Re: [fluka-discuss]: DPA underestimation in Fe target

From: <alfredo.ferrari_at_mi.infn.it>
Date: Wed, 2 Jun 2021 16:38:29 +0200

Sorry

I should have specified to link with rqmd and dpmjet ($FLUPRO/flutil/ldpmqmd)

Alfredo

> Dear Fluka experts
>
> I am a new FLUKA user
>
> When I tried to use this Fe.inp file for the modelling of Radiation
> induce damage, I received this message:
>
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> !!!! ATTENTION PLEASE !!!!
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>
> Coalescence activated and beam above BME limit with no rQMD
> and no or incompatible IONSPLIT option!
> Execution terminated.
>
> This problem has been addressed earlier:
>
>
> From: Paola Sala
> <paola.sala_at_mi.infn.it<mailto:paola.sala_at_mi.infn.it?Subject=Re%3A%20%5Bfluka-discuss%5D%3A%20Problems%20while%20simulating%20residual%20dose>>
> Date: Mon, 9 Sep 2019 09:05:13 +0200
>
> Hello
>
> If coalescence is (correctly!) activated, ions will be produced. The code
> checks that they can be transported and that their interactions are
> simulated. Depending on beam energy, this means that one has to include
> the ion interaction generators (RQMD and DPMJET). you can have a look at
> past answers to learn how
>
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/14583.html
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/15273.html
>
> Regards
> Paola
>
> As a new user I was not able use the two URL's to find out how to
> to include the ion interaction generators (RQMD and DPMJET).
>
>
>
> Would you perhaps have any further advice?
>
>
> Thank you.
>
>
> Regards
>
>
> Phillip
>
>
>
>
> Phillip Pare
>
> S.E.
>
> Tel: +27-12-305-5219
>
> Fax: +27-86-625-5462
>
> Cell: +27-72-397-8356
>
> Email: phillip.pare_at_necsa.co.za
>
> Website: www.necsa.co.za<http://www.necsa.co.za>
>
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> From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> on
> behalf of Answers <answers_at_pcfluka.mi.infn.it>
> Sent: Wednesday, 02 June 2021 09:17:12
> To: 朱雪燕
> Cc: fluka-discuss_at_fluka.org
> Subject: Re: [fluka-discuss]: DPA underestimation in Fe target
>
> Dear Zhu
>
> first of all there is a misunderstanding about the normalization of
> USRBIN's by regions. The code has no obvious way to know the volume of
> a region, which can be very complex.
> Hence, contrary to cartesian or cylindrical USRBIN's, those by region
> still have to be divided by the region volume by the user (of course it
> is
> unfortunately the user task to calculate that volume). In your case the
> (interesting) region volume is easy to calculate, it is 0.3 cm^3 (of
> course you have to consider only the irradiated volume). Hence, after
> dividing by the region volume, the DPA's are now 0.13/atom for 10^20
> incoming protons.
>
> This is still a factor ~2 less than what reported in the 2011 paper,
> because since that time many refinements and improvements have been
> implemented into the DPA calculations, particularly for particle below
> threshold. Those improvements, related to the correct applications of the
> xsi function (see eq. 2) in the 2011 paper) close to threshold are
> responsible for the present, more correct, value.
>
> In the attached input, which is a slight re-elaboration of your original
> one, you can find a cylindrical bin (so no volume re-normalization issue)
> covering the 1 cm^2 (circular) irradiation area, scoring both DPA's and
> restricted NIEL. If you take the latter and apply without any "higher
> order" correction the NRT formula, DPA=0.8 Tk / 2 Eth, which in this
> case translates to:
>
> DPA = 0.8 NIEL_restr(GeV/cm^3)/(2 Eth(eV))x10^9 x 55.85 / 7.87 / N_av
>
> where 55.85 is the iron atomic weight, 7.87 its density in g/cm^3,
> and N_av the Avogadro number, Eth=40 eV, you will find 0.29 DPA's for
> 10^20 protons (~ the old result) showing how important and delicate is
> to apply the efficiency corrections close to threshold. Since DPA's
> cannot be measured in reality, when comparing results among different
> calulations, or referring to material properties as a function of DPA's,
> it is important to be sure to use the same DPA definition/method of
> calculation, hence for a "standard" NRT calculation one can always resort
> to the restricted NIEL and proceed as above.
>
> Best regards
> The Fluka developers
>
> On Fri, 30 Apr 2021, 朱雪燕 wrote:
>
>> Dear fluka experts,
>>
>> I am trying to reproduce the results from the paper in the attached
>> file.
>> This is a case of 1 GeV proton on 3 mm thick Fe with a beam area of 1
>> m^2.
>> Table 2 in the paper shows the results of the DPA calculated by fluka,
>> which
>> is 0.28 for 1E20 beam particles.
>>
>> My inputfile is in the attachment. USERBIN with region type was used
>> for
>> scoring. The output file print the following result:
>> accurate deposition along the tracks requested
>> 4.2169E-22
>>
>> According to my understanding, 4.2169E-22 * 1E20 = 4.2169E-2 should be
>> the
>> DPA. However, this value is one order of magnitude lower than the value
>> 0.28
>> in the paper.
>>
>> Could you please help to have a look if there is any misunderstanding of
>> the
>> output of fluka or there is any error in my inpufile?
>>
>> Thanks a lot in advance.
>>
>> Best wishes,
>> Xueyan Zhu
>>
>
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Received on Wed Jun 02 2021 - 17:59:14 CEST

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