From: Mina Nozar <>
Date: Fri, 26 Oct 2012 13:24:15 -0700

Dear Mario,

Hello and thank you for checking into this.

On 12-10-25 11:14 AM, Santana, Mario wrote:
> Hi Mina,
> You are right, FLAIR offers that option (maybe for future developments, maybe because LOWENNEU may be accepted in other CARDS), but FLUKA doesn't.
> Actually, if you check in the FLUKA manual under 'Generalised particles (to be used only for scoring)',you will see that low-energy neutrons
> (which internally in FLUKA are = 40), have no associated name string, unlike all other generalized particles.

Yes, I see this in table 5.2 of the FLUKA 2011.2.14 manual.

Incidentally, looking in the manual under the Particle and material codes, I don't see Low energy neutrons associated
with FlUKA number 40. I only see "Reserved" for FLUKA number 40.

> So you would then think that using '40. ' in USRBIN-WHAT(2) would work for your problem. But from my tests, it seems that it doesn't.
> The run doesn't crash, but you get all zero's even when there are neutrons below 20MeV, which is above the energy for which I did my
> test and where NEUTRONS appeared in my USRBIN. Please test this.

The run stops immediately for me with the error message below. We must be running slightly different versions of FLUKA.
    I am running 2011.2.14.
I have checked using USRBDX and I do see neutrons with energies below 20 MeV.

> Next option would be to use AUXSCORE. You write USRBIN for WHAT(1), '40.' for WHAT(2) and in WHAT(4) whatever SDUM identifier you
> had given for your USRBIN. However, in my same tests you get all zeros once more. Please try by yourself too.

I don't see how this is different. What is the AUXSCORE for if we have chosen to look at low energy neutron fluence by
setting WHAT(2) to '40'?

> Thus, the only alternative that I see is that you customize fluscw.f routine, but I am not sure you want to reach there.
> Mario

No, I don't want to get there. Just wanted to look at the spatial distribution of low energy neutrons separately. I am
not (at the moment) comfortable using user routines.

Thanks again for your help.

> On Oct 24, 2012, at 5:03 PM, Mina Nozar wrote:
> Hello everyone,
> One of the selections in the drop-down menu of WHAT(2) for USRBIN with WHAT(1)=10 is LOWENNEU.
> I chose this to look at spatial distribution of low energy neutrons. I can't find any info. on this in the manual.
> USRBIN 10. LOWENNEU -24. 200. 600. 0.LE_N_Fl
> USRBIN -600. -200. -900. 140. 160. 180.&
> When I try to run with this estimator, the run stops shortly with the message:
> *** Unable to resolve name element LOWENNEU in card ***
> USRBIN 10. LOWENNEU -24. 200. 600. 0.LE_N_Fl
> *** run stopped ***
> Is the LOWENNEU not implemented as a possible particle type for USRBIN?
> Thank you in advance,
> Mina
Received on Sat Oct 27 2012 - 00:25:26 CEST

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