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The present ATLAS Inner Detector would be unable to operate in the environment of the HL- LHC. The occupancy and radiation damage would reach unacceptable levels, and it was decided to replace the Inner Detector with a completely new all-silicon tracker. The new system will combine pixels and microstrips.

A Canada-wide collaboration comprising existing ATLAS Canada members at seven universities and TRIUMF has been formed to participate in the detector construction. The proposed Canadian contributions are aimed at the endcap components of the microstrip system. Canada will build about 1500 of the approximately 7,000 silicon strip modules required for this part of the detector. There will be two production sites, one in western Canada (TRIUMF, SFU and UBC) and one in eastern Canada (Toronto, Carleton, Montreal and York Universities). The activities of the eastern site will involve a strong collaboration with industrial partners. The western site will also work on the precision mounting of modules on the carbon-fiber petal structure that integrates the necessary electrical and cooling services.

Silicon Detector cleanroom

The work-flow for the production of modules, and then petals, starts with probing of the ASIC wafers to verify their functional integrity, followed by dicing. The next step, mounting of ASICs on bare hybrids to form an assembled hybrid, will be performed at our industrial partner Celestica. The detailed probing of the silicon microstrip sensors will be performed at two sites in Canada, one at Carleton and one at SFU. The main assembly of sensors and hybrids into completed modules will be performed at TRIUMF (500 modules), SFU (500 modules) and Toronto (500 modules), with all the hybrids produced at Celestica.

Wire Bonding Station

Gluing Station

Endcap Module

Coordinate Measurement Machine

Fiducial Marker 


DAQ System

High Precision Gantry

Module Placement on Petal

Due to the long time required, the QC steps will be distributed across all Canadian ITk institutions, to allow for parallel testing. The final mounting of modules to petals and the associated QC testing will be done at TRIUMF. 

We gratefully acknowledge support from the Natural Sciences and Engineering Research Council of Canada and the the Canada Foundation for Innovation.