Re: Inelastic interactions below 20 MeV

Dear Alberto, Andrea

Thank you for your insight.

I recollect that scoring secondaries is not possible in the low energy
region.
An exception as I recall is the recoil protons from hydrogen, which can be
flagged by the stupre sub routine.

In this case, since the total cross section is sampled, is it true that all
possible interactions including (n,2n) are sampled and transported, but not
flagged for scoring?

The input is attached with this mail.

Best Regards
Sunil

(I recollect from an old post that recoil protons from can be flagged by )

On Thu, Mar 10, 2011 at 9:34 PM, Alberto Fasso'<fasso_at_slac.stanford.edu>wrote:

> Dear Sunil,
>
> as you can see in a prevous mail by Paola Sala:
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/3510.html
> "In the transport of low energy ( below 20 MeV) neutrons, there is no
> distinction between elastic and inelastic scattering".
>
> Multigroup neutron transport is based on a "downscattering matrix".
> An interaction point is sampled based on the total neutron cross section,
> and the matrix is used to sample the new energy group where the neutron
> will be next. You cannot know where the interaction was a scattering
> (elastic or inelastic) or an (n,2n) reaction etc. You know only that
> the neutron has changed energy and direction.
>
> Alberto
>
>
>
> On Tue, 8 Mar 2011, Sunil C wrote:
>
> Hi All
>>
>> Let me also add:
>>
>> It is just not that neutrons are not emerging from the inelastic
>> interactions, but none are entering into an inelastic interaction either,
>> below 19.6 MeV.
>>
>>
>> Regards
>>
>> Sunil
>> ..............
>>
>> On Tue, Mar 8, 2011 at 2:28 PM, Sunil C<csunil11_at_gmail.com> wrote:
>>
>> Hi All
>>>
>>> I have been trying to score some neutrons emerging from inelastic
>>> interactions using the USRYILED option by setting WHAT(4) = -1 and
>>> WHAT(5)-2.
>>> with lead as the target material and neutrons as the primary particle.
>>>
>>> While I can see results above 20 MeV incident energy, it falls to 0.0
>>> right
>>> below that.
>>>
>>> Since there should be some interactions happening below about 15 MeV in
>>> the
>>> case of Pb and many other materials;
>>>
>>> 1. Are such interactions invoked at all below 20 MeV (19.6 MeV to be
>>> precise) due to the group structure?
>>>
>>> 2. Or is it just a matter of scoring through some other technique?
>>>
>>> Thanks a lot
>>>
>>> Sunil
>>>
>>>
>>
>>
>>
> --
> Alberto Fasso`
> SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
> Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
> fasso_at_slac.stanford.edu
>

--20cf3054acc5854211049e2f2a1e
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

Dear Alberto, Andrea<br><br>Thank you for your insight.<br><br>I recollect=
  that scoring secondaries is not possible in the low energy region.<br>An =
exception as I recall is the recoil protons from hydrogen, which can be fla=
gged by the stupre sub routine.<br>
<br>In this case, since=A0 the total cross section is sampled, is it true t=
hat all possible interactions including (n,2n) are sampled and transported,=
  but not flagged for scoring?<br><br>The input is attached with this mail.<=
br>
<br>Best Regards<br>Sunil<br>=A0<br>(I recollect from an old post that reco=
il protons from can be flagged by )<br>
<br><div class=3D"gmail_quote">On Thu, Mar 10, 2011 at 9:34 PM, Alberto Fas=
so&#39;<span dir=3D"ltr">&lt;<a href=3D"mailto:fasso_at_slac.stanford.edu" ta=
rget=3D"_blank">fasso_at_slac.stanford.edu</a>&gt;</span> wrote:<br><blockquot=
e class=3D"gmail_quote" style=3D"margin: 0pt 0pt 0pt 0.8ex; border-left: 1p=
x solid rgb(204, 204, 204); padding-left: 1ex;">

Dear Sunil,<br>
<br>
as you can see in a prevous mail by Paola Sala:<br>
<a href=3D"http://www.fluka.org/web_archive/earchive/new-fluka-discuss/3510=
.html" target=3D"_blank">http://www.fluka.org/web_archive/earchive/new-fluk=
a-discuss/3510.html</a><br>
&quot;In the transport of low energy ( below 20 MeV) neutrons, there is no<=
br>
distinction between elastic and inelastic scattering&quot;.<br>
<br>
Multigroup neutron transport is based on a&quot;downscattering matrix&quot=
;.<br>
An interaction point is sampled based on the total neutron cross section,<b=
r>
and the matrix is used to sample the new energy group where the neutron<br>
will be next. You cannot know where the interaction was a scattering<br>
(elastic or inelastic) or an (n,2n) reaction etc. You know only that<br>
the neutron has changed energy and direction.<br>
<br>
Alberto<div><div></div><div><br>
<br>
<br>
On Tue, 8 Mar 2011, Sunil C wrote:<br>
<br>
<blockquote class=3D"gmail_quote" style=3D"margin: 0pt 0pt 0pt 0.8ex; borde=
r-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hi All<br>
<br>
Let me also add:<br>
<br>
It is just not that neutrons are not emerging from the inelastic<br>
interactions, but none are entering into an inelastic interaction either,<b=
r>
below 19.6 MeV.<br>
<br>
<br>
Regards<br>
<br>
Sunil<br>
..............<br>
<br>
On Tue, Mar 8, 2011 at 2:28 PM, Sunil C&lt;<a href=3D"mailto:csunil11_at_gmai=
l.com" target=3D"_blank">csunil11_at_gmail.com</a>&gt; wrote:<br>
<br>
<blockquote class=3D"gmail_quote" style=3D"margin: 0pt 0pt 0pt 0.8ex; borde=
r-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hi All<br>
<br>
I have been trying to score some neutrons emerging from inelastic<br>
interactions using the USRYILED option by setting WHAT(4) =3D -1 and<br>
WHAT(5)-2.<br>
with lead as the target =A0material and neutrons as the primary particle.<b=
r>
<br>
While I can see results above 20 MeV incident energy, it falls to 0.0 right=
<br>
below that.<br>
<br>
Since there should be some interactions happening below about 15 MeV in the=
<br>
case of Pb and many other materials;<br>
<br>
1. =A0 =A0Are such interactions invoked at all below 20 MeV (19.6 MeV to be=
<br>
precise) due to the group structure?<br>
<br>
2. =A0 =A0Or is it just a matter of scoring through some other technique?<b=
r>
<br>
Thanks a lot<br>
<br>
Sunil<br>
<br>
</blockquote>
<br>
<br>
<br>
</blockquote>
<br></div></div><font color=3D"#888888">
-- <br>
Alberto Fasso`<br>
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025<br>
Phone: (1 650) 926 4762 =A0 Fax: (1 650) 926 3569<br>
<a href=3D"mailto:fasso_at_slac.stanford.edu" target=3D"_blank">fasso_at_slac.sta=
nford.edu</a><br>
</font></blockquote></div><br>

--20cf3054acc5854211049e2f2a1e--
--20cf3054acc5854229049e2f2a20
Content-Type: application/octet-stream; name="pb-19.inp"
Content-Disposition: attachment; filename="pb-19.inp"
Content-Transfer-Encoding: base64
X-Attachment-Id: f_gl4qfhty0
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--20cf3054acc5854229049e2f2a20--
Received on Fri Mar 11 2011 - 15:56:47 CET