LHCb Velo: commissioning, performance and High flux tests. K. Akiba On behalf of the Velo group

LHCb VErtex LOcator Muon HCAL ECAL RICH2 Tracker Magnet TT RICH1 VELO Outer/Inner Tracker Silicon sensors BEAM BEAM Kazu Akiba RD09 Firenze 30.9.2009 2

Velo – A Closer Look Cooling manifold 21 +2 modules 2 retractable detector halves: 21 stations per half with an R and Ф sensor Bi-phase CO2 cooling system Injection 6 cm x y Cooling manifold Stable beams 21 +2 modules Kazu Akiba RD09 Firenze 30.9.2009

Even Closer Electronics Cooling: Thermal highway to remove 18W (ΔT=20C) CO2 evaporator Mechanical Support -sensor R-side circuit -side circuit R-sensor Thermal Pyrolythic Graphite Kazu Akiba RD09 Firenze 30.9.2009

after 3-4 years [~8 fb-1]: Replacement under construction Sensors 300 μm n-in-n strip sensors (Micron Semiconductor) Double metal layer for signal routing R measuring sensors: Pitch=40-102μm Non uniform type inversion (2fb-1) 512 strips Radius (cm) 512 strips 1385 outer strips 683 inner strips Depletion Voltage 512 strips 512 strips Radius (cm) Ф measuring sensors: Pitch=36-97μm VELO closest detector to LHC! expected radiation dose: 1.3 · 1014neq/cm2/year at r = 0.8 cm 5 · 1012neq/cm2/year at r = 4.2 cm after 3-4 years [~8 fb-1]: Replacement under construction Kazu Akiba RD09 Firenze 30.9.2009

Can we make it work? Yes! – Detector in its very final commissioning stage. Short description of the Controls and DAQ system Some calibration plots. Results from LHC injection tests. Kazu Akiba RD09 Firenze 30.9.2009

Service electronics (84) Temperature monitoring Board (6) DAQ/ECS Shielding wall VELO Half (x2) LV CAEN HV ISEG Throughput Rate: 1 MHz lOlOl ADC TELL1 (84) ADC ADC ADC Service electronics (84) LV delays Timing & trigger system 60m analogue cables GBE FPGAs ECS 25m Control Board (14) ECS Temperature monitoring Board (6) delays Optical receiver Kazu Akiba RD09 Firenze 30.9.2009

Working State Test Pulse Noise Measuered with Noise: Noise = offset + slope* Capacitance. Test Pulse Noise Kazu Akiba RD09 Firenze 30.9.2009

LHC shots on TED No Cosmics for the Velo Results from last run: mm No Cosmics for the Velo Results from last run: 6-7th of June. Main objectives: Timing Online monitoring Tracking Alignment Determination of the detector position TI8 LHC mm Transfer line External beam Dump. 340m before LHCb, along beam 2 Aquired around 10k Tracks. Kazu Akiba RD09 Firenze 30.9.2009

Time Shape Fit Timing Event by event pulse shape fit (25 ns spaced steps) The procedure to tune the timing was tested with data acquired on the TED. Can set the time with precision better than 2 ns with ~100 cluster/sensor/step Time (ns) Clusters ADC Counts Average fit, with fine steps (6.5 ns) Time (ns) Can set the time with precision better than 2 ns with ~100 cluster/sensor/step Kazu Akiba RD09 Firenze 30.9.2009

Pulse Shape Time after peak (ns) Pre-spill % Spillover S/N loss 2.0 2.0 24.5 1 4.0 21.8 1.6 2 6.2 19.2 1.5 3 9.2 16.8 2.2 4 13.0 14.6 4.4 5 17.5 12.5 6.4 6 22.9 10.5 8.7 Amplitude Peak (ns) Constant (offset) Spillover = ADC @ Peak +25ns / ADC@peak. Pre-spill = ADC @ Peak - 25ns / ADC@peak. 4 ns Spillover @ +4 ns Fractional charge Kazu Akiba RD09 Firenze 30.9.2009 Fraction of the charge Strip Length (mm)

TED’s Signal Use clusters on tracks and corrected for path-lengths Phi: 34.4 R: 32.8 Signal to Noise: Phi: 20 R: 18 ADC counts ADC counts Kazu Akiba RD09 Firenze 30.9.2009

Resolution Expected resolution vs track angle LHCb tracks TED tracks Preliminary TED tracks Expected resolution vs track angle LHCb tracks Kazu Akiba RD09 Firenze 30.9.2009

Pseudoefficiency by interpolation Exp. Rec. Very Preliminary R sensors 97.2 %  sensors 97.5 % Limited search window: 5 of resolution + Tolerance of 100 m (5 mrad) Mult. Scatter. Higher Efficiency expected for Collision data. Kazu Akiba RD09 Firenze 30.9.2009 14

First evaluation of 2 halves distance Preliminary Resolver x distance 2 mm Distance measured with 255 tracks: 2.163 mm ±0.08 The halves were moved by 450 m. Distance measured with 852 tracks: 2.611 ± 0.09 Preliminary Relative distance between the halves measured: 445 Kazu Akiba RD09 Firenze 30.9.2009

Some Tracks Kazu Akiba RD09 Firenze 30.9.2009

Should we be afraid of LHC? The Velo sits very close to the beam Beam incidents are not to be excluded: incomplete or unsynchronized kicker fire wrong magnet settings in transfer line LHCb wrong magnet settings in the LHC Take a Velo Module to a quasi LHC incident scenario: Velo High Particle Rate Test A.K.A. Zap Test. Kazu Akiba RD09 Firenze 30.9.2009

PS Booster Proton beam with 1.4 GeV energy Intensity: 2x109 – 9x1012 p Beam spot: a few mm Bunch length: ~200 ns Resto 2 Main bldg Compare with LHC Pilot bunch @ injection: 2x109 protons (450 GeV) 300 µm beam spot 0.4 ns bunch length Full luminosity L=1034 4x1013 protons/cm2/bunch 288 bunches Kazu Akiba RD09 Firenze 30.9.2009

The victim Mounted in the beam line LHCb/Velo spare from production Cooled to +1 ˚C (LV on) Florescent screen to view the beam Insert/retract from beam line Remote control and read-out LHCb/Velo spare from production Kazu Akiba RD09 Firenze 30.9.2009

Beam images Combined R-Φ sensor Beam line camera on front-end data scintillating screen Kazu Akiba RD09 Firenze 30.9.2009

Measurements No measurable damage up to Intensity steps: 2x109, 2x1010, 2x1011, 2x1012 , 9x1012 Each step: LV/HV off, LV on/HV off, LV on/HV 150 V , LV on/HV 300V Each beam ‘shot’ follows the same pattern A set of standard measurements I/V of both sensors Noise & pedestal data Test pulse data. Insert the module, acquire during the shot 14 consecutive triggers of front-end data: 350 ns. Repeat the same set of measurements Shots on two sensor positions Shots on five front-end chips (only LV on/off matters) No measurable damage up to 9x1012 @ 300V bias on the sensor 2x1011 (LV on) on the FE chips Kazu Akiba RD09 Firenze 30.9.2009

Survival Proofs Test pulse response @ ‘booster’: in-situ after a few shots at 2x109 ‘lab’: lab measurement after the full program Gain difference due to different analogue drivers/receivers Bad channels identical to production QA Kazu Akiba RD09 Firenze 30.9.2009

Thermal image: No hot-spots Kazu Akiba RD09 Firenze 30.9.2009

Summary The Velo detector is ready for data taking with the LHC. At least one module tested against (and survived) a “beam like incident” particle rates. Kazu Akiba RD09 Firenze 30.9.2009