22, 19.63, 20.34, 3.86, and 2.57 ppm respectively. The results of the elemental contents of volcanic ash that has been obtained can be used as the scientific based data for volcanic material utilization by considering the economic potential of elements contained and also the danger of the heavy metals content. IntroductionMount Sinabung is a stratovolcano, located in Karo Regency, North Sumatra Province of Indonesia. It is a solitary volcano that has a single peak, and classified as B -Type, because since the 1600's there was no record of eruptive activity [1]. But on November 24, 2013, Mount Sinabung were erupted and reach the highest alert level (level 4) since it spat out black and thick smog, followed by rain sand and volcanic ash which covered thousands of hectares of farmer crops under the radius of six kilometers [2]. Volcanic ash is fragments of magma and consists of mineral, volcanic glass and also a material containing high silica and aluminum [2,3]. The composition of particles from volcanic eruptions should reflect the matrix composition of the magma. 06, 14.66, 1.88, 0.07, 0.6, 1.99, 4.18, 2.89, 0.2 % respectively [5]. These materials in the ash can provide important information on the nature of magma because chemical compositions of magma usually show distinct features of each volcano and because the assemblages and compositions of minerals

No abstract

Neutron Activation Analysis (NAA) is a nuclear analytical technique for elemental analysis that has been widely applied in various fields such as environment, industry, health and food. It has high specificity and sensitivity for the analysis of elements with very low concentrations up to the picogram order. In Indonesia, NAA technique was developed in BATAN that has a research reactor as a neutron source. Relative method of NAA that uses the multi-elements standard as a comparison is widely used in Indonesia. At present, BATAN is developing an absolute method k0-NAA that has several advantages such as faster and more economics due to the reduction of multi-elements standard dependence. BATAN k0 Utility (BAkUL) beta version software has also been developed for data processing of the absolute methods. k0-NAA requires reactor parameters (α and f) as well as detector parameters for data analysis. The parameter f is the ratio of the thermal neutron flux to the epithermal whereas α is the epithermal spectrum deviation parameter from the 1/E distribution. The aim of this study is to measure parameters a and f using the triple bare monitor method by irradiating simultaneously Au and Zr without Cd cover. Measurement of reactor TRIGA 2000 parameters (α and f) were carried out at the irradiation positions CT1-1 and G17-2, and the results for α and f parameters at the CT1-1 irradiation position were -0,100 and 8.22 respectively, while at the G17-2 position was - 0.087 and 13.8. Each irradiation position has different α and f values so it is necessary to determine the reactor parameters for other irradiation positions. The measurement results α and f can be used for the next samples irradiation and as a database to support the application of the k0-NAA method in Center for Applied Nuclear Science and Technology (PSTNT) BATAN.