[en] A neutron activation determination of the impurities of the CaF₂, GeO₂, Bi₂O₃ and (NH₄)₂MoO₄.4H₂O was performed. The powder samples (30 mg in weight) packed in aluminium foils were irradiated for 24 h in a 1.4.1o¹³ n/cm².s flux. Soil-5 and Au (0,105 mg) were used as standards. The measurement of 3-5 h were performed using a Ge(Li) detector after 5, 19, 40 days cooling time. The trace elements found are Au, Ag, As, Br, Co, Cs, Fe, Na, Rb, Sc, Sb, Sr, Zn. The background contribution in the Co determination was taken into account

[en] The analysis has been made for the purpose of the animal feeding with some mineral compounds and essential trace minerals. Three calcium carbonate samples from different mining sites all over the country have been analysed. Two irradiations have been carried out: one of 4 hours in a 2.10¹² n/cm².s flux, and a second one - of 30 s. in a 2.10¹² n/cm².s flux in the air rabbit. Sample weights of 40 mg have been used. W-1 reference material has been irradiated as standard. The following elements were determined: Al, As, Au, Ba, Ca, Ce, Co , Cr, Cs, Eu, Fe, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Sm, Sr, Tb, T e, TI, U, V, Zn

[en] Analysis of impurity contents in 4 Romanian semiconductor silicon slides is presented. The samples of n and p type materials having the resistivities between 40 1,4x10¹³ n/cm².s. flux. After 4-5 days cooling time the measurements have been carried out by using a Ge(Li) detector with 2 KeV resolution coupled to a multichannel analyser. As, Au, Br, Co, Ga, Hf, Mo, Na, Sb, Zn, W, Fe, Sc and Ni were found. A study of the variation of some element contents with 3-fold succesive etchings of the samples after irradiation have been made. After the first etching a high decrease of the element contents was observed. After the second etching the element contents decreased in a variable ratio, while the third etching revealed that the sample elemental contents remained constant suggesting no further surface contamination

[en] Trace element concentrations in soil were measured in an intercomparison study organised by the IAEA Analytical Quality Control Service. The purpose of the study was to provide a reference material for multielement analyses and also to verify the performance of different methods of analysis. A multichannel analyser connected to a 65 cm³ Ge(Li) detector with 2 KeV resolution was used. The concentrations of Ba, Ca, Ce, Co, Cs, Cr, Eu, Fe, Hf, La, Lu, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, U, Yb, Zn, Zr were determined after 50 hours irradiation time in a thermal neutron flux of 1.1x10¹¹n/cm².s. The samples and Soil-5, SL-1 and GSP-1 as standards were measured 2 to 5 hours after 10 to 30 days. The concentrations of Al, Dy, Eu, K, Mg, Mn, Na, Sm, Ti, V were determined by irradiating the samples and W-1 standard material for 1 to 3 minutes in a 10¹²n/cm².s flux. Decay and measurement time were 6 min to 24 hours and 100 to 1800 s correspondingly. The averages of 4 independent measurements are taken as concentration values. The results are in good agreement with those presented by IAEA except for U and Sr concentrations. In this case our values were rejected by the statistical test. The measured concentrations of Ca and Zn were taken into account in the estimation of the results although these values were outside the confidence intervals

[en] Instrumental neutron activation analysis has been used to determine the concentrations of 32 elements in three reference materials, for an intercomparison organized by the Institute of Radioecology and Applied Nuclear Techniques, Koshice, Czechoslovakia, with the participation of 34 laboratories from 11 countries. Fly-ash materials from coal fired power plants were analyzed. The concentration of Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, U, Yb, Zn, Zr was determined after a long irradiation (50 hours) of the samples in a thermal neutron flux of 1,1x10¹¹ n/cm².s. The samples and Soil-5, SL-1, GSP-1 as standards were measured 2-5 hours after decay time of 10-30 days. The results obtained for ENO, EOP and ECH are in generally good agreement with the certified values

[en] Thorium content in zircon sand, thorium ore and thorium liquid sample (EU Laboratories Network Intercomparison), as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement, cement mill dust, coal fly ash, bricks, and tile (28 samples) were determined by gamma ray spectrometry. For the building materials, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs specific activities were also measured. The results were compared with the Romanian legal norms concerning the highest admissible levels for ²³²Th, ²²⁶Ra, and ⁴⁰K radioactivity, and to Th, U, and K concentration values previously determined in our laboratory on similar types of samples. (author)

[en] For the analysis of the impurity contents in 4 semiconductor silicon samples the instrumental neutron activation analysis metbod was used. A number of 17 elements in the concentration range 1 ppb (10^-9 g/g)-2ppm were determined. (authors)

[en] Short communication

[en] The concentrations of 23 elements in a zircon sample were determined using instrumental neutron activation analysis. The sample and the SL-1 and Soil-5 standards were irradiated for 50 hours in a thermal neutron flux of 1.1x10¹¹n/cm².s in order to measure the long lived isotopes. For Zr measurements a ZrO₂ standard was used. The measurements were carried out by a Ge(Li) detector with 2 KeV resolution, after 8 to 30 days cooling time. To determine the short lived isotopes as Au, Dy, Mn, Ti and V, the sample was irradiated in a 2x10¹²n/cm²2.s flux for 1 min, using a W-1 standard. The results for major and trace element quantity ratios in zircon prove to be very interesting for geochemists and petrologists

[en] Short communication