Re: Cross section and radiation lenght!

Dear Vasilis,

Thank you for your help.
I still have a problem with my cross-check evaluation for cross section.
I thought it came from USRYIELD but it may be come from USRBDX.

I use 7-Li, with 100 MeV/c per nucleon, on lead target, 0.1 cm thin. For
7-Li, USRYIELD gives me the following cross-section =3D 1.8 barn, but If
I'm looking with USRBDX the 7-Li flux ratio between before and after the
lead target, I have Flux/Flux-initial =3D 0.1 when I am hoping
Flux/Flux-initial =3D 0.994. May be the way I use it, it's wrong?

USRBDX 99. HEAVYION -42. TARGET VOID 100.0BdxAp
USRBDX 10.0 0.01 100. &

What can I do to debug that, some tips to be sure what I am looking at?

Thanks.

Regards,

Jonathan

2008/10/24 Vasilis Vlachoudis <Vasilis.Vlachoudis_at_cern.ch>

> Dear Jonathan,
>
> the scattering length is the average distance to have an interaction and =
it
> is equal to the inverse of the macroscopic cross section,
>
> Scattering_length =3D 1 / (Na/A * rho * cross-section)
>
> Na =3D Avogadro number
> A =3D atomic mass
> rho =3D density
>
> Vasilis
>
>
> jonathan pochon wrote:
>
>> Hi,
>>
>> I'm checking some cross sections with simple set-up before
>> to use something complicated. I'm sometimes surprised
>> with USRYIELD cross section, and I want to be sure on my
>> understanding.
>>
>> For this reason, I would like to know how to extract initial cross
>> section that FLUKA uses for example with a proton beam and
>> a carbon target. I saw the standard output with scattering length
>> but I'm not sure it's the scattering length from
>> Cross-section =3D cst * Scatt-Length=B2
>>
>> It must be a vocabulary problem or something like that.
>>
>> Thanks,
>>
>> Jonathan
>>
>
>
Received on Thu Oct 30 2008 - 12:40:19 CET