Re: Low Residual Nuclei output

Thanks a lot Paola for giving attention to this problem and solving it.
I am sorry for scaring you all. I was also pretty disappointed for last
two weeks for getting unexpected results with the new version. Now I
would like to get some of my more doubts cleared in this forum.
1) Do I have to switch on the "IONTRANS" card for scoring energy
deposition due to 4-He and 6-Li generated from neutrons ?
2) Can I transport 4-He in any reaction it is produced or only
specifically from the one produced from B-10 ?
3) If I take 4-He as primary source, what is the lowest energy for its
transportation in any material and for nuclear reaction ? (As per the
old Fluka release, the lowest energy for nuclear reation was 100 MeV/n).

With Regards,
S. Chatterjee
Scientific Officer,
TLD Unit, BARC
Variable Energy Cyclotron Centre,
1/AF, Bidhannagar,Kolkata-64
Off:+91-33-23184207
Fax:+91-33-23346871

----- Original Message -----
From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Friday, April 22, 2011 12:17 pm
Subject: Re: Low Residual Nuclei output

> Dear S. Chatterjee,
>
> Your problem scared us..but fortunately it is a problem of
> "labelling",and is solved by changing the what(1) field in the
> RESNUCLEI card.
>
> This may be relevant to other users, please read the explaination:
>
> Yes, something changed in the last version, and we forgot to
> document it
> in the release notes, sorry.
>
> The change is in the low energy neutron treatment, and has a
> consequenceon how residual are flagged:
>
> In FLUKA2011, the 4-He and 6-Li from neutron capture on 10-B are
> explicitely generated and transported like all secondaries from
> inelasticinteractions, and become indistinguishable from all other
> interactionsecondaries..This is independent on the choice made for
> ion transport.
> As a consequence, when they stop they are scored as residuals from
> inelastic interactions, not as residuals from low energy neutrons.
>
> If you change what(1) in the RESNUCLEI card from 2.0 ( low-energy
> neutronresiduals) to 3.0 ( all residuals) you'll get back all the 4-
> He you need.
>
> Warning, valid already for fluka2008: the SAME treatment, and
> "labelling",applies to protons pronuced in (n,1H) reactions and in
> (n,14-N) reactions.
> If the pointwise treatment is activated, the same applies also to all
> products from n reactions on 6-Li.
>
> For your specific case, the new treatment of 10-B may be very useful,
> since now you can not only count alphas, but also, if you wish,
> simulatetheir energy deposition and containment in the detectors.
>
> Best regards
> Paola
>
>
>
>
>
>
>
>
>
>
> > Content-disposition: inline
> >
> > Dear Fluka experts,
> > I have been using a particular input file since Fluka's last
> version i.e.,
> > Fluka 2008.3d. The residual nuclei output of He-4 was of the
> order of
> > 10^-4. Now after switching over from the 2008.3d version to 2011.2.2
> > version, I am finding that suddenly the He-4 production is of the
> order of
> > ~ 10^-9 which is way below the expected values. I have used USRBDX
> > detectors also in the input file and their output remains at par
> with the
> > old version. I would like to know whether there is any change
> with respect
> > to residual nuclei calculation in this new version. I have used two
> > PHYSICS cards in the input as stated in the manual. As I am
> scoring only
> > the no of He-4 ions, I have switched off the ion transportation.
> I am
> > attaching the input file for your reference.
> > I would be thankful for your kind attention in this matter.
> >
> > With Regards,
> > S. Chatterjee
> > Scientific Officer,
> > TLD Unit, BARC
> > Variable Energy Cyclotron Centre,
> > 1/AF, Bidhannagar,Kolkata-64
> > Off:+91-33-23184207
> > Fax:+91-33-23346871
> >
>
>
>
Received on Fri Apr 22 2011 - 12:52:05 CEST