When an incident high-energy heavy ion beam enters into solid material, the energy deposition density along the ion flight path can change the temperature and pressure of macroscopic target, and new material defects can be created under the high-pressure and high-density conditions. To accurately control the extreme state in material generated by heavy ion beam, it is necessary to conduct in-depth research on the energy deposition density of ions and ascertain the new potential defects in matter. Reported in this work is the new experiment conducted on the HIRFL-CSR at Lanzhou, with the extracted 264 MeV/u Xe³⁶⁺ ion beams irradiating an LiF crystal target. The emission spectrum of the LiF is measured in-situ. Moreover, the crystal color is observed to vary along the ion path, and X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used to observe the potential new phases at different positions of crystal through the target dissociation method.

It is apparent that in No. 3-front a new phase around 52.6° is found in XRD result, which is believed to be LiF₃ (LiF+F₂) structural phase and appears in the Bragg peak region of Xe ions in LiF. Furthermore, to verify this result, a similar experiment is done by using a 430 MeV/u ⁸⁴Kr²⁶⁺ ion beam, and the stacked layered LiF target is analyzed after the irradiation. The XPS result shows more complex defects aggregating in the Bragg peak region of Kr ions in LiF at room temperature. In previous study, such complex defects were all created under high temperature conditions. We find that these complex defects can be produced around the Bragg peak region of ions in LiF at room temperature, resulting in a temporally high temperature and high pressure condition. This paper can provide some experimental evidences and references for the target material modification in heavy ion beam driven high-energy density physics research.