RE: p+U reaction

Andrzej,

what is the statistical error of your USRBDX result?
Even if it was zero (which it cannot be), the result is larger than the
reported experimental value by less than 2 standard deviations
(experimental).
I find it a fair agreement...

Alberto

On Fri, 30 Jul 2010, Andrzej Wojciechowski wrote:

> Hi Alberto,
> Thank you for you explanation - Number of secondaries generated in
> inelastic interaction per beam particle"
> refers only to neutron with energy> 20 MeV.
>
> I have a one question yet.
>
> The numnber of the escaped neutrons scored by USRBDX card in the
> boudary between 3 and 4 regions is equal to 42.8 (see attachment) and is
> greater than experimental data (38.8+-5%).
> What is the reasons? What I have done badly?
> Kind reagards
> Andrzej
>
>
> Dnia 26-07-2010, pon o godzinie 06:52 -0700, Alberto Fasso' pisze:
>> Sorry, I had not understood that you had MORE neutrons exiting the target
>> than produced inside it.
>> A likely explanation is the following: in the final statistics of the
>> FLUKA standard output,
>> "Number of secondaries generated in inelastic interaction per beam
particle"
>> refers only to neutron with energy> 20 MeV.
>> Produced low-energy neutrons are accounted for separately in the same
part of
>> the output.
>>
>> Alberto
>>
>>
>> On Wed, 21 Jul 2010, Andrzej Wojciechowski wrote:
>>
>>> Dear Lucia and Alberto
>>> Very thanks for your help.
>>> Unfortunately problem is not clear for me yet.
>>> In my opinion 'Number of secondaries generated in inelastic
>>> interaction per beam particle" means all produced particles (37.8
>>> neutrons).
>>> This number have to be greater or equal than escaped neutrons scored
>>> by USRBDX card in the boudary between 3 and 4 regions. The USRBDX card
>>> using current option (not fluence) give the results - 42.8 neutrons.
>>> (Experimental data 38.8+-5%)
>>> Why all produced neutrons (37.8) is less than exited neutrons (42.8)?
>>> Im my opinion all neutron are inelastic in this problem.
>>> Kind regards
>>> Andrzej
>>>
>>> Dnia 20-07-2010, wto o godzinie 10:51 -0700, Fasso, Alberto pisze:
>>>> Dear Andrzej and Lucia,
>>>>
>>>> the main reason for the difference between neutrons produced and
neutrons exiting from the target
>>>> is that not all produced neutrons can escape, but some interact
inside the target, getting absorbed.
>>>>
>>>> Alberto
>>>>
>>>> ________________________________________
>>>> From: owner-fluka-discuss_at_mi.infn.it
[owner-fluka-discuss_at_mi.infn.it] On Behalf Of Lucia Sarchiapone
[Lucia.Sarchiapone_at_lnl.infn.it]
>>>> Sent: Tuesday, July 20, 2010 4:15 AM
>>>> To: Andrzej Wojciechowski
>>>> Cc: fluka-discuss_at_fluka.org
>>>> Subject: Re: p+U reaction
>>>>
>>>> The main difference is due to the fact that the fluence is a quantity
>>>> that takes into account the direction of the particle with respect to
>>>> the boundary between the regions. In the manual you can read that the
>>>> fluence is weighted with the inverse of the cosine of the angle between
>>>> particle direction and normal to the surface.
>>>> In principle you can get rid of this weighting factor scoring current
>>>> instead of fluence, but you will still find some difference because -I
>>>> guess, and I hope that someone corrects me if I'm wrong - with the
>>>> USRBDX you are scoring neutrons from all interactions, not just the
>>>> inelastic ones.
>>>>
>>>> Lucia
>>>>
>>>> On Jul 19, 2010 02:39 PM, Andrzej Wojciechowski<andrzej_at_cyf.gov.pl>
>>>> wrote:
>>>>
>>>>> Dear Lucia
>>>>> Do you explain me why the total fluence of neutrons scored with the
>>>>> USRBDX estimator, crossing the boundary between region R3 and R4
>>>>> is diferent than the "Number of secondaries generated in inelastic
>>>>> interaction per beam particle" for neutron?
>>>>> Kind regard
>>>>> Andrzej
>>>>>
>>>>> Dnia 15-07-2010, czw o godzinie 14:41 +0200, Lucia Sarchiapone pisze:
>>>>> > Dear Andrzej,
>>>>> >
>>>>> > you are probably looking at the total fluence of neutrons scored
>>>>> > with
>>>>> > the USRBDX estimator, crossing the boundary between region R3 and
>>>>> > R4.
>>>>> > In my opinion if you want to look for the number of neutrons
>>>>> > generated
>>>>> > per primary proton you should look at the standard output file
>>>>> > (*.out).
>>>>> > In the list called "Number of secondaries generated in inelastic
>>>>> > interaction per beam particle" you will find that neutrons are
>>>>> > something
>>>>> > like 37.8 (depending on the number of primaries you run in the
>>>>> > simulation). This value is much closer to the experimental one.
>>>>> > Cheers,
>>>>> >
>>>>> > Lucia
>>>>> >
>>>>> >
>>>>> > On Jul 14, 2010 04:27 PM, Andrzej Wojciechowski<andrzej_at_cyf.gov.pl>
>>>>> > wrote:
>>>>> >
>>>>> > > Dear FLUKA users
>>>>> > > I am traying calculate the total number of neutron produced
during
>>>>> > > reaction p+U-238 (see attachment) (1.22GeV)
>>>>> > > The experimental result[1] equal to 38.8+-5%,
>>>>> > > the calculation result egual to 44.0
>>>>> > > What am I doing badly?
>>>>> > >
>>>>> > > Kind regards
>>>>> > > Andrzej
>>>>> > >
>>>>> > > [1] L. Pienkowski,* F. Goldenbaum, D. Hilscher,=C3=A2? and U.
>>>>> > > Jahnke,
>>>>> > > Neutron
>>>>> > > multiplicity distributions for 1.94 to 5 GeV/c proton-,
>>>>> > > antiproton-,
>>>>> > > pion-, kaon-,and deuteron-induced spallation reactions on thin
and
>>>>> > > thick
>>>>> > > targets.PHYSICAL REVIEW C VOLUME 56, NUMBER 4 OCTOBER 1997
>>>>>
>>>
>>
>

-- 
Alberto Fasso`
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
Phone: (1 650) 926 4762   Fax: (1 650) 926 3569
fasso_at_slac.stanford.edu