Re: USRBIN - lattice & tracker coordinates

From: Paola Sala <>
Date: Wed, 8 Oct 2008 16:56:02 +0200 (CEST)

Dear Chris
TRACKR contains always the "real" coordinates of the particle, not the
ones inside the lattice prototype.
The spatial coordinates of a USRBIN are taken into account.
In light also of your past posts, I would advise you to avoid re-building
all the usrbin logic..

> Dear all,
> I'm currently doing track reconstruction in virtual scoring volumes via
> FLUSCW and I came across a problem regarding lattice for which I would
> need some additional information as I didn't find any specific
> documentation. One can use lattice functionality via input cards which
> define the transformation matrix and, as far as I know, for the purpose
> of tracking a particle entering such a lattice cell will be transformed
> back to the original mother volume via this matrix.
> This leads me to my actual question. In case I obtain the coordinates of
> track segments from the tracker (XTRACK, YTRACK, ZTRACK) in FLUSCW,
> which is called from a USRBIN detector, will those coordinates be given
> in terms of where the interactions physically take place, which could be
> within a lattice cell in case the track traverses such a volume, or will
> they be given in the coordinate frame of the mother volume that is used
> for the actual tracking?
> In know that in the case of the region based USRTRACK detector one
> scores tracks in the source volume even if they traverse the lattice
> replica only. This indicates that the scoring is done before the
> transformation back to the lattice coordinate frame is performed. For
> USRBINs this is obviously not the case for the final results, but I'm
> not sure what the state of the XTRACK,YTRACK,ZTRACK arrays is when the
> call to FLUSCW is performed. If anybody has information on this topic
> I'd very much appreciate any hint.
> Furthermore, I have another question regarding USRBIN, USERWEIGH &
> ROT-DEFI cards. According to the manual the setting of WHAT(3) of the
> USERWEIGH card specifies that FLUSCW is called only after
> checking that the respective USRBIN detector applies. Does anybody know
> whether the actual spatial layout of the USRBIN detector (cartesian,
> cylindrical) and the associated ROT-DEFI cards are taken into account in
> the process of determining the applicability of a USRBIN?
> I'd greatly appreciate any further information that anybody could give
> me regarding this matter.
> Thanks a lot
> Chris

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
Received on Wed Oct 08 2008 - 17:00:12 CEST

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