Re: Activation by photons(low MeV)

Dear Patrick,

Energy threshold of C-12(gamma, n)C-11 reaction is approximately 18.7
MeV and of C-12(n, 2n)C-11 - approximately 20.3 MeV. 15 MeV maximum
energy photon spectrum does not produce C-11 through these two reactions.

   -George

--
George Kharashvili
Jefferson Lab Radiation Control
1-757-269-6435
Patrick Dethlof wrote:
> Hello everybody,
>
> i add a lam-bias card and got some nuclide but i did not get the
> nuclide a expected. I am irradiating bone with a 15MV spectrum i want
> to get K-38, K-40 and C-11.
>
> The only nuclide i got is K-40 and in the real measurment it was
> indeed very low like in my simulation.
>
> The problem is, that i did not get K-38 and C-11.
>
> One time i forgot to add the source card so that i was irradiating
> with 20MeV Photons and this time i got additional the C-11 nuclide.
> but the real measurement was with the 15MV spectrum.
>
> About the K-38 i am quiet unsure if it is a nuclide of bone or if
> there might be rest of meat in or at the bone because i did not do the
> measurments.
>
> Thanks for your help
>
>
> Patrick
>
> 2011/8/28 Santana, Mario <msantana_at_slac.stanford.edu>:
>> Patrick,
>>
>> Use the LAM-BIAS card to enhance the photonuclear reactions, a factor of
> 50 is typical (WHAT(2)=0.02).
>> Mario
>>
>>
>> On Aug 25, 2011, at 4:00 AM, Patrick Dethlof wrote:
>>
>>> Hello everybody,
>>>
>>> i am trying simulations to activate bone, muscle, steel or lead by a
>>> 15MV photon spectrum in order to compare them with measurements.
>>>
>>> But i did not get any results in my resnuclei scoring.
>>>
>>> When i used protons or neutrons i got results, but this is not really
>>> what i want.
>>>
>>> I attached my inp file and my source file with the needed spectrum.dat.
>>>
>>> Is there a physic missing, which i have to activate? Especiallyi
>>> wonder if there will be a neutron transport in my simulation.
>>>
>>> Thanks for your help
>>>
>>> Patrick Dethlof
>>> <linearPunkt.f><run.inp><spectrum.dat>
>>