Re: Re: Re: [fluka-discuss]: negative deposit energy from EVENTBIN using Fluka2011.2x.8

From: 崔明阳 <mycui_at_pmo.ac.cn>
Date: Tue, 10 Mar 2020 21:39:40 +0800 (GMT+08:00)

Dear Paola,

Thanks a lot for your help!
For event 56, there is large discrepancy for region VP11 and VP16.

Best regards,
Mingyang



> -----原始邮件-----
> 发件人: "Paola Sala" <paola.sala_at_mi.infn.it>
> 发送时间: 2020-03-05 20:48:30 (星期四)
> 收件人: "\"崔明阳\"" <mycui_at_pmo.ac.cn>
> 抄送: paola.sala_at_mi.infn.it, fluka-discuss_at_fluka.org, paolo.bernardini_at_le.infn.it
> 主题: Re: Re: [fluka-discuss]: negative deposit energy from EVENTBIN using Fluka2011.2x.8
>
> Dear Mingyang
> I confirm that the negative energy deposition you see is indeed physically
> sound: It comes from a neutron at ~ thermal energy hitting an Hydrogen
> atom and gaining energy from the thermal motion of the target.
>
> This can happen only when pointwise treatment of neutron transport is
> activated, as it happens since a while with the DEFAULTS PRECISION (only
> for a few materials, see the manual)
>
> For groupwise transport, kerma is averaged and is never negative.
>
> If you do not "like" to see negative energies, (which are tiny quantities
> indeed), you can either
> - disable pointwise treatment through the LOW-NEUT card . This I do not
> advise, the simulations will be less precise
> - intercept them with a comscw.f routine. I attach an example that writes
> informations whenever a negative energy dep occours. It has to be
> activated with a USERWEIG card, what(6)=3.
>
> I am sorry I cannot find the other discrepancy you mention, probably I
> missed it: you point to event 56, could you, please, tell me in which
> region do you see it?
>
> Be careful: the two MULSOPT cards have wrong SDUMS, they should be GLOBEMF
> and GLOBHAD.
>
>
>
> > Dear Paola,
> >
> > The attachment is an example to illustrate the problem.
> >
> > More details:
> > If conducting a run using FLUKA 2011.2x.8,
> > 1) You'll find negative deposit in 62nd event in
> > negative_demo001_fort.113.
> > 2) The relative difference of energy deposit extracted from EVENTDAT and
> > EVENTBIN card could be very large, say 90%, for instance in 56th event.
> >
> > Thanks a lot for your help!
> >
> > Best regards,
> > Mingyang
> >
> >
> >> -----原始邮件-----
> >> 发件人: "Paola Sala" <paola.sala_at_mi.infn.it>
> >> 发送时间: 2020-02-28 17:15:43 (星期五)
> >> 收件人: "\"崔明阳\"" <mycui_at_pmo.ac.cn>
> >> 抄送: fluka-discuss_at_fluka.org, "\"李翔\"" <xiangli_at_pmo.ac.cn>,
> >> "\"岳川\"" <yuechuan_at_pmo.ac.cn>, "\"袁强\""
> >> <yuanq_at_pmo.ac.cn>
> >> 主题: Re: [fluka-discuss]: negative deposit energy from EVENTBIN using
> >> Fluka2011.2x.8
> >>
> >> Dear Migyang
> >> Could you, please, give some more details about your simulation and the
> >> effect you see?
> >> ( You can send me your input file if you wish)
> >> Please note that very small negative energy depositions are possible
> >> when
> >> thermal neutrons are transported: being thermal, they can gain energy by
> >> reducing the thermal motion of the target.
> >> Hope this helps
> >> Paola
> >> > Dear Fluka experts,
> >> >
> >> >
> >> >
> >> >
> >> > When we update Fluka from version 2011.2x.7 to 2011.2x.8 recently, a
> >> > problem arises.
> >> >
> >> > Negative energy deposit will occur as we scoring energy using EVENTBIN
> >> > card.
> >> >
> >> > Besides, we have added SDUM=OLDFLAIR in the GLOBAL card as mentioned
> >> in
> >> > the release note.
> >> >
> >> >
> >> >
> >> >
> >> > Are there other necessary modifications on input file?
> >> >
> >> > We appreciate your help with this.
> >> >
> >> >
> >> >
> >> >
> >> > Best,
> >> >
> >> > Mingyang
> >>
> >>
> >> Paola Sala
> >> INFN Milano
> >> tel. Milano +39-0250317374
> >> tel. CERN +41-227679148
>
>
> Paola Sala
> INFN Milano
> tel. Milano +39-0250317374
> tel. CERN +41-227679148

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Received on Tue Mar 10 2020 - 16:45:25 CET