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Simulation and Analysis of VTX03
and Upgrades to LASS
Ryan Page
Vertex Model 03 (VTX03)
• Allows many parameters of the vertex detector to be changed
• Active Si (green)
• Thickness of ladders (red)
VTX03 Parameter Changes
• Created two new VTX03 ladder setups• Be ladder thickness changed to
equivalent thickness of 1.5mm of RVC and SiC foam
• Active Si changed from 0.037mm to 0.020mm
• These two and the default setup where run in MOKKA
Event Generation
• Events in MOKKA generated using single muons
• Point of origin (0,0,0.02)• Smeared over momentum range of
6GeV• Theta of 180 degrees• Phi of 360 degrees
Reconstruction
• MARLINRECO used to reconstruct tracks• No MC data was used to cheat the tracks• From this can get the track parameters• Variance of the impact parameter• Track pass rate
Single Track Pass Rate
• For RVC 99%
• For SiC 98.6%
• For Be 98.76%
Impact Parameter Resolution for RVC
Impact Parameter Resolution for SiC
Impact Parameter Resolution for Be
Fit Values
€
€
σ = a2 +b2
Pt 2
⎛
⎝ ⎜
⎞
⎠ ⎟
RVC a= 8.6 microns
b= 7.9 microns
SiC a= 8.56 microns
b= 9.88 microns
Be a= 8.56 microns
b= 9.28 microns
Continued study using VTX03
• More data over higher Pt
• Effect of inner radius change
• b-tagging and c-tagging efficiencies using these ladder setup’s
• Vertex charge allocation
• Continue to develop analysis package
VX03 Problems• Tried to change
VTX03 parameters to get as close to all SiC model as possible
• Caused ladder overlap problems
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
New VTX• Current model
uses Be support structure with ladder blocks
• Develop in MOKKA an all SiC VTX
• Try to conform to drawings produced by A. Nichols and A. Lintern
VTX04
• 3 layer double sided VTX
• Same flexibility as VTX03
• Added parameter of ladder gap size
Results so far
• Used 1.5mm RVC• Ran MOKKA using same event generation• Then same reconstruction was used• 70.5% of events had no tracks• Out of 2949 events left only 26% had
parameters that were non zero• 766 events with tracks out of 10000• Fixing a=8.6 microns b= 22 microns• Look at fixed angle with smeared Pt
LASS Upgrades
• A. Nichols starting to draw up ideas to change mock beam pipe
• Allow SiC ladders to be tested in SiC holder• Start looking at possible procedures to allow
us to fix the ladder into the holder• Changes hopefully will not involve modifying
the cryostat• Waiting on results from company from High
Wycombe to see how easy the SiC is to machine
Survey program change
• Currently have a program that will do two rotations to the data and 3 translations
• Would like to incorporate this into the labview program
• Final rotation done at runtime
Ladder Materials
• New materials arriving include– RVC with altered cell geometry – SiC with a relative density of 4%– Selection of other SiC densities