Overlaps in ideal Tofino geometry
The pictures below show views of the Tofino module at ideal position. The actual
geometry shows overlaps in two regions:
- The keep-in volume (pink) sticks out of the sector (green).
- The outer and inner paddles also overlap, not only the volumes filled with air,
but also the sensitive volumes in a small region.
Fig 1: Tofino in sector 1 (view along the beam axis)
Fig 2: Keep-in volume of Tofino (midplane)
Fig 3: Zoom of Tofino keep-in volume (lower left region of figure 2)
NOV01 Alignment in GEANT
The following files contain the alignment for NOV01 (version 36 used for DST production).
/misc/ilse/cvsgeant/geodat/new/sect_nov01_align.geo
/misc/ilse/cvsgeant/geodat/new/richAprMay01_nov01_align.geo
/misc/ilse/cvsgeant/geodat/new/mdc_200503_nov01_align.geo
/misc/ilse/cvsgeant/geodat/new/shower_200503_nov01_align.geo
/misc/ilse/cvsgeant/geodat/new/tofplustofino_200503_nov01_align.geo
I shifted the RICH in z-direction to shift the target. The x- and y-shifts of the target must be considered as a shift of the beam focus, not of the target itself.
The sectors are also shifted in z_direction by the same amount.
The MDC and Shower have new shrinked keep-in volumes, which do not reach out to the sector edges anymore. This allows alignment to some extend.
The TOF file contains only the outer 8 TOF modules and the TOFINO (still the old geometry!).
To allow for TOF alignment, I changed the code:
The keep-in volumes of the TOF are discarded and the modules directly placed in the sectors. The inner 14 TOFs are not read anymore.
The new code is not yet committed in CVS. You can find it in
/misc/ilse/cvsgeant/test/ggeo/hgeotof.h
/misc/ilse/cvsgeant/test/ggeo/hgeotof.cc
Using these files I have seen various overlaps between TOF modules.
I have not carefully checked the MDC.
The shower entrances frames (blue) stick out of the sectors (red) and have overlap in sector 4 and 5 (see figure 4).
Fig 4: View of Shower entry frames (view of cave along the z-axis)
Conclusion
Before running GEANT with alignment one should (to my opinion) do the following steps first:
- Redefine the TOFINO geometry (by somebody with the technical drawings)
- Check the alignment, respectively the size of the modules, frames, ... in the geometry files
- Carefully check for overlaps or daughter volumes not fitting into mother volumes.
The program using the TGeoManager for checking is not yet ready.