[fluka-discuss]: Re: Primary protons absorbed in a nuclear interaction vs elastic large angle scattered

From: Ferreira De Almeida Lourenco, Ana <am.lourenco_at_ucl.ac.uk>
Date: Tue, 3 Nov 2015 12:34:13 +0000

Dear Anton and all,

Thank you for your e-mail.

I have a few questions that I would like to clarify.

ICRU63 defines an elastic nuclear reaction as follows:
* A reaction in which the incident projectile scatters off the target
nucleus, with the total kinetic energy being conserved (the internal
state of the target nucleus and of the projectile are unchanged by the

while nonelastic
* ... is a general term referring to nuclear interactions that are not
elastic (i.e., kinetic energy is not conserved). For instance, the target
nucleus may undergo breakup, it may be excited into a higher quantum
state, or a particle transfer reaction may occur.

and inelastic
* ... refers to a specific type of nonelastic reaction in which the kinetic
energy is not conserved, but the final nucleus is the same as the
bombarded nucleus.

1- Are particles from inelastic and nonelastic nuclear reactions considered as secondaries in FLUKA? Even the final state protons from inelastic and nonelastic reactions, right?

2- Final state protons from elastic nuclear reaction are considered as primaries, right?

3- I am interested to analyse the fraction of protons that undergo an elastic nuclear interaction. And I believe these protons will be included in BEAMPART, where some have suffered electromagnetic interactions and others elastic nuclear reactions. Is this right? If so, how can I distinguish them?

Many thanks,


De: Anton Lechner <Anton.Lechner_at_cern.ch>
Enviado: 8 de outubro de 2015 19:43
Para: Ferreira De Almeida Lourenco, Ana; fluka-discuss_at_fluka.org
Assunto: RE: Primary protons absorbed in a nuclear interaction vs elastic large angle scattered

Dear Ana,

You could determine the number of inelastic collisions of primary protons in the relevant regions. One way to do that is to score with USRBIN (per region scoring) the number of "stars" of primary protons (using BEAMPART).

On the other hand, one could also count manually the collisions in the USDRAW entry of the MGDRAW routine, which is called after each interaction. This is maybe more bothersome than the above approach, but allows to access additional information (like the position, secondaries produced etc.). With following code snippet you could filter out the events which are inelastic collisions of primaries (using the generation number LTRACK, which is 1 for primaries and making use of the ICODE variable, which is 101 for inelastic nuclear collisions):

* Inelastic collision of a primary particle
      IF ( LTRACK .EQ. 1 .AND. ICODE .EQ. 101 ) THEN

* Writing position of inelastic collisions
            WRITE( 98,* ) "Inelastic coll at", XSCO, YSCO, ZSCO
      END IF

Cheers, Anton

From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Ferreira De Almeida Lourenco, Ana [am.lourenco_at_ucl.ac.uk]
Sent: 07 October 2015 17:57
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: Primary protons absorbed in a nuclear interaction vs elastic large angle scattered

Dear Fluka experts,

I am studying the number of primary protons that are removed from a proton beam. For that, I would like to distinguish between the protons that are absorbed in a nuclear interaction from the ones that are elastic large angle scattered. How can I get this information from FLUKA?

Many thanks,


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Received on Tue Nov 03 2015 - 15:57:25 CET

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