COMPARISON OF AUTO VERSUS MANUAL CALCULATION OF K-40 ACTIVITY CONCENTRATION IN POWDERED MILK MEASURED USING GAMMA SPECTROMETRY SYSTEM
Gamma spectrometry counting system nowadays equipped with commercial analysis software to calculate the radionuclide activity automatically but manual calculation still a common practice in some laboratories. This paper reported and compared the activity concentration of 40K in 120 powdered milk samples that had been quantified and calculated using both automatic and manual approaches. From software calculation, 40K radioactivity found varies from 212 Bq/kg to 508 Bq/kg with the average of 294 ± 73 Bq/kg and the activity uncertainty associated with samples ranged of 1.9% to 2.8%. Meanwhile, from the manual calculation, 40K radioactivity varies from 206 Bq/kg to 501 Bq/kg with the average of 285 ± 73 Bq/kg and the uncertainty of manual calculations were between 6.8% to 7.0%. Almost all results (except two samples) showed that the auto calculation had activity higher than that obtained from the manual calculation. Overall all samples activities had a difference of less than 9 percent between the auto and manual calculation. However, U-score calculation showing none of the difference between the auto and manual value was significant.