Dear Francesco,
I tried to verify the cross section you obtain by directly counting fission events by means of MGDRAW (in the USDRAW entry one can verify if an interaction involved fission by checking the logical flag LFSSSC; at the same time you can check that the projectile was a proton). I can indeed reproduce the value you get, i.e. I obtain ~2.1b for 50 MeV protons in U-238.
The issue here is not due to fission but can be attributed to the total interaction cross section which appears to be too elevated around this energy (for Z > 90).
(thanks to Alfredo for checking the latter point)
Cheers, Anton
________________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Francesco Rossetto [francesco.rossetto_at_lnl.infn.it]
Sent: 22 April 2014 11:35
To: fluka-discuss_at_fluka.org
Cc: Majordomo_at_fisica.unimi.it
Subject: [fluka-discuss]: Proton induced fission cross section
Dear Fluka experts,
I was trying to measure the fission cross section for proton at
different energies against a U-238. I obviously chose a thin target in
order to preserve the original power amount of the proton as best as
possible.
What I measured is a cross section over 2 barns, which is excessively
higher than what described by experiments and other models.
I also tried to use the card DISCARD in order to exclude neutrons from
the process and have a purely proton induced proton fission process, but
still I have strange results.
Could you please tell me how I should improve the configuration of the
virtual experiment in order to get better data?
I attached a plot with the fission cross section as a function of the
incoming proton energy.
--
Francesco
Received on Tue Apr 29 2014 - 21:50:16 CEST