The Measurement Of High Gain Micro Structure Gas Detector

High gain is one of the main performance indicators of microstructured gas detectors.It can effectively improve the signal-to-noise ratio of the detectors.It is an important direction for the development of microstructured gas detectors.The main purpose of this experiment is to verify the feasibility of THGEM-MICROMEGAS detector designThe cascade mode of multiple detectors is usually used to obtain higher gain.The main work of this thesis is to design a new mode of THGEM in micro-induction region.The working mode of THGEM and MICMOGAS is formed by reducing the sensing interval distance of THGEM detector and strengthening the electric field in the induction region,so as to obtain higher gain.The feasibility of the design is studied experimentallyIn the experiment,the sensing interval of THGEM detector is reduced from 1 to 2 mm to 100 microns,and the voltage of the lower surface of THGEM is increased while the upper and lower electrodes of THGEM are kept in the normal working voltage difference,so that the electric field of the micro-induction region is enhanced to achieve two-stage amplification.When the voltage difference between the upper and lower surfaces of THGEM is kept at 600V and the voltage difference between the micro-induction region is 300V,the signal amplitude increases 1.8 times than that of THGEM when it works alone,while the MICROMEGAS detector composed of the micro-induction region alone can not work normally at this time,but the ignition rate increases greatly to 0.6,and the energy resolution becomes worse compared with THGEM.The variation of energy resolution is due to the inconsistency of electric field in the micro-induction region caused by the increase of electric field intensity at the edge of the surface electrode under THGEM compared with the corresponding electric field intensity at the micro-induction region of the THGEM hole.Under the same conditions,the signal amplitude of the detector increases by 1.6 times and the ignition rate increases to about 0.9,but the energy resolution of the detector becomes worse when the voltage difference between the upper and lower surfaces of THGEM is increased to 650 V.The experimental results preliminarily verify the feasibility of high gain design for THGEM detectors in micro-induction region.In order to solve the problem of ignition rate and improve the energy resolution of the detector,we suggest that the lower surface electrode of THGEM be replaced by stainless steel wire mesh cloth to obtain more consistent electric field strength,which needs to be further optimized and tested.