1. on behalf of LHCb RICH Group
Technical Design Report
for LHCb RICH Detectors
Presentation to LHCC
4 October 2000
D.Websdale, G.Wilkinson
on behalf of LHCb RICH Group
Dedicated to Tom Ypsilantis

2. Requirements for Particle ID in LHCb
Selection of specific B-decay channels for CP-violation measurements
Kaon tagging of B-flavour via b-c-s cascade

3. Requirements for Particle ID in LHCb
Momentum distributions
Particle ID required from GeV/c
Requires RICH system with 3 radiators
Momentum vs polar angle in B--> pp
RICH system divided into 2 detectors

4. LHCb Spectrometer, seen from above

5. Content of RICH TDR presentation
Evolution since Technical Proposal
RICH system overview
Prototype tests
Physics performance through simulation
Technical design
Project organisation, schedules, costs
Guy Wilkinson

6. Evolution since Technical Proposal (20.2.98)
Photodetector Choice:
3 options studied: PAD HPD pads, 1mm x 1mm, analogue readout (M x 2.3)
Pixel HPD pixels 0.5mm x 0.5mm, binary readout (M x 5)
Hamamatsu MAPMT - 64 anodes, 2mm x 2mm, analogue readout
Prototype measurements in Lab and as Cherenkov detector in test beams
Performance studies through simulation
Costs, Risks and resource requirements
Pixel HPD selected as BASELINE (performance milestones)
MAPMT as BACKUP
Readout Electronics - Binary system
Prototype tests: photodetectors, radiators, mirrors, mirror supports
Detector geometry and mechanics
Structural calculations of engineering design
Beam-pipe sealing
Photodetector and Mirror mounting
Software development
Full GEANT simulation, including pattern recognition
C++ framework established

7. RICH system Overview RICH1: RICH2: 5cm aerogel n = 1.03, 2-11 GeV
4 m3 C4F10 n = , GeV
RICH2:
100 m3 CF4 n = , GeV

8. RICH system Overview RICH photodetector requirements
Cover total area ~ 2.6 m2
Single photon sensitivity
Granularity ~ 2.5mm x 2.5mm
Visible and UV sensitivity
25ns time resolution
80mm Pixel HPD (schematic)
Good photoelectron resolution
Low occupancy
Binary Readout electronics

9. RICH system Overview RICH radiators HPD Photon Detector
Refractive index vs photon energy
HPD Photon Detector
Quantum efficiency (measured)
vs photon energy

10. RICH system Overview Characteristics of LHCb RICH detectors:
Radiator properties
Contributions to
Cherenkov angle precision
Cherenkov photon yield
Optical system alignment, mirror quality and stability ~ 0.1 mrad

11. Prototype Tests 1. RICH1, RICH2 prototypes in test beam 2. HPD tests
Performance of aerogel, C4F10, CF4 radiators
Photon yield
Cherenkov angle precision
Chromatic properties
Scattering
Simultaneous imaging of Cherenkov rings from gas and aerogel
2. HPD tests
Detecting Cherenkov rings in beam tests
Response to traversing charged particles
Electron optics, including magnetic field tests
Tests of prototype pixel readout chips
3. Optical system tests
Mirror optical quality
Mirror support, precision and stability
Verify parameters assumed in RICH performance studies

12. 1/4-scale prototype RICH1
Simultaneous imaging of Cherenkov rings
from aerogel and C4F10 radiators

13. Prototype RICH2

14. Prototype RICH2

15. Prototype RICH2
Using a CEDAR Cherenkov counter upstream in the testbeam to tag kaons.

16. Prototype performance compared with simulation
Photon Yields
Cherenkov Angular resolution [mrad]

17. encapsulated pixel chip (LHC1)
40mm HPD pixels 0.05mm x 0.5mm
encapsulated pixel chip (LHC1)
Pion /electron separation
in RICH1 at 10 GeV/c
Angular resolution in RICH2
prototype GeV/c p beam

18. Full-scale: 80mm prototype HPD
61 pixels 2mm x 2mm
external readout
Photon yields, in low pressure
runs, where ring is contained in
a single HPD
Figure of Merit:
N0 = Npe / eALsin2q = 202 cm-1

19. 80mm HPD - phosphor anode + CCD test of electron optics
Left: Magnification
vs radial position
Right: Point Spread function
Images of Cross with
3 mT magnetic field
Left: Transverse field
Right: Axial field

20. Mirror Tests: Automated optical test facility (TA2- CERN)
Mirror quality:
analysis of image of reflected point source
40 mirrors tested (6-7 cm-thick)
R, s q
95% light in circle of 2 cm diameter
s q = 0.03 mrad

21. Mirror Tests: Automated optical test facility (TA2- CERN)
Precision and Long-term stability of Mirror Supports < .02 mrad

22. Aerogel Tests: Samples with n ~ 1.03
Matsushita - hydrophobic: C = 0.008
Novosibirsk - hygroscopic: C = 0.005
I=I0 exp (-CL/l4)
C: Clarity coeff [mm4 cm-1 ]
Pion - proton separation at 8 GeV
Photon yields: Data and simulation

23. Technical Design Pixel HPD Photon detector
Encapsulated pixel readout chip
Readout electronics
RICH mechanics and optics
Gas systems
Alignment
Monitoring and Control
Cabling, Infrastructure
Safety

24. Pixel HPD: Photon detector
168 HPDs in RICH1
262 HPDs in RICH2
Photocathode diameter = 75 mm: Overall diameter = 83mm (82% active)
Photocathode voltage = -20kV: e signal at silicon anode
Electron optics: Cross-focussed: Demagnification ~ 5
Anode: Silicon pixel detector, bump-bonded to pixel readout chip
Pixel cell: 50um x 500um: 320 x 32 matrix
Effective pixel size at photocathode: 2.5mm x 2.5mm: channels
Magnetic shielding: mm Mumetal

