**From:** Alberto Fasso' (*fasso@SLAC.Stanford.EDU*)

**Date:** Tue Mar 04 2008 - 00:31:19 CET

**Previous message:**hamide jalali: "deq99c.f & dose equivalent"**Maybe in reply to:**Alberto Fasso': "Re: residue nuclei for thin target (fwd)"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ] [ attachment ]

Dear Harphool,

first, a recommendation to you and to all FLUKA users: please don't write

privately to me or to any of my colleagues, but keep all correspondence and

discussion on the fluka-discuss list. Everybody must be able to participate

in the discussion, not only you and me. And maybe somebody else is more

qualified than me for answering.

Coming to your question: of course you get a very high cross section. You

are getting residual nuclei not from the primary protons only, but from all

the secondaries. A 10 cm thick target is not a "thin" target! Check at the

end of your xxx.out file: how many secondary particles are produced?

Make your target 0.01 cm thick, and decrease accordingly the WHAT(2)=20

parameter in LAM-BIAS to something like 1.E-5 or 1.E-6.

How to calculate the cross section?

The number of residual nuclei of one type per primary, R, is given by:

R =3D N s d

where

s =3D cross section

N =3D number of atoms per cm3 =3D Av * rho / A

(Avogadro's number * density / mass number: Ns is the so-called

macroscopic cross section, which gives the probability of interaction

per unit length)

d =3D foil thickness

therefore

s =3D R/(Nd)

Alberto

*> Date: Mon, 3 Mar 2008 01:08:31 -0800 (PST)
*

*> From: harphool kumawat <kumawat77@yahoo.com>
*

*> To: Alberto Fasso' <fasso@slac.stanford.edu>
*

*> Subject: Re: residue nuclei for thin target
*

*>
*

*> Dear Alberto,
*

*> Please see the attached file and output data.
*

*> Can you please write me about the normalization cross-section
*

*> to get the value in cross-section.
*

*> I have used 1870mb for Pb+1GeV proton reaction but then the
*

*> values from FLUKA goes very high. Most probably I am making
*

*> some mistake. Please correct me.
*

*> Best regards,
*

*> Harphool
*

*>
*

*> Alberto Fasso' <fasso@slac.stanford.edu> wrote:
*

*> Dear Harphool,
*

*>
*

*> describe a thin target, and increase as you wish the number of interactio=
*

ns=20

*> in
*

*> the target by means of two commands LAM-BIAS, the first with SDUM =3D bla=
*

nk

*> and WHAT(2) < 1, the second with SDUM =3D INEPRI.
*

*> See the detailed description of LAM-BIAS in the manual.
*

*>
*

*> Alberto
*

*>
*

*>
*

*> On Thu, 21 Feb 2008, harphool kumawat wrote:
*

*>
*

*>> Dear all,
*

*>> May I ask you to suggest, how to calculate the residual nuclei for the
*

*>> thin targets? I wanted to calculate GSI data for Inverse kinematics
*

*>> or other thin target experimental data.
*

*>> Thanking you,
*

*>> Harphool
*

*>
*

*>
*

--=20

Alberto Fass=F2

SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025

Phone: (1 650) 926 4762 Fax: (1 650) 926 3569

fasso@slac.stanford.edu

--1334196310-408197497-1204587079=3D:26811--

**Previous message:**hamide jalali: "deq99c.f & dose equivalent"**Maybe in reply to:**Alberto Fasso': "Re: residue nuclei for thin target (fwd)"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ] [ attachment ]

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