External photon source

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viksap
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External photon source

Post by viksap » Fri Nov 16, 2018 6:25 pm

Hi!

I am new to SERPENT and modelling a HPGe detector response for a Photon source. I need to know how to define an external source.
An isotropic point source collimated into a cone.
cone's vertex half angle is 30 degrees about y-axis, energy of the photons are 662KeV and photons are confined into the upward cone (+y axis).

Thank You

Toni Kaltiaisenaho
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Re: External photon source

Post by Toni Kaltiaisenaho » Thu Nov 29, 2018 3:12 pm

The latest version (2.1.30) doesn't support a cone source, but it will be included in the next release. Also, Gaussian energy broadening of a pulse height detector output will be possible in 2.1.31.

kaartinen
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Re: External photon source

Post by kaartinen » Mon Dec 03, 2018 5:40 pm

You could make a physical collimator into your geometry. Have an isotropic source and a lead collimator shaped into a cone. It should even make the calculations more realistic as you would need a real collimator anyway for calibrating a real detector.

viksap
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Re: External photon source

Post by viksap » Mon Dec 17, 2018 5:05 pm

How to check whether the defined source is correct or not? Like I have defined a simple source: Mono-directional, mono-energetic source of 662KeV energy Photons, moving in +y direction, is it correct?

src 1 p sp 0 -20 0 sd 0 1 0 se 0.662

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Jaakko Leppänen
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Re: External photon source

Post by Jaakko Leppänen » Wed Dec 19, 2018 12:40 pm

The fastest way to get an idea whether the source works or not is to use the track plot features in Serpent 2:

http://serpent.vtt.fi/mediawiki/index.p ... he_results

If you run the calculation with "-tracks <N>" command line option, you should get <N> particle tracks started from the source in your geometry plots.
- Jaakko

viksap
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Re: External photon source

Post by viksap » Fri Dec 21, 2018 4:15 pm

Thank you very much. This is really helpful!

viksap
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Re: External photon source

Post by viksap » Tue Apr 02, 2019 6:46 pm

Hi!,

How can we define an extended source like the surface source?

Thanks

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Jaakko Leppänen
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Re: External photon source

Post by Jaakko Leppänen » Wed Apr 03, 2019 9:04 am

Unfortunately the surface source options in Serpent are quite limited. If you have a complicated source, the best option is usually to write a usersrc.c subroutine.
- Jaakko

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