I have a doubt regarding USRBDX result,
I have run three cases for Photonuclear reaction,
1) With No LAM Bias card
2) With hadronic inelastic interaction length in LAM Bias card =0.03
3) With hadronic inelastic interaction length in LAM Bias card =0.0003
I am attaching usrbdx result of one way scoring of current for three cases.
for case 1) integrated neutron/pr=1.9914856e-5
for case 2) integrated neutron/pr=1.9187546e-5
for case 3) integrated neutron/pr=1.9493287e-5
Approximately similar.
But neutron distribution are totally different for these three cases.
why is the difference? I am sending you three distribution files.
> The distribution will always be the same. Biasing, if it is done
> correctly, doesn't change the result but converges faster to it.
> Your problem is, if you overdo it, you will flood the stack with too
> many particles and in the end you will not gain in efficiency as you
> should.
>
> But try it, and see what happens!
>
> Alberto
>
>
> On Wed, 5 Jun 2013, pkrai_at_barc.gov.in wrote:
>
>> But in my case photonuclear target is Beryllium.
>> In this case there is a reaction 9Be(r,n)8Be.The threshold energy for
>> this
>> photonuclear reaction is 1.666 MeV.And cross-section for this reaction
>> is
>> ~2 milibarn in the energy range below 10MeV.
>>
>> so If I keep the reduction factor of the hadronic inelastic interaction
>> length around 0.0003 or 0.03 or 0.0, will the result will be same or
>> different?(that means I will get same neutron ditribution or not?)
>>
>> Pravin Rai
>>
>>
>>> If the energy of primary electron and photon is about 10 MeV,
>>> there will be practically no photonuclear interaction! Or very little.
>>> The threshold is generally close to 8 MeV and even above threshold the
>>> cross
>>> sections are very small. Secondary photons have certainly not enough
>>> energy
>>> to interact.
>>> Therefore, I don't think that 0.0003 will over predict.
>>>
>>> Alberto
>>>
>>> On Wed, 5 Jun 2013, pkrai_at_barc.gov.in wrote:
>>>
>>>>
>>>>
>>>> I have a question regarding LAM-BIAS,
>>>>
>>>>
>>>> It is written in the manual that,Biasing of the hadronic inelastic
>>>> interaction length can be applied also to photons (provided option
>>>> PHOTONUC is also requested) and For photons, a typical reduction
>>>> factor
>>>> of
>>>> the hadronic inelastic interaction length is the order of 0.01-0.05
>>>> for
>>>> a
>>>> shower initiated by 1 GeV photons or electrons, and of 0.1-0.5
>>>> for one at 10 TeV.
>>>>
>>>> But what about if the energy of primary electron and photon is about
>>>> 10
>>>> MeV? By what amount I have to keep the reduction factor of the
>>>> hadronic
>>>> inelastic interaction length?
>>>>
>>>> In my case I have kept it around 0.0003, is it ok? or it will over
>>>> predict?
>>>>
>>>>
>>>> From,
>>>> PRAVIN RAI
>>>
>>>
>>
>>
>>
>
> --
> Alberto Fass
>
Received on Mon Jun 24 2013 - 09:52:05 CEST
