Small-strip Thin Gap Chambers Research Articles

Development of scanning technique for sTGC detectors production quality control

The innermost station of the ATLAS muon end-cap system will be replaced during the forthcoming Phase-I upgrade of the ATLAS detector. The small-strip Thin Gap Chambers (sTGC) are supposed to operate at harsh radiation conditions of super LHC. X-ray scanning technique for production quality control is proposed to ensure long-term reliability of these chambers. It allows to reveal different types of technological defects critical for sTGC chambers operation.

Small-strip Thin Gap Chambers for the muon spectrometer upgrade of the ATLAS experiment

The ATLAS muon system upgrade to be installed during the LHC long shutdown in 2018/19, the so-called New Small Wheel (NSW), is designed to cope with the increased instantaneous luminosity in LHC Run 3. The small-strip Thin Gap Chambers (sTGC) will provide the NSW with a fast trigger and high precision tracking. The construction protocol has been validated by test beam experiments on a full-size prototype sTGC detector, showing the performance requirements are met. The intrinsic spatial resolution for a single layer has been found to be about 45μm for a perpendicular incident angle, and the transition region between pads has been measured to be about 4mm.

Micromegas detectors for the upgrade of the ATLAS muon spectrometer

The upcoming luminosity upgrades of the LHC accelerator up to an ultimate value of 5 × 1034 cm−2s−1 require a replacement of the innermost forward muon tracking stations (Small Wheels) of the ATLAS detector in 2018 and 2019. These New Small Wheels (NSW) will contain resistive strip micromegas and small-strip Thin Gap Chamber detectors. The resistive strip micromegas detector concept is presented, together with the μTPC (micro Time Projection Chamber) track reconstruction technique for a single plane track angle measurement. The mechanical layout of the NSW micromegas chambers is discussed as well, as the features of the specially designed front-end electronics. A pre-series micromegas chamber will be installed within ATLAS already in 2014. It will be integrated into the ATLAS data acquisition system with help of a custom micromegas Read Out Driver (ROD), based on the Scalable Readout System (SRS).

Study of the performance of the Micromegas chambers for the ATLAS muon spectrometer upgrade

Micromegas (Micro Mesh Gaseous Structures) chambers and sTGC (small-strip Thin Gap Chambers) have been chosen for the upgrade of the forward muon detectors of the ATLAS experiment to provide precision tracking and trigger capabilities.The Micromegas chambers for ATLAS have been designed to allow operation in a high rate environment, to guarantee a resolution below 100 μm per point on a large area and to provide a fast trigger signal.In the last months several tests have been done on small area prototypes in order to verify that the requirements on resolution and rate capabilities are well matched.The results of the performance studies done on beams at CERN and of the ageing studies done at CEA Saclay are presented.

Performance studies of MicroMegas for the ATLAS experiment

The performance of MicroMegas (MM) has been extensively studied during several test beam campaigns with high energy particle beams at CERN up to the year 2012, and more recently (June 2013) with electron beams at DESY. Main objectives of the tests were to demonstrate that the requirements could be achieved for the upgrade of the ATLAS Muon Spectrometer, where the MicroMegas will be mounted (along with small-strip Thin Gap Chambers — sTGC) on the New Small Wheel for forward muon detection. The MM layout and operating settings have then been chosen to satisfy the ATLAS upgrade requirements and trigger timing constraints. Results for efficiencies, time resolution and spatial resolution for perpendicular and inclined tracks are presented. Moreover, in ATLAS the MM will operate in a non-uniform magnetic field up to 0.3 T. Dedicated test beam measurements have been carried out in a variable magnetic field between 0 and 1 T. The performance of MM in magnetic fields is also reported along with a comparison to simulations.