Hello Stefan,
Thank you for your reply to my question.
So the zenith angle distribution of the secondary cosmic rays can be directly derived from the coordinator vector and particle direction/momentum direction. However, somehow I still can't get the cos2(theta) distribution for cosmic muons...
Best,
Chuanlei
-----Original Message-----
From: Stefan Roesler [mailto:sroesler_at_mail.cern.ch]
Sent: 2019-04-06 5:47 AM
To: Liu, Chuanlei (HC/SC)
Cc: fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: particle cosine direction in mgdraw in cosmic ray simulations
Dear Chuanlei Liu
The direction cosines are defined in the coordinate frame of your
simulation geometry (geomagnetic system)
Please see also
https://indico.cern.ch/event/334606/contributions/779790/attachments/653365/898411/AdvancedCosmicRays2014.pdf
Hope this anwsers your question
Cheers
Stefan
On Tue, 2 Apr 2019, Liu, Chuanlei (HC/SC) wrote:
>
> Dear Fluka Experts/Users,
>
>
>
> We are trying to study the secondary cosmic flux at a certain location with
> Fluka and save all boundary crossing particles in a file by using mgdraw
> subroutine (and USRBDX command). The earth model was created with
> atmloc_2011.f program.
>
>
>
> We understood that the crossing position can be retrieved in mgdraw with
> XSCO/YSCO/ZSCO variables and, in our case, these coordinates are in the
> geomagnetic system. However one thing we are not quite clear is that, in
> which coordinate system the particle direction (CXTRCK/CYTRCK/CZTRCK) was
> calculated. We want to check the particle zenith angle distribution (dot
> production between the position vector and the direction vector), but have
> to make sure all these vectors are defined in the same system. Can someone
> confirm the system in which the direction (cosine values) was calculated
> please? Thanks.
>
>
>
> We also tried to understand the third parameter in the subroutine
> GEOGMG(arg1, arg2, par). We know par=4 is to convert system from Cartesian
> to geomagnetic system, but what parameter 1, 2, and 3 mean in this
> subroutine. Thanks.
>
>
>
> Best,
>
> Chuanlei Liu
>
>
>
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Received on Mon Apr 08 2019 - 20:34:41 CEST