RE: [fluka-discuss]: Low Energy Photon Detecting

From: Anton Lechner <Anton.Lechner_at_cern.ch>
Date: Mon, 7 Jul 2014 13:21:49 +0000

Dear Mohammad,

The reason you don't see anything for source photons of 30 keV is that they are not transported, i.e. their energy already lies below the transport threshold when they are created. You are setting PRECISIO for DEFAULTS, which will give you (in general) a transport and production threshold of 33 keV for photons. Note that you can find the photon transport and production threshold in the .out file (search for "Pcut" and "Ap", respectively).

In addition to PRECISIO, what you need to do is to reduce the thresholds by applying appropriate EMFCUT cards. Note that production cuts are set for different materials, while transport cuts are set for different regions. For example, to set electron/positron and photon cuts to 1 keV for the entire geometry, following cards must be included:
EMFCUT -1E-6 1E-6 0.0 1.0 _at_LASTMAT 1.0PROD-CUT
EMFCUT -1E-6 1E-6 0.0 1.0 _at_LASTREG 1.0
(note that WHAT(1) is negative: this means that electron/positron cuts are set in terms of their kinetic energy and not total energy)

Last but not least, I would like to stress that cuts must not be too low. Let me quote the manual: "The minimum threshold energy for transport and production of photons is 100 eV. For electrons and positrons, it is 1 keV."

Cheers, Anton



________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of MOHAMMAD TAGHI HAJ HEIDARI [mohammadtaghi_at_aut.ac.ir]
Sent: 07 July 2014 13:52
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: Low Energy Photon Detecting

​Dear Anton
Thanks for your attention but i mean while the energy of source is below 40keV, i get nothing in DETECT bins.
For example when i set the energy of source to 30keV, all DETECT bins get zero.
thanks.
Received on Mon Jul 07 2014 - 16:40:42 CEST