Date: Mon, 1 Nov 2021 14:52:46 +0000
Dear Paola,
Thank you very much for your time. I tried to contact the authors with no answer so far.
My department's team conducts experiments with dosimetric gels, so I'm investigating how MC simulation could help them.
I barely starting to see the effects with 0.05%wt, more significant with 0.5%wt and added 5%wt for illustration purposes. It's something similar to what you've mentioned, as well as what's stated in the paper you've shown (it is indicated that the higher the energy the lesser the effects, I believe). What I can see that the higher concentrations just strengthen the effects we see, and I cannot reproduce such big “the scattered part from 8 kev to 30 kev” (only small peaks 7-14 kev) or significantly expressed “absorbed part 80-85 kev” as stated in the plots in that article. I was afraid that maybe my simulation lacks some sort of additional mechanism I must add in the input, but from your response I understand that this is not the case.
One more question. The various nanoparticles are added to the gel to improve their “dose sensitivity”. Is the Fluka simulation with absorbed dose scoring the best method for simulating "dose sensitivity": the more the compound absorbs the dose, the more sensitive it is to the dose, or whether there are any nuances to pay attention to?
[cid:image003.png_at_01D7CF3F.620A4B10]
Best Regards
Alexander
From: Paola Sala paola.sala_at_mi.infn.it<mailto:paola.sala_at_mi.infn.it>
Sent: Monday, November 1, 2021 15:37
To: Ševčik Aleksandras <aleksandras.sevcik_at_ktu.edu>; fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: Monte Carlo spectrometry
Dear Aleksander,
It seems to me that the information contained in the reference you quote is not complete. I suspect that the "mM/L " unit applies only to the creation of nanoparticles, while the addition of gold to the gel is given in mM..without specifying the volume (or mass) of the gel.
Thus..we do not know the percentage.
I agree that a minimum amount of gold is necessary to start seeing some effect. However, I tried to play with the concentration of gold, and as soon as I see some visible effect, I I also see the gold K-Xrays at 67, 69 and 78 keV, as well as a general reduction and distortion of the spectrum with maybe a more pronounced absorption just above 80keV. Similar effect was observed, for instance, in
https://doi.org/10.1155/2013/865283
I do not understand how the plots you quote were produced (and I fully trust Penelope for this job!!), sorry!
Maybe a better understanding of the experimental conditions (size, concentration..) could help.
Regards
PAola
On 10/28/21 7:21 PM, Ševčik Aleksandras wrote:
Dear experts,
I would like to get your insights and possible help regards so called “Monte Carlo spectrometry”.
I am trying to reproduce the results obtained in this paper: https://iopscience.iop.org/article/10.1088/1742-6596/250/1/012084/pdf
In this paper 250 kV x-ray beam was simulated to irradiate the polymer gel mixed with gold nanoparticles and the following spectra was obtained:
[cid:image001.png_at_01D7CF37.70A177A0]
I prepared the simulation with 250 keV polychromatic x-ray and created the Material where I combined the typical gel with gold, however, nothing similar could be obtained.
Such small amount of gold barely had any impact on the spectra at all in my simulation.
I attach my input files. Source file is here: https://we.tl/t-kZDidbnid5
I would be grateful if anyone could provide some insight or point out any errors.
Thank you,
Alexander
__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
(image/png attachment: image001.png)
(image/png attachment: image003.png)