Re: Understanding EMF-CUT and residual dose rate

Dear Francesco,

Another quit note on region setting in the EMFCUT.

As I mentioned in my earlier messages, the default region setting of #2 is
not working through flair. So if one does not choose any region for "Reg"
or "to Reg", there is no regions selected.

This is not a big deal since even this default setting is not what the
user should be using if he/she intends that the transport and production
cuts be properly applied.

Best wishes and thank you again,
Mina

> Dear Mina,

> Finally, your first try assumes the default region range, which is limited
> to the region #2 - as written in the manual, EMFCUT card - (and makes
> your threshold setting ineffective also for photons if the corresponding
> material is VACUUM or BLCKHOLE).
>
> Ciao
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. ++41 22 7678962
> fax ++41 22 7668854
>
> On Wed, 28 Mar 2012, nozarm_at_triumf.ca wrote:
>
>> Dear Stefan,
>>
>> Thank you for this information which has helped me investigate this
>> puzzle
>> but I am still having difficulty understanding what is exactly going on
>> with the EMFCUT for gammas and e+/e- and I would appreciate if someone
>> could help clarify this.
>>
>> I have run three sets of runs for a given setup (only varying EMFCUT).
>> I
>> had run two before your message and I ran one after your message and
>> reading the EMFCUT and DEFAULTS part of the manual few times, trying to
>> understand.
>>
>> Please note in all of these tries I used NEW-DEFAults.
>>
>> The relevant EMF default cuts here are:
>> - Particle transport threshold set at 10 MeV
>> - Delta ray production on with threshold 1 MeV
>>
>> 1st try:
>> ========
>> EMFCUT card:
>> EMFCUT 2.0000E-05 2.0000E-05 0.000 0.000 0.000 0.000
>>
>> Here I am only setting the transport energy cut-off for gammas and e+/e-
>> (total energy) here but since I did not defined any region, no cut
>> should
>> have been applied. I had assumed the default behaviour for no region
>> selected would be (from 1st to last region but I was wrong). But even
>> the
>> default behaviour in flair for starting and ending regions does not
>> work.
>>
>> Looking at the output and searching for the Ecut and Pcut for the 11
>> regions defined, I see:
>>
>> Ecut = 1.5110E+00 MeV, Pcut = 3.3333E-01 MeV, BIAS = T, Ray. = F,
>> S(q,Z) = T, Pz(q,Z) = F
>>
>> ===> For all regions, with the exception of BLKHOLE and VACUUM, Ecut is
>> set to 1.511 MeV (Total E) and 0.33333 MeV for gammas.
>>
>> Where is the 1 MeV cut for e+/e- and 333.33 keV for gammas coming
>> from???
>>
>> 2nd try:
>> ========
>> EMFCUT card:
>> EMFCUT 2.0000E-05 2.0000E-05 0.000 3.000 11.00 0.000
>>
>> Here I am again only setting the transport energy cut-off for gammas and
>> e+/e- (total energy) for the regions of interest. So the EMFCUT of 20
>> keV
>> should have been applied to e+/e- and gammas. But did it?
>>
>> Ecut = 1.5110E+00 MeV, Pcut = 2.0000E-02 MeV, BIAS = T, Ray. = F,
>> S(q,Z) = T, Pz(q,Z) = F
>>
>>
>> ===> Aside from the VACUUM regions, I see that a 20 keV cut is applied
>> to
>> gammas but no cut is applied to e+/e-.
>>
>> After re-reading the manual under the EMFCUT, under NOTE 2, I see:
>>
>> "When instead the transport cutoffs are lower than the production ones,
>> they are increased to be equal to them."
>>
>> So I thought, the default production threshold for e+/e- must be set to
>> higher (1 MeV) and that is why I am seeing this behaviour. Is this from
>> the DETLA-RAY production threshold from NEW-DEFAults? Then why is the
>> gamma production threshold not set to 10 MeV?
>>
>>
>> 3rd try:
>> ========
>> EMFCUT cards:
>>
>> EMFCUT 2.0000E-05 2.0000E-05 0.000 3.000 710.0 0.000 PROD-CUT
>> EMFCUT 2.0000E-05 2.0000E-05 0.000 3.000 11.00 0.000
>>
>>
>> Here I am setting both the transport and production thresholds for
>> gammas
>> and e+/e- (total energy). So in principle the EMFCUT of 20 keV should
