Dear Yang,
There are two things one has to distinguish:
1) The variables UBEAM/VBEAM/WBEAM in (BEAMCM) give the direction cosines with respect to "beam reference frame", i.e. wrt the coordinate system defined by the BEAMAXES cards (if BEAMAXES is not there, then UBEAM/VBEAM/WBEAM are just the direction cosines wrt geometry reference frame). These 3 variables are the ones defined as WHAT(4)-(6) on the BEAMPOS card.
2) The beam reference frame is specified by the BMAXIS (i,j) variables in (BEAMCM), where i,j=1,2,3 (they are defined by the BEAMAXES cards). If you want to define the direction cosines in the "geometry reference frame" inside the source routine, then you have to do the following:
TX = UBEAM * BMAXIS (1,1) + VBEAM * BMAXIS (1,2) + WBEAM * BMAXIS (1,3)
TY = UBEAM * BMAXIS (2,1) + VBEAM * BMAXIS (2,2) + WBEAM * BMAXIS (2,3)
TZ = UBEAM * BMAXIS (3,1) + VBEAM * BMAXIS (3,2) + WBEAM * BMAXIS (3,3)
Cheers, Anton
________________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Zi-Yi Yang [s9811249_at_m98.nthu.edu.tw]
Sent: 11 December 2016 06:07
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: Combination of SOURCE and BEAMAXES card.
Dear FLUKA user
I’m trying to define a specific beam direction to bombard a target.
From the FLUKA manual, a better way to do the task with arbitrary beam direction is to define a “beam reference frame” which is not consistent with original “geometry frame” and use subroutine SOURCE.
I had both tested the subroutine SOURCE and BEAMAXES function, and they can successfully work separately.
But when I put them together, the BEAMAXES card is disabled; the beam is along the default positive z-axis direction. (I defined a geometry there to certificate this.)
The active functions in the SOURCE are as following:
TKEFLK (NPFLKA) =RT ( PBEAM**2 + AM (IJBEAM)**2 ) - AM (IJBEAM)
TXFLK (NPFLKA) =EAM
TYFLK (NPFLKA) =EAM
TZFLK (NPFLKA) =EAM
XFLK (NPFLKA) =EAM
YFLK (NPFLKA) =EAM,
ZFLK (NPFLKA) =EAM
Where the definition of XBEAM, YBEAM, ZBEAM are followed by “geometry frame” and UBEAM, VBEAM, VBEAM are followed by “beam reference frame” (following the description in the (BEAMCM).)
Is there any other option need to be activated? or the order of input card will influence the results? (For example, as I know, the SOURCE card should be put after the BEAM, BEAMPOSit card)
Best regards,
Yang
__________________________________________________________________________
You can manage unsubscription from this mailing list at
https://www.fluka.org/fluka.php?id�c_info
(Ƨځ맲r*'~&x%Zm 0nߖi'iw
Received on Thu Dec 15 2016 - 15:29:27 CET