The STAR detector hardware has undergone incremental changes between
the runs conducted in 2003 and 2004. This included:
As was announced a while
ago, the Silicon Strip detector geometry code has
been factored out of the Silicon Vertex Detector (the SVT)
and is now a separately maintained file.
The geometry of the Zero Degree Calorimeter will not be 100% correctly
represented in Y2004, as stated by Aihong. This is not
of much concern because (a) it's likely to require custom
simulation run anyway, because of its extreme position
in the STAR detector (b) it won't affect the background,
in the rest of the STAR detector elements, again, because
of its position
The Forward Pion Detector will have the most
recent geometry description in Y2004, however according to Akio
their group is not planning on using the results from this
detector in the upcoming wave of simulation. An interesting fact is
that the simulation of Cherenkov photons can be prohibitively
expensive, according to Akio. This is worth checking in a realistic
Missing in 2003 and in most of the Y2004 simulations was the model
of the FTPC Readout Electronics cage, termed FTRO in our model.
This was included in the last cut of the 2004 geometry and in
all of the 2005 cuts (table below).
The base geometry tag for this configuration is called Y2004.
Subsequent corrected and otherwise modified versions are
labeled Y2004A,Y2004B etc. The tag Y2004X
is reserved for a geometry similar to Y2004B but with a full
barrel calorimeter. This is a convention similar we used in 2003
and shall continue using in 2005.
Note that all of the below contains 1 Full Endcap EMC. "Option 1" means
low thresholds for the electromagnetic processes simulation in PMD,
whereas "Option 2" is standard thresholds for the electromagnetic processes simulation
Augmented silicon strip detector (SSD) configuration (10 ladders located at specific angles).
Further, there was an addtional version of the SSD code that included
additional structural elements and hence more material in the
geometry model. See table below.
Augmented Barrel TOF detector configuration (to be documented separately).
Additional modules in the barrel EMC, covering
a half of the East half-barrel. Now there are 60 modules
in the West part, and 30 in the East.
Additional sectors in the endcap EMC (west), completing
The Photon Multiplicity Detector (PMD)
|Y2004|| PMD + 3/4 Barrel EMC + 10 ladders of SSD (unmodified) + Option 1|
|Y2004a||PMD + 3/4 Barrel EMC + 10 ladders of SSD (unmodified) + Option 2|
|Y2004b||PMD + 3/4 Barrel EMC + 10 ladders of SSD (modified) + Option 2|
|Y2004x||PMD + 4/4 Full Barrel EMC + 10 ladders of SSD (unmodified)+ Option 2|
|Y2005|| PMD + 3/4 Barrel EMC + 10 ladders of SSD (modified) + Option 2|
|Y2005x||PMD + 4/4 Full Barrel EMC + 10 ladders of SSD (modified) + Option 2|
If you are interested in the technical documentation
about individual subsystems in STAR, it can be found
For quick reference, here is a list of subsystems included in the
year 2004 geometry definition, their respective source files, status
and contact persons.
|Name||Geometry Source File||New/Changed||Usable in Y2004||Contact person(s)
|Beam Beam counter|| bbcmgeo.g || ||+ ||Akio Ogawa |
|Barrel Calorimeter|| calbgeo.g ||+ ||+ ||Alexei Pavlinov |
|Endcap Calorimeter|| ecalgeo.g ||+ ||+ ||Jan Balewski |
|Zero Degree Calorimeter|| zcalgeo.g ||+ || ||Aihong Tang |
|Forward Pion Detector|| fpdmgeo.g || || ||Akio Ogawa |
|Photon Multiplicity Detector|| phmdgeo.g ||+ ||+ ||Subhasis Chattopadhyay, Dipak Mishra|
|Vertex Position Detector|| vpddgeo.g ||+ ||+ ||Frank Geurts, Bill Llope|
|Silicon Strip Detector|| sisdgeo.g ||+ ||+ ||Christelle Roy |
|Silicon Vertex Detector|| svttgeo3.g || ||+ ||Helen Caines|
|Barrel TOF Detector|| btofgeo2.g ||+ ||+ ||Frank Geurts, Bill Llope|
|TPC|| tpcegeo.g || ||+ ||  |
|Forward TPC (FTPC)|| ftpcgeo.g || ||+ ||Janet Seyboth |
|FTPC support structure|| supogeo.g || ||+ ||Maxim Potekhin |
|FTPC Readout Electronics|| ftrogeo.g || ||+ ||Tapan Nayak |
|Beam Pipe|| pipegeo.g || ||+ ||Bill Christie |
The Y2004 configuration of the Barrel Time-of-Flight system
The following is an exerpt from the
"MC Geometry page" in the production area:
- TOF: two trays, TOFp (at new location) and TOFr, on the east side
- TOFp tray in East Barrel at the position 33, covers about 1 unit of pseudorapidity and ~1/60th of the azimuth
- TOFr tray in East Barrel at the position 23, new construction, the 2nd generation prototype,
covers in total ~30-40% of a unit of pseudorapidity and ~1/60th of the azimuth
Appendix I: The FTPC readout electronics cage
The FTPC readout electronics is suppported by, and housed in a cylindrical cage-like structure
comprising 5 identical sectors. It is formed by flanges on either end of the sylinder
connected by stuts running
lengthwise, with PCB's mounted in between. Here is a recent picture of the assembly:
The material present in this structure affects the response of the Photon Multiplicity Detector
located downstream, and whose acceptance is largely covered by the projection of the FTPC
readout. It is important therefor to include this structure into the STAR Geant simulation.
The first cut of the geometry has been made and added to the code base as the directory
"ftro", for "FTPC readout". Further developement will be done by Maxim Potekhin and
Tapan Nayak, who's representing the PHMD group, and a member of the FTPC team TBA.
This is the graphic of the existing model which includes main aluminum structures
Appendix II: The IST and FST Detectors
The IST and FST stand for Inner STAR Tracker and Forward STAR Tracker, correspondingly.
At the time of this writing (December 2004) these are upgrade projects in preliminary
stages of planning and simulation.
A separate document
by Gerrit van Nieuwenhuizen describes the layout of the proposed detectors.
Currently, we have a geometry tag IST1 that's an experimental one, i.e. it doesn't
receive production support. It is used to model and investigate the preliminary versions
of the two detectors. Once activated, it would cause the STAR Geant geometry to contain these
two systems (please refer to the link above).
Last updated by Maxim Potekhin on 12/06/2004