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Background effect to Vertex Detector and Impact parameter resolution T. Fujikawa(Tohoku Univ.) Feb. 4 2005 LC Detector Meeting.

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Presentation on theme: "Background effect to Vertex Detector and Impact parameter resolution T. Fujikawa(Tohoku Univ.) Feb. 4 2005 LC Detector Meeting."— Presentation transcript:

1 Background effect to Vertex Detector and Impact parameter resolution T. Fujikawa(Tohoku Univ.) Feb LC Detector Meeting

2 Purpose Goal: estimate the vertex detector performance background study Step: impact parameter resolution Tracking efficiency, b-tag and c-tag efficiency

3 Pair background hit rate study Simulation tools Monte-Carlo program for the beam-beam interaction. (by Yokoya-san) Included interactions are… ・ Jupiter JLC Uniform Particle Interaction and Tracking EmulatoR. GEANT4 based full simulator for ILC (under construction…) CAIN(for e  e  pair background (dominant) generation) (for pair background hit rate estimation)

4 Beam parameters (for the CAIN) Beam parameters are mostly the same as the TESLA TDR. In order to obtain the high luminosity, beam focus is set in 250 micron in front of IP, and crab angle is included. IP = focus

5 Detector configuration (for the Jupiter) Detector is constructed with the Beam pipe, Vertex detector (Ladder construction), Intermediate tracker, Mask, etc. and base geometry is “Old” one. (Namely, designed for “Warm” machine.)

6 The configuration of the vertex detector These conditions are applied to estimate pair background hit rate as first layer radius is varied.

7 The configuration of the forward region Al(thickness=2mm) tungsten QC1 polyethylene 7.3cm 3.5cm 8.0cm L*=350cm324.5cm197.3cm 149.9cm 334cm

8 Pair background hit rate for the vertex detector 1.hit point uniformity (for 1st. layer) We can use the average hit rate to estimate the occupancy. Z B = 3tesla, R1 = 1.2cm. Phi vs. Z

9 2. Number of fired pixels per track hit (for 1st. layer) Number of fired pixel per track hit Number of fired pixels per 1 track passage is about 3.7. (independent of radius and B field) Pair background hit rate for the vertex detector

10 3. Determination of first layer radius 20 readouts per train 3.7 fired pixels per track hit Pixel occupancy(%) = hit rate (/bunch/cm 2 ) Set the first layer radius such that its pixel occupancy = 0.5% Pair background hit rate for the vertex detector

11 0.5 % occupancy occurs at fit function: 3 tesla4 tesla5 tesla First layer hit rate vs. first layer radius

12 Impact parameter resolutions 1. TRACKERR TRACKERR: FORTRAN program to calculate tracking error matrix with using cylindrically symmetric system. Energy loss, energy loss fluctuation and multiple scattering effects are included. Track fitting uses Kalman filter. Estimates the impact parameter resolutions and momentum resolutions using TRACKERR. (assume pion).

13 Detector configurations for TRACKERR 3 tesla4 tesla5 tesla Beam pipe (Be) VTX detector (Si pixel) IT (Si strip) TPC

14 Impact parameter resolutions of the r-phi plane Impact parameter resolutions are mostly the same for each magnetic field case. (true for other configurations with different thickness for BP and VTX detector.)

15 Other configuration results are as follows (at polar angle = 90 deg.): For P = 1GeV/c 3tesla is worse than 4(5) tesla by 12.0(19.2) %. For P = 10GeV/c 3tesla is worse than 4(5) tesla by 6.4(8.8) %. Impact parameter resolutions of the r-phi plane

16 Momentum resolutions Momentum resolution is better for high B at low P, and better for low B at high P.

17 Other configuration results are as follows (at polar angle = 90 deg.): Momentum resolution is better for high B at low P, and better for low B at high P. Momentum resolutions

18 Impact parameter resolutions 2. Satellites (not finished…) Satellites: JSF based tracking program for the Jupiter. (under construction…) tracking is performed by track ID the material can be included as “uniform” one to calculate the error. (TPC-like) cylindrical layer the present condition:

19 Impact parameter resolutions Detector configuration for the Jupiter and Satellites 3 tesla Beam pipe (Be) VTX detector(Si ) IT (Si) TPC B field

20 Impact parameter resolutions ref. results by TRACKERR (pion, cos=0.1)

21 Impact parameter resolutions results by Satellites (pion, cos=0.1) P=10GeV/c dr(m) P=100GeV/c dr(m) As mentioned above, results are little doubtful…

22 Next Plan estimate the impact parameter resolutions using Satellites estimate the b-tag, c-tag efficiency (with pair background) To do… include thin layer construction (already implemented by Yamaguchi-san?) make a track finder include the (pair) background hits in Satellites other detector configurations (FPCCD etc.)


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