors that the user can define
is 1000.
Example (number based):
USRYIELD 1399.0 13. 21.0 3.0 2.0 1.0TotPi+(E)
USRYIELD 50.0 0.001 100.03.14159265 0.0 3.0 &
The same example, name based:
USRYIELD 1399.0 PION+ 21.0 ThirdReg RegioTwo 1.0TotPi+(E)
USRYIELD 50.0 0.001 100.03.14159265 0.0 3.0 &
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