atlas semiconductor tracker

Atlas SemiConductor Tracker

Andrée Robichaud-Véronneau

Andrée Robichaud-Véronneau Journée de réflexion DPNC - Cartigny 2

A Toroidal Lhc ApparatuS

The Atlas

Detector is

divided into

several

subdetectors

Out of them, 2 systems are using silicon sensors technologies:

SCT Pixels

One central barrel with 4 layers of rectangular modules

2 end-caps containing 9 disks

Each disk assembled with max. 3 concentric rows of wedge-shaped modules (Made in Geneva)

Andrée Robichaud-Véronneau Journée de réflexion DPNC - Cartigny 3

The SemiConductor

Tracker

61 m2 of Si resulting in 6.2 million readout channels 4088 double-sided modules, coverage 2.5 Modules using optical communication (CLK/COM) Operation temperature : -7 oC (on the Si sensor) using C3F8 Radiation hardness : 2x1014 1-MeV neutron equivalent ·cm-2 (10 years LHC)

Journée de réflexion DPNC - Cartigny 4

From SCT to ID

Different assembly phases for the SCT

2004-2005 Assembly of individual barrels in Oxford Reception testing of the barrels at CERN 4-barrel assembly EC assembly in NIKHEF and Liverpool

2006-2007 ID Barrel integration (SCT->TRT) EC reception at CERN ID Barrel Combined Testing (Cosmics) ID Barrel Integration in ATLAS ID EC integration (A and C) ID EC C Combined Testing (Cosmics) ID EC integration in ATLAS

Andrée Robichaud-Véronneau

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Reception testing

Single barrel tests after reception at CERNDec 2004-July 2005

Were tested: Cooling uniformity +stability DAQ & DCS operations Noise performance Signal response

Results:Module condition unchanged compared to module production

Andrée Robichaud-Véronneau Journée de réflexion DPNC - Cartigny

6

Barrel Cosmics

450 k events taken from March to June 2006

~70 % good tracks

Run at nominal threshold (1 fC)

Allowed for testing of: Online monitoring Event Display Offline

reconstruction Alignment


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In parallel to the detector assembly, the DCS was developed to provide safe operation of the SCT.

It includes the control and monitoring of: Power supplies Environmental conditions (Temp, Humi) Cooling

A hardware interlock on cooling temperature adds an extra protection to the software controls.

The ID combined test were a good opportunity to test these systems and get experience for the final installation.

Detector Control System


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EC C Cosmics

~167 k events taken in December 2006

Scintillators placed to catch horizontal tracks

No dependence on trigger rate in physics mode detected

No influence from TRT activities


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ID integration in ATLAS

ID Barrel lowered in the Atlas pit in Aug. '06 Cabling and testing was completed Feb. '07 EC A was lowered May 25th

EC C was lowered June 18th

The SCT Barrel is now integrated with Atlas central DAQ & DCS

SCT ECs are currently being cabled and currently being tested to participate in Atlas commissioning this fall


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Challenges ahead


Evaporative cooling heaters Used to boil off remaining liquid in coolant between detector and cooling plant Main source of unreliability of the cooling system Repositioned outside cryostat Currently being reworked Will be re-installed temporarily for cosmics running

Module resistance Some modules show a high backplane resistance First on EC C, but also on EC A and Barrel (worst) Might be linked with presence of humidity (DCS) Still under investigation (forward biasing solution)

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Next steps


What will keep us busy for the coming months:

Cabling and testing the SCT ECs

Resolving the heaters issue

Run the detector with cooling inside Atlas (M5 in Oct-Nov 07)

Analyse the first SCT data (alignment, performance)

Manpower is needed for these important steps!

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Conclusion and Outlook

The SCT is integrated in Atlas Barrel has already been tested for noise occupancy Full scale commissioning in 3-4 months

The integration tests were a great success in many aspects

~99.7 % of barrel channels functional (1 module lost - HV)

Cosmics data taken on surface Still a lot of work to be done!

Continue development of Barrel DAQ & DCS for the fall Connect and Test both End-Caps Integrate the End-Caps with Central Atlas Work ongoing on the evaporative cooling heaters Look into the first data to understand e/ performance

=> Looking forward for the first LHC data!


atlas semiconductor tracker

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