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

For the upcoming upgrade of the forward muon stations of the ATLAS detector, 1280m2 of Micromegas chambers have to be constructed. The industrialization of anode board production is an essential precondition. Design and construction methods of these boards have been optimized towards mass production. In parallel quality control procedures have been developed and established. The first set of large size Micromegas anode boards has finally been produced in industries and demonstrates the feasibility of the project on full-scale.

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The Micromegas Surface Commissioning For the ATLAS New Small Wheel

Journal of Physics Conference Series ◽

10.1088/1742-6596/2105/1/012020 ◽

2021 ◽

Vol 2105 (1) ◽

pp. 012020

Author(s):

Athina Kourkoumeli-Charalampidi ◽

Dimitrios Fassouliotis

Keyword(s):

Muon Spectrometer ◽

Atlas Experiment ◽

Full Coverage ◽

Large Size ◽

Innermost Layer ◽

Different Types ◽

End Caps ◽

Precision Tracking ◽

First Time

Abstract In order to cope with the required precision tracking and trigger capabilities from Run III onward in the ATLAS experiment, the innermost layer of the Muon Spectrometer end-cap (Small Wheels) will be upgraded. Each of the two New Small Wheels (NSW) will be equipped with eight layers of MicroMegas (MM) detectors and eight layers of small-strip Thin Gap Chambers (sTGC), both arranged in two quadruplets. MM detectors of large size (up to 3m2) will be employed for the first time in HEP experiments. Four different types of MM quadruplet modules (SM1, SM2, LM1, LM2), built by different Institutes, compose the NSW. The modules are then sent to CERN, integrated into double wedges (DW), tested and sent for commissioning on the wheel itself. At the commissioning stage the MM double wedges along with the sTGC wedges are assembled together into sectors which are then installed and tested on the wheel. Each wheel comprises 8 small (made of SM1 and SM2 modules) and 8 large (made of LM1 and LM2 modules) sectors, in order to provide full coverage of the end caps. The first of the two wheels (NSW-A) has been fully commissioned, installed in ATLAS and the first tests are currently ongoing. The second wheel (NSW-C) is currently under commissioning and is expected to be ready by October this year.

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Design and construction of integrated small-diameter drift tube and thin-gap resistive plate chambers for the phase-1 upgrade of the ATLAS muon spectrometer

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2018.10.139 ◽

2019 ◽

Vol 936 ◽

pp. 445-446

Author(s):

H. Kroha

Keyword(s):

Drift Tube ◽

Phase 1 ◽

Small Diameter ◽

Muon Spectrometer ◽

Resistive Plate Chambers ◽

Design And Construction

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Coherency loss in γ' precipitates in nickel-base superalloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075014 ◽

1983 ◽

Vol 41 ◽

pp. 244-245

Author(s):

R. A. Ricks ◽

Angus J. Porter

Keyword(s):

Lattice Mismatch ◽

Lattice Parameter ◽

Nickel Base Superalloy ◽

Large Size ◽

The Matrix ◽

Nimonic 80A ◽

Interfacial Dislocations ◽

Nickel Base ◽

Coherency Loss ◽

Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

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Automatic analysis of Kikuchi diffraction patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172231 ◽

1994 ◽

Vol 52 ◽

pp. 900-901

Author(s):

H. Weiland ◽

D. P. Field

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Spatial Resolution ◽

Relevant Information ◽

Crystalline Materials ◽

Large Size ◽

Transmission Electron ◽

New Type ◽

Diffraction Patterns ◽

Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

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Immunoprobe localization in mammalian embryos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157693 ◽

1990 ◽

Vol 48 (3) ◽

pp. 32-33

Author(s):

Patricia G. Calarco ◽

Margaret C. Siebert

Keyword(s):

Electron Microscopy ◽

Endoplasmic Reticulum ◽

Thin Sections ◽

Relative Lack ◽

Large Size ◽

Mammalian Embryos ◽

Antigen Localization ◽

Difficult Challenge ◽

Lowicryl K4m ◽

Fertilized Egg

Visualization of preimplantation mammalian embryos by electron microscopy is difficult due to the large size of the ircells, their relative lack of internal structure, and their highly hydrated cytoplasm. For example, the fertilized egg of the mouse is a single cell of approximately 75μ in diameter with little organized cytoskelet on and apaucity ofor ganelles such as endoplasmic reticulum (ER) and Golgi material. Thus, techniques that work well on tissues or cell lines are often not adaptable to embryos at either the LM or EM level.Over several years we have perfected techniques for visualization of mammalian embryos by LM and TEM, SEM and for the pre-embedding localization of antigens. Post-embedding antigenlocalization in thin sections of mouse oocytes and embryos has presented a more difficult challenge and has been explored in LR White, LR Gold, soft EPON (after etching of sections), and Lowicryl K4M. To date, antigen localization has only been achieved in Lowicryl-embedded material, although even with polymerization at-40°C, the small ER vesicles characteristic of embryos are unrecognizable.

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Vibration Isolator System for Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017966x ◽

1990 ◽

Vol 48 (1) ◽

pp. 182-183

Author(s):

K. Ohi ◽

M. Mizuno ◽

T. Kasai ◽

Y. Ohkura ◽

K. Mizuno ◽

...

Keyword(s):

Electron Microscope ◽

Magnetic Fields ◽

Environmental Conditions ◽

Vibration Isolator ◽

Air Conditioners ◽

Vibration Isolators ◽

Large Size ◽

Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

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