Re: [fluka-discuss]: EMFCUT problems about what(3)

From: Luigi Salvatore Esposito <luigi.salvatore.esposito_at_cern.ch>
Date: Thu, 12 Apr 2018 11:54:15 +0000

Dear Yang,
the short answer is that, yes, it was introduced a check on the value FUDGEM with respect to the threshold of generation of secondary electrons.

More in details, in the MCS formula the contribution of atomic electrons is taken into account (in very approximate way) by replacing
Z^2 -> Z*(Z+FUDGEM), where Z is the atomic number of the target.

When a condensed history approach is used for tracking of changed particles (as in FLUKA), there is a threshold to generate
secondary electrons (in FLUKA set by WHAT(1) in EMFCUT with SDUM=PROD-CUT).

For high threshold (> ~100 keV), secondary electrons are not generated and their contribution to the MCS should be taken in to account with the FUDGEM=1.
For low threshold, (<~5 keV), secondary electrons are explicitly produced and therefore FUDGEM=0 in order not to count them twice in the MCS.
In between, a linear interpolation from 0 to 1 can be used. However, the latter is intended only as rough approximation.

In conclusion, the check was introduced in order to make aware the user about the interplay between the explicit production of secondary electrons and
the treatment of the MCS in a condensed history tracking.

Hope this could answer your question.

Best, luigi


On 12 Apr 2018, at 03:46, YANG Tao <yangt_at_ihep.ac.cn<mailto:yangt_at_ihep.ac.cn>> wrote:


Dear Luigi,

Thanks for your reply. I don't set the EMF-BIAS card, the error is caused by the EMF-CUT card.I run the my original input file that I send to you, and indeed it reproduces the error again. Attachments are the error files, and I run it on the latest version fluka. I guess may be the cutoff I set is 1E-5, i.e.,10keV, what(3) should be set to 1.0, I run it without error(test2.inp). Then I set the cutoff to 1E-6 and the what(3) blank, program also runs without error. I read the manual mentioned the what(3) about EMF-CUT card:

     WHAT(3) = FUDGEM parameter. This parameter takes into account the
               contribution of atomic electrons to multiple scattering. For
               production and transport cutoffs larger than 100 keV it must be
               set = 1.0, while in the keV region it must be set = 0.0
               Default: 0.0

So 1E-5=10keV,it is not larger than 100 kev, why what(3) must be set to 1.0? And the error message always shows "Atomic electron contribution to mcs for material 3(HYDROGEN) set to 0, are you sure?", this is very strange, why it is only related to HYDROGEN? Besides, I ran the input files(test1.inp) on the old version FLUKA long time ago or the latest free-installation version, it doesn't report any error.

Best regards.

Yang


-----原始邮件-----
发件人:"Luigi Salvatore Esposito" <luigi.salvatore.esposito_at_cern.ch<mailto:luigi.salvatore.esposito_at_cern.ch>>
发送时间:2018-04-12 00:00:52 (星期四)
收件人: "YANG Tao" <yangt_at_ihep.ac.cn<mailto:yangt_at_ihep.ac.cn>>
抄送:
主题: Re: [fluka-discuss]: EMFCUT problems about what(3)

Dear Yang,
I’m not able to reproduce your error about EMF-BIAS.
Once I set WHAT(3) different from 0, the run is fine.
Are you sure to have send me the input file that generates the error?
Best, luigi


On 11 Apr 2018, at 10:21, YANG Tao <yangt_at_ihep.ac.cn<mailto:yangt_at_ihep.ac.cn>> wrote:


Dear Luigi,

Attachment is the input file,thanks.

Best regards

Yang

-----原始邮件-----
发件人:"Luigi Salvatore Esposito" <luigi.salvatore.esposito_at_cern.ch<mailto:luigi.salvatore.esposito_at_cern.ch>>
发送时间:2018-04-11 16:02:12 (星期三)
收件人: "YANG Tao" <yangt_at_ihep.ac.cn<mailto:yangt_at_ihep.ac.cn>>
抄送:
主题: Re: [fluka-discuss]: EMFCUT problems about what(3)

Dear Yang,
could you possibly send your input file — or a minimal version of it — to reproduce the issue?
Thanks, luigi

On 11 Apr 2018, at 03:55, YANG Tao <yangt_at_ihep.ac.cn<mailto:yangt_at_ihep.ac.cn>> wrote:


Dear fluka users,

Recently, I meet a strange thing about the EMFCUT card, I run an input file in the new version fluka, it gives the error message as follows:


*** Atomic electron contribution to mcs for material 3(HYDROGEN) set to 0, are you sure? ***
 *** if so re-enter it as 1.E-05 and run again, if not check the manual for the ***
 *** EMFCUT card, PROD-CUT, what(3), execution stopped meanwhile ***

Then I check the relevant card:

EMFCUT -1E-05 1.0E-5 BLCKHOLE _at_LASTMAT PROD-CUT
EMFCUT -0.0001 1.0E-5 bh _at_LASTREG
EMFCUT -0.0005 2.0E-5 pole1 xshuigd8
EMFCUT -1E-06 1.0E-7 detector detector


The strange thing is that the input file can be successfully ran on the old version FLUKA and it has no problem. I guess it may be related to the upgrade of the new version FLUKA, I read the manual, is says:

     WHAT(3) = FUDGEM parameter. This parameter takes into account the
               contribution of atomic electrons to multiple scattering. For
               production and transport cutoffs larger than 100 keV it must be
               set = 1.0, while in the keV region it must be set = 0.0
               Default: 0.0

I think the problem is the cutoff energy I set,i.e., 1e-4,5e-4 is larger than 100keV. So then I add What(3) of EMFCUT card as follows:

* ..+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
EMFCUT -1E-05 1.0E-5 BLCKHOLE _at_LASTMAT PROD-CUT
EMFCUT -0.0001 1.0E-5 1.0 bh _at_LASTREG
EMFCUT -0.0005 2.0E-5 1.0 pole1 xshuigd8
EMFCUT -1E-06 1.0E-7 detector detector

Unfortunately, I still get an error as follows:

Setting EMF leading particle biasing with What(3) of EMFCUT is deprecated!
If you really want EMF leading particle biasing use the EMF-BIAS card instead.

I don't know why. And I don't know why it can be run on the old version FLUKA and the current free-installation version(flupix-2011.2c-6_flair-2.3-1_x86_64.iso). <https://www.fluka.org/packages/flupix-2011.2c-6_flair-2.3-1_x86_64.iso>

Could anyone help me to point out what's wrong with my input file? Thanks!


Best regards!


Yang

E-mail:yangt_at_ihep.ac.cn<mailto:yangt_at_ihep.ac.cn>




<test.inp>



<test.inp><test001.err><test001.log><test001.out><test2.inp>


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Received on Thu Apr 12 2018 - 15:34:33 CEST

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