RE: [fluka-discuss]: Fwd: Gamma-ray experiment

From: Joachim Vollaire <joachim.vollaire_at_cern.ch>
Date: Tue, 22 Nov 2016 16:31:22 +0000

Dear Beatrice

So for the flux you get 2.54 E -04 photons/cm2 per primary using single photons with an energy averaged over the ones of the two Co60 gammas and 5E-04 photons/(cm2 Bq) which seems consistent with the fact that two photons are emitted per decay.

I have used nucleonica, a 8.97e12 Bq source corresponds to an exposure Rate 6.85E+07 µGy/h at 20 cm.

For concrete here is the corresponding attenuation thickness reported by Nucleonica….

Half-Value Shield Thickness(cm) 13.10
 Tenth-Value Shield Thickness(cm) 30.53

Cheers
Joachim

From: Beatrice Pomaro [mailto:beatrice.pomaro_at_dicea.unipd.it]
Sent: 19 November 2016 09:51
To: Joachim Vollaire <joachim.vollaire_at_cern.ch>
Cc: FLUKA discussion <fluka-discuss_at_fluka.org>; owner-fluka-discuss_at_mi.infn.it
Subject: RE: [fluka-discuss]: Fwd: Gamma-ray experiment


Dear Joachim and dear Fluka experts,
thank you for your reply; I checked the results in terms of photon flux at the face of the samples in front of the source by using ISOTOPE in the BEAM card but I can not reach the same value for the photon flux:

- if I use the BEAM card with PHOTONs and the average energy of the gamma rays (1.25MeV) I get 2.5E-4 photons/(cm2 primary) from the USRBIN results in terms of photon flux. Then I multiply it by 7.36E+10 photons/(s kg), which corresponds to the primary flux as checked with Dr. Cerutti in the mail below, and by the sample density (2.398 kg/dm3) and by the sample volume (1dm3) so that I obtain: 4.6E+07 photons/(cm2 s);

- if I use the BEAM card with ISOTOPE I get 5E-04 photons/(cm2 Bq) from the USRBIN results in terms of photon flux. Then I multiply it by the source activity (8.97E+12 Bq) so that I obtain: 4.5E+09 photons/(cm2 s).

Can you explain to me what is wrong, since I find 2 orders of magnitude more photon flux with the ISITOPE sdum, than with the PHOTONs sdum?
Also, I noticed that in both cases the ratio of the photon flux out and in of the sample leads to an attenuation coefficient of 0.14cm-1 for the sample (ordinary concrete), which corresponds to a half-value thickness of 4.8cm only. Is it realistic? Can you suggest me anything to improve the analysis in case?

Thank you very much for your help,
Best regards
Beatrice






---
**************************************************
Ing. Beatrice Pomaro

Universita' degli Studi di Padova
Dipartimento di Ingegneria Civile, Edile e Ambientale
Via F. Marzolo, 9 - 35131 Padova (Italy)
tel.: +39 049 8275592
e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>

Il 17-11-2016 22:01 Joachim Vollaire ha scritto:
Hi Beatrice
Your assumption is correct, quantities normalized per primary photons with your previous approach are now normalized to one decay : 1 Bq, thus you can use the source activity to compare with your experimental data.
Cheers
Joachim


From: Beatrice Pomaro [mailto:beatrice.pomaro_at_dicea.unipd.it]
Sent: 17 November 2016 11:41
To: Joachim Vollaire <joachim.vollaire_at_cern.ch<mailto:joachim.vollaire_at_cern.ch>>
Cc: FLUKA discussion <fluka-discuss_at_fluka.org<mailto:fluka-discuss_at_fluka.org>>; owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it>
Subject: RE: [fluka-discuss]: Fwd: Gamma-ray experiment


Dear Joachim,
thank you very much. Does it mean that photon energies and deposited energies are no more per unit primary (photons/s) but per unit activity of the source (Bq), now that the source is modeled via ISOTOPE?
Shall I multiply by Bq to get [photons/(cm2 s)] or [GeV/(cm3 s)]?
Thank you in advance
Best regards,
Beatrice


---
**************************************************
Ing. Beatrice Pomaro

Universita' degli Studi di Padova
Dipartimento di Ingegneria Civile, Edile e Ambientale
Via F. Marzolo, 9 - 35131 Padova (Italy)
tel.: +39 049 8275592
e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>



