Gang Chen

As the main detector of the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor mission (GECAM), the calibration of the energy response and detection efficiency of the gamma-ray detector (GRD) is the main content of the ground-based calibration. This article mainly focuses on the calibration of the energy response and detection efficiency in the 8–160 keV with a refined measurement around the absorption edges of the lanthanum bromide crystal ($\rm {LaBr_3}$). The GRD performances for different crystal types, data acquisition modes, working modes, and incident positions are also analysed in detail. We show that the calibration campaign is comprehensive, the detector performance meets the flight requirements, and the calibration results generally agree with simulations as expected. The detector’s model was corrected by the ground-based calibration, which led to the establishment of the calibration data base.

Amorphous Sb₂Te₃ thin films are synthesized using electrodeposition in different thicknesses to explore their solid electrolytic nature with respect to some noble metals. Au and Pt are used as the substrate materials and thermally diffused into the Sb₂Te₃ films under passivated and nonpassivated conditions. Rutherford backscattering spectrometry is used to study the Au and Pt diffusion into the films as a function of depth. It is found that Au diffuses into the Sb₂Te₃ thin films even at room temperature. In contrast, there is no observable diffusion of Pt at room temperature. At a higher temperature (i.e., 200 °C), both Au and Pt diffuse into the Sb₂Te₃ thin films and Au diffusion is more significant than Pt. The findings suggest that amorphous Sb₂Te₃ can be used as a good solid electrolyte to permit the diffusion of some noble metals such as Au and Pt.

We have applied x-ray scattering to characterize residual strain in nanostructured glasses. The first sharp diffraction peak (FSDP) and the nanostructures of periodic mesoporous silica were investigated as a function of annealing temperature. It is found that position and width of the FSDP exhibit different temperature dependencies, which correspond to two types of residual strain caused by defects and constrained nanostructures, respectively. The latter appear to be inherent to the periodic mesoporous material as confirmed by the small-angle x-ray scattering analysis. Our study has implications for the structural properties of periodic mesoporous materials.