Dear Riya,
you can certainly use USRBDX for to estimate the spectra.
At the energy you are considering the emission of a bremsstrahlung photon does not occur often.
To improve your statistics you can consider to use biasing to increase the probability of bremsstrahlung.
In particular you can use EMF-BIAS card with SDUM = LAMBBREM (LAMbda Biasing for BREMsstrahlung interactions).
You can reduce the mean free path for electron and positron bremsstrahlung by a given factor (specified in WHAT(1)).
You can also set the generation up to which the biasing has to be applied (WHAT(3)).
The weights of both the incident and the secondary particle are automatically adjusted according to the ratio between the biased and the physical interaction probability at the sampled distance.
Please have a look at the EMF-BIAS card in the manual for more details.
For what concerns the Emax and Emin values in the USRBDX, I would use as maximum the maximum energy of your problem (0.15 MeV) and as minimum the transport threshold, for both electrons and photons.
Best regards,
Ilaria
On 19 Sep 2019, at 10:27, riya dey <riyadey_at_barc.gov.in<mailto:riyadey_at_barc.gov.in>> wrote:
Dear FLUKA Experts,
I simulated a spherical beta source having a spectra ( max beta energy 0.15 MeV) and tried to obtain electron spectra as well as Bremsstrahlung spectra at a detector position. To do this I have used two USRBDX card, one with WHAT(2) particle: ELECTRON and other one with WHAT(2) particle: PHOTON. I have used 1E-05 GeV as electron cut-off and 1E-6 GeV as gamma cut-off in both transport and production cut-off card. The output file contains > 10% error in the USRBX result for both electron and photons although the particle histories are 5E+9.
I have following queries:
1. Is this the correct way of estimation of Bremsstrahlung spectra?
2. The Emax and Emin values in the USRBDX card for electron have been taken from the min and max energy in the beta spectra which I have used as input in the source file. What are the values of Emax and Emin for scoring photons (Bremsstrahlung spectra)?
Thanks and Regards
~~~~~~~~~~~~~~~~~~~~~~~~~
Riya Dey
__________________________________________________________________________
You can manage unsubscription from this mailing list at
https://www.fluka.org/fluka.php?id=acc_info
Received on Fri Sep 20 2019 - 21:26:18 CEST