ldcprime optimization studies ilc/ecfa warsaw, poland, 9 – 13 june, 2008 m. valentan for the...

LDCPrime optimization studies

ILC/ECFA Warsaw, Poland, 9 – 13 June, 2008 M. Valentan for the Vienna ILC group

New results from LDCPrime optimization studies

with theVienna Fast Simulation Tool

(“LiC Detector Toy”)



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 Gauss-Markov (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, χ2, etc.)– Interface for subsequent vertex fit, as used by CMS



A. Yamaguchi et. al.

Comparison with Jupiter, MokkaLeft up: σ(Δpt/pt

2) with JupiterLeft down: σ(Δpt/pt

2) with LDTred: TPC on, SIT + VTX offgreen: TPC + SIT on, VTX offblue: TPC + SIT + VTX on

Down: green: σ(Δpt/pt2) with Mokka

blue: σ(Δpt/pt2) with LDT

A. Raspereza



Detector description:Barrel silicon detectors

[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 14, 2008

Name R [mm] z [mm] Thickness [%X0] σ(RΦ) [μm] σ(z) [μm] Remarks

Beam pipe[1] 15 - 0.14[1] - - Passive

VTX1[1] 15.866 / 16 50 0.0587 / 0.053 4 4 Passive / Pixels





VTX shell[1] 65 135 0.14 - - Passive

SIT1 160.137[1] / 160.775[1] 380[2] 0.29[2] / 0.4[2] (0.5[2]) 4[2] 50[2] Strips / Passive

SIT2 270.137[1] / 270.775[1] 660[2] 0.29[2] / 0.4[2] (0.5[2]) 4[2] 50[2] Strips / Passive

SET1 1850 (1587.5[2]) 2368 (1500[2]) 0.69[2] 7[2] 100[2] Strips + Passive

SET2 1855 (1592.5[2]) 2368 (1500[2]) 0.69[2] 7[2] 100[2] Strips + PassiveGreen: Adjusted to match TPC dimensionsRed: To be refined



Detector description:TPC

[3]: R. Settles: private communication, Vienna ILD mini workshop, March 26-28, 2008

Name R [mm] z [mm]Thickness

[%X0]σ0(RΦ) / σ1(RΦ)

[μm]σ0(z) [μm]

Cdiff(RΦ) [μm/√m]

Cdiff(z) [μm/√m]

TPC inner wall 305[1] 2350[1] 1.3[1] - - - -

227 pad rows 371[1] – 1733[1] 2247.5[1] 5.7 ∙ 10-5 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 ±2350 15[3] - - - -

σ²(RΦ) = σ02(RΦ) + σ1²(RΦ) sin² + Cdiff

2(RΦ) 6mm/h sin ∆z[m], σ²(z) = σ0(z) + Cdiff

2(z) ∆z[m]

h = padrow pitch, = φ – Φ, = polar angle



LDCPrime used in this study

SET adjusted to cover whole TPC

Old FTD geometry used to avoid overlaps



σ(Δpt/pt2) Projected

impact

Study 1: Effectiveness of the SIT

• 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)

Blue: Original SITGreen: RΦ error x2Red: SIT removed



Study 2: VTX alternativesName R [mm] z [mm] Thickness [%X0]

VTX115.866 /

1650 0.0587 / 0.053

VTX224.866 /

25120 0.0571 / 0.053

VTX336.866 /

37120 0.0559 / 0.053

VTX447.866 /

48120 0.0558 / 0.053

VTX559.866 /

60120 0.0559 / 0.053

Name R [mm] z [mm] Thickness [%X0]

VTX1-115.866 /

1650 0.0587 / 0.053

VTX1-217.866 /

1850 0.0587 / 0.053

VTX236.866 /

37120 0.0559 / 0.053

VTX3-157.866 /

58120 0.0559 / 0.053

VTX3-259.866 /

60120 0.0559 / 0.053

Name R [mm] z [mm] Thickness [%X0]

VTX1-115.866 /

1650 0.0587 / 0.053

VTX1-217.866 /

1850 0.0587 / 0.053

VTX2-136.866 /

37120 0.0559 / 0.053

VTX2-238.866 /

39120 0.0559 / 0.053

VTX3-157.866 /

58120 0.0559 / 0.053

VTX3-259.866 /

60120 0.0559 / 0.053

Original:5 equidistant layers

Double layers outsideSingle layer in

the center

GLD-like with3 double layers



VTX alternatives: Comparison

σ(Δpt/pt2) Projected

impact

Slight differences,GLD-like 3 double layer

version (red) seemsbest solution



VTX alternatives: Inefficiencies at traversal of full TPC

Beam halo: innermost layer(s) may sometimes fail

5 layers equidistant 2 double, 1 single GLD-like 3 double

θ = 90ºPt = 100 GeV/c

GLD-like layoutinsensitive to in-efficiencies

σ(Δpt/pt2)

proj. impact



VTX alternatives:Inefficiencies at traversal of half TPC

θ = 27ºPt = 100 GeV/c

θ = 27º: all VTX layers hit, traversing TPC endplate→ more sensitive to lossof innermost measurement

σ(Δpt/pt2)

proj. impact



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 V0 finding

• Vertex detector alternatives:– Only slight differences

– GLD-like 3 double layer setup most robust against inefficiencies of the innermost layers

– Additional layer, but not yet overinstrumentated



LDT on the web:

http://wwwhephy.oeaw.ac.at/p3w/ilc/lictoy/

Acknowledgements• 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.

References• Atsushi Yamaguchi et al: A study of tracker performance with Jupiter, 8th

ACFA Workshop, Daegu, Korea, July 11-14, 2005• Alexei Raspereza: Tracking performance with new Mokka Models LDC01_06Sc &

LDCPrime_02Sc, ILD Meeting 23/04/2008

LDTsource_20.zipUserGuide_20.pdf



Detector description: forward/rear

Name z [mm] Rin [mm] Rout [mm] Thickness [%X0] σ(RΦ) [μm] σ(R) [μm] Remarks

FTD1 220[2] 29[2] 140[2] 0.58[2] 7[2] 100[2] Pixels

FTD2 350[2] 32[2] 140 (210[2]) 0.58[2] 7[2] 100[2] Pixels

FTD3 500[2] 35[2] 210 (270[2]) 0.58[2] 7[2] 100[2] Pixels

FTD4 850[2] 51[2] 290[2] 0.69[2] 7[2] 1000[2] Double Strips




ETD1 2368[2] 305[2] 1850 (1500[2]) 0.69[2] 7 (u)[2] - Single Strips

ETD2 2368[2] 305[2] 1850 (1500[2]) 0.69[2] 7 (v)[2] - Single Strips

ETD3 2368[2] 305[2] 1850 (1500[2]) 0.69[2] 7 (x)[2] - Single Strips



LDCPrime as per summary table

SET doesn’t cover whole TPC

Overlaps between SIT and FTD



LDCPrime as used in this study

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