STI Timing


Comparison of the simplfied IST model to the full IST model.  We see a speedup of ~2x with the simplified IST model  (native STI implementation).  n.b.  This is run against 15 GeV Monte Carlo. 


Comparison of the 9 cylinder model of the SSD to the 3 cyl SSD model.  Full HFT.  3% speed difference..


Data sample:

200 GeV AuAu
60 cm wide z-vertex distribution (gaussian)
Generate / reconstruct against library SL14i
Simulation was performed with the y2014a geometry.

Reconstruction was performed on the above data sample with the HFT passive.  i.e. TPC hits only in reconstruction.  We ran the reconstruction under 5 different conditions, modifying the HFT geometry to evaluate the time  required to propagate through the dead material.  The five configurations run in the simulation are--

1. TPC: y2014a minus HFT
2. TPC+HFT:  y2014a standard geometry
3. TPC+PXL: y2014a minus SSD, IST
4. TPC+SSD: y2014a minus PXL,IST
5. TPC+IST: y2014a minus PXL,SSD

Figure 1 -- LEFT: The time per event for TPC+HFT vs  TPC.  RIGHT:  (TPC+HFT)/TPC.  HFT slows down the chain by a factor of about 2.

Figure 2 -- LEFT: The time per event for TPC+PXL vs  TPC.  RIGHT:  (TPC+PXL)/TPC.  Pixel detector adds 25% to the chain.

Figure 3 -- LEFT: The time per event for TPC+SSD vs  TPC.  RIGHT:  (TPC+SSD)/TPC.

Figure 4 -- LEFT: The time per event for TPC+IST vs  TPC.  RIGHT:  (TPC+IST)/TPC.