Upgrading the ATLAS Experiment at the CERN LHC

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With the observation of a Higgs boson, the future physics program with ATLAS at the CERN Large Hadron Collider is coming into focus. In addition to precise measurements of the couplings and other properties of this newly discovered particle, the motivation for new TeV-scale electroweak physics to stabilize the Higgs vacuum remains strong. The future LHC program was affirmed as the top priority of European particle physics in recent strategic planning, and the future of LHC and ATLAS operations is secure. The ATLAS detector requires upgrades to operate at the increasing energy and rates expected in the coming years, and maintaining Canadian involvement in ATLAS includes Canadian participation in the ATLAS detector upgrade program. Canadian groups are currently focusing on two near-term “phase 1” ATLAS upgrades: (i) construction, testing and installation of high-rate thin gap chambers (sTGC) for the new muon end cap “small wheel” and (ii) design, assembly, testing and installation of upgraded front-end electronics for the liquid argon calorimeter (LAr) trigger. Both of these upgrades are designed to allow ATLAS operation with low lepton (muon and electron) trigger transverse momentum thresholds which are essential for the studies of the Higgs and searches for new electroweak-scale physics processes such as supersymmetry, extra dimensions, or more generally the physics that could explain the nature of dark matter and help stabilize the Higgs vacuum. The Canadian sTGC program involves building one third of the sTGC chambers planned for ATLAS, or 64 “quadruplets”. The three Canadians sites include: (1) TRIUMF-based cathode preparation and carbon/epoxy spray facility to ensure precise resistive layer coating of the chamber interior walls; (2) Carleton-based wire winding and chamber assembly facility to complete the quadruplets for gas and high-voltage application; (3) McGill-based chamber cosmic ray testing facility to ensure the Canadian-built chambers are fully functional before shipping them to CERN. A significant part of the laboratory infrastructure for chamber construction and testing is being purchased with the funds from the NSERC RTI award from the 2013 competition, along with material for prototype chamber construction. Most of the remainder of the laboratory infrastructure, plus initial chamber construction materials, would be purchased with funds from the NSERC RTI request in the 2014 competition, allowing us to ramp up our chamber production facilities on the timescale required by ATLAS. The Canadian LAr Electronics program involves designing, prototyping and building new front-end crate baseplanes for the Canadian-built Hadronic Endcap Calorimeter (HEC). We will also design, build and test several parts of the analogue electronics for the project, and purchase ADC components for the boards. The 2013 NSERC RTI award funds are being used for initial baseplane design and component testing, including verifying their neutron irradiation tolerance. The funds requested in the NSERC 2014 SAPES RTI competition would be used to construct and test a full-scale prototype of the HEC baseplane. The funds requested in this RTI application are required in Fiscal Year 2014-2015 for continued Canadian leadership in ATLAS upgrades. The majority of the capital and labour costs for project completion will be requested from the Canada Foundation for Innovation in the upcoming competition.