Re: Using LOW_BIAS to discard Fissions from low energy (<20 MeV)

neutrons
Sender: owner-fluka-discuss_at_mi.infn.it

Thank you for your response Alberto. The reason I wasn't sure about the
LE/HE energy cut off is the results of the "LE & HE" score estimator
results in the output files.

I am including results from just one run, 1 Million primaries each for
two separate runs: Run A: No LOW-BIAS card, Run B: With LOW-BIAS card
(ECUT set at 20 MeV). I would have expected the LE-FISS SD to be zero
for the run B. But we are getting 6.65228E-04 which is a small number.
Should I be accepting this as consistent with zero?

Also, should we not be getting 0 secondaries created by low energy
neutrons per beam particle (as reported in the output file as well) for
Run B? [out of curiousity, shouldn't the sum of the particle type
contributions add up to 100%?].

The reason we imposed the ECUT in LOW-BIAS card for neutrons is because
we are interested in distinguishing low- and high-energy neutron
contribution to residual nuclei yield. So, Run B, resnuclei yield
results should be in principle lower than those from Run A since we have
discarded low energy neutrons. I think we could accomplish this by
setting Type (WHAT(1)) to 1 (Spallation) and to 2 (Low Energy) in the
RESNUCLEi estimator. Am I right?

Thank you and best wishes,
Mina

NOTES: SD is Star Density

Run A: 1M primaries (protons), No LOW-BIAS card

Region Volume LE-FISS SD HE-FISS SD NEUTRON SD
         cm^3 Stars/(cm^3.p) Stars/(cm^3.p) Stars/(cm^3.p)
===============================================================
rTaCont 1.0 0.00000E+00 3.80000E-05 4.22900E-03
rUO2Tgt 1.0 6.59889E-02 3.89387E-01 6.48250E-02

Number of secondaries created by low energy neutron per beam particle:
Prompt radiation Radioactive decays
3.9215E+00 (100.%) 0.0000E+00 (100.%)
2.0986E+00 (53.5%) 0.0000E+00 ( 0.0%) NEUTRON
2.0663E-01 ( 5.3%) 0.0000E+00 ( 0.0%) fission NEUTRON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) PROTON
2.0663E-01 ( 5.3%) 0.0000E+00 ( 0.0%) PHOTON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) DEUTERON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) TRITON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) 3-HELIUM
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) 4-HELIUM

Run B: 1M primaries (protons) With LOW-BIAS card (ECUT set at 20MeV)

Region Volume LE-FISS SD HE-FISS SD NEUTRON SD
         cm^3 Stars/(cm^3.p) Stars/(cm^3.p) Stars/(cm^3.p)
===============================================================
rTaCont 1.0 0.00000E+00 4.80000E-05 4.21700E-03
rUO2Tgt 1.0 6.65228E-04 3.88645E-01 6.41160E-02

Number of secondaries created by low energy neutron per beam particle:
Prompt radiation Radioactive decays
4.0117E-02 (100.%) 0.0000E+00 (100.%)
2.2190E-02 (55.3%) 0.0000E+00 ( 0.0%) NEUTRON
2.0770E-03 ( 5.2%) 0.0000E+00 ( 0.0%) fission NEUTRON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) PROTON
2.0770E-03 ( 5.2%) 0.0000E+00 ( 0.0%) PHOTON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) DEUTERON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) TRITON
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) 3-HELIUM
0.0000E+00 ( 0.0%) 0.0000E+00 ( 0.0%) 4-HELIUM

On 11-07-15 06:24 AM, Fasso, Alberto wrote:
> Mina,
>
> using LOW-BIAS, indeed you get rid of neutrons with energy< 20 MeV,
> and therefore the only fissions you score are those from high energy
> hadrons. But why do you want to do that, when it is possible to
> obtain both at the same time, using LE-FISSION and HE-FISSION? The
> cutoff energy for the LE/HE is 20 MeV, of course.
>
> Alberto ________________________________________ From: Mina Nozar
> [nozarm_at_triumf.ca] Sent: Thursday, July 14, 2011 1:37 PM To:
> fluka-discuss_at_fluka.org Subject: Using LOW_BIAS to discard Fissions
> from low energy (<20 MeV)
>
> neutrons? Sender: owner-fluka-discuss_at_mi.infn.it
>
> Hi all,
>
> Setup: 500 MeV protons on UO2 target encased inside Ta container.
>
> Objective: Isolate low energy (<= 20 MeV) neutron contribution to
> fission product yields from hight energy protons and neutrons.
>
> Questions: 1- Can I achieve the above objective by using LOW-BIAS to
> set the energy cutoff for low energy neutrons. I am only setting the
> ECut WHAT(1):
>
> LOW-BIAS 1. 0.0 rUO2Tgt
>
> 2- I am looking at the LE-FISSION and HE-FISSION densities via the
> SCORE estimator; however, I do not know what the cut off energy is
> for the LE/HE. I could not find it in the manual.
>
> Thank you in advance, Mina
>
Received on Sat Jul 16 2011 - 16:35:17 CEST