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To reduce the manufacturing difficulty and improve the robustness of traditional boron-lined detectors that may replace the 3He counter, the honeycomb neutron converter-based gaseous neutron detector has been proposed. A drift electric field is applied to drive electrons ionized by $\alpha$ or 7Li after the 10B(n, $\alpha$ )7Li reaction from their origination positions to the incident surface of the gas electron multiplier (GEM), which multiplies electrons and forms the neutron signal. As the working gas affects the energy deposition of $\alpha$ or 7Li, the transverse diffusion of electrons in the migration process, as well as the multiplication of electrons in the GEM detector, the working gas selection of the honeycomb converter-based detector would be very important. Fourteen different working gases are investigated in detail through simulation research. Four working gases, Ar:iC4H10:CF4 = 90:7:3, Ar:CO2 = 95:5, Ar:CH4 = 90:10, and Ar:DME = 95:5, are experimentally tested. Both the simulation and experimental results demonstrate that working gases of Ar:iC4H10:CF4 = 90:7:3, Ar:CO2 = 95:5, and Ar:DME = 95:5 show good performances benefitting from both the large stopping powers of $\alpha$ or 7Li and the small transverse diffusion coefficients of electrons. The simulation results indicate that the detection efficiency with one of the three gases is 1.33 to 1.48 times the Ar:CH4 = 90:10, while the experimental results demonstrate that there is 1.34–1.49 times of the detection efficiency. The research in this paper helps improve the performance of the honeycomb converter-based neutron detector. [ABSTRACT FROM PUBLISHER]

A new design of the boron-lined gaseous neutron detector composed of a boron-lined honeycomb neutron converter and an electron multiplier is proposed in this paper. The motivation for this research was to decrease the manufacturing difficulty and improve the robustness of the boron-lined gaseous neutron detector. The numerous anode wires in the traditional designs were removed, and the gas electron multiplier (GEM) was used as the electron multiplier. To drive the ionized electrons produced inside the honeycomb structure out to the incident surface of the GEM, a drift electric field was applied inside the holes of the honeycomb structure. The design principles of this detector were discussed. Geant4, Maxwell11, and Garfield9 were used to estimate the neutron absorption efficiency and the electron migration process. A prototype detector was constructed and experimentally evaluated. Both the simulation and experimental results indicate that this detector has the potential to be used in the applications of small angle neutron scattering for scientific research, and to replace the currently used 3He detectors, which have the trouble of very limited supply of 3He gas. [ABSTRACT FROM PUBLISHER]

The counting rate capability of a resistive micro-pattern gas detector (MPGD) is limited due to the effect of flowing current and accumulated charge on the resistive layer when evacuating the multiplied electrons to the ground. Thus, the design and optimization of new detector structures that evacuate the electrons to the ground nearby, but not via long-distance transmission on the resistive layer, are essential for the development of the detector rate capability. This type of MPGD design is known as fast grounding. In this study, systematic simulations for the rate capability with various fast grounding designs are conducted, including simulation of the flowing current and charge accumulation effects of the resistive layer. By comparing with experimental results based on strip-grounded, double layer resistive (DLR) and point-grounded micro-resistive WELL (μ -RWELL) detectors, the accuracy of the simulations is validated and demonstrated. These simulations can also be used to optimize the fast grounding design of MPGDs with a resistive layer. Our study indicates that the point-grounded fast grounding design has a good gain performance at a high counting rate and can achieve a compromise between detector performance, manufacturing difficulty and detector dead area. The simulation and experimental results also indicate that the gain decrease can be controlled within ∼ 5.2% at 1 MHz/cm 2 of 8.1 keV X-ray irradiation, with ideal grounded point arrays with a 5 mm pitch and a 0.5 mm radius. [ABSTRACT FROM AUTHOR]