Structural, optical, and mechanical properties of gamma beam-irradiated pure and CeCl₃-doped potassium hydrogen phthalate (KHP) crystals for scintillating applications

Potassium hydrogen phthalate (KHP) is a high-energy scintillating material having superior properties. The solution crystal growth technique at room temperature is employed for growing undoped and CeCl₃-doped KHP crystals. The ⁶⁰Co γ-ray-irradiated crystals were analyzed through powder X-ray diffraction analysis to evaluate the cell parameters of the pure and doped KHP crystals. The functional groups and vibration modes were identified by Fourier transform infrared spectral analysis. The optical transparency of the grown crystals was analyzed by UV–vis spectroscopy which shows less absorption in the CeCl₃-doped KHP crystals when compared to pure KHP. The vibration properties were discussed with the use of Raman spectra of pure and doped crystals. The photoluminescence analysis reveals broad peaks from green to violet ranges for undoped and CeCl₃-doped KHP crystals. The microhardness test was carried out at different applied loads varying in the range 25–100 g. It is revealed that the Vicker’s hardness values (Hv) increase with increasing applied load. The Meyer’s index number (n) is determined and it confirms that the gamma-irradiated pure, CeCl₃-doped KHP crystals belong to the soft material category. The mechanical properties such as the elastic stiffness constant (C₁₁), yield strength (σ_v), brittleness index (Bi), and the fracture toughness (K_c) are measured for both pure and 1–4 mol% CeCl₃-doped KHP crystals.