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The LHCb Vertex Detector

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RICH system divided into 2 detectors and 3 radiators: aerogel, C4F10, CF4. 11/10/09 ... Aerogel C4F10 CF4. L 5 85 167 cm. n 1.03 1.0014 1.0005. qc 242 53 32 ... – PowerPoint PPT presentation

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Title: The LHCb Vertex Detector


1
The LHCb Vertex Detector
  • T. Bowcock
  • University of Liverpool

2
Overview
  • Detector Design
  • LHCb Components and Status
  • Physics
  • Vertex Detector
  • Summary

3
Detector Design(1)Goals
  • A CP violation experiment
  • Simultaneous measurements of ?,?,?, and ??
  • Exploration of Bs sector
  • Access to rare b-decays

4
Detector Design(2)
a
g
b
5
Detector Design(3)
  • O(1012)bbpairs/year
  • ?bb500?b
  • ?bb/ ?inelastic510-3
  • Pairs produced at small angles
  • Modest luminosity

6
LHCb(1)Components
Reversible field
7
LHCb(2)Particle ID
  • ID 1-150GeV/c
  • RICH system divided into 2 detectors and 3
    radiators aerogel, C4F10, CF4

8
LHCb(3)RICH
  • Acceptance
  • 300 mrad RICH 1
  • 120 mrad RICH 2
  • Radiators thickness L, refractive index n, angle
    ?c, ?/K threshold
  • Aerogel C4F10 CF4
  • L 5 85 167 cm
  • n 1.03 1.0014 1.0005
  • qc 242 53 32 mrad
  • p 0.6 2.6 4.4 GeV
  • K 2.0 9.3 15.6 GeV

9
LHCb(4)Particle ID
  • 3s separation pK 3-80GeV/c
  • 2s separation pK 1-150GeV/c
  • of detected photons
  • 7 Aerogel 33 C4F10 18 CF4

10
LHCb(5)Particle ID
Bd ? ?? ? (a)
Bs ? Ds?K? (g)
11
LHCb(6)Vertex Detector - VELO
Series of disks
12
LHCb(7)Status
  • LHCb Experiment Approved Sep 1998
  • Technical Design Reports
  • Magnet
  • Calorimeter
  • Muon
  • RICH
  • VELO
  • Outer Tracker

13
LHCb(8)Improving Performance
  • Reducing Material Budgets
  • VELO 0.19X0 0.04?
  • RICH1 0.14X0 0.05?
  • Tracking 0.27X0 0.11?
  • Beam Pipe
  • VELO material, stations
  • RICH Mirror
  • Tracking Stations
  • Trigger efficiencies

14
Physics(1)2005
  • BABAR, BELLE

15
Physics(2)LHCb 200x
16
Physics(4)LHCb Performance
17
Physics(5)LHCb Performance
18
Vertex Detector
Bs ? Ds K
  • Precision tracking that
  • B vertices
  • lifetime (40fs)

19
Vertex Detector
  • Radiation Hard Sensors
  • Analogue Electronics
  • Precise Alignment
  • Level 1 Trigger

20
Geometry
Positioning and movement to 5mm
10cm
21
UK
  • Responsible for
  • Sensors
  • Hybrids
  • Modules
  • Cooling
  • Alignment

22
Operating Parameters
  • Voltage
  • Details of sensor technology
  • Efficiency
  • Temperature
  • Mechanical construction
  • Minimize cooling requirements
  • Thickness
  • Signal

23
Damage
24
LHC prediction (p-type)
25
Depletion Voltages
26
Depletion Voltages
27
Operating Temp
28
Sensor Design
29
Sensors
  • R-measuring-double metal

Al
30
Testbeam
UK Purchased Hamamatsu prototypes-1998 to present
31
Laboratory
  • Irradiation of n-in-n and p-in-n Comparison with
    simulations
  • Comparison of charge collection efficiency vs
    voltage curves obtained with beta particles
    (106Ru source) and 1060 nm laser
  • Signal to noise with SCT128-VG
  • Comparison of CCE with n and p read out strips
    (n-in-n vs p-in-n diode geometry)

32
Technical Choices
  • p bulk on n-bulk
  • Isolation techniques (n-bulk)
  • Individual p-stops (Hamamatsu)
  • P-spray (Micron)
  • Do these work in case of intense non-uniform
    irradiation?(PPESP)

