# Research on a Neutron Detector with a Boron-Lined Multilayer Converter
## 3 Experiments with \({}^{241}\)Am-\({}^{239}\)Pu Mixture Source  
Figure 7 depicts the BMCND packaging process. A resin bracket, manufactured by 3D printing technology, supports the field cage and boron-lined ultrathin glass. One by one, the boron-lined ultrathin glass was inserted into each resin bracket card slot and secured with hot melt adhesive after the field cage had been fastened within the resin bracket using polyimide tape. A manufactured BMC and an MWPC were connected by eight plastic screws and nuts, sealed into the aluminum chamber, to complete the BMCND packaging. We applied a \({}^{241}\)Am-\({}^{239}\)Pu mixture \(\alpha\) source to verify the ability of the BMCND to detect charged particles. Figure 8 displays the schematic diagram of the \(\alpha\) radioactive source experiment. The \({}^{241}\)Am-\({}^{239}\)Pu mixture \(\alpha\) source was fixed on the cathode before the boron-lined ultrathin glass was installed. One ORTEC 556 high-voltage power supply (Atlanta, GA, USA) was used to provide -2500 V to the cathode, and another was used to provide +1160 V to the CAEN 1422 preamplifier (Viareggio, Italy), which provided a bias voltage to the anode reel of the MWPC. A ground electrode was used to provide 0 V  
Figure 5: Charged particle EDS of different slits. Figure 6: EDS of different particles. to the protection ring. Meanwhile, the nuclear signals were led into an oscilloscope from the CAEN 1422 preamplifier and ORTEC 672 main amplifier (Atlanta, GA, USA). Nuclear Instrumentation Module bins provided the power supply for the ORTEC 556 and ORTEC 672. Finally, the computer stored the nuclear signal from the ORTEC 672 main amplifier after dealing with the ORTEC EASY-MCA (Atlanta, GA, USA). A radioactive source, AMPU1103, employed by the \({}^{241}\)Am-\({}^{239}\)Pu mixture \(\alpha\) source, was provided by the CAEA Innovation Center of Nuclear Environmental Safety Technology of Southwest University of Science and Technology. Table 1 shows the detailed information. The mixture source mainly comprises \({}^{241}\)Am and \({}^{239}\)Pu nuclides with 2\(\pi\)\(\alpha\) charged particle emission rates of 282.2 s\({}^{-1}\) and 390.7 s\({}^{-1}\), respectively, where the total emission rate is 672.9 s\({}^{-1}\). The reference time is 10 August 2011, and the expanded uncertainty (k = 2) is 2.5%. The \(\alpha\) charged particle characteristic kinetic energy of \({}^{241}\)Am and \({}^{239}\)Pu is 5.486 MeV and 5.157 MeV, respectively, referring to the nuclide database. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Source Number** & **Nuclide** & **Particle Emission Rate over 2\(\pi\) (s\({}^{-1}\))** \\ \hline \multirow{2}{*}{AMPU1103} & Am-241 & 282.2 \\ \cline{2-3}  & Pu-239 & 390.7 \\ \hline Reference Time & 10 August 2011 \\ \hline \hline \end{tabular} Expanded Uncertainty (k = 2) & 2.5\%  
\end{table} 
Table 1: Detailed information about the \(\alpha\) radioactive source used. Figure 8: Schematic diagram of \(\alpha\) radioactive source experiment. Figure 7: BMCND packaging process. Figure 9 depicts the layout of the \(\alpha\) radioactive source experiment, as shown in Figure 8. The results of \(\alpha\) radioactive source experiments are shown in Figure 10, indicating that no nuclear signal was seen other than noise when there was no \({}^{241}\)Am-\({}^{239}\)Pu \(\alpha\) source. On the contrary, we observed many nuclear signals when the \({}^{241}\)Am-\({}^{239}\)Pu \(\alpha\) source was used. The two recorded Gaussian peaks, for the \({}^{241}\)Am nuclide at 5.486 MeV and for the \({}^{239}\)Pu nuclide at 5.157 MeV, correspond to two kinds of \(\alpha\) charged particles. Moreover, low-energy \(\alpha\) particles have higher counts, and high-energy \(\alpha\) particles have lower counts, agreeing with the original provided data on \(\alpha\) particles. The calculated total measured count rate is 599.5 s\({}^{-1}\), 89% of the theoretical \(\alpha\) particle emission rate of 672.9 s\({}^{-1}\).