RE: LOW ENERGY NEUTRONS

From: Lawrence Mhatiwa <lawrencemhatiwa_at_hotmail.com>
Date: Mon, 27 Jul 2009 17:11:09 +0000

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Dear Alberto

Thanks Alaberto. I removed the LOW-BIAS and it worked. I also changed
the cut-off to to the lowest neutron group 260 and I got plenty of
neutrons.

Thanks once again

Cheers

        Lawrence

> Date: Wed=2C 22 Jul 2009 10:28:09 -0700
> From: fasso_at_SLAC.Stanford.EDU
> To: fluka-discuss_at_fluka.org
> CC: lawrencemhatiwa_at_hotmail.com
> Subject: Re: LOW ENERGY NEUTRONS
>=20
> Hi Lawrence=2C
>=20
> in your input you have a line:
> LOW-BIAS 73. 72. 0.85 BLKBODY @LASTREG 1.0
>=20
> This command sets a neutron energy cutoff at group 72 (the last group
> in the old neutron library). But in the new library group 72 is about
> 2.7 MeV=2C and most giant resonance neutrons have lower energies.
> I have removed the command and I have got plenty of neutrons.
> So=2C either remove the command=2C or leave it with a different group
> number (e.g. 261 instead of 73)=2C or force FLUKA to use the old
> library by means of a LOW-NEUT command.
>=20
> Best regards=2C
>=20
> Alberto
>=20
> On Tue=2C 21 Jul 2009=2C Lawrence Mhatiwa wrote:
>=20
> >=3D20
> > Dear Fluka Users
> >=3D20
> > =3DA0
> >=3D20
> > I am studying=3DA0 photoneutron processes in targets using FLUKA. In my
> > input file I have an electron beam striking a compound target
> > (Tungsten and gold) and I am scoring neutron fluence in tungsten=2C gol=
d
> > and lead as shown in the input file.Unfortunately I can not get any
> > neutron output yet iam using a 15MeV beam but photoneutrons are
> > generally produced from 10MeV onwards in most materials.
> >=3D20
> > =3DA0
> >=3D20
> > =3DA0Can someone please help me to identify what could be wrong with my
> > input file?
> >=3D20
> > =3DA0
> >=3D20
> > Thank you
> >=3D20
> > =3DA0
> >=3D20
> > Lawrence =3DA0=3DA0
>=20
>=20
> --=3D20
> Alberto Fasso`
> SLAC-RP=2C MS 48=2C 2575 Sand Hill Road=2C Menlo Park CA 94025
> Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
> fasso_at_slac.stanford.edu
>=20

_________________________________________________________________
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Dear Alberto<BR><BR>
Thanks&nbsp=3BAlaberto i removed&nbsp=3B the&nbsp=3BLOW-BIAS and it worked =
.I also changed the cut-off to&nbsp=3Bto the lowest neutron group =2C260 an=
d i got plenty of neutrons.<BR>
&nbsp=3B<BR>
Thanks once again<BR>
&nbsp=3B<BR>
Cheers<BR>
&nbsp=3B<BR>
Lawrence&nbsp=3B<BR>&gt=3B Date: Wed=2C 22 Jul 2009 10:28:09 -0700<BR>&gt=
=3B From: fasso_at_SLAC.Stanford.EDU<BR>&gt=3B To: fluka-discuss_at_fluka.org<BR>=
&gt=3B CC: lawrencemhatiwa_at_hotmail.com<BR>&gt=3B Subject: Re: LOW ENERGY NE=
UTRONS<BR>&gt=3B <BR>&gt=3B Hi Lawrence=2C<BR>&gt=3B <BR>&gt=3B in your inp=
ut you have a line:<BR>&gt=3B LOW-BIAS 73. 72. 0.85 BLKBODY @LASTREG 1.0<BR=
>&gt=3B <BR>&gt=3B This command sets a neutron energy cutoff at group 72 (t=
he last group<BR>&gt=3B in the old neutron library). But in the new library=
 group 72 is about<BR>&gt=3B 2.7 MeV=2C and most giant resonance neutrons h=
ave lower energies.<BR>&gt=3B I have removed the command and I have got ple=
nty of neutrons.<BR>&gt=3B So=2C either remove the command=2C or leave it w=
ith a different group<BR>&gt=3B number (e.g. 261 instead of 73)=2C or force=
 FLUKA to use the old<BR>&gt=3B library by means of a LOW-NEUT command.<BR>=
&gt=3B <BR>&gt=3B Best regards=2C<BR>&gt=3B <BR>&gt=3B Alberto<BR>&gt=3B <B=
R>&gt=3B On Tue=2C 21 Jul 2009=2C Lawrence Mhatiwa wrote:<BR>&gt=3B <BR>&gt=
=3B &gt=3B=3D20<BR>&gt=3B &gt=3B Dear Fluka Users<BR>&gt=3B &gt=3B=3D20<BR>=
&gt=3B &gt=3B =3DA0<BR>&gt=3B &gt=3B=3D20<BR>&gt=3B &gt=3B I am studying=3D=
A0 photoneutron processes in targets using FLUKA. In my<BR>&gt=3B &gt=3B in=
put file I have an electron beam striking a compound target<BR>&gt=3B &gt=
=3B (Tungsten and gold) and I am scoring neutron fluence in tungsten=2C gol=
d<BR>&gt=3B &gt=3B and lead as shown in the input file.Unfortunately I can =
not get any<BR>&gt=3B &gt=3B neutron output yet iam using a 15MeV beam but =
photoneutrons are<BR>&gt=3B &gt=3B generally produced from 10MeV onwards in=
 most materials.<BR>&gt=3B &gt=3B=3D20<BR>&gt=3B &gt=3B =3DA0<BR>&gt=3B &gt=
=3B=3D20<BR>&gt=3B &gt=3B =3DA0Can someone please help me to identify what =
could be wrong with my<BR>&gt=3B &gt=3B input file?<BR>&gt=3B &gt=3B=3D20<B=
R>&gt=3B &gt=3B =3DA0<BR>&gt=3B &gt=3B=3D20<BR>&gt=3B &gt=3B Thank you<BR>&=
gt=3B &gt=3B=3D20<BR>&gt=3B &gt=3B =3DA0<BR>&gt=3B &gt=3B=3D20<BR>&gt=3B &g=
t=3B Lawrence =3DA0=3DA0<BR>&gt=3B <BR>&gt=3B <BR>&gt=3B --=3D20<BR>&gt=3B =
Alberto Fasso`<BR>&gt=3B SLAC-RP=2C MS 48=2C 2575 Sand Hill Road=2C Menlo P=
ark CA 94025<BR>&gt=3B Phone: (1 650) 926 4762 Fax: (1 650) 926 3569<BR>&gt=
=3B fasso_at_slac.stanford.edu<BR>&gt=3B <BR><br /><hr />See all the ways you =
can stay connected <a href=3D'http://www.microsoft.com/windows/windowslive/=
default.aspx' target=3D'_new'>to friends and family</a></body>
</html>=

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Received on Mon Jul 27 2009 - 21:32:27 CEST

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