Re: [fluka-discuss]: USRYIELD spectrum for PROTON and BEAMPART in SOBP beam

From: Franz Englbrecht <>
Date: Thu, 13 Jul 2017 16:45:15 +0200

On 07/12/2017 04:13 PM, Francesca Fiorini wrote:
> Dear experts,
> I am plotting the spectra of protons in water in the middle of a SOBP in a phantom. I am using USRYIELD, and in two different cards I'm scoring the spectrum for PROTON and BEAMPART. According to what I could understand from some emails in the mailing list and manual, BEAMPART should include incident protons plus those that only undergo elastic interactions, while PROTON should include all protons (primaries + secondaries). First of all, is this second assumption correct?
> If it is, when I plot the USRYIELD data, I have the spectrum of BEAMPART way above the spectrum of PROTON (almost 10 orders of magnitude larger), which would make sense only if, for some reason, the BEAMPART and PROTON spectra were normalised using different numbers, or... I made some mistake somewhere.
> However if I repeat the same simulation without using a SOBP, but a simple pencil beam (one single energy instead of many), I have no problem in producing sensible results, with the data from PROTON slightly higher than BEAMPART as it should be. I've also noticed that in the case of the SOBP, also other particle spectrum scorings from USRYIELD have a weird normalisation, as they are about 3x10^3 times larger than the case with only one single energy beam. While I expected the SOBP case to show a higher number of secondary particles, a ratio of this magnitude is perhaps a bit too large.
> Does all of this depend on the fact that in the SOBP case there are many initial beams and FLUKA is not picking the exact total number of particles to do the normalisation? However why would it pick two different numbers for BEAMPART and PROTON?
> I have used BEAMPART and PROTON before in USRBIN scorings and never found anything that didn't convince me, so I am uncertain here on how to treat these results.
> If you could enlighten me on this I would be extremely thankful.
> Many thanks
> Francesca
> CRUK and MRC Oxford Institute for Radiation Oncology
> Department of Oncology, University of Oxford
> Old Road Campus Research Building
> Roosevelt Drive
> Oxford, OX3 7DQ
> UK

Dear Francesca,

how did you produce the SOBP? Could you send us your input files and
user routines?



You can manage unsubscription from this mailing list at
Received on Thu Jul 13 2017 - 17:47:37 CEST

This archive was generated by hypermail 2.3.0 : Thu Jul 13 2017 - 17:47:39 CEST