[en] Thermal annealing effect and pre-dose effect on the TL properties of Egyptian sand (97.94% SiO2) of grain size between 71 and 200 micron was investigated. Experimental results indicated that thermal annealing above 6000C introduces a new trap level at 1400C and the sensitivity of the phosphor to radiation increases as the annealing temperature is increased. The sensitivity of sand is enhanced by previous exposure to a high level of radiation. (U.K.)