Unexpected peaks and high-energy tails in volumetric source simulations (Co-60 and Cs-137) with a well-type HPGe detector

Physics, Transport and Magnetic Fields
3

Dear Gabriele,

what you observe is the contribution coming from the electrons created during decays.
While you raised the production and transport thresholds for electrons, it is not working in your case because:

  1. Your cylindrical source extends over the SAMPLE into the vacuum region of the HPGe.
  2. The production threshold is not applied to the source.
  3. The transport threshold is not applied to the VACUUM material.

This means you still get electrons in the sensitive region. If you reduce the radius of the cylindrical source (as you did with switching to a point source), the contribution from the electrons disappears.

Cheers,
David

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