Dear Zhefu,
Indeed, the solution I described below sets up a single particle per primary event. Is there a specific reason why do you want to simulate particles of each beam in the same primary event? Since Monte Carlo simulations require anyway a large number of events to achieve statistical convergence, it is not at all necessary to implement intensity ratios on single event basis. If you implement the sampling procedure I mentioned below, then - with sufficient statistics - you will get the correct intensity ratios of the beams. As a logical consequence, you need to multiply the results with the sum of beam intensities since your results will be per particle.
Cheers, Anton
________________________________
From: lzfneu [lzfneu_at_live.com]
Sent: 02 June 2016 16:11
To: Anton Lechner
Cc: fluka-discuss_at_fluka.org; neu lzf
Subject: RE: [fluka-discuss]: Question about three different sources?
Dear Anton,
Thanks for your reply.
I have one more question to consult you:
in the step 1), "IF ELSE IF" command can determin which ONE source works in source.f file, but in my opinion the others two sources do not work at this time.
That is to say the three sources don't emit at the same time. In addition to multiply with the total intensity of all three beams, whether the absolute results need to multiply 3 to plot the total dose equivalent distribution by using USRBIN card? I am quite confused about this issue.
Thanks in advance.
Zhefu
________________________________
From: Anton.Lechner_at_cern.ch
To: lzfneu_at_live.com; fluka-discuss_at_fluka.org
Subject: RE: [fluka-discuss]: Question about three different sources?
Date: Thu, 2 Jun 2016 10:35:44 +0000
Dear Zhefu,
Yes, this can be done with the source routine.
The relevant variables to define the phase space of a beam in the source routine are:
A) XFLK(NPFLKA)/YFLK(NPFLKA)/ZFLK(NPFLKA) (=cartesian coordinates)
B) TXFLK(NPFLKA)/TYFLK(NPFLKA)/TZFLK(NPFLKA) (=direction cosines)
To define three beams one could do the following:
1) randomly sample one of the three beams depending on their relative intensity, i.e. beam 1 is selected with a probability I1/(I1+I2+I3), beam 2 with a probability I2/(I1+I2+I3), and beam 3 with a probability I3/(I1+I2+I3), where I1/I2/I3 are the intensities of the three beams
2) for the beam selected in step 1), randomly sample from the phase space distribution of this beam (e.g. Gaussian shape) and fill the above mentioned phase space variables
If the different beams have different energies, you can also select this in the second step (either by defining the kinetic energy TKEFLK(NPFLKA) or the momentum PMOFLK(NPFLKA), of course making sure that they are consistently defined in the source routine).
Note that the results of scorings like USRBIN will then be per particle. In order to get absolute results you need to multiply with the total intensity of all three beams, i.e. I=I1+I2+I3
You can also find many more details on how to program source routines in the following course slides:
https://indico.cern.ch/event/334606/contributions/779780/attachments/653355/898394/AdvancedUserRoutines2014.pdf (routines in general)
https://indico.cern.ch/event/334606/contributions/779788/attachments/653364/898409/AdvancedSources2014.pdf (source routine)
Cheers, Anton
________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of lzfneu [lzfneu_at_live.com]
Sent: 02 June 2016 01:44
To: fluka-discuss_at_fluka.org
Cc: lzfneu_at_live.com
Subject: [fluka-discuss]: Question about three different sources?
Dear all,
My problem is concerned with three different sources with different beam intensities hit one same target at the same time.
Maybe the problem could be solved in source.f file, but I am not quite sure.
I have two questions to consult you:
1)how to define three different beam intensities in source.f file.
2)how to define three different sources hit the same target at the same time.
Any help will be appreciated and thanks in advance!
Zhefu
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Received on Thu Jun 02 2016 - 18:17:20 CEST