Study Of The Micromegas Development And Performance

Micromegas detector (MICRO MEsh GAseous Structure) is a gaseous detector initially developed for tracking in high-rate, high-energy physics experiments since 1990's. It shows supereme counting rate capacity up to 108 mm-2s-1, spatial resolution better than 100μm and good performance of radiation hardness, which make it a suitable candidate in high-intensity X-ray detection and tomography. With proper neutron converters made of thin solid target it can also be applied in high-flux neutron detection and tomography. Its simple structure and low financial budget, has been adopted by many experiments in particle physics experiments, such as charged particle localization, Time Projection Chamber (TPC), neutron or x-ray imaging.Micromegas consists of a conversion gap (3mm～10mm) in which radiations liberate ionization electrons and of a thin amplification gap (50μm～100μm). The two regions are separated by a thin micromesh grid. Several micromegas modules have been designed and constructed. Their performance is measured with radioactive sources for a 90% Ar + 10% isobutane mixture gas. The electron transfer verse different field ration and uniformity are studied too. The energy resolution of 26% for 55Fe 5.9 keV x-ray and gain of～20000 are obtained under mesh applied voltage is 550V. The range of 241Amαparticle is～14mm in Ar + 10% isobutane mixture gas after it is through 15mm air and 10μm Mylar film window.Micromegas structure design and key properties such as high counting rate capability, radiation hardness, space resolution, energy resolution, efficiency and manufacture of Micromegas bulk technique should be continue studied and improve the fabrication process and testing system according to the tested results. It is experted to reach the international standards and bring forth some new ideas. More application of Micromegas in the future include high-luminosity pixel detectors in ultra high-rate environments such as the third-generation synchronization radiation light sources and the spallation neutron sources with good time and space resolution, which can be widely applied in particle physics, medical engineering and industrial X-ray tomography.