>> now
>> be definitely be applied to e+/e- and gammas. Did it?
>>
>> Ecut = 5.1200E-01 MeV, Pcut = 2.0000E-02 MeV, BIAS = T, Ray. = F,
>> S(q,Z) = T, Pz(q,Z) = F
>>
>> Now, I see a total energy cut of 0.512 MeV for e+/e- and 20 keV for
>> photons which sounds about right.
>>
>>
>> In summary: Ecut (MeV) Pcut (MeV)
>>
>> 1st try 1.5110E+00 3.3333E-01 No
>> EMFCUT (effectively)
>>
>> 2nd try
>> EMFCUT (20 keV transport for e+/e-& g) 1.5110E+00 2.0000E-02
>>
>> 3rd try
>> EMFCUT (20 keV tran.& prod. for e+/e-& g) 5.1200E-01 2.0000E-02
>>
>>
>> It is clear that setting the production cut for both e+/e- is essential
>> if
>> the transport cuts are lower than the production cuts. But this is not
>> the case for gammas.
>>
>> It is not clear to me where the default production cut for gammas
>> (3.3333e-1 MeV) comes. In NEW-DEFAults, the default transport cut is
>> set
>> to 10 MeV. As I understand it, this cut applies to all particles,
>> unless
>> changed via EMFCUT card for e+/e-, and gammas and via LOW-NEUT card for
>> neutrons.
>>
>> At the end of the day, the difference between the 3rd and 1st try in
>> terms
>> of dose rates 5 years after EOB is about 9% increase for the 3rd try
>> (which is not much).
>>
>>
>> Thank you and best wishes,
>> Mina
>>
>>
>>> Dear Mina
>>>
>>> 1) Please see the manual under EMFCUT Notes 1) and 2) which give some
>>> hint
>>> on the default settings. As Note 2) explains the actual settings can be
>>> found in the output file (search for 'Ecut' and 'Pcut').
>>>
>>> 2) Yes any modification factors defined with RADDECAY/WHAT(5) apply to
>>> the
>>> EMFCUT settings.
>>>
>>> Cheers
>>> Stefan
>>>
>>>
>>> Re: Understanding EMF-CUT and residual dose rate
>>> * This message: [ Message body ] [ More options ]
>>> * Related messages: [ Next message ] [ Previous message ] [ In reply to
>> ]
>>> From: Mina Nozar<nozarm_at_triumf.ca>
>>> Date: Tue, 13 Mar 2012 11:58:12 -0700
>>> I just realized I attached the wrong file with this message. Here is
>>> the correct plot showing residual dose rates for
>>> six targets (separate runs and fluka setups) as a function of time in a
>>> cylindrical detector a meter away from the beam
>>> line. When comparing does rates for a given target at a given cooling
>>> time
>>> (1.2 years after EOB), we are seeing a
>>> factor of 2 less in dose rates from FLUKA than those measured at the
>>> same
>>> time. I am still trying to figure out why
>>> this is.
>>> I have tested few other runs where I don't include an EMFCUT card. The
>>> results are the same as the time when I did not
>>> specify a region for the 20 keV transport card. Confirming this by
>>> looking
>>> at the echoed input in the output files,
>>> this means the default behaviour as stated in the manual is not
>>> correct:
>>> WHAT(4) = lower bound (or corresponding name) of the region indices
>>> with
>>> electron cutoff equal to |WHAT(1)|
>>> and/or photon cutoff equal
>>> to WHAT(2) and/or leading particle biasing
>>> ("From region WHAT(4)...") Default: = 2.0.
>>> i.e. not defining any lower and upper bound regions for transport
>>> energy cut-offs in the EMFCUT card, does not set the
>>> lower and upper bound regions to the 2nd region in the drop down menu
>>> (on
>>> the list of Regions) and the EMFCUT is simply
>>> not applied.
>>> What I still do not understand are:
>>> 1) How are the default decay and prompt transport energy cut-offs
>>> determined if one does not use an EMFCUT card. My
>>> results show that the default energy cut-off does not come from
>>> PART-THRES
>>> (10 MeV) in NEW-DEFA.
>>> and
>>> 2) Do the decay and prompt cuts in RADDECAY card use the transport cut
>>> as
>>> defined in the EMFCUT card?
>>> I would appreciate if one of the FLUKA gurus could shed some light on
>>> this.
>>> Thanks again,
>>> Mina
>>>
>>>
>>
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Received on Fri Mar 30 2012 - 13:41:43 CEST