Assembly procedures and QA/QC tests of the new double-ends readout panels of the new layer of trigger chambers for the phase II upgrade of the ATLAS barrel muon spectrometer.

With the view to high-luminosity LHC upgrade, the ATLAS experiment will add a new layer of RPC trigger chambers into the barrel muon spectrometer. These next-generation RPC chambers will use a $1 {mm}$ gap and a single type of readout strips coupled to front-end electronics capable of providing both coordinates in the detector plane. In this communication we present the procedures for assembling the readout panels and the QA/QC tests on the individual components and on the final product, and the results on the construction of the first prototypes of $2500\times$ 650 ${mm}$ paper honeycomb strip panel.