Determination of short half-life elements in biological, foodstuff, and environmental samples qualitatively by neutron activation analysis

NAA applications at routine operation power of 15 MW at Multipurpose Reactor GA Siwabessy (MPR-GAS) for sample matrices analysis have been widely applied. However, the results are not optimum for some matrices especially for short half-live elements. Preliminary study of short half-life elements determination in biological, foodstuff, and environmental samples using 1 MW power have been conducted to solve this problem. The samples were irradiated in rabbit system of MPR-GAS for 5 minutes, counted for 200 seconds by HPGe detector, and the spectrum were analyzed further using software Genie 2000 and Bandung NAA Utility. Analysis under 1 MW power on biological and foodstuff samples were capable to detect eight elements: Al, Br, CI, Ca, I, K, Mg, Ti, and Na for biological samples; Al, Br, CI, Ca, I, K, Mg, Mn, and Na for foodstuff samples, while at 15 MW power only three elements (CI, K, Na) were detected. At 1 MW power the counting process is more optimum due to smaller radiation exposure and dead time. For the environmental samples, the number of elements detected by 1 MW and 15 MW powers did not differ significantly. Generally, the results on the three types of samples showed that the elements of short half-life are better detected at 1 MW than that of 15 MW power. Further research needs to be done to obtain the optimum analytical conditions for irradiation and counting time determination. (author)