New results from LDCPrime optimization studies

Transcription

1 New results from LDCPrime optimization studies with the Vienna Fast Simulation Tool ( LiC Detector Toy )

2 The Vienna Fast Simulation Tool LDT Simple, but flexible and powerful tool Version 2.0 available for MatLab and GNU Octave Detector design studies Geometry: cylinders (barrel) or planes (forward/rear) Material budget, resolutions, inefficiencies Simulation Solenoid magnetic field, helix track model Multiple scattering, measurement errors and inefficiencies No further corruption, therefore no pattern recognition Strips and pads, uniform and gaussian errors (in TPC with diffusion corr.) Reconstruction Kalman filter Optimal linear estimator according to GaussMarkov (no corruption) Fitted parameters and corresponding covariances at the beamtube Output Resolution of the reconstructed track parameters inside the beam tube Impact parameters (projected and in space) Test quantities (pulls, χ 2, etc.) Interface for subsequent vertex fit, as used by CMS

3 Comparison with Jupiter, Mokka A. Yamaguchi et. al. Left up: Left down: red: green: blue: σ( p t /p t2 ) with Jupiter σ( p t /p t2 ) with LDT TPC on, SIT + VTX off TPC + SIT on, VTX off TPC + SIT + VTX on Down: green: σ( p t /p t2 ) with Mokka blue: σ( p t /p t2 ) with LDT A. Raspereza

4 Detector description: Barrel silicon detectors Name R [mm] z [mm] Thickness [%X 0 ] σ(rφ) [µm] σ(z) [µm] Remarks Beam pipe [1] [1] Passive VTX1 [1] / / Passive / Pixels VTX2 [1] / / Passive / Pixels VTX3 [1] / 37 Passive / Pixels VTX [1] / / Passive / Pixels VTX5 [1] / 60 Passive / Pixels VTX shell [1] Passive SIT [1] / [1] 380 [2] 0.29 [2] / 0. [2] (0.5 [2] ) [2] 50 [2] Strips / Passive SIT [1] / [1] 660 [2] 0.29 [2] / 0. [2] (0.5 [2] ) [2] 50 [2] Strips / Passive SET ( [2] ) 2368 (1500 [2] ) 100 [2] Strips + Passive SET ( [2] ) 2368 (1500 [2] ) 100 [2] Strips + Passive [1]: Frank Gaede, gear_ldcprime_02sc.xml & steer_ldctracking.xml, private communication, April 11, 2008 [2]: M. Vos, LDC Silicon tracker elements, summary table, phone meeting may 1, 2008 Green: Adjusted to match TPC dimensions Red: To be refined

5 Detector description: TPC Name R [mm] z [mm] Thickness [%X 0 ] σ 0 (RΦ) / σ 1 (RΦ) [µm] σ 0 (z) [µm] C diff (RΦ) [µm/ m] C diff (z) [µm/ m] TPC inner wall 305 [1] 2350 [1] 1.3 [1] 227 pad rows 371 [1] 1733 [1] [1] each 50 [3] / 900 [3] 20 [3] 53 [3] 800 [3] TPC outer wall 1800 [1] 2350 [1] 2 [1] TPC endcaps 305 [2] 1800 ± [3] σ²(rφ) = σ 02 (RΦ) + σ 1 ²(RΦ) sin²β + C diff2 (RΦ) 6mm/h sinϑ z[m], σ²(z) = σ 0 (z) + C diff2 (z) z[m] h = padrow pitch, β = φ Φ, ϑ = polar angle [3]: R. Settles: private communication, Vienna ILD mini workshop, March 2628, 2008

6 LDCPrime used in this study SET adjusted to cover whole TPC Old FTD geometry used to avoid overlaps

7 Study 1: Effectiveness of the SIT Blue: Original SIT Green: RΦ error x2 Red: SIT removed σ( p t /p t2 ) Projected impact Differences in momentum resolution only for high momenta Useless for track fit below 100 GeV/c Question: Is it worth including the SIT? Improvement of PR, e.g. jet analysis? (V. Saveliev) Improvement of neutral vertex finding? (A. Raspereza)

