Re: Score neutron from 16O(p,xn) reaction

From: Vasilis Vlachoudis <>
Date: Mon, 15 Dec 2008 17:27:18 +0100

Dear Lee,

in your case, the units indeed are be mb/MeV but with NOT the correct
value (at least what you would expect). If you use a target material in
USRYIELD, FLUKA will multiply the double differential quantity you are
scoring by the requested inelastic cross section and at the end
normalize by dividing with the total number of primary particles.
However to calculate the cross section, you should multiply by the
inelastic cross section and divide by the number of interacting particles.
Maybe the easiest way would be, NOT to use any target material in
USRYIELD and later do the conversion to cross section by your self
assuming the atomic density and thickness of your material.

Another problem in your input, is that you want to define O-16 as
MATERIAL #9, but you didn't supply the "mass number" WHAT(6)=16. So you
have created a "natural" Oxygen with "average atomic weight" of 16.

Best Regards
Vasilis wrote:
> Dear Francesco:
> I set the target thin to score the cross-section of 20MeV proton
> (p,xn) reaction of Oxygen-16 EMERGING from target.
> 100micro meter depth of water to make the energy loss of proton small
> (around 1MeV).
> The output result of total response 0-0.15 MeV, 0-180deg bin from
> 51_sum.lis is 23.3.
> Does this mean that the cross-section I scored of (p,n) of material
> Oxygen-16 : 23.3 barn/ [GeV] (barn or mbarn ?),which equals 23.3
> mb/MeV ?
> I benefit a lot from your advice for the choice of LAM-BIAS for
> applying this case.
> Did I still make obvious mistake? Once again,
> ,thanks
> Please advise me to do the comparison with ICRU , the magnitude
> relation still deviates.
> My Best Regards
> Lee
Received on Mon Dec 15 2008 - 17:55:52 CET

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