From: Stefan Roesler (sroesler@mail.cern.ch)
Date: Thu Feb 01 2007 - 16:05:26 CET
---------- Forwarded message ----------
Date: Thu, 1 Feb 2007 14:21:19 +0100 (CET)
From: Stefan Roesler <sroesler@mail.cern.ch>
To: Nisy Ipe <nisy@comcast.net>
Cc: Alberto Fasso' <FASSO@SLAC.STANFORD.EDU>
Subject: Re: FW: Question
Hello Nisy,
When you score low-energy neutrons you can only score in the bin-structure
given by the neutron cross section data sets and you can only set the
lower energy limit but not the upper one. The number of bins in this case,
What(6), is meaningless and is determined by the lower energy limit,
What(2) in the continuation card. In case the latter value, as given by
the user in the input, does not coincide with a bin limit of the group
structure, it is internally re-adjusted to the next lower bin limit.
In your case the best solution is, as suggested by Alberto, to calculate
the cummulative over the corresponding energy region. Your upper limit of
10MeV fortunately coincides with one of the limits in the bin-structure.
Your question could be of interest to the community- thus, I suggest that
you post it together with my answer on fluka-discuss (or I can do it for
you if you agree).
Greetings
Stefan
On Tue, 30 Jan 2007, Nisy Ipe wrote:
>
> Hi Stefan,
>
> Do you know the answer to my question below?
>
> -----Original Message-----
> From: Alberto Fasso' [mailto:fasso@slac.stanford.edu]
> Sent: Tuesday, January 30, 2007 4:11 PM
> To: Nisy Ipe
> Subject: Re: Question
>
> Hi Nisy,
>
> I am not sure: the number of energy intervals below 20 MeV must always
> be 72 and cannot be changed. You can try a short run and see what you get.
> But there is another way: ask for a number of energy bins > 72, and
> then look at the cumulative "spectrum" that you get from ustsuw.
> I say "spectrum" because it is not really a spectrum, but a spectrum
> folded with the dose conversion factors. The differential one does
> not mean much for you, but the cumulative one is just the dose due
> to neutrons with energy less than a given energy (or higher, I don't
> remember, but it comes to the same thing)
>
> Alberto
>
> On Tue, 30 Jan 2007, Nisy Ipe wrote:
>
> > Hi Alberto,
> >
> > If I am only interested in neutrons below 10 MeV, can I use USRTARCK as
> > follows:
> >
> >
> > USRTRACK 1.0 8.0 -26. 4. 493410.53 1.
> > AMB74-01
> > USRTRACK 0.01 0.0
> >
> > Thanks,
> >
> > Nisy
>
>
-- ___________________________________ Stefan Roesler CERN, SC/RP CH-1211 Geneva 23 Switzerland Phone: +41-22-7679891 Fax: +41-22-7669639 E-mail: Stefan.Roesler@cern.ch
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