Fraction of deposited energy converted to optical photons

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1

Dear Experts and @vojtech.stransky
I read this post:
Continuing the discussion from Simulating scintillation response:

I have two questions:
1-In the example: If it is 64 000 photons of 2.252 eV per 1 MeV of deposited energy, the fraction should be 0.16128.

we must calculate fraction by this formula: Fraction=(number photonsEnergy of photons)/(deposited energy)
so for this example: (1000000)/(640002.252)=0.144128
but in the text said 0.16128
can you help me to understand which part of the calculation is wrong?
2-second question: where can I find this number? Is there any standard database?

3

Dear Mohammad,

  1. It seems that I made some numerical error when calculating the fraction (possibly when converting nm to eV), your result should be correct. I will double-check.

  2. The light yield (photons per MeV) and the central wavelength can usually be found on websites of scintillator producers. Is there any particular scintillator you are interested in?

Kind regards
Vojtěch

4

Dear @vojtech.stransky,
Thanks so much for clarifying.
In this step, I work on LYSO.
If I wanna study continue wavelength, Do you think if I define loop it is a good idea? or no?
Best regards,
Mohammad.

5

Dear Mohammad,

for LYSO, here is an example of a data sheet as given by a scintillator manufacturer - you can find all the necessary information there.

As for continious wavelength, it really depends what you would like to study. Using a loop you can easily have results for a set of wavelengths - just keep in mind that you have to normalize the results according to the scintillator emission spectrum.

If you really need a true continious spectrum I see some advanced options that would require usage of user routines, please let me know whether I should describe those in detail.

Kind regards
Vojtěch

6

Thanks @vojtech.stransky
If you have time, Is it possible to explain how I can implement continuous spectrum by advanced options?
Thanks in advance,
Best regards,
Mohammad

7

Dear Mohammad,

in order to create a continious spectrum of photons, you would have to write a source routine with optical photons as a source particle and sample their energy from a spectrum. An example of a source routine for optical photons can be found here. If you are studying the production of scintillation light as a result of energy deposition, you would also need to sample the starting position of optical photons according to the energy deposition. But this really depends on the problem you are studying.

Kind regards
Vojtěch

8

Thanks, @vojtech.stransky .
I tried to run some simulations, First of all, I run a simulation that an electron beam interacts with a crystal LYSO that covers BaSO4. But I am not sure about my simulation is correct or no so I removed the cover from the simulation to calculate the number of photons, But now the simulation is not finished.
I do not know what’s happen.
I tried to reduce the dimension of the simulation, the energy of the electron beam, and the number of primary particles but I can not see any effect.

My purpose for this step is to verify the number of photons generation by simulation and compare it with the analytical way.
Is it possible to consult with you on this?
LYSO_IN_VACUUM.flair (3.7 KB)

Thanks in advance,
Best regards,
Mohammad.

9

Dear Mohammad,

the problem is that the absorption coefficient of LYSO is set (by default) to 0. This leads to an infinite loop, since optical photons are being reflected inside the LYSO. I tried to increase the absorption coefficient to 0.1 and the simulation runs.

absorption
absorption722×187 21.2 KB

Kind regards
Vojtěch

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