X-rays are a form of ionizing radiation. They are high-energy photons (electromagnetic radiation) released when inner shell electrons that have been excited to higher energy levels release their excess energy.
They are like gamma-ray with longer-wavelength and can have lower energy than gamma radiation. Radiation shielding is the ability to reduce a wave or ray’s effect by blocking the particles through a barrier or shield. Since X-rays have higher energy levels than those displayed by ultraviolet or visible light, high-density materials like lead and very thick glasses of certain refractivity are more effective in blocking or shielding them.