USRTRACK Manual Entry Clarification

Scoring
1

In reading the documentation for USRTRACK, I was hoping to get some clarification on it’s entry.

Note 1. says

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).

Processing USRTRACK with FLAIR calls the USTSUW program. Based on Note 1., bolded wording, makes it sound like the result from processing USRTRACK with FLAIR would be integral binned results with fluence in cm^-2 per energy bin per primary.

However, Note 7. says

It returns differential and cumulative fluence, with the corresponding percent errors, in a file, and differential fluence in another file formatted for easy plotting. It also returns a binary file that can be read out in turn by USTSUW.

Where the actual output from FLAIR calling USTSUW is

**** Different. Fluxes as a function of energy **** **** (integrated over solid angle) ****
Flux (Part/GeV/cmq/pr):

and

**** Cumulative Fluxes as a function of energy **** **** (integrated over solid angle) ****
Cumul. Flux (Part/cmq/pr):

Neither of which are fluence in cm^-2 or tracklength in cm per energy bin per primary.

Am I misinterpreting the manual?

2

The second (i.e., Cumul. Flux (Part/cmq/pr) in the .sum.lis file), as a function of the energy bin, is fluence in cm^-2 [cmq] per primary resulting from the integration over the energy interval from the lower limit of the current bin up to the requested maximum energy.
The difference between two consecutive values (corresponding to the bins i+1 and i, where E_{i+1} < E_i) gives the fluence in cm^-2 per primary over the energy range of the bin i+1.

The integral over the whole energy range requested is also provided, and coincides with the Cumul. Flux of the lowest bin.

On the other hand, what one usually wants to plot as a function of energy is the Flux (Part/GeV/cmq/pr), whose values remain differential and are not integrated over any energy range.

3

I see. The Cumulative Flux can give the fluence per bin, albeit with little manual effort.

Thank you for the clarification.