Re: [fluka-discuss]: Question about energy loss

From: Shirley Li <shirleyli.phys_at_gmail.com>
Date: Fri, 25 Apr 2014 14:58:54 -0400

Dear Anton,

I added up all the neutrino energies and now the number makes much more
sense. Also, I did use the attached user routine, and added up the energy
in my python analysis code. After you mentioned it, adding up the energy
in mgdraw.f seems like a much better idea...

Thank you so much for your help!!

Best,
Shirley


On Fri, Apr 25, 2014 at 1:30 PM, Anton Lechner <Anton.Lechner_at_cern.ch>wrote:

> Dear Shirley,
>
> First of all, in FLUKA the energy is conserved on an event-by-event basis
> [except for low-energy neutron interactions where it is conserved on
> average]. There is a specific reason for your observations: since you
> switch on photo-nuclear interactions, there can be events where a
> significant amount of energy (~GeV) goes into neutrinos (decay of pions
> produced in the nuclear interactions); since neutrinos are then discarded
> they don't appear in your energy balance.
>
> If you are interested, you can intercept the produced neutrinos on the
> stack (in USDRAW). By looping over all secondaries on GENSTK and matching
> against neutrino particle IDs, you can determine the energy of neutrinos,
> e.g. for muon antineutrinos:
> DO 207 INMB = 1, NP
> IF( KPART(INMB).EQ.28 ) THEN
> * you can then access the neutrino energy via
> TKI(INMB)
> END IF
> 207 CONTINUE
>
> Apart from this, it is correct to add up the continuous energy loss along
> a step (sum over the DTRACK array in MGDRAW) and discrete energy
> depositions (RULL in ENDRAW). Note that you can also access the escaping
> energy via RULL (see the different ICODES in the header of of ENDRAW). One
> also has to take care not to double count (which could have been an issue
> for other users, as you mention in your Email).
>
> BTW, you attached probably a wrong routine, since it does not sum up the
> energy as you describe in your Email.
>
> Cheers, Anton
>
>
>
>
>
> ------------------------------
> *From:* Shirley Li [shirleyli.phys_at_gmail.com]
> *Sent:* 25 April 2014 15:55
> *To:* Anton Lechner
> *Cc:* fluka-discuss_at_fluka.org
> *Subject:* Re: [fluka-discuss]: Question about energy loss
>
> Dear Anton,
>
> I attached the input and mgdraw.f. To check the energy, I add up RULL
> and DTRACK and kinetic energy of particle leaving the water region to see
> if it's close to 10 GeV.
>
> Thank you very much!
>
> Best,
> Shirley
>
>
> On Fri, Apr 25, 2014 at 5:31 AM, Anton Lechner <Anton.Lechner_at_cern.ch>wrote:
>
>> Dear Shirley,
>>
>> Could you please be so kind and send me your input file+routines such
>> that I can give a look to your problem.
>>
>> Thanks!
>> Cheers, Anton
>>
>>
>>
>>
>> ------------------------------
>> *From:* owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it]
>> on behalf of Shirley Li [shirleyli.phys_at_gmail.com]
>> *Sent:* 24 April 2014 22:47
>> *To:* fluka-discuss_at_fluka.org
>> *Subject:* [fluka-discuss]: Question about energy loss
>>
>> Dear FLUKA users,
>>
>> I'm simulating photon (electromagnetic) showers in water. The primary
>> photon energy is 10 GeV. As a check, I want to make sure I find where the
>> energy goes on a event-by-event basis. For every primary photon, I add up
>> all the continuous energy loss (DTRACK) and the point energy loss (RULL),
>> and they count for most of the energy (>99%). I also add the energies
>> carried away by particle escaping the water region. However, for some
>> (very small portion) primaries, the energy in DTRACK + RULL + boundary
>> crossing is only around 7-8 GeV, compared to the total 10 GeV.
>>
>> My question is where else could the energy go? Is there anything I'm
>> missing?
>>
>> I read some discussions on similar topics in the list. But, it seems
>> like they tend to have the opposite problem, i.e., deposited energy is more
>> than the primary energy. Also, I couldn't imagine neutron interaction or
>> nuclear interaction affect this much energy.
>>
>> Thank you very much!!
>> Shirley
>>
>
>
Received on Fri Apr 25 2014 - 22:33:59 CEST

This archive was generated by hypermail 2.3.0 : Fri Apr 25 2014 - 22:34:04 CEST