[fluka-discuss]: RE: PHYSICS of the photon beam from the madical linear accelerator

From: Anton Lechner <Anton.Lechner_at_cern.ch>
Date: Wed, 1 Feb 2017 18:31:11 +0000

Dear Karolina,

1. You would only need to set this card if your beam would be polarized (not in your case).

2. Actually, you activate photonuclear interactions if you let SDUM blank on the PHOTONUC card, with SDUM=ELECTNUC you activate electro-nuclear interactions. Photonuclear interactions are relevant if you are for example interested in the produced neutrons (e.g. in the linac head, or linac collimator). Neutrons can be the reason for secondary cancer induction, and they can be relevant for shielding calculations (neutron production occurs for photon energies above ~7-8 MeV and there are resonances (GDR)). The cross-section for electro-nuclear interactions is much smaller, hence less relevant.

3. Not relevant in your case (only at very high energies).

Cheers, Anton


________________________________________
From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Karolina Kokurewicz [karolina.kokurewicz_at_strath.ac.uk]
Sent: 01 February 2017 16:17
To: FLUKA discussion
Subject: [fluka-discuss]: PHYSICS of the photon beam from the madical linear accelerator

Dear FLUKA Experts,


I would like to simulate 10-15 MeV photon beam from the medical linear accelerator. Literally, I would like to reproduce all features typical for the photon beam from the medical LINAC. In the FLUKA manual I found three extra cards to be added, these are:

1. POLARIZA - it is used to set polarisation. What pcosx, pcosy and pcosz should be in this case (assuming that photons propagate along z)?

2. PHOTONUC with Type: ELECTNUC (used together with LAM-BIAS)- it is used to activate photonuclear interactions. What kind of photonuclear interactions should I include in this card for 10-15 MeV photon beam, if most of them have extremely small cross section below 10 MeV?

3. PHOTONUC with Type: MUMUPAIR - it is used to activate photomuon production. Should I include this card if I'm using PRECISIO settings?

Is this everything what I need for the photon beam from the medical LINAC?


Is there maybe any FLUKA example of the photon beam from the medical LINAC?


I appreciate your help,

Karolina

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Received on Wed Feb 01 2017 - 21:10:25 CET

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