Recently, the excited nuclei, while inserted into materials, have been delivering important information on the physical properties of crystals. For achieving this information, we have to find the exact position of radioactive ionic probes in the lattice and the nature of defects around probes, which is not possible investigated with conventional characterization techniques. In particular, techniques such as perturbed angular correlation (PAC), and emission Mössbauer spectroscopy are outstanding examples of used experimental methods. They can provide detailed information on phase transition, hyperfine fields, lattice location in different types of materials. In addition, The use of perturbed angular correlation (PAC) experiments combined with simulations in the DFT framework provide a unique tool to support the interpretation of experimental data at the atomic scale. The significant interest in these experiments encourages academic and industrial centers to construct robust and sophisticated spectrometry measurement facilities rather than conventional offline measurement techniques. One of the big centers that produce different online radioactive isotopes is ISOLDE/CERN for material sciences. In this talk, I will present the production process of radioactive ions and doing PAC experiments at ISOLDE and I will tell one example of using the numerical method to study the physics behind of ionic probes inside the semiconductors.
