Re: [fluka-discuss]: Interpreting USRBIN for energy of photons

From: Santana, Mario <>
Date: Wed, 5 Jun 2019 07:56:09 +0000

Hi Andrew,

This scoring is normalized per total statistical weight of your starting particles (typically this is the number of primaries in your simulation), hence the low value, i.e. it is the average energy density deposited by each photon.


On Jun 4, 2019, at 11:49 AM, Andrew Hastings <<>> wrote:

Fluka Team,

I’m interested in properly interpreting the USRBIN entry for scoring Energy. I’ve filtered it via AUXSCORE to show only photons, and the reported values seem very low. I’m assuming there’s some factor I need to multiply by in order to scale the values properly.

My source is a 180 MeV electron beam, impinging on a 90-degree bend with no magnetic field. As such, I am expecting to see photon energies of similar and lower magnitudes as the source. My bins are as follows:
        Type:10 [XYZ] Score:208
        X: [-200 .. 300] x 355 (1.40845)
        Y: [-120 .. 200] x 355 (0.901408)
        Z: [0 .. 700] x 355 (1.97183)

1.40845x 0.901408 x 1.97183 = 2.5034 cm^3

With the palette showing about 8 decades of energy from e-5 to e-13, and the USRBIN Energy output being GeV/cm^3, I would initially report energies from 0.025 MeV to 0.025 e-8 MeV after multiplying by the volume of the bin. Is there some multiplication variable I haven’t considered here? I was under the impression that multiplying by # of simulated particles shouldn’t be necessary for this output format, but these energy values are incredibly small.

USRBIN 10. ENERGY -21. 300. 200. 700.Phil
USRBIN -200. -120. 0.0 355. 355. 355. &

Kindest Regards,

Andrew D. Hastings
Medical Physics and Health Physics Graduate Student (MS)
Louisiana State University


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Received on Wed Jun 05 2019 - 11:38:12 CEST

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