Dear FLUKA Experts, with regards to this issue about Uncertainty propagation and average energy from the DETECT card vs that from the USRBIN card (**Uncertainty Propagation Vs USRBIN Energy Deposition**) that was already treated, I however thought I should write this for the purpose of completeness and future reference.

I scored energy deposition in Tissue Equivalent gasses using FLUKA to calculate radiation damage to simulated tissue in Microdosimetry, using Tissue Equivalent Proportional Counters (TEPCs). This is done by calculating lineal energy (y) and specific energy (z) distributions and their respective averages from the recorded spectra of the DETECT card, and then using this information to calculate radiation quality and associated uncertainty.

Since we are calculating radiation damage, it means there must be some energy deposited in the target. Thus, the above specific and lineal energy distributions are for (E>0 or z>0, or y>0).

I also understand that the zero energy deposition events are ONLY included (z=0) for the purpose of completeness based on poison assumption of the statistics.

See screenshot from this paper: Microdosimetry: Principles and applications - PubMed

As such, this often presents a large peak at zero in the recorded distributions which researchers get rid of by either deleting the first bin in downstream processing or setting E_min>0 in the DETECT card .

This therefore means that the average energies recorded by the USRBIN which takes into account the zero energy deposition events as we established here (Uncertainty Propagation Vs USRBIN Energy Deposition) and the one calculated from the DTECT Card could indeed be different if a e_min =/ 0 is set on the DETECT card (which is what I do). I set E_min ~ 1e-9 or 1e-12.

I choose this approach because I think that the first bin will always differ in energy width, depending on the E_max and so, setting E_min = 0 and deleting it later might result to some loss of information (especially when dealing with very low density gases where sparse ionizations are predominant, my case) **Please, Correct me if I am wrong!**

So, after you last reply, I settled on calculating the average energy and uncertainty form the DETECT with appropriated settings and propagating the associated uncertainty. I then used the USRBIN values just for confirmation since both will still be close enough.

Kindly let me know if this helps and I’m open for any corrections.

Thanks.