Speaker
Description
In 2018, Dubna team assembled the first LM2 module for ATLAS New Small Wheel upgrade, replacing the innermost and first station of the Muon end cap system.
Assembled modules have to pass quality and performance tests on-site including gas leaking, high voltage and MIP efficiency measurement on cosmic stand. The latter is important also as an extention of the HV test and a check of mere possibility for the correct readout boards installation. Cosmic tests started with a severe handicap - a lack of readout boards to fully populate the module - with a following consequences.
First an algorithm was developed to measure efficiency in a single point of one layer in a module using reconstructed probe tracklet in 3 other layers of the same module, so called "module self-testing" compared to other imaginable scenarios where the probe track is provided by another LM2 module or MDT chamber or another precision tracking system. While giving a 2-D map of efficiency for each of 4 layers, this method has limitations which will be discussed.
Next a specific installation method for both compression bars and readout cards was developed. It saves the readout cards from mechanical damages which accumulates over time as the cards are reinstalled 3 times per module in 2019 and 2 times per module in 2020. Also it allows for easier and more regular installation process which was considered as fully "expert-mode" but now allowed for trained people with only a few expert interventions.
Cosmic stand setup description, installation technique details, efficiency and signal amplitude distributions over panel area, HV turn-on curves and efficiency pressure dependence are included.
