Hi Paola,
Thank you so much for your valuable response. I have made one
fresh input file as per your suggestion. Presently I have taken
the beam direction along Z-axis and the beam particles are
traveling in a cone of radius 2 cm from a distance of 50.17 cm
from the surface of the radiator. The detector material has been
changed to CR-39 (PADC) from PMMA. The energy of the incoming
neutrons is taken as 1 MeV.
Now I have got some results from USRYIELD card as briefed below:
The number of recoil protons which are transported from RADIATOR to
DETECTOR region is 2.30E-2 per primary. Whereas the result from RESNUCLEI
card shows that the total no. of recoil protons in RADIATOR region is
1.20E-2 per primary which is less than the previous value!!!
Again in 23 _tab.lis file results are given in four columns, what I am
guessing is
(1st -2nd column) -range of LET,
3rd column - yield of recoil proton and
4th column - associated errors.
If it is so then what is the unit of LET??
Actually I wanted to calculate the total LET deposited by the recoil
protons within the 0.07 cm of detector thickness. This will certainly be
the sum of the following two events:
1. Those recoil protons which are transported from RADIATOR region to
DETECTOR and depositing the energy.
2. Those recoil protons which are directly formed between the interaction
of incoming neutron and Hydrogen (1H) atom present in the detector
(CR-39).
In the first case WHAT (4) and WHAT (5) in the USRYIELD card are region
“rad” and “DETECT” respectively where I have got yield of 2.30E-2 per
primary.
But in the second case I have put “DETECT” in both WHAT (4) and WHAT (5)
in USRYIELD. This gave yield of 0 (zero).
[The input file, the source card and the results are attached below].
May be I am doing something wrong!!
But how can I get total LET (KeV/micron) within the detector region??
thanks in advance,
Meghnath
> Dear Meghnath Sen,
> The parameters in the USRYIELD card can be easily guessed by reading the
> manual and using Flair. As example:
> USRYIELD 123. PROTON -23. VOID DETECT
> USRYIELD 100. 0.0 100. 1. 0. 3. &
>
> However:
> - In your input, the source is isotropic and far away from a small
> radiator+detector. The probability to have a neutron reaching the radiator
> is fractions of permill, to be multiplied by the reaction probability..
> Probably if you tried your input you could not score anything. Try
> reducing the emission solid angle. To do this, it would be much better to
> build the geometry so that the preferential axis is the z axis (the
> standard beam axis for fluka) instead of the y axis.
> - A warning: neutrons below 20 MeV, only protonds generated by reactions
> on Hydrogen will be visible, the ones generated on Carbon are not
> transported.
>
> Hope this helps
> Paola
>> Hi,
>> I am interested to calculate the LET (KeV/micron) of recoil proton
>> (generated from interaction of neutron of energy 10 MeV with a thin
>> polyethylene radiator) within a detector having material as PMMA.
>> Fluka manual states that using USRYIELD card LET can be calculated. What
>> parameters I should set in that card ??
>> I have attached the corresponding input file . Can anyone please help me
>> to solve the problem.....
>>
>> thanks in advance,
>> Meghnath Sen
>> Scientific Officer
>> BARC, INDIA
>
>
> Paola Sala
> INFN Milano
> tel. Milano +39-0250317374
> tel. CERN +41-227679148
>
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- application/octet-stream attachment: 1mev.f
- application/octet-stream attachment: test5.inp
Received on Fri Apr 15 2016 - 15:40:40 CEST