Il 17-11-2016 10:31 Joachim Vollaire ha scritto:
Dear Beatrice

You have to activate the decay in semi-analogue mode :

RADDECAY 2.
You don't need to the DCYTIMES card and you need

DCYSCORE -1. FREF3 FBAR1 1.USRBIN


             = -1.0 : if option RADDECAY<http://www.fluka.org/fluka.php?id=man_onl&sub=65> has been requested with WHAT(1) > 1.0,
                     i.e. for radioactive decays activated in semi-analogue mode,
                     the detectors defined by WHAT(4)-WHAT(6) will score both
                     prompt and radioactive decay particles
Be sure to associate all detectors (including USRBDX) to DCYSCORE.

Il also noticed that you want to see photon fluence spectra with USRBDX. For radioactive decay of isotopes you may want to consider a different energy binning (linear ?) in the 0 few MeV range

USRBDX 99. PHOTON -33. rAir1 rSample2 ABAR2
USRBDX 1. 1E-30 80. &

Hoping this help
Joachim


From: Beatrice Pomaro [mailto:beatrice.pomaro_at_dicea.unipd.it]
Sent: 16 November 2016 17:51
To: Joachim Vollaire <joachim.vollaire_at_cern.ch<mailto:joachim.vollaire_at_cern.ch>>
Cc: FLUKA discussion <fluka-discuss_at_fluka.org<mailto:fluka-discuss_at_fluka.org>>; owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it>
Subject: RE: [fluka-discuss]: Fwd: Gamma-ray experiment


Dear Joachim,
in replay to your last mail I have considered to use ISOTOPE for the Cobalt 60 source (so by using RADDECAY and DCAYSCORE) as suggested, however with these modifications to the input file, it stops with 'TIME OUT' signal.
Could you please have a check if the cards associated to the radioactive decay of the source are correct?
With the introduction of ISOTOPE, does it mean that the USRBIN results (photon flux and deposited energy) must be multiplied by the initial activity of the source and by the duration of the decay times?
Thank you very much,
Best regards,
Beatrice




---
**************************************************
Ing. Beatrice Pomaro

Universita' degli Studi di Padova
Dipartimento di Ingegneria Civile, Edile e Ambientale
Via F. Marzolo, 9 - 35131 Padova (Italy)
tel.: +39 049 8275592
e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>

Il 19-10-2016 11:01 Beatrice Pomaro ha scritto:



Dear Joachim,
thank you very much for your reply. The problem with normalization to me is: if I use PHOTONs as primary particles instead of directly simulating the 60Co through ISOTOPE, results should be normalized per [photons/s] correct?
Do I get this flux rate from the dose and energy of the source _at_ 20cm (where the samples are placed) or the dose and energy exactly at the source?
I understand that the results are normalized per activity of the source if I use ISOTOPE, instead.
Thank you in advance,
Best regards,
Beatrice




---
**************************************************
Ing. Beatrice Pomaro

Universita' degli Studi di Padova
Dipartimento di Ingegneria Civile, Edile e Ambientale
Via F. Marzolo, 9 - 35131 Padova (Italy)
tel.: +39 049 8275592
e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>



Il 18-10-2016 17:35 Joachim Vollaire ha scritto:
Dear Beatrice

Maybe a first suggestion (as already mentioned by Francesco) is to use the decay of Co-60 in the source definition (it is more elegant than averaging the two gamma rays) and would allow you to use your source activity for the normalization. Consider the following cards:

BEAM 0.0 ISOTOPE
HI-PROPE 27. 60.
RADDECAY 1.

And don't forget DCYSCORE otherwise you will not get any contribution associated to the decay of Co-60....

DCYSCORE -1.0 0. 0. ***** ***** USRBIN
*
Concerning the transport threshold I would use something lower for electrons (1 MeV is high), what about using 100 keV as for photons....

Could you please reformulate your question on the normalization, not sure I understand properly. You source is calibrated and you know it gives 53 Gy/h _at_ 20 cm ? If this is the case, you should use this value to derive the corresponding Co-60 activity (1 Bq leading to two photons in 99.88 % branching ratio) and use this for normalization all quantities scored with FLUKA.

Looking at analytical codes based on gamma conversion factor, your source strength should be of the order of 6.5 TBq, does it make sense ?

