Working Gas Selection of the Honeycomb Converter-Based Neutron Detector

To reduce the manufacturing difficulty and improve the robustness of traditional boron-lined detectors that may replace the
³
He counter, the honeycomb neutron converter-based gaseous neutron detector has been proposed. A drift electric field is applied to drive electrons ionized by α or
⁷
Li after the
¹⁰
B(n, α)
⁷
Li 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 α or
⁷
Li, 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:iC
₄
H
₁₀
:CF
₄
= 90:7:3, Ar:CO
₂
= 95:5, Ar:CH
₄
= 90:10, and Ar:DME = 95:5, are experimentally tested. Both the simulation and experimental results demonstrate that working gases of Ar:iC
₄
H
₁₀
:CF
₄
= 90:7:3, Ar:CO
₂
= 95:5, and Ar:DME = 95:5 show good performances benefitting from both the large stopping powers of α or
⁷
Li 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:CH
₄
= 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.