From: Sebastien WURTH (wurth@ipno.in2p3.fr)
Date: Tue Sep 19 2006 - 15:59:43 CEST
Hello,
In your example, you cannot have a neutron fluence, you put WHAT(2) =
7.0 in your first USRBDX card, this would give you photon fluence (maybe
you choose only the wrong example to illustrate).
To answer your question (I was asking me the same one once), I quote the
manual from USRBDX part :
*********
Notes
1. IMPORTANT! The results of a USRBDX boundary crossing estimator are
always given as double differential
distributions of fluence (or current) in energy and solid angle, in
units of cm−2 GeV−1 sr−1 per incident primary,
even when only 1 interval (bin) has been requested, which is often the
case for angular distributions.
Thus, for example, when requesting a fluence or current energy spectrum,
with no angular distribution, to
obtain integral binned results (fluence or current in cm−2 per energy
bin per primary) one must multiply the
value of each energy bin by the width of the bin (even for logarithmic
binning), and by 2 pi or 4 pi (depending
on whether one-way or two-way scoring has been requested).[...]
*********
Best Regards.
Sebastien.
Nicole Patricia Lee Pratt-Boyden a écrit :
>Hello,
>
>I'm using a USRBDX card to score neutron fluence (linear angular and
>energy bins). The programme seems to be running fine, and I'm compiling
>the data with the usxsuw.f programme.
>
>I asked for eight energy bins, and one angular bin.
>
>USRBDX 101.0 7.0 -48.0 3.0 4.0 400.0
>PH-199m
>USRBDX 6.5E-4 2.5E-4 8.0 0.0 1. &
>
>The *_tab file only returns the differential fluence integrated over
>solid angle; there are no double differential values returned at all,
>no mention of solid angle boundaries.
>
>Assuming this is fine, do I still need to multiply the differential
>values by 2PI (one-way scoring) in order to get diff. fluence in
>particles/GeV/cm^2/primary, or do I only do this if I want fluence
>(/cm^2/pr)?
>
>Apologies if this is extremely simple, I was just thrown by the lack of
>any information for the double differential! Best regards,
>
>Nicole Pratt-Boyden.
>
>
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