From: Reinhart, Anna Merle <m.reinhart_at_Dkfz-Heidelberg.de>
Date: Tue, 17 Sep 2013 17:28:40 +0200

Dear Fluka-users,

we have encountered a strange problem and are not sure where the error is. Any help would be greatly appreciated.

We are trying to model a stack of pixelated silicon detectors; each detector consists of a sensitive layer, an insensitive layer and 256x256 bump-bonds (one for each pixel).
Thus, we built a prototype with only 16x128 pixels and we use the LATTICE and rot-DEFI cards to translate the prototype to the placeholder regions, to reproduce the whole detectors.

This gives no errors and is also running without problem. However, to check whether we correctly translated the prototype, we defined the material of the insensitive layer as blackhole and scored in the sensitive layer of the second detector, expecting to see no events. But for some reason we recorded a few events!

We then closely checked the geometry, and in the Flair-geoviewer one can see small gaps of 1e-8 cm between the placeholder regions. Thus we suspect that the particles are crossing there. When we put a blackhole directly behind the first detector, no events are scored.

Without the LATTICE card, this problem does not appear. Could it be a precision problem in the translations or the matching of the placeholders into the prototype?

A simplified input file (without the bump-bonds and only 4 placeholder regions but with the same problem) is attached.

It would be great if you could tell us where our error is or if you have any suggestions on how to solve the problem. We have run out of ideas.
Thank you very much in advance,

Giulia and Merle

Received on Tue Sep 17 2013 - 18:13:58 CEST

This archive was generated by hypermail 2.3.0 : Tue Sep 17 2013 - 18:13:59 CEST