No Arabic abstract
A centenary after the invention of the basic principle of gas amplification, gaseous detectors - are still the first choice whenever the large area coverage with low material budget is required. Advances in photo-lithography and micro-processing techniques in the chip industry during the past two decades triggered a major transition in the field of gas detectors from wire structures to Micro-Pattern Gas Detector (MPGD) concepts, revolutionizing cell-size limitations for many gas detector applications. The high radiation resistance and excellent spatial and time resolution make them an invaluable tool to confront future detector challenges at the frontiers of research. The design of the new micro-pattern devices appears suitable for industrial production. In 2008, the RD51 collaboration at CERN has been established to further advance technological developments of MPGDs and associated electronic-readout systems, for applications in basic and applied research. This review provides an overview of the state-of-the-art of the MPGD technologies and summarizes recent activities for the next generation of colliders within the framework of the RD51 collaboration.
Gaseous detectors are fundamental components of all present and planned high energy physics experiments. Over the past decade two representatives (GEM, Micromegas) of the Micro-Pattern Gas Detector (MPGD) concept have become increasingly important; the high radiation resistance and excellent spatial and time resolution make them an invaluable tool to confront future detector challenges at the next generation of colliders. Novel structures where GEM and Micromegas are directly coupled to the CMOS multi-pixel readout represent an exciting field and allow to reconstruct fine-granularity, two-dimensional images of physics events. Originally developed for the high energy physics, MPGD applications have expanded to astrophysics, neutrino physics, neutron detection and medical imaging.
The Compact Linear Collider (CLIC) is a high-energy high-luminosity linear electron-positron collider under development. It is foreseen to be built and operated in three stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. It offers a rich physics program including direct searches as well as the probing of new physics through a broad set of precision measurements of Standard Model processes, particularly in the Higgs-boson and top-quark sectors. The precision required for such measurements and the specific conditions imposed by the beam dimensions and time structure put strict requirements on the detector design and technology. This includes low-mass vertexing and tracking systems with small cells, highly granular imaging calorimeters, as well as a precise hit-time resolution and power-pulsed operation for all subsystems. A conceptual design for the CLIC detector system was published in 2012. Since then, ambitious R&D programmes for silicon vertex and tracking detectors, as well as for calorimeters have been pursued within the CLICdp, CALICE and FCAL collaborations, addressing the challenging detector requirements with innovative technologies. This report introduces the experimental environment and detector requirements at CLIC and reviews the current status and future plans for detector technology R&D.
A new concept for a hybrid structure gaseous detector module with ion backflow suppression for the time projection chamber in a future circular collider is presented. It is a hybrid structure cascaded Gas Electron Multiplier (GEM) with a Micromegas detector. Both Micromegas and GEM have the capability to naturally reduce most of the ions produced in the amplification region. The GEM also acts as the preamplifer device and increases gas gain together with the Micromegas. Feasibility tests of the hybrid detector are performed using an ${}^{55}$Fe X-ray source. The energy resolution is better than 27% for 5.9 keV X-rays. It is demonstrated that a backflow ratio better than 0.2% can be reached in the hybrid readout structure at a gain of 5000.
We demonstrate practically approximation-free electrostatic calculations of micromesh detectors that can be extended to any other type of micropattern detectors. Using newly developed Boundary Element Method called Robin Hood Method we can easily handle objects with huge number of boundary elements (hundreds of thousands) without any compromise in numerical accuracy. In this paper we show how such calculations can be applied to Micromegas detectors by comparing electron transparencies and gains for four different types of meshes. We demonstrate inclusion of dielectric material by calculating the electric field around different types of dielectric spacers.
NEXT is an experiment dedicated to neutrinoless double beta decay searches in xenon. The detector is a TPC, holding 100 kg of high-pressure xenon enriched in the $^{136}$Xe isotope. It is under construction in the Laboratorio Subterraneo de Canfranc in Spain, and it will begin operations in 2015. The NEXT detector concept provides an energy resolution better than 1% FWHM and a topological signal that can be used to reduce the background. Furthermore, the NEXT technology can be extrapolated to a 1-ton scale experiment.