Effect of Time and Temperature Changing on The Radioactive Measurements for NaI(Tl) Detector

Abstract

There are many and varied working conditions very important for the researcher. In this work, two of these conditions and their change effects on the radioactive measurement were studied, time and temperature. Seven powder samples of the most commonly spices which used in the Iraqi kitchens were collected from different markets. The radioactive spectrum of each sample is taken by using NaI(Tl) detector have crystal of (3×3) inch, then the specific activity were calculated with two times, 3 hrs. and 24 hrs. and compared with their effect on the samples. The results shows that the specific activity values of the three nuclides ⁴⁰K, ²¹⁴Bi and ²⁰⁸Tl decrease with the increasing of measurement time. This result leads to whenever the time of measurement is higher the specific activity is lower, therefore, the measurement at 24 is more suitable for all radioactivity measurements for low radioactive materials like spices.

With respect to the temperature change, the measurements, hence specific activity were estimated in Summer and Winter seasons. The results show that all the specific activity values of the nuclide ⁴⁰K increase with the decreasing of measurement temperature, while It is the opposite behavior for the nuclides ²¹⁴Bi and ²⁰⁸Tl.  All these increasing and decreasing behavior are very slight, therefore, the changing of temperature or weather of measurement for low radioactive materials has no significant effects on the results