Next generation Ionizing radiation detection

High-energy detection is being revolutionized by integrating photonic elements into scintillators, transforming the field of scintillating materials. Our ongoing collaboration with the university of Tokushima and industrial partners, Nichia the leader in LED and phosphor technologies (Japan) aimed to a scalable and cost-effective method to achieve tunable emission across the visible spectrum by colloidal self-assembly of photonic crystals on scintillator surfaces. We demonstrate this concept, for Eu3+/Tb3+-doped Gd and Ta oxides (Adv. Optical Mater. 2024, 2401030).  Widely available and affordable colloidal nanospheres of SiO2 or PMMA are self-assembled on the scintillators forming photonic layers. The resulting structures are homogeneous and closed-packed SiO2 or PMMA nanosphere films with a clear photonic bandgap in the visible range. Under X-ray excitation scintillator covered with our photonic layers, exhibits enhanced light extraction in the direction perpendicular to the scintillator surface, compared to isotropic emission in the bare scintillator. Such scintillation directionality when optically matched with a proper detector will result in higher efficiency of the overall detection system. Moreover, X-ray imaging analysis demonstrates an enhancement of 25% in system resolution of the scintillator supplemented with photonic layers compared to unmodified scintillators. The proposed methods are scintillator and colloidal nanocrystal agnostic, a promising versatile approach for directing the scintillation light toward a photodetector increasing detection system performance as well as offering a more economically viable solution for high-resolution imaging applications.

Additionally, a project with the Advanced defense industry is dedicated to measuring the fast X-ray detector prototype using a dedicated pulsed setup. The experimental setup was built in our lab, making use of external facilities provided by our collaborators. These facilities were adapted and upgraded to meet the specific requirements of our study. The general work principle of the setup is the following: high power  short-pulsed laser is focused on a target inside a vacuum chamber to produce a hot plasma blob, inside which, among other emissions, short X-ray pulses are generated. The method is prominent due to the possibility of generating very short X-ray pulses; a laser with sub-picosecond pulses allows to reach an X-ray pulse duration of units of picoseconds.

The setup allows fast characterization of the scintillation decay time with a current resolution of 4 ns, with the possibility of improvement.

The project is dedicated to fabrication of next-generation scintillator materials, utilizing the benefits of highly efficient nanocrystal emitters and photonic means to control and enhance light emission.

Halide perovskite nanocrystals are a promising scintillator due to their bright emission, fast decay time in the nanosecond range, high radiation hardness, and considerable stopping power. So, in this part of the project we use halide perovskite nanocrystals as a heavy filler in plastic scintillator.