25. Pixel HPD Prototype 80mm HPD Final Anode assembly
3 equipped with 61-pixel anode
1 equipped with phosphor + CCD anode
Final Anode assembly
Ceramic PGA carrier
Silicon sensor, bump bonded to pixel chip
and wire-bonded to carrier

26. Pixel Chip Requirements Characteristics of LHCb pixel chip
Discriminate single photoelectron hits: Threshold ~ 2000e
Time-tag with LHC bunch crossing : Time resolution ~ 25 ns
1 MHz Level-0 trigger, 4 us latency
30 kRad radiation dose over 10 years
Characteristics of LHCb pixel chip
0.25 um CMOS process
Cell size: 50 um x 500 um - matched to silicon sensor
Low input capacitance and reduced occupancy
Pre-amp RMS noise: e
Shaping time: ns
Discriminator threshold (3-bit adjust) 2000e
Super-pixel: 10x OR: um x 500 um 1024 channels
Power consumption of chip ~ 0.5 W
Bump-bonded to silicon sensor

27. Pixel Chip Pixel Cell Current Development Next steps
ALICE-LHCb chip: cells 50 um x 425 um
Fabrication completed: Testing begins October
Next steps
Prepare anode assemblies: bump-bonded sensor + PGA carrier
Encapsulate in 80 mm HPD
Design and fabricate final LHCb pixel chip - minor modifications

28. Readout Electronics 1. Pixel chip, encapsulated in HPD
Binary signals at 40 MHz, MUX 32:1
2. Level-0 adapter Board
Drive Distributes clocks, triggers via TTC to pixel chip
Controls DC power levels for pixel chip
MUX 16:1
Gbit optical links (100 m to counting room)
3. Level-1 Board
In counting room (no radiation problem)
Buffers data during Level-1 latency
Filters Level-1 triggers
Provides zero suppression
Interfaces TTC, DCS
Transports data to DAQ and event builder
430 x
Level-0
On detector
220 x
Level-1
Counting room
54 x
RICH not in Level-0 nor Level-1 trigger

29. Readout electronics schematic

30. RICH1 - Mechanics and Optics
Top view
Side view

31. RICH1 Mechanics and Optics
Kapton beam-pipe seals
Part of HPD array
in 1 quadrant of RICH1
Space frame supporting
mirror adjustment points
in RICH1

32. RICH2 Mechanics and Optics

33. RICH2 Mechanics and optics
Top view of one half of RICH2
HPD mounting

34. RICH2 Mechanics and optics
FEA of RICH2 space frame
Mode 1: 1.2 Hz oscill along z
Mode 2: 1.4 Hz oscill along z
Mode 3: 2.9 Hz oscill along x
Mirror support

35. RICH Gas Systems C4F10 Gas distribution system
Cherenkov Gas parameters
C4F10 Gas distribution system

36. Monitoring and Control
Alignment
Cherenkov angle precision: RICH1: 1.4 mrad RICH2: 0.5 mrad
Alignment strategy:
Installation and survey: precision < 1mm at photodetector plane
Monitoring with laser system (ATLAS muon spectr); initial alignment ~ 0.5 mrad
Alignment using data: qrec- qp = A cos(frec- f0) ; final alignment < 0.2 mrad
Monitoring and Control
Gas: Flow, pressure, temperature
Purity: water, oxygen < 200 ppm
nitrogen: constant, <1%
Transparency: monochromator; nm
Mechanical stability; Lasers and semi-transparent silicon sensors
Electronics: HV monitor
Bias, leakage currents at pixel sensor
Discriminator thresholds
Calibration test pulses
Protocals: JCOP, Joint Control Project (LHC common)
SCADA, Supervisor, Control and DAQ (LHC common)

37. Project Management Schedules for: Milestones Costs
Completion of R & D pixel chip end 2001
engineering design end 2001
alignment systems end 2001
readout electronics mid 2002
aerogel end 2003
Construction and testing RICH vessels mid 2003
completion dates HPDs end 2003
Readout electronics end 2003
Gas system mid 2004
Installation / Commissioning Installation beg 2004
Commissioning mid mid 2005
Milestones
Costs
Division of Responsibilities

38. Project Management

39. Project Milestones Date Milestone Mechanics and Optics Photodetectors
2002/Qtr1 Mechanical designs completed
2003/Qtr4 Mechanics and Optics completed
2004/Qtr1 Begin Assembly RICH1 in IP8
2004/Qtr3 Begin installation RICH2 in IP8
Photodetectors
2000/Qtr4 Prototype HPD completed ***
2001/Qtr3 Place HPD order ***
2004/Qtr1 Production / testing completed
Readout electronics
2002/Qtr2 Prototype chain tests completed
RICH Detectors
2005/Qtr2 Commissioning completed

40. Project Costs (kCHF) Item RICH1 RICH2 Mechanics, Optics 527 1204
Photodetectors
Electronics
Gas system, monitoring
Aerogel
Total:
Total Cost (incl. spares) kCHF

41. Division of responsibilities
LHCb RICH Group
Bristol Univ
Cambridge Univ
CERN
Genova Univ
Glasgow Univ
Edinburgh Univ
Milano Univ
Oxford Univ
Imperial College
Rutherford Appleton Lab

42. MultiAnode PMT Hamamatsu R7600-03-M64. 8x8 channels. Size: 26x26 mm2.
Bialkali PC: Q.E. ~ 22% at lmax = 400 nm. Gain  106.
Active area fraction 38%.
Active area fraction
Increased by lenses (78%).

43. MultiAnode PMT Cluster test
Without lenses
With lenses

44. MultiAnode PMT Project Schedule