CERN New Small Wheel - ATLAS upgrade Witold Niewiem

ATLAS UPGRADE

NEW SMALL WHEEL

One of the challenges during the Phase-1 ATLAS upgrade is the replacement of two Small Wheels. The goal is to meet the challenges of the High-Luminosity LHC through the modernization. The two symmetrical New Small Wheels will replace the old detectors. However, the principle structure is similar for the new and the old version; the foregoing chambers will be replaced by the novel Micro-mesh gaseous structures and enriched by small strip Thin Gap chambers (sTGC).

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Double Wedge alignment

sTGC assembly on a granite table

Micromegas support structure validation

IMG_2265

sTGC reference transfer

Assembly of JD shielding

Spokes and HUB correction

Survey of New Small Wheel on each step of the assembly

Chamber construction has been taking place in all production sites: Chile, China, Canada, Israel and Russia for the sTGC; Germany, France, Italy, Greece and Russia for the Micromegas. The final testing of the chambers is performed on the spot at CERN. Upon successfully passing these tests, chambers are assembled into what is called a double wedge; the Micromegas of each of the 16 detector sectors. The sTGC chambers undergo similar reception tests. Following these steps, each of the three chambers is assembled into the sTGC wedge. Wedge assemble is done by placing the sTGC chambers on a granite table, aligning them with great precision against a reference jigging, and then gluing a fiberglass support frame on top of them.

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