Hi Alex,
See comments inserted
>>To update and specify the question:
>>I made a setup where 50x50 cm beam made from source.f hits 50x50x1 RPP detector at 100 cm distance, see attached inp file and result pictures.
>>My goal is to get photon/mm^2 equal to the spectrum source, see attached comparison picture.
>>If I understand correct:
>> USRTRACK gives me the number of photons entering the detector in such way : nr of photon multiplied by each energy bin expressed in GeV per cm-2. So I need to divide each bin (y) value by its energy >>and normalize to mm^2 in order to have photons/mm^2.
No, you “must multiply the value of each energy bin by the width of the bin (even for logarithmic binning)”, see the FLUKA Manual.
>>USRBDX gives me the number of photons leaving the surface area of the 2nd region in the card (?). I choose one way linear scoring and actually I am not sure what I am getting despite that I read the >>manual.Does it also show nr of photon in each energy range(bin) expressed in GeV per cm-2?
Assuming there’s no angular dependence you can obtain the same result with USRBDX, but, additionally, you must multiply by 2*Pi, see from FLUKA Manual:
“IMPORTANT! The results of a USRBDX boundary crossing estimator are
always given as DOUBLE DIFFERENTIAL distributions of fluence (or
current) in energy and solid angle, in units of cm-2 GeV-1 sr-1 per
incident primary, EVEN WHEN ONLY 1 INTERVAL (BIN) HAS BEEN
REQUESTED, which is often the case for angular distributions.
Thus, for example, when requesting a fluence or current energy
spectrum, with no angular distribution, to obtain INTEGRAL
BINNED results (fluence or current in cm-2 PER ENERGY BIN per
primary) one must multiply the value of each energy bin by the
width of the bin (even for logarithmic binning), AND BY 2 pi
or 4 pi (depending on whether one-way or two-way scoring has
been requested).”
>>I am sorry if it's too obvious but for the first time with this scoring, I am lost. Could someone help me a little bit in this case?
>>Regards
>>Alex
- Mario
________________________________
From: Ševčik Aleksandras
Sent: Saturday, August 19, 2017 10:57:11 AM
To: Santana, Mario; fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: Normalization of results for x-ray tube output / source.f
Hi, Mario,
Thank you very much, I was thinking about integration of the curve but could you please tell how viable is the option to place the plane detector in the front of phantom and to score the number of photon crossing it, thus I can calculate average number of photons per mm^2 - just for double check. USRBDX would be suitable for this?
Alex
________________________________
From: Santana, Mario <msantana_at_slac.stanford.edu>
Sent: Saturday, August 19, 2017 1:10:43 AM
To: Ševčik Aleksandras; fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: Normalization of results for x-ray tube output / source.f
Hi Alex,
If you take the function photons(E) that you plot in “spektasjpg.jpg’ and you compute <photons> = INT_{Emin,Emax}(photons(E) x dE) / (Emax-Emin), this will tell you how many photons/mm^2 in average you will produce per mAs of current for your x-ray source.
So, for a long enough simulation, you could just multiply the usual fluka normalization by that number:
(pSv/primary) x (photons/mAs) -------> (pSv/mAs) because primary=photons
of course this assumes that in your sampling ‘source.f’ routine you haven’t biased the weights of the starting photons.
-Mario
From: <owner-fluka-discuss_at_mi.infn.it> on behalf of Ševčik Aleksandras <aleksandras.sevcik_at_ktu.edu>
Date: Friday, August 18, 2017 at 1:25 PM
To: fluka-discuss <fluka-discuss_at_fluka.org>
Subject: [fluka-discuss]: Normalization of results for x-ray tube output / source.f
Dear experts,
I have made a test simulation but now I am not sure about the correct way to normalize the results.
I generated x-ray spectrum sample with SPEKTR 3.0 software, and using the help provided in this forum I was able to use modified source.f routine to re-create the beam and score the dose. I understand that that I get effective dose in pSv / primary. My question is what would be the correct approach to convert pSv/photon to pSv/mAs (x-ray Milliamp Seconds). Any comment / insight would be help,
Regards
Alex
__________________________________________________________________________
You can manage unsubscription from this mailing list at
https://www.fluka.org/fluka.php?id=acc_info
Received on Mon Aug 21 2017 - 05:03:05 CEST