This page contains simulation studies regarding the Forward Silicon Tracker (FST).

Forward Tracking software developed by Daniel Brandenburg can be found here.

2021/03/31:  

2021/03/31: FST Tracking Simulation

The following slides include the comparison of the simulated FST tracking performance for the CVS1.17 Geometry and the updated CVS1.17 geometry. Refer to the entry below for more details on the geometry differences.

STAR/system/files/userfiles/6551/FastForwardTrackingPerformance_20210331.pdf

The "true" z-location of individual modules/sensors was implemented in the track reconstruction for the updated CVS1.17 geometry results. The track reconstruction provides manual shifts to account for the "true" position of the modules/sensors, but it would be more ideal to read directly from geometry. Daniel Brandenburg has been looking into how to read z-location directly from the geometry.

n.b. these results use track reconstruction with McSeed = true in the .xml configuration file. This results in unrealistic results for the FTT only tracking. (More on this later). 

2021/03/31: FST Material Budget (CVS1.17 vs Updated CVS1.17)

In the slides below, the material budget results for an updated version of the CVS1.17 geometry and the original CVS1.17 geometry are shown. The main differences in the geometries are outlined in the slides and the changes to the material budget are consistent with expectations. 

STAR/system/files/userfiles/6551/FST_MaterialBudget_20210331.pdf

It should be noted that the support rings are included in the eta distribution for an individual FST disk, but the support rings are not actually part of the FST disk. This was added to help understand the peaks in the overall eta distribution of the full FST + beam pipe material budget.

2021/01/30: Comparison of Forward Tracking (FTT & FTT+FST)

In the slides below, the results for pt-resolution and charge miss-ID are shown for FTT tracking and FTT+FST tracking.

STAR/system/files/userfiles/6551/ForwardTracking_20210130.pdf

2021/01/26: Monte Carlo Hit Map on FST

The hit display for MC hits on the FST were plotted to clarify if z-location was properly defined in CVS Geometry. The x vs y hitmap is shown for each FST disk and the phi vs. z hitmap is shown for each disk with separate plots for inner and outer sensors. The FST disks are labeled 4,5,6, which are found at z-locations 140.286011,154.286011, and 168.286011 cm respectively.

STAR/system/files/userfiles/6551/FastQA_MC_Hitmap.pdf

Code can be found at /star/u/gwilks3/fst/star-fwd-integration_01112020/batch_integration/

                                                                                                                                                

2021/01/21: Material Budget

The physical composition of the FST disks was studied by measuring the effect on the energy of incoming particles for each component of FST. The current results are compared to results from Shenghui Zhang in July 2020.

Notes on the slides: 

• The support rings are not shown in these results as individual components, but are included in the full FST and beampipe results. 
• Results on the first slide are only for one FST disk, in addition to phi vs eta plot on second slide.
• The main difference in the current results is the shift in the effective eta for each FST disk, which is due to shifting the z-locations in the geometry.

STAR/system/files/userfiles/6551/FST_MaterialBudget_20210121.pdf

Code can be found at /star/u/gwilks3/fst/MaterialBudgetStudy/

2021/01/13: Forward Tracking Results (edit: these results only perform FTT tracking)

When simulation multiple sets of events on the RCF cluster, a seed is defined for each set by file number (seed = 1,2,3,...). However, the seed implementation was not working properly, resulting in large fluctuations in charge miss-ID rate and pt-resolution. Through the use of RANLUX in the testg.kumac file, the seed was properly implemented and the results appear far more reasonable for pt-resolution and charge miss-ID rate, along with efficiency vs eta, phi, and pt. Various plots from previous results in March 2020 and December 2020 are shown in comparison to current results are found in the file below.

STAR/system/files/userfiles/6551/star-fwd-integration_01132021_WorkingSeed.pdf 

Some things to note regarding these slides:

• Results from March 2020 treat the FST disks as silicon slabs, rather than using their true geometry. 
• CVS 1.15 Geometry is used in December 2020 Results.
• CVS 1.17 Geometry is used in results from 01/13/2021.
• Seed implementation was not properly working in December 2020 results.
• March 2020 results do not have as many events.

Code can be found at /star/u/gwilks3/fst/star-fwd-integration_01112020/batch_integration/