As an emerging scintillation material, metal halide perovskite (CsPbX3) has been deemed the most potentially valuable candidate in X-ray detection and medical imaging. Nevertheless, it is a continuing challenge to implement efficient radioluminescence (RL) with high radiation stability and moisture resistance. Moreover, the optimized luminescence properties and excellent uniformity of CsPbX3 glass are also key points for obtaining perfect X-ray images. Herein, we have successfully precipitated Eu3+-doped CsPbBr3 nanocrystals (NCs) with improved photoluminescence quantum yield (≈58.6%) because partial Eu3+ entered the perovskite lattice in a robust borosilicate glass matrix by in situ crystallization. The small amount of Eu addition made the lattice of NCs shrink and promoted uniform distribution of CsPbBr3 NCs in the glass, which effectively reduced the light scattering of the sample. Subsequently, multimodal RL intensity of the CsPbBr3/CsPbBr3:xEu NCs glasses (CPB-0Eu/CPB-xEu) as a function of X-ray dose rate showed a superlinear relationship to the benefit of obtaining satisfactory X-ray images. Also, the outstanding radiation stability and water resistance of CPB-xEu were confirmed due to the protection of the robust glass matrix. Finally, an X-ray imaging system using a CPB-xEu scintillator was constructed, and the spring in the opaque sample was legibly detected under the motivation of X-rays, indicating that CsPbX3 glasses possess extensive application prospects in terms of X-ray detection and medical imaging.

In this study, we investigate a new simple scheme using a planar undulator (PU) together with a properly dispersed electron beam ( beam) with a large energy spread ( ) to enhance the free-electron laser (FEL) gain. For a dispersed beam in a PU, the resonant condition is satisfied for the center electrons, while the frequency detuning increases for the off-center electrons, inhibiting the growth of the radiation. The PU can act as a filter for selecting the electrons near the beam center to achieve the radiation. Although only the center electrons contribute, the radiation can be enhanced significantly owing to the high-peak current of the beam. Theoretical analysis and simulation results indicate that this method can be used for the improvement of the radiation performance, which has great significance for short-wavelength FEL applications.

Real-time single-shot measurement of the femtosecond electron beam duration in laser wakefield accelerators is discussed for both experimental design and theoretical analysis that combines polarimetry and interferometry. The probe pulse polarization is rotated by the azimuthal magnetic field of the electron beam and then introduced into a Michelson-type interferometer for self-interference. The electron beam duration is obtained from the region size of the interference fringes, which is independent of the pulse width of the probe laser. Using a larger magnification system or incident angle, the measurement resolution can be less than 1 fs.

Beam quality degradation during the transition from a laser wakefield accelerator to the vacuum is one of the reasons that cause the beam transport distortion, which hinders the way to compact free-electron-lasers. Here, we performed transition simulation to initialize the beam parameters for beam optics transport. This initialization was crucial in matching the experimental results and the designed evolution of the beamline. We experimentally characterized properties of high-quality laser-wakefield-accelerated electron beams, such as transverse beam profile, divergence, and directionality after long-distance transport. By installing magnetic quadrupole lenses with tailored strength gradients, we successfully collimated the electron beams with tunable energies from 200 to 600 MeV.