Synthesis and characterization of high-sensitivity Dy,Eu co-doped CaSO 4 thermoluminescent phosphor using coprecipitation technique.

In this work, (99 - x)CaSO 4 -Dy 2 O 3 -xEu 2 O 3 , (where x = 0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) thermoluminescence phosphors were prepared using a coprecipitation method. The thermoluminescence (TL) dosimetry (TLD) characteristics such as TL sensitivity, dose-response, minimum detectable dose, thermal fading, and the effect of sunlight on the prepared phosphors were investigated. The obtained results indicated that the most sensitive phosphor was obtained at x = 0.05. Large thermal fading of 6% after 1 h and 26% after 24 h from irradiation followed by 71% after 1 month with no additional fading was observed within a time frame exceeding 2 months throughout the remaining duration of the investigation, which also spanned over 2 months. Despite the phosphor's high fading rate, the relative sensitivity of the prepared samples was ~90% compared with TLD-100. The marked effect of day sunlight was also determined. High dose-response within the low-dose range from 0.01 to 5 Gy was observed. The obtained results suggested that the synthesized phosphor is well suited for applications involving radiation biology and radiotherapy dosimetry.