Beam made of different kinds of particles

Dear FLUKA and FLAIR experts,

I need clarification on these two questions:

1- How can I define a beam made of different kinds of particles?

2- Is it possible to have multiple particles per primary? For example: Every primary consists of 2 tauons and 3 pions instead of only 1 particle.

Any help would be appreciated.

Best regards,


I would recommend you to check one of the special sources SPECSOUR - BEAMSPOT.

BEAMSPOT, the source consists of multiple beam spots. The user defines through the cards [SPOTBEAM], [SPOTPOS], [SPOTDIR] and [SPOTTRAN] the locations, directions, transformation and beam characteristics of those sources. In this case, the card needs as WHAT(1) is the number of beam spots that are used. The user can define up to 15000 beam spots with different weights.

Afterwards, you normalize your result as usual. In your case weight (defined in the SPOBEAM card) for tauon beam will be 2/5 and for pion beam will be 3/5. Afterwards, you normalize output by *5 (particles).

Dear Wioletta,

Thank you for your input.

I’ve been using the cards you mentioned.

Once defined each beamspot I have the following question:

How can I assign a different distribution to each beam through an user defined source routine?

Best Regards,

Dear Carlos,

the SPECSOUR - BEAMSPOT source only allows to use the standard Gaussian / Flat distribution for the particle’s momentum.

For other distributions a source user routine has to be used. However in this case the specified beam spots are ignored, and the starting location has to be defined in the source user routine.