Determination and spatial distribution of <Superscript>137</Superscript>Cs in soils,mosses and lichens near Kavanayen,Venezuela

The activity of ¹³⁷Cs was determined in soils, mosses, lichens and other vegetation along the Caruay River and near the town of Kavanayen. The range of values for the soils was from <1.2 Bq·kg⁻¹ of ¹³⁷Cs (our detection limit) to 14.1 Bq·kg⁻¹. The range of ¹³⁷Cs activities in the mosses ranged from 9.9 to 17.9 Bq·kg⁻¹ with a mean value of 13.4±4 Bq·kg⁻¹; all the moss samples were found along the river. While the ¹³⁷Cs activities in the lichens ranged from 9.1 to 29.8 Bq·kg⁻¹; the two values along the river were about three factors higher than the one near Kavanayen. It was concluded that the ¹³⁷Cs activities in the soils, mosses and lichens are much higher along the river in respect to the nearby town of Kavanayen.     

Measurement of the ground state 2n pickup probability for 28Si+68Zn and its role in sub-barrier fusion enhancement

The ground state and excited state transfer yields for the 2-neutron pickup channel in the ²⁸Si+⁶⁸Zn system have been measured explicitly. The recoil mass separator at the nuclear Science Centre, New Delhi was used for the measurement. A NaI(T1) detector was used for detecting the deexcitation γ’s from the transfer products. The kinematic coincidence technique was employed for the transfer measurement. Simplified coupled channels calculations show that out of all transfer channels the major contribution to the sub-barrier enhancement comes from the ground state 2 neutron pickup channel with a ground state Q-value of+1.83 MeV.     

Determination of radon-222 in a natural thermal water spring shortly before and after the July 9, 1997 earthquake (Ms=6.8) in the State of Sucre, Venezuela

The original purpose of this investigation started in 1996 was to study the radiological impact on the local population of the village of Chichiviriche de La Costa. But, soon after the major earthquake (Ms=6.8) in the state of Sucre on July 9, 1997, the objective was changed to study the fluctuation of radon (²²²Rn) to see if it could be correlated to seismic activity and/or if the amonlous change just before the earthquake can be considered a precusor for it. Measurements of²²²Rn by simply de-gassing about 250 ml of natural thermal water employing a Pylon AB-5 radiation monitor and counting the radiation after it reached equilibrium were performed. The values for four sampling periods in the first half of 1996 were about 17 Bq/l of²²²Rn, a month before the earthquake they were less than 15 Bq/l and increased about 70% to 25 Bq/l two days before the seismic event. In about two weeks, they returned to about 18 Bq/l. But, surprisingly, they have gradually increased to about 35 Bq/l, before leveling off at about 27 Bq/l.     

The comparison of the results of two independent intercomparison studies (BAK-1 and SLB-1) from the same bulk material of a lateritic soil

Summary A comparison of the results for major, minor and trace elements from the BAK-1 intercomparison study [1] and that of SLB-1 [2] are presented. These two independent studies were based on the same bulk material of a lateritic bauxite (soil) from Suriname but different preparation and homgeneity testing schemes were employed. The values for Al₂O₃, Fe₂O₃, TiO₂ and LOI were not significantly different while the SiO₂ value determined by the SLB-1 intercomparison run was 1.88%±0.34% in respect to 3.93%±2.65% from the BAK-1 study. An attempt to explain this difference in the SiO₂ values was made on the basis of the sample preparation and the participating analytical laboratories. Finally, provisional values and uncercainty limits for major elements and LOI are presented for SLB-1 reference material.