Dear Anton and Forum :
2013/11/30 Anton Lechner <Anton.Lechner_at_cern.ch>
> Dear Lee,
>
> You can interpret the values you specify (from the summary file created
> with USYSUW) as follows: for example, the differential yield of 0.1 GeV^-1
> you get in the energy interval 0-0.01 GeV simply means that 0.1
> GeV^-1*0.01GeV=1E-03 neutrons with E<10 MeV were produced in inelastic
> hadronic interactions within your entire geometry (also in the surrounding
> air). Of course this is consistent with the value you got for the larger
> energy interval, since most neutrons are below 10 MeV.
>
From the link you included in your file, I guess that you are only
> interested in neutrons produced in following reaction:
> p + O18 -> F18 + n
> If this is the case, you should not forget that a non-negligible fraction
> of neutrons also emerge from other processes, e.g.:
> p + O18 -> O17 + n + p
> p + O18 -> N14 + n + alpha
> USRYIELD will count all neutrons, also those from the latter interactions.
> If you are only interested in the first reaction, you could for example
> use USDRAW in the MGDRAW user routine. By including
> '(RESNUC)', you have access to the atomic and mass number of the residual
> nucleus and you can filter neutrons accordingly. I included some sample
> code below.
>
Thank for your reply, I do not even know there is non-negligible fraction
of neutrons from other processes.
I will try the function when I'm more familiar with it.
The output of yield from USRYIELD makes much more sense to me now.
However, it seems to me that I can not interpret the cross section part as
yield.
The XS0-0.01, 61 bin scores the neutron binning from 0 to 10MeV.
The results of cross section give around 30mb/GeV.
Is cross section (with E<10MeV were produced) 30mb/GeV * 10MeV = 0.3mb ?
0.3mb is consistent with the results from XS0-1, 65 bin from 0 to 1GeV.
But It deviates too much from the recommended cross section which gives
87mb.
Thank in advance
Lee
Received on Sat Nov 30 2013 - 03:33:25 CET