Dosimetry is a widespread material science field dealing with detection and quantification of ionizing radiation using electronic processes in materials. One of the main aspects that determines the performance of dosimeters is the type of defects the material contains. Crystalline lattice imperfections are formed around impurity ions, which may have a smaller or larger size, or different oxidation states compared to host ions. In this study, we show what effects Cr impurities have on the luminescent properties of alumina. Porous ${\mathrm{Al}}_2{\mathrm{O}}_3:\mathrm{Cr}$ microceramics synthesized using the sol-gel method showed a higher thermoluminescence response than a single crystal ruby. We have found that ${\mathrm{Cr}}_2{\mathrm{O}}_3$ concentration of 0.2 wt% was optimal; it yielded the highest X-ray luminescence and thermostimulated luminescence readout of all studied additive concentrations added to alumina during synthesis. Our results show that Cr doped alumina could potentially be used as a promising new material for dosimetry of ionizing radiation.