RE: [fluka-discuss]: About EMF-CUT threshold and the distribution of the birth location of photoneutron

From: Anton Lechner <>
Date: Thu, 13 Jul 2017 11:58:21 +0000

Dear Qi,

I assume that you didn't mean USRBIN since USRBIN cannot score particle energy spectra. Anyway, if you use DEFAULTS with PRECISIO then the photon generation and transport threshold is typically 33.3 keV and not 100 keV (electron/positron cuts are 100 keV). But you can easily verify this by looking at the "Pcut" and "Ap" variable printouts in the output file which give the photon cuts.

Because of the discrete nature of photon interactions it is still not excluded that there are photons below thresholds - simply because photons can of course be above threshold before an interaction and below threshold after an interaction (at which stage the photon is discarded).

Concerning the birth location of particles in interactions, the way to go is via a customized USDRAW entry in the mgdraw routine (to be activated via the USERDUMP card).

Cheers, Anton

From: [] on behalf of []
Sent: 11 July 2017 15:49
Subject: [fluka-discuss]: About EMF-CUT threshold and the distribution of the birth location of photoneutron

Dear Fluka experts,

I am simulating the photon generation and transportation in Ta target,with injection of electrons, so I wrote DEFAULTS card as follows;
* --+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----*
which means EMF-CUT threshold is set to 100keV for photons generation and transportation in the FLUKA Manual.
However, as I use USRBIN to get the spectra of the emitting photons after the Ta target, I get the photons with energy between 50-100KeV.
Are these photons effective data or calculation err?

Otherwise, I want to know the space distribution of the birth location of photoneutron via Ta181(,n) reaction in Ta target. Which card should I use? How to use the card?

Thank you
Best Regards

Qi Wei

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Received on Thu Jul 13 2017 - 15:01:55 CEST

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