Re: [fluka-discuss]: USRTRACK outputs

From: Paola Sala <>
Date: Fri, 2 Oct 2020 16:24:56 +0200

results are per primary AND per GeV: Integral values are obtained by
multiplying by the bin width
 I copy here the notes in the manual

1) IMPORTANT! The results of USRTRACK are always given as DIFFERENTIAL
            distributions of fluence (or tracklength, if the detector region
            volume is not specified) in energy, in units of cm-2 GeV-1 (or
            cm GeV-1) per incident primary unit weight. Thus, for example, when
            requesting a fluence energy spectrum, to obtain INTEGRAL BINNED
            results (fluence in cm-2 or tracklength in cm PER ENERGY BIN per
            primary) one must multiply the value of each energy bin by the width
            of the bin (even for logarithmic binning). This is done automatically
            by the dedicated post-processing utility program USTSUW (see Note 7).

7) A program USTSUW is available with the normal FLUKA code distribution
            in directory $FLUPRO/flutil. USTSUW reads USRTRACK results in
            form from several runs and allows to compute standard
deviations. It
            returns differential and cumulative fluence, with the
            percent errors, in a file, and differential fluence in another
            formatted for easy plotting.

The file with integrated quantities is the one with extension _sum.lis
The one for plotting is _tab.lis

> Dear FLUKA experts,
> I am using two USRTRACK score cards, for transmission and scattering
> geometry, to estimate the fluence of gamma photons.
> In scattering, the maximum output range (Y-axis) of spectrum is ~0.0025
> (<<1) and in transmission this value is ~12 (>1).
> The simulation was run for 10^5 number of histories. If the counts on the
> Y-axis are per photon then scale seems OK for scattering measurement but I
> am a little confused about scale obtained for transmission measurement,
> why
> it is greater than 1 ?
> Please comment on my doubt to get clarity of this confusion.
> Thanks in advance.
> Regards,
> A. Sharma

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148

You can manage unsubscription from this mailing list at
Received on Fri Oct 02 2020 - 18:29:56 CEST

This archive was generated by hypermail 2.3.0 : Fri Oct 02 2020 - 18:30:16 CEST