what is the relation between yield and cross section?

Hello everyone,

    As beginner, I want to re-calculate some processes in paper of
＾Treating High Energy Showers￣(downloaded from fluka site). I use the USRYIELD card to
recalculate the double differential spectra(Figure 26 and Figure 28 in paper).
In continuation card, for WHAT(6), ixa=1. So i can obatain the double-differential cross section
d^2 sigma/d x1 d x2, Then I use usysuw to read the data out from the binary files. The energy-spectra
shade of curves for deferent degree is very similar to Figure 28, but the order of magnitude is not right.
Then I set ixa=3 to calculate double differential yield d^2 N/ d x1 d x2.
I find the ratio of d^2 N/dx1 dx2 to d^2 sigma/dx1 dx2 is just a constant.
Generally, the relation is d^2 N/ d x1 d x2 = (d^2 sigma/dx1 dx2)*(L*rho)/mA,
where the L is the target thickness, rho the nuclear density and mA the target-nucleus mass.
If I firstly calculated the yield and multipled by (L*rho)/mA, I find the rusults are correct.
What is the constant between d^2 N/dx1 dx2 (ixa=3) and d^2 sigma/dx1 dx2 (ixa=1) in fluka?
Thank you very much in advance.

Sincerely yours,
　　　　　　　　jinghantao
　　　　　　　　jinght@mail.ihep.ac.cn 2008-08-31
Received on Mon Sep 1 09:04:27 2008