Greetings
Joachim


From: owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it> [mailto:owner-fluka-discuss_at_mi.infn.it] On Behalf Of Beatrice Pomaro
Sent: 13 October 2016 10:56
To: Francesco Cerutti <Francesco.Cerutti_at_cern.ch<mailto:Francesco.Cerutti_at_cern.ch>>
Cc: FLUKA discussion <fluka-discuss_at_fluka.org<mailto:fluka-discuss_at_fluka.org>>
Subject: RE: [fluka-discuss]: Fwd: Gamma-ray experiment




Dear Dr. Cerutti,
sorry but I'd have another question about the photon flux rate of the experiment with gamma-ray source that I submitted to the forum's attention: since 53 Gy/h is the declared dose at 20cm from the source (in contact with the irradiated concrete sample) shall I use 53Gy/h for the computation below (which leads to 7.668E10 photons/(s kg_concrete) ) or shall I use the dose exactly at the source?
And should I multiply the photon flux obtained from Fluka (particle/(cm2 primary)) by the same quantity: photons/(s kg_concrete) to get the flux rate: photons/(cm2 s kg_concrete) ?
In the input file I used NEW-DEFA and card EMFCUT with sdum: PROD-CUT for electron kinetic energy threshold 0.001: GeV and photon production threshold: 0.0001 GeV . Hope it is fine.
Many thanks for your kind attention,
Best regards,
Beatrice
---
**************************************************
Ing. Beatrice Pomaro

Universita' degli Studi di Padova
Dipartimento di Ingegneria Civile, Edile e Ambientale
Via F. Marzolo, 9 - 35131 Padova (Italy)
tel.: +39 049 8275592
e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>



Il 09-10-2016 23:07 Francesco Cerutti ha scritto:

actually the average gamma energy is 1.25 MeV, giving 7.36E10 photons/(s kg)

On Sun, 9 Oct 2016, Francesco Cerutti wrote:




Dear Beatrice,

fine with the first point. Then, when one divides by 1.2 MeV transformed into J [assuming the all energy is absorbed in the sample], the result is 7.668E10 photons/(s kg), to be multiplied by the sample mass [assuming an uniform irradiation].
I understand that you already multiplied by the concrete density and are left with the volume normalization, that's correct.

Kind regards

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Sun, 9 Oct 2016, Beatrice Pomaro wrote:






 Dear Dr. Cerutti,

 thank you very much for your explanation. I agree with you in the
 definition of the
 energy deposition in a volume. Also I am using PHOTONs as primary
 particle, yes.
 If I want to compute the photon rate, the 60Co source working at
 53Gy/h=0.01472
 Gy/s and 1.2MeV, shall I transform 0.01472 Gy/s into 0.01472 W/kg where
 this
 quantity is per kg of the concrete sample placed around the source (to be
 tested),
 is it correct?
 Then I need to divide it for the electronic charge (1.6*10-19 C) and the
 energy of
 the gamma rays (1.2*10+6 eV) so to obtain: 1.92*10+8 photons/(cm3 s) where
 cm3 is
 the volume of the concrete sample?
 Is it correct?
 Thank you in advance,
 Best regards,
 Beatrice

 ---
 **************************************************
 Ing. Beatrice Pomaro

 Universita' degli Studi di Padova
 Dipartimento di Ingegneria Civile, Edile e Ambientale
 Via F. Marzolo, 9 - 35131 Padova (Italy)
 tel.: +39 049 8275592
 e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>



 Il 07-10-2016 19:17 Francesco Cerutti ha scritto:


       Dear Beatrice,

       I miss the expected meaning of GeV/(cm2 s). Energy is deposited in a
       volume and with a cartesian or cylindrical USRBIN [*not* with a
       USRBIN
       per region] you get GeV/(cm3 primary) as you wrote. Multiplying by
       the
       photon rate (I assume you decided to use PHOTONs as primary
       particles
       instead of directly simulating the 60Co decay through ISOTOPE), you
       will get power deposition density (that can be expressed in W/cm3)
       and
       I would be pretty happy with that, with no need for a further
       manipulation by an ill-defined quantity.
       Do not hesitate to come back with your thoughts if in fact you turn
       out
       not to be happy.

