# RE: what is the relation between yield and cross section?

From: Markus Brugger <Markus.Brugger@cern.ch>
Date: Sat Sep 06 2008 - 13:32:55 CEST

Hi Jinghantao,

in one case you score the double differential distribution of the
outgoing particles, whereas in the in the other you obtain the
double-differential cross section. As you correctly indicate both scale
by number of incoming particles, the density and the target length. What
concerns your question, if I understand correctly, the 'scaling' between
the two scorings is nothing else then the differential cross section
itself: d2N/dx1dx2 * sigma =3D d2sigma/dx1dx2 -> does this answer your
question?

cheers

Markus

> -----Original Message-----
> From: owner-fluka-discuss@mi.infn.it [mailto:owner-fluka-
> discuss@mi.infn.it] On Behalf Of jinghantao
> Sent: 31 August 2008 15:48
> To: fluka-discuss@fluka.org
> Subject: what is the relation between yield and cross section?
>=20
> Hello everyone,
>=20
> As beginner, I want to re-calculate some processes in paper of
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=3D1. 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=3D3 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 =3D (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=3D3) and d^2 sigma/dx1
> dx2 (ixa=3D1) in fluka?
> Thank you very much in advance.
>=20
> Sincerely yours,
> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1jinghantao
> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1jinght@mail.ihep.ac.cn =
2008-08-31
>=20
Received on Sat Sep 6 15:10:56 2008

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