# Efficiency calculation using EVENTBIN card

Dear Fluka expert,

I am trying to calculate the detector efficiency using EVENTBIN output. According to the definition of efficiency, I need to count the pulses. In the output file, there are number of hit sells. see below example hit cells=1, Does the number 756 represent the counts related to that particular energy? should I accumulate all these counts ? or should I accumulate the number of hit cells and then divide it from number of protons (
10^3)?

Binning n: 3, "Edep ", Event #: 983, Primary(s) weight 1.0000E+00
Number of hit cells: 1
756 8.967714966274798E-04

Or is there any way that I don’t know to convert energy deposition into pulses?

Could you send me your input file in order to understand a bit more what you are trying to simulate?

Thank you!

Best,
André

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Test1_10Feb21.flair (2.5 KB)

There is additional problem, when i change the beam to isotope, I did not get any hit cells. I only get hit cells in the eventbin out file if i use gaussian distribution.

So, if i want to use Cs-137, how should i change the input file?

Eventbin output files contains following details :

Binning n: 3, "Edep ", Event #: 983, Primary(s) weight 1.0000E+00
Number of hit cells: 1
756 8.967714966274798E-04

I am stuck with reading output files . What Does “756” represent related to that particular energy ? Pulse height ?
Any guidelines are appreciated.

Thank you for sending the input file.
First of all let’s try to understand a bit more the cards that you are trying to use:

EVENTBIN: If you have a bit of experience with the USRBIN card, the is basically the same, but
the binning data are printed at the end of each event (primary history).
From the manual you can see the answer for your first question:

"Does the number 756 represent the counts related to that particular energy? "

Not Really, if you look at these lines in the manual:

756 is the cell index of the cell where the particle #983 deposited energy.
and 8.967714966274798E-04 is the energy deposited [GeV]

DETECT: Just to be sure that you know what this card does, here you are “scoring the energy deposition on an event by event basis”. The output that you obtain is the spectrum of energy deposited, normalised by the number of primary particles. Here you are not getting the information of every particle in the output. Thus, It’s not the best option of what you are trying to do.

The question that we need to answer first is, how do we define a pulse? (Or at least for your problem)
We can say that we have a pulse when "the energy deposited by a particle is above a particular energy threshold

In that case, you can use easily use EVENTBIN biasing to obtain all the pulses. You will only need to process by yourself all the hits with an energy deposited above a value that you defined. (BTW, you don’t event need to add bins for your mesh, Nx=Ny=Nz=1)

Another option is with mgdraw. I leave you this thread where you can find information about this routine. But in a few words, here you can obtain the information of your particles on every step, and in that way you can dump what you need.

Finally, in order to define the isotope that you want, the manual tells us that we have to add an extra card → HI-PROPErt
With that card you can choose the isotope that you want.

Ok, I hope this is useful.
Let me know if you have any other question.

Cheers!
André

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Dear Andre,
Many Thanks for the explanations. It is very helpful for me.

When I use Cs-137, I used the HI-PROPE card, also used RADDecay card, but still i do not get any hit cells. If I change it to gaussian distribution, then i get the hit cells.

you must add an extra card (DCYSCORE) to associate your EVENTBIN scoring, and use this card and RESDECAY in the semi-analog option.

An important fact to consider is that the angular distribution of your source is isotropic. Just to take into account, because in your input you are defining a particular angular range.

You should get hit cells after these changes.
I still not sure why it changes when you select the gaussian distribution…
Are you taking about the angular distribution?

Best,
André

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Dear andre,

I have added DCYSCORE. But then I get the same results. Please see the attached input file.
LGB_22Nov21.inp (2.8 KB)

Long time no see!
Thanks for the question.

As I said In previous answers, you are using an isotropic distribution for the angular emission of your primary particles. Due to this, and the position of the source, the following picture shows you the issue:

Here you can see that the neutrons are not touching your detector (of course, depending on the number of events that you use, at some point you should get a hit, but the probability is very low).
I suggest you to change the angular distribution for your primary particles in the case of neutrons, and the position of the source closer to the detector.
In the case of isotopes, you can’t define the angular distribution (it’s always isotropic), but depending on what you need, you can find ways to “collimate” the beam, and count the primaries reaching the target.

Cheers,
André

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