**From:** Francesco Cerutti (*Francesco.Cerutti@cern.ch*)

**Date:** Mon Jan 29 2007 - 21:10:31 CET

**Previous message:**Francesco Cerutti: "Re: Understanding RESNUC scoring"**Maybe in reply to:**hamide jalali: "problem with USRBIN & USRBDX results"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ] [ attachment ]

Dear Hamide,

*> First,in the case of ENELOW and ENEUP values' in source.f, They are in
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*> term of Gev/n, Should I convert them to Gev,then FLUKA itself consider them
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*> in term of Gev/n for heavy ion?
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TKEFLK (NPFLKA) is the TOTAL kinetic energy of your nucleus expressed in

GeV. So if you load values in GeV/n, you have to multiply your ENERGY

variable by dble(IPROA) (i.e. 12) before assigning its value to

TKEFLK(NPFLKA).

*> Second,you had mentioned that I must define an isotropic property of my
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*> source in my own source.f .I had done it before but I omitted it according
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*> to Fasso's recommendation.If I eliminate the commands of Cos(tx,ty,tz) from
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*> my source.f is it correct to consider this character with BEAM?
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*> I had given these commands in source.f to define an isotopic source.
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*>
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*> * Isotropic angular distribution
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*> YI = FLRNDM(DUMMY)
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*> COSTH = ONEONE - 2.D0 * YI
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*> IF (COSTH .GT. ONEONE) THEN
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*> COSTH = ONEONE
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*> ELSE IF (COSTH .LT. -ONEONE) THEN
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*> COSTH = -ONEONE
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*> END IF
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*> ZI = FLRNDM(DUMMY)
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*> ANG = TWOPIP * ZI
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*> UBEAM = SQRT (ONEONE - COSTH * COSTH) * COS(ANG)
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*> VBEAM = SQRT (ONEONE - COSTH * COSTH) * SIN(ANG)
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*> WBEAM = COSTH
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If you want an isotropic distribution, you do not need a customized source

routine (the point - right - of Alberto). But if you need your own source

routine for other reasons (sampling from a special spectrum), then you

have to define there the direction cosines too. Your above coding seems to

be correct.

Remember that you have to define U[vw]BEAM BEFORE assigning

their values to TX[yz]FLK (NPFLKA). The same holds for X[yz]BEAM with

respect to X[yz]FLK (NPFLKA).

Florian was just hinting at this point:

*> **In your source.f you set the beam position for the first particle to the
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*> defaults i.e. (0.,0.,0.) and for the remaining particles to
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*> XBEAM = 4.D05
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*> YBEAM = 4.D05
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*> ZBEAM = 4.D05
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This is because you write

XFLK (NPFLKA) = XBEAM

YFLK (NPFLKA) = YBEAM

ZFLK (NPFLKA) = ZBEAM

XBEAM = 4.D05

YBEAM = 4.D05

ZBEAM = 4.D05

instead of

XBEAM = 4.D05

YBEAM = 4.D05

ZBEAM = 4.D05

XFLK (NPFLKA) = XBEAM

YFLK (NPFLKA) = YBEAM

ZFLK (NPFLKA) = ZBEAM

The first particle starts at the center of your Al shell, the following

ones almost 7km far away.

*> Then you set the direction cosines to:
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*>
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*> (UBEAM, VBEAM, WBEAM)= (0., 0. , 1.)
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This is because you do not define the direction cosines (default values

are taken).

*> With this settings you may hit the volume defined by your USRBIN with
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*> the first particle but never with the others and therefor the output
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*> contains only zeros.**
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The effect is that only the first particle goes through your Al shell, the

others never see it.

But please note that placing an isotropic source 7km far away from a 20m

diameter sphere means that the probability that one nucleus impinges on it

is VERY small since the solid angle covered by your shell is less than

10 usr (i.e. 10^-5 sr, to be compared with 4*pi sr!). Thus you have to

sample much more efficiently the carbon directions (you are interested

just in the ions hitting the Al shell).

Finally your USRBIN R-PHI-Z binning looks strange: you are scoring over a

cylinder at z~5.5m and R~10m, i.e. OUTSIDE the Al shell (at z~5.5m your Al

shell has a distance R from the z axis of about 8m) where you have vacuum

and so you will get always zero energy deposition.

Ciao!

Francesco

**************************************************

Francesco Cerutti

CERN-AB

CH-1211 Geneva 23

Switzerland

tel. ++41 22 7678962

fax ++41 22 7668854

**Previous message:**Francesco Cerutti: "Re: Understanding RESNUC scoring"**Maybe in reply to:**hamide jalali: "problem with USRBIN & USRBDX results"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ] [ attachment ]

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