Understanding the Impact of PROD-CUT and Transport-Cut on Penetration Depth

Dear experts,

I am seeking clarification regarding PROD-CUT and Transport-Cut, as I am unsure if I have fully understood their effects. I have attached my input file for reference.

Based on my understanding, I believed that the penetration depth should vary with different values of the Transport-Cut. To test this, I tried various combinations of Transport-Cut (with PROD-CUT = KE where transport cut = KE + 511 keV) and the FUDGEM parameter:

  • (10 keV + 511 keV = 521 keV (transport cut), 10 keV (PROD-cut), FUDGEM = 0.0 & 0.5)
  • (100 keV + 511 keV = 611 keV (transport cut), 100 keV (PROD-cut), FUDGEM = 1)
  • (1000 keV + 511 keV = 1511 keV (transport cut), 1000 keV (PROD-cut), FUDGEM = 1)

If I set the beam energy (in BEAM card) to 1 MeV and use a Transport-Cut of 1.511 MeV (3rd case of above list), my expectation is that the penetration depth of electrons in water should be ~ zero. However, despite changing the cut values, the results remain the same in terms of penetration depth (i.e. ~4 mm in water).

I have attached the input files used to check the effect for different beam energies. (I have checked for above all 3 cases with different beam energies (in BEAM card), however here I am sharing only the input file for 3rd case for the reference)

BEAM_2MeV_Case3.inp (2.0 KB)
BEAM_3MeV_Case3.inp (2.0 KB)
BEAM_1MeV_Case3.inp (2.0 KB)

Could you please help clarify whether this is the expected behavior or if I am misunderstanding how the cuts should impact the results?