Speaker
Mr
Irakli Minashvili
(JINR)
Description
The upgrade of the Large Hadron Collider (LHC) to the High
Luminosity LHC (HL-LHC) is required to probe the physics beyond
Standard Model. After the ongoing long shutdown (LS2), the accelerator
luminosity will be increased 2 to 3 times as compared to designed
luminosity value i.e. 1 X 10^34 cm-2s-1. To meet the requirements of higher
rates environment of HL-LHC era, the muon system of ATLAS detector
needs to be upgraded. Therefore, the small wheel comprised of Cathode
Strip Chambers (CSC) and monitored Drift Tubes (MDT) chambers will
be replaced by the new small wheel (NSW). The NSW will be constituted
by Micromesh Gaseous Structure (Micromegas) detectors and small-strip
Thin Gap Chambers (sTGC). Micromegas detectors will be used for
tracking as well as triggering purpose. In each of the NSW (A&C), 16
modules will be installed in 16 sectors i.e. 8 large sectors and 8 small
sectors; covering total area of ~ 1200 m2. Micromegas are ionizationbased
gaseous detectors made up of parallel plates, having a thin
amplification region separated from the conversion region via thin metallic
mesh. The production of Micromegas detectors as well as methods adopted
to achieve required geometrical precision are presented. Specific
measurement devices have been developed in the last few years to
determine the quality of Micromegas chambers required for NSW.
Planarity measurements of drift, readout panels as well as modules after
assembly are done with a specific CMM (co-ordinate measuring machine),
results are shown for drift, readout panels as well as modules. Results of
in-plane measurements (XY co-ordinate), performed using Rasnik masks
etched on the PCBs are also reported. Modules constructed using the
dedicated tools and methods are validated using cosmic muons, results of
one such module are shown.
Primary authors
Mr
Irakli Minashvili
(JINR)
Muon Coll. ATLAS
(ATLAS)
