The two peaks at higher temperature in thermoluminescence (TL) glow curve of MgSO 4:Dy are enhanced when a certain amount of P was co-doped into MgSO 4:Dy. One main dosimetric peak at about 283.6 ℃ and a satellite peak at about 352.7 ℃ are involved in the TL glow curve of the MgSO 4:Dy

P. The TL sensitivity of MgSO 4:Dy

P phosphor is two times higher than that of LiF:Mg

Ti. The dose responses to gamma rays in the dose range from 0.1Gy to 20kGy were obtained and fitted by the composite action dose response function to get the nonlinear characteristic parameters which indicate that the TL dose responses for the two peaks of MgSO 4:Dy

P are supralinear. While a trace amount of Cu was co-doped into MgSO 4:Dy

P the TL glow peak at 352.7 ℃ was suppressed and the TL sensitivity and the nonlinearity of dose response for the main dosimetric peak at 283.6℃critically depends on the concentration of dopant Cu. The dose response of MgSO 4:Dy

P

Cu (0.1 mol%

0.5 mol%

0.01 mol%) phosphor is linear-sublinear. The MgSO 4:Dy

P

Cu (0.1 mol%

0.5 mol%

0.004mol%) phosphor has a wider linear range in the dose response than MgSO 4:Dy

P(0.1 mol%

0.5 mol%) and its TL sensitivity is close to MgSO 4:Dy

P (0.1 mol%

0.5 mol%). It may be a candidate to measure radiation dose under higher dose circumstances. Furthermore

the composite action model was described further. The experimental results of the MgSO 4:Dy

P and MgSO 4:Dy

P

Cu obtained in this work show that the dosimetric properties of TL materials are linked with the defect structure in these materials

which is useful for understanding the TL mechanism of sulphates with cooperating the TL 3D emission spectra of these phosphors.