A Co‐Precipitated α‐Alumina (Al2O3) used as a TL‐Micro Dosimeter.

This study describes the preparation method of alumina (Al2O3) as a type of thermoluminescence dosimeter (TLD) to monitor gamma photons (γ‐rays) in abroad band of radioactive doses (0.5 : 2000 Gy). Alumina is selected in this study because it has a relatively low cost TL material and can be easily prepared. Aluminum oxide (Al2O3) was chemically prepared using two different methods which are the Sol‐Gel and Co‐precipitation methods. For each method, the produced alumina (Al2O3) was divided into 4 groups which was thermally treated at (400, 600, 800, 1100 °C) respectively for 6 hours for each group. The crystalline features, morphology and sample composition of the prepared samples were chemically characterized by X‐ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X‐ray (EDX). Al2O3 prepared by the Co‐precipitation method which was treated at 1100 °C (P4) was found to exhibit the highest gamma ray response compared to other samples. The deconvolution analysis showed that the main TL glow curve consisted of (5) overlapped peaks corresponding to number of traps. The linearity of the gamma response for this sample appeared in doses ranging from 1 Gy up to 200 Gy. The minimum detectable dose that can be detected by precipitated‐alumina sample (P1) was calculated mathematically to be 3.653 mGy. The fading was found to be 45.6 % after being stored for 45 days at room temperature and approximately 65 % after 90 days. This sample was reproducible according to the repeated TL results for the same sample for 5 times as their values were very close from one other with standard deviation (±σ) 0.96 %. Henceforth, Co‐precipitated α‐alumina can be used as a TL‐Micro dosimeter. [ABSTRACT FROM AUTHOR]