       Cheers

       Francesco

       **************************************************
       Francesco Cerutti
       CERN-EN/STI
       CH-1211 Geneva 23
       Switzerland
       tel. ++41 22 7678962
       fax ++41 22 7668854

       On Thu, 6 Oct 2016, Beatrice Pomaro wrote:


             Dear Anton,
             thank you very much for your advice, may I ask you also about the output
             results of a USRBIN score? We read in fact from the manual: "The results
             from USRBIN are normalised per unit volume and per unit primary weight,"
             does it mean that for energy deposition in order to get GeV/(cm2 s) out of
             GeV/(cm3 primary) one needs to multiply Fluka result by the particle flux
             (particle/s) and the length in direction orthogonal to the flux of the
             region of interest for the scoring?
             Thank you in advance for your explanation,
             Best regards,
             Beatrice



             Il 27-09-2016 15:49 Anton Lechner ha scritto:

                   Dear Beatrice,

                   Running your input file, one gets following error message:

                    *** Too many terms in parenthesis expansion ***
                    *** Execution terminated ***

                   I think the message is quite self-explaining. The issue lies in
                   the definition of the second zone of the rAir region. As a good
                   practice, I would try not to use too many parenthesis (you can
                   equally define the geometry without using any parenthesis at
                   all). Also note that if you have too many bodies in a zone
                   definition this can also slow down the simulation. It is better
                   to have more zones with fewer bodies than to have one zone with
                   many bodies.

                   Besides, on the EMFCUT card you set the production cuts for
                   e-/e+ and photons to 0. Note that physics models are no longer
                   applicable at very low energies and one should respect the
                   minimum values recommended in the manual. I quote:
                   "The minimum threshold energy for transport and production of
                   photons is 100 eV. For electrons and positrons, it is 1 keV."

                   Cheers, Anton





             ____________________________________________________________________________
                   From: owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it>
                   [owner-fluka-discuss_at_mi.infn.it<mailto:owner-fluka-discuss_at_mi.infn.it>] on behalf of Beatrice Pomaro
                   [beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>]
                   Sent: 27 September 2016 15:00
                   To: fluka-discuss
                   Subject: [fluka-discuss]: Fwd: Gamma-ray experiment


             Dear Fluka experts,
             I am trying to reproduce an irradiation experiment due to gamma-rays
             from a Cobalt60 source.
             I am using Flair. I can not run the input file because the 001.out
             file stops before reading regions, while the file .out gives a
             generic error message (that I am reporting here below):

             Dir: /home/flupix/Desktop/Prova
             Cmd: /usr/bin/nohup /usr/local/fluka/flutil/rfluka -e
             /home/flupix/Desktop/Prova/Prova.flair -M 2 Prova
             $TARGET_MACHINE = Linux
             $FLUPRO = /usr/local/fluka

             Initial seed copied from /usr/local/fluka
             Running fluka in /home/flupix/Desktop/Prova/fluka_2030

             ======================= Running FLUKA for cycle # 1
             =======================
             /usr/local/fluka/flutil/rfluka: line 359: 2058
             Aborted (core dumped) "${EXE}" < "$INPN" 2> "$LOGF" >
             "$LOGF"



             No .err files are produced yet, since the analysis stops before.
             I am attaching here my input file. Would you tell me what I am doing
             wrong, please?
             Thank you in advance,
             Best regards,
             Beatrice Pomaro


             --
             **************************************************
             Ing. Beatrice Pomaro

             Universita' degli Studi di Padova
             Dipartimento di Ingegneria Civile, Edile e Ambientale
             Via F. Marzolo, 9 - 35131 Padova (Italy)
             tel.: +39 049 8275592
             e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>
             --
             **************************************************
             Ing. Beatrice Pomaro

             Universita' degli Studi di Padova
             Dipartimento di Ingegneria Civile, Edile e Ambientale
             Via F. Marzolo, 9 - 35131 Padova (Italy)
             tel.: +39 049 8275592
             e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>



             --
             **************************************************
             Ing. Beatrice Pomaro

             Universita' degli Studi di Padova
             Dipartimento di Ingegneria Civile, Edile e Ambientale
             Via F. Marzolo, 9 - 35131 Padova (Italy)
             tel.: +39 049 8275592
             e-mail: beatrice.pomaro_at_dicea.unipd.it<mailto:beatrice.pomaro_at_dicea.unipd.it>



__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
Received on Tue Nov 22 2016 - 20:31:06 CET

This archive was generated by hypermail 2.3.0 : Tue Nov 22 2016 - 20:31:09 CET