LHCb VErtex LOcator & Displaced Vertex Trigger Vertex Detector Design Test Beam Results Displaced...

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LHCb LHCb VE VE rtex rtex LO LO cator cator & Displaced Vertex & Displaced Vertex Trigger Trigger Vertex Detector Vertex Detector Design Test Beam Results Displaced Vertex Trigger Displaced Vertex Trigger Algorithm Test Beam Emulation Conclusions Conclusions Summary Future Plans Chris Parkes, CER Beauty ‘99
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Transcript of LHCb VErtex LOcator & Displaced Vertex Trigger Vertex Detector Design Test Beam Results Displaced...

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LHCb VErtex LOcator & Displaced Vertex Trigger Vertex Detector Design Test Beam Results Displaced Vertex Trigger Algorithm Test Beam Emulation Conclusions Summary Future Plans Chris Parkes, CERN Beauty 99 Slide 2 Chris Parkes Beauty 99 LHCb Detector Slide 3 Chris Parkes Beauty 99 Resolution Secondary Vertices B tagging Rejection of background Primary vertex resolution 40 m Slide 4 Chris Parkes Beauty 99 Geometry 10cm Detectors separated 6cm during injection series of discs small overlap Slide 5 Chris Parkes Beauty 99 Vertex Locator Detector Length 1m Station spacing varying from 4 - 12cm Phi Overlap of detectors Each Station has an R and a Phi measuring detector Stereo angle between successive Phi Detector layers Slide 6 Chris Parkes Beauty 99 r-measuring detectors -measuring detectors Prototype Design 5 stereo tilt Both detectors utilize a double metal layer to readout inner strips whilst keeping electronics outside active area. r-detectors -detectors Slide 7 Chris Parkes Beauty 99 New Design 180 degree R & Phi Detectors 2048 strips Smooth variation in pitch Ready in Autumn 16 chip Hybrid Slide 8 Chris Parkes Beauty 99 Mechanics Slide 9 Chris Parkes Beauty 99 Vacuum Vessel manipulators window Top Half primary vacuum vessel detectors 100cm RF shield vacuum barrier Slide 10 Chris Parkes Beauty 99 Radiation Environment 10 13 10 14 1 MeV equivalent neutrons/cm 2 1 2 3 4 5 6 cm station 6 Dose after 1yr Including effects of walls, vessel High doses at tips (1/r 2 ) Detectors Irradiated Test-Beam September n+ on n Silicon as base solution Slide 11 Chris Parkes Beauty 99 Modelling u Cooling Required u Electric Field Distortions u Radiation Response Slide 12 Chris Parkes Beauty 99 Software LHCb will use C++ BUT Technical Proposal work was in FORTRAN Test Beam used to gain experience with new language and Root All reconstruction software in C++ Cluster Making, Event Display, Track Fit, Alignment, Noise Studies... Software Designed for future use both useful code, and class design Slide 13 Chris Parkes Beauty 99 Trigger Levels Slide 14 Chris Parkes Beauty 99 Second Level Trigger Vertex Algorithm IDEA Separation of minimum bias events and B events by using the signature of displaced secondary vertices. AIM Minimum bias retention of less than 4% and a signal efficiency of more than 50%. Boundary Conditions Input event rate of 1 MHz or 2Gbytes/second. Average execution time of about 250 microseconds. Implementation benchmark results show can be performed by 120 1000 MIP processors Slide 15 Chris Parkes Beauty 99 Present Algorithm 2d Track finding using triplets of r-clusters track search starts in inner r sector Primary vertex reconstruction, x y z, by crossing tracks of opposite phi-sectors x y - resolution given by phi-sector Selection of tracks with large impact parameter Rejection of pile-up events z r Slide 16 Chris Parkes Beauty 99 Algorithm cont. 3d Add phi info. for large impact parameter tracks ambiguities resolved by stereo angle and impact parameter in xy-projection find two track combinations which are close calculate probability that one of the two tracks originate from the primary vertex based on impact parameter and geometry calculate total L1 probability by multiplying the individual probabilities Slide 17 Chris Parkes Beauty 99 Present Performance 2d and 3d track reconstruction efficiency of 98% and 95%. Primary vertex resolution of 80 micron and 20 micron for z and x/y. Slide 18 Chris Parkes Beauty 99 Test Beam Spring 98 12 Silicon Planes Slow Electronics Slide 19 Chris Parkes Beauty 99 Vertex Trigger Peformance Use Targets to simulate Primary Vertex Resolution Simulation 80 m Test Beam Extrapolated 80 m Assess sensitivity to detector misalignments Slide 20 Chris Parkes Beauty 99 Artificial B events Virtual B ! Five events form one target minimum bias One From next target B event Good Performance Slide 21 Chris Parkes Beauty 99 Overview of the readout scheme uAnalogue readout FE Rad. Hard >2Mrad/yr uFADC + L1 buffers 10m away uProcessing in DSPs after L1 accept Front End Chip DMILL- SCTA or 0.25 m CMOS- BEETLE Slide 22 Chris Parkes Beauty 99 LHC Speed Readout Chip Test-Beam Spring 99 Aim Evaluateperformance of detector equipped with SCT128A 40MHz FE chip Setup 6 plane Telescope + 2 Test Detectors Slide 23 Chris Parkes Beauty 99 Test-Beam Results Clear Signal Observed Correlated with reference Telescope Slide 24 Chris Parkes Beauty 99 Time Response Rise Time ~ 25ns Pulse Remaining after 25ns ~ third of Signal 25ns ~ third of Signal 40% of LHCb events are preceded by an event simulation of B Trigger efficiency drops above 30% overspill Signal:Noise ~ 20:1 Slide 25 Chris Parkes Beauty 99 Conclusions Prototype Detectors Tested New Design Displaced Vertex Trigger Future Work .. So far the project is flying... Slide 26 Chris Parkes Beauty 99 Milestones u 2000 : Full Half station at 40MHz u 2001 : Technical design Report u 2003 : Construction u 2004 : Commissioning u 2005 : Start Data Taking But there is still a long way to cycle..