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The ATLAS SemiConductor Tracker commissioning at SR1

APS and JPS joint conference

October 30, 2006

Ryuichi Takashima （ Kyoto Univ. of Education ）For the Atlas SCT collaboration

SR1

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Calorimeter (<4.9)Liq.Ar EM/HAD/FCAL, Tile HADgood e/ id, energy, ET

miss

A Toroidal LHC ApparatuS (ATLAS)Muon Spectrometer(<2.7)

MDT/CSC, RPC/TGC air-core toroidal magnet

Bdl = 2~6Tm (4~8Tm)

Inner Tracking (<2.5)

Pixel, Silicon Strip, TRT2T solenoid magnet

good e/ id, b-tag

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SCT Barrel 4 layers, 2112 modulesBinary read out via opt fiber, work independently

SCT Endcap A,C 9 disks, 1976 modules

1492mm

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The SCT Barrel module

•Survive through direct irradiation by primary proton beam

Operational until 4X1014protons/cm2 .•deep submicron technology gives the radhard feature to the ABCD3T chip.

•remarkable precision < 5 m by exquisite constructionprocedure.

•Channel by channel adjustment of threshold to give uniform response to signal.•Two readout links can bypass through a dead chip.

•Chips generates ~6W.Elaborate thermalproperty design needed.•Carbon has good thermal conductivity.

Strip pitch:80mStereo Angle:40mrad

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Goals of SR1 Commissioning

• Detector Operation & Commissioning of System:• Gain experience with detector operation• Test combined detector supply systems

• Development of standalone & combined monitoring tools• Commission and test combined readout and trigger

• Commission offline SW chain with real data

• The detector performance aspects:• TRT performance with SCT inserted and powered

• Test 4 SCT barrels together and operation with TRT• Checks of grounding for SCT and TRT

• Test synchronous operation and check for X-talk and noise• Collect cosmics for efficiency, alignment & tracking studies

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Assembly at Oxford

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Barrel 3 insertion into Barrel 4,5,6 and thermal enclosure

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Barrel SCT insertion into barrel TRT

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Individual test at SR1 for barrel 3 through 5

defective channels 0.3%

expected electron number for 285mm Si ~20000=3.2fC

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Detector Tests

• Detector performance checks– Standalone calibration tests on SCT and TRT after insertion– Noise studies on SCT and TRT before installation in the pit

• Physics-mode running with common readout and trigger for SCT and TRT

• Synchronous readout of 4 SCT barrels and SCT+TRT• Noise on SCT from TRT + Noise on TRT from SCT• Test with heater system• Feedback of readout cycle to FE noise

– Studies with cosmics currently ongoing• Track Reconstruction• First look at efficiencies in SCT and TRT• Residuals• Detector alignment and test/tuning of different alignment metho

ds

• Analysis of data is on-going, so please consider the following slides as preliminary results

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Cosmics

• First cosmics very helpful in commissioning the online and offline SW chain – Combined DAQ, DCS and LTP trigger + TOF of Scintillator– Configuration, data handling, mapping, BS converter, monito

ring and event display– Software frame work is different. Offline uses Athena. Online

uses Scram.– Data base shifted to COOL which interfaces to Oracle, MyS

QL and sqlite.

• Preliminary results from the cosmic data taking and analysis ….(talk by Y. Nagai)– Run at nominal thresholds (1fC SCT)– Collected 0.5M cosmic triggers

• ~70% with good tracks

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Barrel Configuration in SR1 Test

View from outside towards Side A • SCT:

– 468 of 2112 modules ~ 1/4 of SCT barrel

– Keep detector dry using dry air to thermal enclosure

– Readout using 12 ROD +1 TIM+1LTP

• TRT– 2x ~6600 Channels ~ 1

/8 of TRT barrel– Readout in 9 ROD

• Note: usually no electronics on bottom -Z sector

• 3 scintillators for trigger

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Alignment using Cosmic tracks

red dots: space poits, orange dots: cluster hits

Residual without alignment

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Robust pattern recognition even in tripled noise condition.

Noise counts tripled in expand mode on the ROD and hit mode on the chip.

Very few fake space points

V pattern of SPs in pseudo- plane gives track param

s. Minimize the sum of residulals on the surface of wafers.

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Noise Occupancy at SR1 compatible with production

<NO> = 4.5 x 10-5

Noise Occupancy at 1fC threshold

Module production

(NO specs: < 5 x 10-4)

run3065 side0 side1

Barrel 3 4.87 4.94

Barrel 4 4.36 4.91

Barrel 5 4.26 4.89

Barrel 6 4.90 4.75

1fC Noise run at SR1(Offline Monitor)

x 10-5

run3065,black,500Hz

run3066,red,5kHz

run3067,blue,50kHz

Chip NO. No trigger rate dependence

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ENC = 1605 electrons

•ENC can be derived fitting a plot of occupancy vs threshold using error function.•Offline value matched with production.

•Noise runs changing threshold•Equivalent Noise Charge

is very sensitive to the threshold setting.

•~ 1600 e- ENC at 30C

hybrid temperature•reduces at final operation

temperature by ~ 5e-/C * 30C

Num

ber

of

chip

s

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Quiet, Stable, Respond properlyNoise run of 1.0 fC threshold Typical Cosmic-ray run

Nhit (Number of hits /event) Nhit (Number of hits /event)

Cut Nhit < 200

Perfect Gaussian!

Longest 30kHz noise run of 10M event observed no spike

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Summary

• SCT and TRT barrel tested for 3 months in SR1 with 1/4 of SCT and 1/8 of TRT connected

– Gained a lot of experience on detector operation

• Noise studies– Have not observed any cross talk between SCT and TRT– Noise on SCT well below specs– No evidence of significant noise increase in SCT with all 4 barrels together

and inside TRT during tests

• Cosmic runs– Tracked cosmics through both barrels!– First efficiency and noise-hit studies confirm expected detector performance– Alignment work is going on.

• Threshold can be checked by noise. But no experience of extra noise.• Cosmic trigger at the PIT expected to be ~0.03Hz. So SR1 cosmic data

are very important.• 2 chips out of 5832 was not functional.• Learned much SCT jargon.

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