Quantification of various factors influencing repeatability and reproducibility of TLD-600 detector

Abstract EN

Various factors affecting the random and systematic error in the repeatability and reproducibility of thermoluminescent 6LiF:Mg,Ti dosimeters were investigated.

These characteristics were examined by irradiating them with different doses in the range 3.8 µG to 433.94 mGy from a Cs-137 gamma source.

Values of the element correction factors (ECFs) were obtained by exposing the chips to a dose of 433.93 mGy five times.

This investigation denotes that more correction will be obtained by calculating the error due to non-subtracting zero dose reading from the delivered dose, which decreases the coefficient of variation as a percentage of the mean from range of 2.4%-18.6% to only 0.7%-16.9%.

Using the individual sensitivity factor and repeating five calibrations decrease the coefficient of variation as a percentage of the mean to only 0.54% and the values of the Variability Index for System (SVI), Reader (RVI) and Detector (DVI) are 1.46 %, 1.40% and 0.34% respectively.

Also, it is clear from the results that the best repeatability and reproducibility are going to be obtained by using the element correction factor associated with each dosimeter rather than carefully selecting the individual dosimeters.

Finally, from the results we can note that at low doses the value of relative coefficient of variation becomes very large while at high doses it becomes basically constant and of the order of a few percent.