Thermoluminescence efficiency and glow curves of Cr-doped Al₂O₃ ceramic TLD for a wide linear energy transfer range

We investigated the thermoluminescence (TL) efficiency and the glow curve of Cr-doped alumina (Al₂O₃) ceramic thermoluminescent dosimeters (TLDs) for heavy charged particles. The TLDs were irradiated with beams of protons, helium, and carbon ions. A 6-MV X-ray was used as the reference radiation for investigating the relative TL efficiency. The relative TL efficiency reaches its peak when the linear energy transfer (LET) is approximately 6 keV/μm and decreases with increasing LET. Moreover, the relative TL efficiency was 1.09 for the helium beam (LET: 11.5 keV/μm) and 1.22 for the carbon beam (LET: 13.3 keV/μm). This indicates that the relative TL efficiency of a Cr-doped Al₂O₃ ceramic TLD varies not only with the LET but also with the particle species. In order to investigate the relationship between the trap center of the Cr-doped Al₂O₃ ceramic TLD and the LET, the glow curve for each irradiation condition was also measured. As a result, the shape of the glow curve remained the same for a wide LET range, between 0.5 keV/μm and 128 keV/μm.