8 Study 2: VTX alternatives Name R [mm] z [mm] Thickness [%X 0 ] VTX / / VTX2 VTX3 VTX / / / / / Original: 5 equidistant layers VTX / 60 Name R [mm] z [mm] Thickness [%X 0 ] VTX11 VTX12 VTX2 VTX / / / / / / Double layers outside Single layer in the center VTX / 60 Name R [mm] z [mm] Thickness [%X 0 ] VTX / / VTX12 VTX21 VTX / / / / GLDlike with 3 double layers VTX / 58 VTX / 60

9 VTX alternatives: Comparison σ( p t /p t2 ) Projected impact Slight differences, GLDlike 3 double layer version (red) seems best solution

10 VTX alternatives: Inefficiencies at traversal of full TPC 5 layers equidistant 2 double, 1 single GLDlike 3 double Beam halo: innermost layer(s) may sometimes fail θ = 90º P t = 100 GeV/c GLDlike layout insensitive to inefficiencies σ( p t /p t2 ) proj. impact

11 VTX alternatives: Inefficiencies at traversal of half TPC θ = 27º: all VTX layers hit, traversing TPC endplate more sensitive to loss of innermost measurement θ = 27º P t = 100 GeV/c σ( p t /p t2 ) proj. impact

12 Conclusions Effectiveness of the SIT: Track fit purposes: SIT useless below 100 GeV/c Omit it and save money? If needed, optimization in scope of PR and V 0 finding Vertex detector alternatives: Only slight differences GLDlike 3 double layer setup most robust against inefficiencies of the innermost layers Additional layer, but not yet overinstrumentated

13 LDT on the web: References Acknowledgements LDTsource_20.zip UserGuide_20.pdf Atsushi Yamaguchi et al: A study of tracker performance with Jupiter, 8 th ACFA Workshop, Daegu, Korea, July 111, 2005 Alexei Raspereza: Tracking performance with new Mokka Models LDC01_06Sc & LDCPrime_02Sc, ILD Meeting 23/0/2008 The software was designed and developed by the Vienna ILC Project Group in response to encouragement from the SiLC R&D Project. The development and the studies were supervised by M. Regler. Efficient helix tracking was actively supported by W. Mitaroff. Thanks are due to R. Frühwirth for the barrel Kalman filter algorithms used in the program. Special thanks are due to R. Settles and F. Gaede for fruitful discussions and for their help with comparing LDT with Jupiter and Mokka.

14 Detector description: forward/rear Name z [mm] R in [mm] R out [mm] Thickness [%X 0 ] σ(rφ) [µm] σ(r) [µm] Remarks FTD1 220 [2] 29 [2] 10 [2] 0.58 [2] 100 [2] Pixels FTD2 350 [2] 32 [2] 10 (210 [2] ) 0.58 [2] 100 [2] Pixels FTD3 500 [2] 35 [2] 210 (270 [2] ) 0.58 [2] 100 [2] Pixels FTD 850 [2] 51 [2] 290 [2] 1000 [2] Double Strips FTD5 0 [2] 72 [2] 290 [2] 1000 [2] Double Strips FTD [2] 93 [2] 290 [2] 1000 [2] Double Strips FTD [2] 113 [2] 290 [2] 1000 [2] Double Strips ETD [2] 305 [2] 1850 (1500 [2] ) 7 (u) [2] Single Strips ETD [2] 305 [2] 1850 (1500 [2] ) 7 (v) [2] Single Strips ETD [2] 305 [2] 1850 (1500 [2] ) 7 (x) [2] Single Strips

15 LDCPrime as per summary table SET doesn t cover whole TPC Overlaps between SIT and FTD

16 LDCPrime as used in this study