Support
Design document by Felix (pptx)

Yuri looked at geometry difference before and after FST was installed.
see  https://drupal.star.bnl.gov/STAR/system/files/Y2021vsY2025.pdf


Updated version (07/03/25)  https://drupal.star.bnl.gov/STAR/system/files/Y2021vsY2025_0.pdf

We have published a NIMA paper on FST, https://arxiv.org/abs/2407.09952 

You may find some info useful. 

 

1) There are 3 identical FST disks installed at Z=152,165,179 cm. Their inner (outer) radius is 5 (28) cm.

 

2) What are modeled in the simulation.

*FST modules and support rings (see Figure 24)

(Figure 2 shows the material budget of one FST module for perpendicular tracks) 

 

3) What are not modeled in simulation include

*cables, and cable trays at 1/3/9/11 clock positions (Figure 24 and attached pic) 

*cooling tubes, coolant in the tubes, and cooling tube trays at 12 and 6 clock positions (see attached pic)

*support frame (Figure 25)

 [ From Xin ]

1) The FST disk material in the active region is included in GEANT3.

2) The service material (support, cables) is not included in GEANT3.

3) None of these materials is included in StiCA tracking for FXT data reconstruction.

 

And also from my discussion with Zhenyu, it seems if we want to remove FST, it may take ~4 days

to do it. Zhenyu, please correct me if there is some misunderstanding. We may fold in these factors

when we consider the plan.

 

In my opinion, if the removal is not taking too long, it would be best to spend a few days removing

the detector and taking clean data (even saying to lose 4 days of beam data).