English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Large area Micromegas detectors will be employed for the first time inhigh-energy physics experiments. A total surface of about $\mathbf{150~m^2}$ ofthe forward regions of the Muon Spectrometer of the ATLAS detector at LHC willbe equipped with 8-layer Micromegas modules. Each layer covers more than$\mathbf{2~m^2}$ for a total active area of $\mathbf{1200~m^2}$. Together withthe small strip Thin Gap Chambers they will compose the two New Small Wheels,which will replace the innermost stations of the ATLAS endcap muon trackingsystem in the 2018/19 shutdown. In order to achieve a 15$\mathbf{\%}$transverse momentum resolution for $\mathbf{1~TeV}$ muons, in addition to anexcellent intrinsic resolution, the mechanical precision of each plane of theassembled module must be as good as $\mathbf{30~\mu m}$ along the precisioncoordinate and $\mathbf{80~\mu m}$ perpendicular to the chamber. The design andconstruction procedure of the Micromegas modules will be presented, as well asthe design for the assembly of modules onto the New Small Wheel. Emphasis willbe on the methods developed to achieve the challenging mechanical precision.Measurements and simulations of deformations created on chamber prototypes as afunction of thermal gradients, internal stress (mesh tension and modulefixation on supports) and gas over-pressure were essential in the developmentof the final design. During installation and operation all deformations andrelative misalignments will be monitored by an optical alignment system andcompensated in the tracking software.

Design and Construction of Large Size Micromegas Chambers for the Upgrade of the ATLAS Muon Spectrometer