33
n-strip in n-bulk
34
Non-uniform irradiation
ISE simulation of the electric field (120 V
applied bias) in the high gradient area of an
irradiated (gt6.1014 cm-2) n-in-n silicon detector
and signal of two neighbour strips generated by a
MIP crossing mid way of the two strips. The
difference in signal height corresponds to the
one obtained by moving the impact point of the
MIP off centre by half a micron.
35
ISE simulation of the electric field (300 V
applied bias) in the high gradient area of an
irradiated (gt4.1014 cm-2) p-in-n silicon detector
and signal of two neighbour strips generated by a
MIP crossing mid way of the two strips
36
Laser Injector
37
Laser
  • 2µm step which allows the intermediate
    positioning with 1 µm precision. The light spot
    has a FWHM of about 7µm.
  • The metalisation on the backside of the detector
    has holes to avoid reflections of the laser
    light.

38
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39
Irradiation
  • n-in-n and a p-in-n phi detectors have been
    irradiated

40
The effective doping concentration as measured by
the CCE curves in correspondence of laser
illumination of different strips. The high
gradient region is about from strip 550 to 600.
41
Measure ?
R
L
?R/(RL)
x
42
Distortions-low gradient
Measurement of the h function in differently
irradiated area of the detector low gradient
area (irradiation about at type inversion
fluence)
43
Distortions-high gradient
Measurement of the h function in differently
irradiated area of the detector high gradient
area
44
Distortions-high dose
Measurement of the h function in differently
irradiated area of the detector most irradiated
area
45
Laser versus MIPS
Comparison between CCE obtained with 1060 nm
laser and 106Ru source
46
nn v pn
Preliminary comparison of CCE between n-in-n and
p-in-n detectors highly irradiated region. The
signal was induced by 1060 nm laser. The
detectors were irradiated together. Thickness of
both types 200 µm.
47
Noise
  • S/N with SCT128VG(LHC speed)on 200 micron thick
    n-bulk detectors
  • 161 (uncorrected) unirradiated
  • 141 highly irradiated
  • Noise independent of bias 50-500V
  • Operated up to 1000V

48
Conclusions on Lab tests
  • Distortion of the resolution due to
    non-homogeneous irradiation does not need
    correction
  • CCE with n-strip read-out superior at low
    voltages after irradiation
  • No evidence of microdischarges up to 500 V in
    n-in-n (p-spray) detectors
  • 200 micron thick
  • pn detectors(300micron) operated at 1000V

49
Hybrid-SC128a
  • IDEAS
  • ?-detector
  • Irradiated
  • 1968-19-1
  • 300?m Oxy

50
Results with populated (12 chips) IDE hybrid and
irradiated 200µm p-in-n detector
51
Kapton-SCT128a (IDEAS)
K-01
52
Module(4)
  • Alignment
  • 5-10microns

53
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54
Curvature of Sensors
55
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56
Curvature
57
Prototype Module
  • Similar to TDR

Pipe slides through paddle
58
Prototype Module
  • Base simplified(?)
  • Production in CF

59
Prototype Module
  • Single (asymmetric) Cooling Pipe

60
VELO Module
Hybrid(SCT-VELO)
Base
Paddle
61
VELO Sensor Support
  • Substrate
  • Hybrid(K-02)
  • Fanins
  • Sensor(200?m)
  • Chips
  • Adhesives
  • Connectors

62
Material Table
63
Material Traversed
Tracks with uniform density in ?
Average
average
64
Average
RL 2.87 0.00 0.00 0.19 0.06 0.01 0.09 0.01
0.06 0.16 0.25 0.00 0.01 0.32 0.02 0.11
0.01 Tot 4.18
65
Hardware Module(1)
  • Thermal models for TDR
  • Cooling system
  • Safety issues addressed

66
Module
67
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68
Cooling System
  • Safety compliant (factor 10!)
  • certified
  • Leak tested
  • CO2 monitor

69
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70
Summary
  • Second generation b-physics experiment
  • day-one operation
  • UK RD sensor development a success
  • Vital to keep lead
  • Superb instrument for exploring possible
    deviations from SM in B sector
  • Preparation progressing well
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