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[ <--- prev -- ] [ HOME ] [ -- next ---> ] ## USRYIELDdefines a detector to score a double-differential particle yield
around an extended or a point target
For SDUM = anything but BEAMDEF: WHAT(1) = ie + ia * 100, 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 (#) = 15 : polar angle in the c.m.s. frame (#) = 16 : square transverse momentum in (GeV/c)**2 = 17 : weighted angle in the lab frame (#) = 18 : 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 ) (#) ( = 25 : like 15, but with input data given in degrees rather than in radians ) (#) = 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) = 34-36: not used ( = 37 : like 17, but with input data given in degrees rather than in radians ) (#) WHAT(2) > 0.0: number or name of the (generalised) particle type to be scored < -80.0 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) = -100 -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 energy value WHAT(2) = Lower limit of the scoring interval for the first quantity Default: 0.0 if linear binning, 1.0 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 a cross section, otherwise ixm = 0) 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 ixa = 7 : double differential yield d2 (x2 x2 N) / d x1 d x2 where x1, x2 are the first and second quantities ixa = 8 : double differential yield d2 (x1 x1 N) / d x1 d x2 where x1, x2 are the first and second quantities ixa = 16 : double differential fluence yield d2 (x2 N) / d x1 d x2 cos(theta) where x1, x2 are the first and second variables, and theta is the angle of the particle direction with the normal to the crossed surface ixa = 26 : double differential fluence yield d2 (x1 N) / d x1 d x2 cos(theta) where x1, x2 are the first and second variables, and theta is the angle between the particle direction with the normal to the crossed surface ixm : material number of the target for cross section or LET calculations (default: HYDROGEN) 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 = VBEAM, 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 addition, if WHAT(2) in the same card is < -80.0, 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.
- 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, 17,18,24,25) 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 27x27 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). A list of possible quantity combinations is given below:
- 11) 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).
Example (number based): *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8 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 & * Score double differential yield of positive pions going from region 3 to * region 2 with a polar angle between 0 and pi with respect to the beam * direction. Energy distribution is in 100 logarithmic intervals between 1 MeV * and 50 GeV. Normalisation factor = 1. Results are written formatted on * unit 21. The same example, name based: *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8 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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