In this paper,the performance of a type of domestic THGEM(THick Gaseous Electron Multiplier)working in Ar/CO_2 mixtures is reported in detail.This kind of single THGEM can provide a gain range from 100to 1000,which is very suitable for application in neutron detection.In order to study its basic characteristics as a reference for the development of a THGEM based neutron detector,the counting rate plateau,the energy resolution and the gain of the THGEM have been measured in different Ar/CO_2 mixtures with a variety of electrical fields.For the Ar/CO_2(90%/10%) gas mixture,a wide counting rate plateau is achieved from 720 V to 770 V,with a plateau slope of 2.4%/100 V,and an excellent energy resolution of about 22%is obtained at the 5.9 keV full energy peak of the ^(55)Fe X-ray source.
With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in ~3He gas supply, research on new types of neutron detector as an alternative to ~3He is a research hotspot in the field of particle detection. GEM(Gaseous Electron Multiplier) neutron detectors have high counting rate, good spatial and time resolution, and could be one future direction of the development of neutron detectors. In this paper, the physical process of neutron detection is simulated with Geant 4 code, studying the relations between thermal conversion efficiency, boron thickness and number of boron layers. Due to the special characteristics of neutron detection, we have developed a novel type of special ceramic n THGEM(neutron THick GEM) for neutron detection. The performance of the n THGEM working in different Ar/CO_2 mixtures is presented, including measurements of the gain and the count rate plateau using a copper target X-ray source. A detector with a single n THGEM has been tested for 2-D imaging using a ^(252)Cf neutron source. The key parameters of the performance of the n THGEM detector have been obtained, providing necessary experimental data as a reference for further research on this detector.
A Monte Carlo method of the 3D GEM simulation is introduced.The physical process of the neutron detection is described with the Geant4 code and the Garfield code.The results of the optimized electric-fields,the emitted ions spectrum,the electrons transverse diffusion and the signal width are presented.Moreover,the preliminary result with a CF-252 neutron source is reported.These are useful in designing detector structures and to provide an optimized option for the development of the boron-coated GEM neutron beam monitor.
WANG YanFengSUN ZhiJiaZHOU JianRongYANG GuiAnXU HongWANG TuoCHEN YuanBo
A new thermal neutron detector with a domestically produced THGEM(Thick Gas Electron Multiplier)was developed as an alternative to3 He to meet the needs of the next generation of neutron facilities. One type of Au-coated THGEM was designed specifically for neutron detection. A detector prototype has been developed and the preliminary experimental tests are presented, including the performance of the Au-coated THGEM working in Ar/CO2 gas mixtures and the neutron imaging test with252 Cf source, which can provide the reference for experimental data for research in the future.
