[ <--- prev -- ] [ HOME ] [ -- next ---> ]
A "collision tape" is a file where quantities describing selected events
are recorded in the course of a FLUKA run.
This file is the standard output of the MGDRAW user routine, that can be
customised by the user to get different and/or more complete output
(see description of user routine MGDRAW in Chap. (13)).
Note that "event" would be a more appropriate word than "collision",
and "file" better than "tape". For historical reasons, however,
the expression "collision tape" is used in Monte Carlo jargon rather
than "event file". It is true that most interesting events are generally
collision events (but also boundary crossings, decays, etc.), and that
the large size of the file may require the use of a magnetic tape (or at
least, that was often the case in the past).
Recently, the expression "phase space file" has also been used.
There are several reasons for which the user might decide to write a
collision tape. Some examples are:
FLUKA allows to write a complete dump of each source particle, of each trajectory and of each energy deposition event, possibly under event-driven conditions specified by the user (see description of user routine MGDRAW in (13)).
To obtain a collision tape, the user must input option USERDUMP with
WHAT(1) >= 100.
The user can choose to dump all data concerning particle trajectories, data
concerning continuous energy deposition, data concerning local (point) energy
deposition, or any combination of the three. By default, data are written on
the collision tape in single precision and unformatted, but it is also possible
for the user to modify the MGDRAW subroutine and to obtain a more customised
output file (see (13)).
The variables written by the default version of MGDRAW}, and their number,
differ in the three cases. The sign of the first (integer) variable dumped at an
event indicates how to interpret the following ones:
In Case 1, the following variables are written: First record:
NTRACK, MTRACK, JTRACK, ETRACK, WTRACK, (three integers and two real variables)
Next record:
(XTRACK(I), YTRACK(I), ZTRACK(I), I = 0, NTRACK), (DTRACK(J), J = 1, MTRACK), CTRACK (NTRACK+MTRACK+1 real variables)
where:
NTRACK = number of trajectory segments MTRACK = number of energy deposition events along the trajectory JTRACK = particle type (see (5)) ETRACK = total energy of the particle (rest + kinetic) WTRACK = particle weight XTRACK(I), YTRACK(I), ZTRACK(I) = coordinates defining the upstream end of the (I+1)th segment; for I = NTRACK, the end of the trajectory DTRACK(J) = energy deposition in the Jth deposition event along the trajectory CTRACK = total curved path
In Case 2, the following variables are written: First record:
0, ICODE, JTRACK, ETRACK, WTRACK (three integers and two real variables)
Next record:
XSCO, YSCO, ZSCO, RULL (4 real variables)
where:
JTRACK, ETRACK, WTRACK have the meaning explained above, XSCO, YSCO, ZSCO = coordinates of the energy deposition point RULL = amount of energy deposited ICODE = indicates the type of point event giving raise to energy deposition, as explained below:
1x = call from KASKAD (hadronic part of FLUKA); 10: elastic interaction recoil 11: inelastic interaction recoil 12: stopping particle 13: pseudo-neutron deposition 14: escape
2x = call from EMFSCO (electromagnetic part of FLUKA); 20: local energy deposition (i.e. photoelectric) 21: below user-defined cutoff 22: below user cutoff 23: escape
3x = call from KASNEU (low-energy neutron part of FLUKA) 30: target recoil 31: neutron below threshold 32: escape 4x = call from KASHEA (heavy ion part of FLUKA) 40: escape
5x = call from KASOPH (optical photon part of FLUKA) 50: optical photon absorption 51: escape
In Case 3, the following variables are written: First record:
-NCASE, NPFLKA, NSTMAX, TKESUM, WEIPRI, (three integers and two real variables)
Next record:
(ILOFLK(I), ETOT(I), WTFLK(I), XFLK(I), YFLK(I), ZFLK(I), TXFLK(I), TYFLK(I), TZFLK(I), I = 1, NPFLKA ) (NPFLKA times (one integer + 8 real variables))
where:
NCASE = number of primaries treated so far (including current one) NPFLKA = number of particles in the stack NSTMAX = maximum number of particles in stack so far TKESUM = total kinetic energy of the primaries of a user written SOURCE WEIPRI = total weight of the primaries handled so far ILOFLK(I) = type of the Ith stack particle (see (5)) ETOT(I) = total energy of Ith stack particle XFLK(I), YFLK(I), ZFLK(I) = source coordinates for the Ith stack particle TXFLK(I), TYFLK(I), TZFLK(I) = direction cosines of the Ith stack particle