Luminescence and scintillation properties of Tm 3+ 0.1–15% doped CaF 2 crystals were systematically investigated. The crystals were grown by a simple solidification method which allowed us to obtain single crystals conveniently. In X-ray induced radio luminescence spectra, the luminosity of the self-trapped-exciton (STE) emission of CaF 2 at 270nm decreased with increasing of Tm 3+ concentration. The Tm 3+ 5d-4f transition based emission lines appeared at 175nm (4f 11 5d high spin state (HS)→ 3 H 6 ) and at 165nm (low spin state (LS) to 3 H 6 ). Pulse height spectra were measured under α-ray irradiation by using vacuum ultra-violet (VUV) sensitive photomultiplier tube (PMT) R8778 and Tm 3+ 0.1% doped specimen exhibited the highest light yield.